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## 2.17.0
### Core libraries
#### `dart:core`
- Add `Finalizer` and `WeakReference` which can potentially detect when
objects are "garbage collected".
- Add `isMimeType` method to `UriData` class, to allow case-insensitive
checking of the MIME type.
- Add `isCharset` and `isEncoding` methods to `UriData` class,
to allow case-insensitive and alternative-encoding-name aware checking
of the MIME type "charset" parameter.
- Make `UriData.fromString` and `UriData.fromBytes` recognize and omit
a "text/plain" `mimeType` even if it is not all lower-case.
#### `dart:ffi`
- Add `ref=` and `[]=` methods to the `StructPointer` and `UnionPointer`
extensions. They copy a compound instance into a native memory region.
#### `dart:html`
- Add `scrollIntoViewIfNeeded` to `Element`. Previously, this method was nested
within `scrollIntoView` based on the `ScrollAlignment` value. `scrollIntoView`
is unchanged for now, but users who intend to use the native
`Element.scrollIntoViewIfNeeded` should use the new `scrollIntoViewIfNeeded`
definition instead.
#### `dart:indexed_db`
- `IdbFactory.supportsDatabaseNames` has been deprecated. It will always return
`false`.
#### `dart:io`
- **Breaking Change** [#47887](https://github.com/dart-lang/sdk/issues/47887):
`HttpClient` has a new `connectionFactory` property, which allows socket
creation to be customized. Classes that `implement HttpClient` may be broken
by this change. Add the following method to your classes to fix them:
```dart
void set connectionFactory(
Future<ConnectionTask<Socket>> Function(
Uri url, String? proxyHost, int? proxyPort)?
f) =>
throw UnsupportedError("connectionFactory not implemented");
```
- **Breaking Change** [#48093](https://github.com/dart-lang/sdk/issues/48093):
`HttpClient` has a new `keyLog` property, which allows TLS keys to be logged
for debugging purposes. Classes that `implement HttpClient` may be broken by
this change. Add the following method to your classes to fix them:
```dart
void set keyLog(Function(String line)? callback) =>
throw UnsupportedError("keyLog not implemented");
```
- Add a optional `keyLog` parameter to `SecureSocket.connect` and
`SecureSocket.startConnect`.
- Deprecate `SecureSocket.renegotiate` and `RawSecureSocket.renegotiate`,
which were no-ops.
#### `dart:isolate`
- Add `Isolate.run` to run a function in a new isolate.
### Tools
#### Dart command line
- **Breaking change** [#46100](https://github.com/dart-lang/sdk/issues/46100):
The standalone `dart2js` tool has been
marked deprecated as previously announced.
Its replacement is the `dart compile js` command.
Should you find any issues, or missing features, in the replacement
command, kindly file [an issue](https://github.com/dart-lang/sdk/issues/new).
- **Breaking change** [#46100](https://github.com/dart-lang/sdk/issues/46100):
The standalone `dartdevc` tool has been marked deprecated as previously
announced and will be deleted in a future Dart stable relase. This tool
was intended for use only by build systems like bazel, `build_web_compilers`
and `flutter_tools`. The functionality remains available for those systems,
but it is no longer exposed as a command-line tool in the SDK.
Please share any concerns in the
[breaking change tracking issue](https://github.com/dart-lang/sdk/issues/46100).
- **Breaking change** [#46100](https://github.com/dart-lang/sdk/issues/46100):
The standalone `dartdoc` tool has been removed as
previously announced. Its replacement is the `dart doc` command.
- The template names used in the `dart create` command have been simplified,
and the current template names are now the set shown below. (Note: for
backwards compatibility the former template names can still be used.)
```
[console] (default) A command-line application.
[package] A package containing shared Dart libraries.
[server-shelf] A server app using package:shelf.
[web] A web app that uses only core Dart libraries.
```
#### Linter
Updated the Linter to `1.19.2`, which includes changes that
- adds new lint: `use_super_initializers`.
- adds new lint: `use_enums`.
- adds new lint: `use_colored_box`.
- improves performance for `sort_constructors`.
- improves docs for `always_use_package_imports`,
`avoid_print`, and `avoid_relative_lib_imports` .
- updates `avoid_void_async` to skip `main` functions.
- updates `prefer_final_parameters` to not super on super params.
- updates lints for enhanced-enums and super-initializer language
features.
- updates `unnecessary_late` to report on variable names.
- marks `null_check_on_nullable_type_parameter` stable.
## 2.16.1 - 2022-02-09
This is a patch release that fixes an AOT precompiler crash when building some
Flutter apps (issue [flutter/flutter#97301][]).
[flutter/flutter#97301]: https://github.com/flutter/flutter/issues/97301
## 2.16.0 - 2022-02-03
### Core libraries
#### `dart:core`
- Add `Error.throwWithStackTrace` which can `throw` an
error with an existing stack trace, instead of creating
a new stack trace.
#### `dart:io`
- **Security advisory**
[CVE-2022-0451](https://github.com/dart-lang/sdk/security/advisories/GHSA-c8mh-jj22-xg5h),
**breaking change** [#45410](https://github.com/dart-lang/sdk/issues/45410):
`HttpClient` no longer transmits some headers (i.e. `authorization`,
`www-authenticate`, `cookie`, `cookie2`) when processing redirects to a
different domain.
- **Breaking change** [#47653](https://github.com/dart-lang/sdk/issues/47653):
On Windows, `Directory.rename` will no longer delete a directory if
`newPath` specifies one. Instead, a `FileSystemException` will be thrown.
- **Breaking change** [#47769](https://github.com/dart-lang/sdk/issues/47769):
The `Platform.packageRoot` API has been removed. It had been marked deprecated
in 2018, as it doesn't work with any Dart 2.x release.
- Add optional `sourcePort` parameter to `Socket.connect`, `Socket.startConnect`, `RawSocket.connect` and `RawSocket.startConnect`
#### `dart:isolate`
- **Breaking change** [#47769](https://github.com/dart-lang/sdk/issues/47769):
The `Isolate.packageRoot` API has been removed. It had been marked deprecated
in 2018, as it doesn't work with any Dart 2.x release.
### Tools
#### Dart command line
- **Breaking change** [#46100](https://github.com/dart-lang/sdk/issues/46100):
The standalone `dartanalyzer` tool has been
marked deprecated as previously announced.
Its replacement is the `dart analyze` command.
Should you find any issues, or missing features, in the replacement
command, kindly file [an issue][].
[an issue]: https://github.com/dart-lang/sdk/issues/new
- **Breaking change** [#46100](https://github.com/dart-lang/sdk/issues/46100):
The standalone `dartdoc` tool has been
marked deprecated as previously announced.
Its replacement is the `dart doc` command.
Should you find any issues, or missing features, in the replacement
command, kindly file [an issue][].
[an issue]: https://github.com/dart-lang/sdk/issues/new
- **Breaking Change** [#46100](https://github.com/dart-lang/sdk/issues/46100):
The deprecated standalone `pub` tool has been removed.
Its replacement is the `dart pub` command.
Should you find any issues, or missing features, in the replacement
command, kindly file [an issue][].
[an issue]: https://github.com/dart-lang/pub/issues/new
#### Pub
- Fixed race conditions in `dart pub get`, `dart run` and `dart pub global run`.
It should now be safe to run these concurrently.
- If (when) Pub crashes it will save a verbose log in
`$PUB_CACHE/log/pub_log.txt` This can be used for filing issues to the issue
tracker.
`dart --verbose pub [command]` will also cause the log file to be written.
- `dart pub add` can now add multiple packages in one command.
#### Linter
Updated the Linter to `1.18.0`, which includes changes that
- extends `camel_case_types` to cover enums.
- fixes `no_leading_underscores_for_local_identifiers` to not
mis-flag field formal parameters with default values.
- fixes `prefer_function_declarations_over_variables` to not
mis-flag non-final fields.
- improves performance for `prefer_contains`.
- updates `exhaustive_cases` to skip deprecated values that
redirect to other values.
- adds new lint: `unnecessary_late`.
- improves docs for `prefer_initializing_formals`.
- updates `secure_pubspec_urls` to check `issue_tracker` and
`repository` entries.
- adds new lint: `conditional_uri_does_not_exist`.
- improves performance for
`missing_whitespace_between_adjacent_strings`.
- adds new lint: `avoid_final_parameters`.
- adds new lint: `no_leading_underscores_for_library_prefixes`.
- adds new lint: `no_leading_underscores_for_local_identifiers`.
- adds new lint: `secure_pubspec_urls`.
- adds new lint: `sized_box_shrink_expand`.
- adds new lint: `use_decorated_box`.
- improves docs for `omit_local_variable_types`.
## 2.15.1 - 2021-12-14
This is a patch release that fixes:
- an AOT compilation failure in some Flutter apps (issue [#47878][]).
- `dart pub publish` for servers with a path in the URL (pr
[dart-lang/pub#3244][]).
[#47878]: https://github.com/dart-lang/sdk/issues/47878
[dart-lang/pub#3244]: https://github.com/dart-lang/pub/pull/3244
## 2.15.0 - 2021-12-08
- **Security advisory**
[CVE-2021-22567](https://github.com/dart-lang/sdk/security/advisories/GHSA-8pcp-6qc9-rqmv):
Bidirectional Unicode text can be interpreted and compiled differently than
how it appears in editors and code-review tools. Exploiting this an attacker
could embed source that is invisible to a code reviewer but that modifies the
behavior of a program in unexpected ways. Dart 2.15.0 introduces new analysis
warnings that flags the use of these.
- **Security advisory**
[CVE-2021-22568](https://github.com/dart-lang/sdk/security/advisories/GHSA-r32f-vhjp-qhj7):
A malicious third-party package repository may impersonate a user on pub.dev
for up to one hour after the user has published a package to that third-party
package repository using `dart pub publish`. As of Dart SDK version 2.15.0
requests to third-party package repositories will no longer include an OAuth2
`access_token` intended for pub.dev.
### Language
The following features are new in the Dart 2.15 [language version][]. To use
them, you must set the lower bound on the SDK constraint for your package to
2.15 or greater (`sdk: '>=2.15.0 <3.0.0'`).
[language version]: https://dart.dev/guides/language/evolution
- **[Constructor tear-offs][]**: Previous Dart versions allowed a method on an
instance to be passed as a closure, and similarly for static methods. This is
commonly referred to as "closurizing" or "tearing off" a method. Constructors
were not previously eligible for closurization, forcing users to explicitly
write wrapper functions when using constructors as first class functions.
See the calls to `map()` in this example:
```dart
class A {
int x;
A(this.x);
A.fromString(String s) : x = int.parse(s);
}
void main() {
var listOfInts = [1, 2, 3];
var listOfStrings = ["1", "2", "3"];
for(var a in listOfInts.map((x) => A(x))) {
print(a.x);
}
for(var a in listOfStrings.map((x) => A.fromString(x))) {
print(a.x);
}
}
```
New in Dart 2.15, constructors are now allowed to be torn off. Named
constructors are closurized using their declared name (here `A.fromString`).
To closurize unnamed constructors, use the keyword `new` (here `A.new`).
The above example may now be written as:
```dart
class A {
int x;
A(this.x);
A.fromString(String s) : x = int.parse(s);
}
void main() {
var listOfInts = [1, 2, 3];
var listOfStrings = ["1", "2", "3"];
for(A a in listOfInts.map(A.new)) {
print(a.x);
}
for(A a in listOfStrings.map(A.fromString)) {
print(a.x);
}
}
```
Constructors for generic classes may be torn off as generic functions, or
instantiated at the tear-off site. In the following example, the tear-off
`G.new` is used to initialize the variable `f` produces a generic function
which may be used to produce an instance of `G<T>` for any type `T` provided
when `f` is called. The tear-off `G<String>.new` is used to initialize the
variable `g` to produce a non-generic function which may only be used
to produce instances of type `G<String>`.
```dart
class G<T> {
T x;
G(this.x);
}
void main() {
G<T> Function<T>(T x) f = G.new;
var x = f<int>(3);
G<String> Function(String y) g = G<String>.new;
var y = g("hello");
}
```
[constructor tear-offs]: https://github.com/dart-lang/language/blob/master/accepted/2.15/constructor-tearoffs/feature-specification.md
- **[Generic type literals][explicit instantiation]**: Previous Dart versions
allowed class names to be used as type literals. So for example,`int` may be
used as an expression, producing a value of type `Type`. Generic classes (e.g.
`List`) could be referred to by name as an expression, but no type arguments
could be provided and so only the `dynamic` instantiation could be produced
directly as an expression without using indirect methods:
```dart
// Workaround to capture generic type literals.
Type typeOf<T>() => T;
void main() {
var x = int; // The Type literal corresponding to `int`.
var y = List; // The Type literal corresponding to `List<dynamic>`.
// Use workaround to capture generic type literal.
var z = typeOf<List<int>>(); // The Type literal for `List<int>`.
}
```
New in Dart 2.15, instantiations of generic classes may now be used as Type
literals:
```dart
void main() {
var x = int; // The Type literal corresponding to `int`.
var y = List; // The Type literal corresponding to `List<dynamic>`.
var z = List<int>; // The Type literal corresponding to `List<int>`.
}
```
- **[Explicit generic method instantiations][explicit instantiation]**: Previous
Dart versions allowed generic methods to be implicitly specialized (or
"instantiated") to non-generic versions when assigned to a location with a
compatible monomorphic type. Example:
```dart
// The generic identity function.
T id<T>(T x) => x;
void main() {
// Initialize `intId` with a version of `id` implicitly specialized to
// `int`.
int Function(int) intId = id;
print(intId(3));
// Initialize `stringId` with a version of `id` implicitly specialized to
// `String`.
String Function(String) stringId = id;
print(stringId("hello"));
}
```
New in Dart 2.15, generic methods may be explicitly instantiated using the
syntax `f<T>` where `f` is the generic method to specialize and `T` is the
type argument (in general, type arguments) to be used to specialize the
method. Example:
```dart
// The generic identity function.
T id<T>(T x) => x;
void main() {
// Initialize `intId` with a version of `id` explicitly specialized to
// `int`.
var intId = id<int>;
print(intId(3));
// Initialize `stringId` with a version of `id` explicitly specialized to
// `String`.
var stringId = id<String>;
print(stringId("hello"));
}
```
[explicit instantiation]: https://github.com/dart-lang/language/blob/master/accepted/2.15/constructor-tearoffs/feature-specification.md#explicitly-instantiated-classes-and-functions
- **[Generic instantiation of function objects][object instantiation]**: Generic
function instantiation was previously restricted to function declarations. For
example, as soon as a function had been torn off, it could not be
instantiated:
```dart
// Before Dart 2.15:
X id<X>(X x) => x;
void main() {
var fo = id; // Tear off `id`, creating a function object.
var c1 = fo<int>; // Compile-time error: can't instantiate `fo`.
int Function(int) c2 = fo; // Same compile-time error.
// Constants are treated the same.
}
```
New in Dart 2.15, this restriction has been lifted. It is now possible
to obtain a generic instantiation of an existing function object, both
explicitly and implicitly (again, this works the same for non-constants):
```dart
X id<X>(X x) => x;
X other<X>(X x) => throw x;
void main() {
const fo = id; // Tear off `id`, creating a function object.
// Generic function instantiation on `fo` is no longer an error.
const c1 = fo<int>; // OK.
const int Function(int) c2 = fo; // OK.
// This also generalizes function instantiation because we can,
// e.g., use non-trivial expressions and go via a constructor.
const c3 = A(true); // OK.
}
class A {
final int Function(int) x;
// `(...)<T>` is now allowed, also in a `const` constructor.
const A(bool b): x = (b ? id : other)<int>;
}
```
[Object instantiation]: https://github.com/dart-lang/language/pull/1812
- Annotations on type parameters of classes can no longer refer to class members
without a prefix. For example, this used to be permitted:
```dart
class C<@Annotation(foo) T> {
static void foo() {}
}
```
Now, the reference must be qualified with the class name, i.e.:
```dart
class C<@Annotation(C.foo) T> {
static void foo() {}
}
```
This brings the implementation behavior in line with the spec.
- Initializer expressions on implicitly typed condition variables can now
contribute to type promotion. For example, this program no longer produces a
compile-time error:
```dart
f(int? i) {
var iIsNull = i == null;
if (!iIsNull) {
print(i + 1); // OK, because `i` is known to be non-null.
}
}
```
Previously, the above program had a compile-time error due to a bug
([#1785][]) in type promotion which prevented the initializer expression
(`i == null`) from being accounted for when the variable in question
(`iIsNull`) lacked an explicit type.
To avoid causing problems for packages that are intended to work with older
versions of Dart, the fix only takes effect when the minimum SDK of the source
packages is 2.15 or greater.
[#1785]: https://github.com/dart-lang/language/issues/1785
- Restrictions on members of a class with a constant constructor are relaxed
such that they only apply when the class has a _generative_ constant
constructor. For example, this used to be an error, but is now permitted:
```dart
abstract class A {
const factory A() = B;
var v1;
late final v2 = Random().nextInt(10);
late final v3;
}
class B implements A {
const B([this.v3 = 1]);
get v1 => null;
set v1(_) => throw 'Cannot mutate B.v1';
final v2 = 0;
final v3;
set v3(_) => throw 'Cannot initialize B.v3';
}
```
This implements a relaxation of the specified rule for a `late final`
instance variable, and it brings the implementation behavior in line with
the specification in all other cases.
- **Function object canonicalization and equality**: Several corner cases in the
area of function object canonicalization and function object equality have
been updated, such that all tools behave in the same way, and the behavior
matches the specification.
In particular, function objects are now equal when they are obtained by
generic instantiation from the same function with the same actual type
arguments, even when that type argument is not known at compile time.
When the expressions are constant then the function objects are identical.
Constant expressions are treated as such even when they do not occur in a
constant context (e.g., `var f = top;`).
### Core libraries
#### `dart:async`
- Make the `unawaited` function's argument nullable, to allow calls like
`unawaited(foo?.bar())`.
#### `dart:cli`
- The experimental `waitFor` functionality, and the library containing only that
function, are now deprecated.
#### `dart:core`
- Add extension `name` getter on enum values.
- Add `Enum.compareByIndex` helper function for comparing enum values by index.
- Add `Enum.compareByName` helper function for comparing enum values by name.
- Add extension methods on `Iterable<T extends Enum>`, intended for
`SomeEnumType.values` lists, to look up values by name.
- Deprecate `IntegerDivisionByZeroException`.
Makes the class also implement `Error`. Code throwing the exception will be
migrated to throwing an `Error` instead until the class is unused and
ready to be removed.
Code catching the class should move to catching `Error` instead
(or, for integers, check first for whether it's dividing by zero).
#### `dart:io`
- **Breaking change** [#46875](https://github.com/dart-lang/sdk/issues/46875):
The `SecurityContext` class in `dart:io` has been updated to set the minimum
TLS protocol version to TLS1_2_VERSION (1.2) instead of TLS1_VERSION.
- Add `RawSocket.sendMessage`, `RawSocket.receiveMessage` that allow passing of
file handle references via Unix domain sockets.
#### `dart:js_util`
- The `js_util` methods `setProperty`, `callMethod`, and `callConstructor` have
been optimized to remove checks on arguments when the checks can be elided.
Also, those methods, along with `getProperty` and `newObject`, now support a
generic type argument to specify a return type. These two changes make simple
`js_util` usage, like reading and writing primitive properties or calling
methods with simple arguments, have zero overhead.
#### `dart:web_sql`
- **Breaking change** [#46316](https://github.com/dart-lang/sdk/issues/46316):
The WebSQL standard was abandoned more than 10
years ago and is not supported by many browsers. This release completely
deletes the `dart:web_sql` library.
#### `dart:html`
- **Breaking change** [#46316](https://github.com/dart-lang/sdk/issues/46316):
Related to the removal of `dart:web_sql` (see above), `window.openDatabase`
has been removed.
### Tools
#### Dart command line
- **Breaking change** [#46100][]: The standalone `dart2native` tool has been
removed as previously announced. Its replacements are the
`dart compile exe` and `dart compile aot-snapshot` commands, which offer the
same functionality.
- **Breaking change**: The standalone `dartfmt` tool has been removed as
previously announced. Its replacement is the `dart format` command.
Note that `dart format` has [a different set of options and
defaults][dartfmt cli] than `dartfmt`.
- When a script is `dart run` it will always be precompiled, but with
incremental precompilation for following runs.
#### Dart VM
- **Breaking change** [#45451](https://github.com/dart-lang/sdk/issues/45451):
Support for `dart-ext:`-style native extensions has been removed as previously
announced. Use `dart:ffi` to bind to native libraries instead.
- **Breaking change** [#46754](https://github.com/dart-lang/sdk/issues/46754):
Isolates spawned via the `Isolate.spawn()` API are now grouped, operate on the
same managed heap and can therefore share various VM-internal data structures.
This leads to ~100x faster isolate startup latency, ~10-100x lower
per-isolate base memory overhead and ~8x faster inter-isolate communication.
Making isolates operate on the same heap will also make them collaborate on
garbage collections, which changes performance characteristics for GC-heavy
applications that may - in rare cases - negatively affect pause times or
throughput.
- Allow closures both in inter-isolate messages as well as as entrypoints in
`Isolate.spawn(<entrypoint>, ...)` calls. Closures and their enclosing context
may need to be copied in this process. The enclosing context is - as with
normal messages - verified to only contain objects that are sendable.
Note of caution: The Dart VM's current representation of enclosing variables
in closures can make closures hang on to more variables than strictly needed.
Using such closures in inter-isolate communication can therefore lead to
copying of larger transitive object graphs. If the extended transitive
closure includes objects that are illegal to send, the sending will fail.
See [#36983](https://github.com/dart-lang/sdk/issues/36983), which tracks this
existing memory leak issue.
#### Linter
Updated the Linter to `1.14.0`, which includes changes that
- improves performance for `annotate_overrides`, `prefer_contains`, and
`prefer_void_to_null`.
- marks `avoid_dynamic_calls` stable.
- fixed `avoid_null_checks_in_equality_operators` false positive with
non-nullable params.
- update `avoid_print` to allow `kDebugMode`-wrapped print calls.
- adds support for constructor tear-offs to `avoid_redundant_argument_values`,
`unnecessary_lambdas`, and `unnecessary_parenthesis`.
- improves messages for `avoid_renaming_method_parameters`.
- improves regular expression parsing performance for common checks
(`camel_case_types`, `file_names`, etc.).
- fixed `file_names` to report at the start of the file
(not the entire compilation unit).
- allow `while (true) { ... }` in `literal_only_boolean_expressions`.
- fixed `omit_local_variable_types` false positives.
- fixed `omit_local_variable_types` to not flag a local type that is required
for inference.
- fixed `overridden_fields` false positive with static fields.
- fixed `prefer_collection_literals` named typed parameter false positives.
- fixed `prefer_const_constructors` false positive for deferred imports.
- fixed `prefer_final_parameters` handling of initializing formals.
- fixed `prefer_generic_function_type_aliases` false positives with incomplete
statements.
- fixed `prefer_initializing_formals` false positives with factory constructors.
- fixed `prefer_void_to_null` false positive with overridden properties.
- fixed `prefer_void_to_null` false positives on overriding returns.
- fixed `prefer_void_to_null` false positives.
- adds a new lint: `unnecessary_constructor_name` to flag unnecessary uses of
`.new`.
- updates `unnecessary_getters_setters` to only flag the getter.
- fixed `unnecessary_parenthesis` false positive with function expressions.
- fixed `use_build_context_synchronously` false positive in awaits inside
anonymous functions.
- improve control flow analysis for `use_build_context_synchronously`.
- fixed `use_rethrow_when_possible` false positives.
- fixed `void_checks` false positives with incomplete source.
### Pub
- If you have analytics enabled `dart pub get` will send
[usage metrics](https://github.com/dart-lang/pub/blob/0035a40f25d027130c0314571da53ffafc6d973b/lib/src/solver/result.dart#L131-L175)
for packages from pub.dev, intended for popularity analysis.
- Adds support for token-based authorization to third-party package-repositories
with the new command `dart pub token`.
- Credentials are no longer stored in the pub-cache, but in a platform dependent
config directory:
* On Linux `$XDG_CONFIG_HOME/dart/pub-credentials.json` if `$XDG_CONFIG_HOME`
is defined, otherwise `$HOME/.config/dart/pub-credentials.json`
* On Mac OS: `$HOME/Library/Application Support/dart/pub-credentials.json`
* On Windows: `%APPDATA%/dart/pub-credentials.json`
- The syntax for dependencies hosted at a third-party package repository has
been simplified. Before you would need to write:
```yaml
dependencies:
colorizer:
hosted:
name: colorizer
url: 'https://custom-pub-server.com'
version: ^1.2.3
environment:
sdk: '>=2.14.0 < 3.0.0'
```
Now you can write:
```yaml
dependencies:
colorizer:
hosted: 'https://custom-pub-server.com'
version: ^1.2.3
environment:
sdk: '>=2.15.0 < 3.0.0'
```
This feature requires
[language-version](https://dart.dev/guides/language/evolution#language-versioning)
2.15 or later, e.g. the `pubspec.yaml` should have an SDK constraint of
`>=2.15 <3.0.0`.
- Detect potential leaks in `dart pub publish`.
When publishing, pub will examine your files for potential secret keys, and
warn you.
To ignore a file that has a false positive, add it to a
[`false_secrets`](https://dart.dev/go/false-secrets) section of your
`pubspec.yaml`.
- Fixes unicode terminal detection windows.
- New flag `--example` to the commands
`dart pub get/upgrade/downgrade/add/remove` that will result in the `example/`
folder dependencies to be updated after operating in the current directory.
### Other libraries
#### `package:js`
- Extensions on JS interop or native `dart:html` classes can now declare
members as `external`. These members are equivalent to regular extension
members that use `js_util` to expose the underlying JavaScript.
## 2.14.4 - 2021-10-14
This is a patch release that fixes:
- a memory leak of analyzer plugins (issue [flutter/flutter#90868][]).
- the Dart VM sometimes loading expired certificates on Windows (issues
[#46370][] and [#47420][]).
[flutter/flutter#90868]: https://github.com/flutter/flutter/issues/90868
[#46370]: https://github.com/dart-lang/sdk/issues/46370
[#47420]: https://github.com/dart-lang/sdk/issues/47420
## 2.14.3 - 2021-09-30
This is a patch release that fixes:
- a code completion performance regression (issue
[flutter/flutter-intellij#5761][]).
- debug information emitted by the Dart VM (issue [#47289][]).
[flutter/flutter-intellij#5761]:
https://github.com/flutter/flutter-intellij/issues/5761
[#47289]: https://github.com/dart-lang/sdk/issues/47289
## 2.14.2 - 2021-09-16
This is a patch release that fixes:
- two dartdoc crashes (issues [dart-lang/dartdoc#2740][] and
[dart-lang/dartdoc#2755][]).
- error messages when using the `>>>` operator on older language versions
(issue [#46886][]).
- invalid `pubspec.lock` paths on Windows (issue [dart-lang/pub#3012][]).
[dart-lang/dartdoc#2740]: https://github.com/dart-lang/dartdoc/issues/2740
[dart-lang/dartdoc#2755]: https://github.com/dart-lang/dartdoc/issues/2755
[#46886]: https://github.com/dart-lang/sdk/issues/46886
[#45767]: https://github.com/dart-lang/sdk/issues/45767
[dart-lang/pub#3012]: https://github.com/dart-lang/pub/issues/3012
## 2.14.1 - 2021-09-09
- Fixed an issue specific to the macOS ARM64 (Apple Silicon) SDK, where the Dart
commandline tools did not have the expected startup performance.
## 2.14.0 - 2021-09-09
### Language
- Add an unsigned shift right operator `>>>`. Pad with zeroes, ignoring the sign
bit. On the web platform `int.>>>` shifts the low 32 bits interpreted as an
unsigned integer, so `a >>> b` gives the same result as
`a.toUnsigned(32) >>> b` on the VM.
- Prior to Dart 2.14, metadata (annotations) were not permitted to be specified
with generic type arguments. This restriction is lifted in Dart Dart 2.14.
```dart
class C<T> {
const C();
}
@C(); // Previously permitted.
@C<int>(); // Previously an error, now permitted.
```
- Prior to Dart 2.14, generic function types were not permitted as arguments to
generic classes or functions, nor to be used as generic bounds. This
restriction is lifted in Dart 2.14.
```dart
T wrapWithLogging<T>(T f) {
if (f is void Function<T>(T x)) {
return <S>(S x) {
print("Call: f<$S>($x)");
var r = f<S>(x);
print("Return: $x");
return r;
} as T;
} // More cases here
return f;
}
void foo<T>(T x) {
print("Foo!");
}
void main() {
// Previously an error, now permitted.
var f = wrapWithLogging<void Function<T>(T)>(foo);
f<int>(3);
}
```
### Core libraries
#### `dart:async`
- The uncaught error handlers of `Zone`s are now run in the parent zone of the
zone where they were declared. This prevents a throwing handler from causing
an infinite loop by repeatedly triggering itself.
- Added `ignore()` as extension member on futures.
- Added `void unawaited(Future)` top-level function to deal with the
`unawaited_futures` lint.
#### `dart:core`
- Introduce `Enum` interface implemented by all `enum` declarations.
- The native `DateTime` class now better handles local time around daylight
saving changes that are not precisely one hour. (No change on the Web which
uses the JavaScript `Date` object.)
- Adds static methods `hash`, `hashAll` and `hashAllUnordered` to the `Object`
class. These can be used to combine the hash codes of multiple objects in a
consistent way.
- The `Symbol` constructor now accepts any string as argument. Symbols are equal
if they were created from the same string.
#### `dart:ffi`
- Adds the `DynamicLibrary.providesSymbol` function to check whether a symbol is
available in a dynamic library.
#### `dart:html`
- `convertNativeToDart_Dictionary()` now converts objects recursively, this
fixes APIs like MediaStreamTrack.getCapabilities that convert between Maps and
browser Dictionaries. [#44319]
- Added some access-control HTTP header names to `HttpHeaders`.
[#44319]: https://github.com/dart-lang/sdk/issues/44319
#### `dart:io`
- BREAKING CHANGE (for pre-migrated null safe code): `HttpClient`'s
`.authenticate` and `.authenticateProxy` setter callbacks must now accept a
nullable `realm` argument.
- Added some access-control HTTP header names to `HttpHeaders`.
#### `dart:typed_data`
- **BREAKING CHANGE** (https://github.com/dart-lang/sdk/issues/45115) Most types
exposed by this library can no longer be extended, implemented or mixed-in.
The affected types are `ByteBuffer`, `TypedData` and _all_ its subclasses,
`Int32x4`, `Float32x4`, `Float64x2` and `Endian`.
#### `dart:web_sql`
- `dart:web_sql` is marked deprecated and will be removed in an upcoming
release. Also the API `window.openDatabase` in `dart:html` is deprecated as
well.
This API and library was exposing the WebSQL proposed standard. The standard
was abandoned more than 5 years ago and is not supported by most browsers. The
`dart:web_sql` library has been documented as unsupported and deprecated for
many years as well and but wasn't annotated properly until now.
### Dart VM
- **Breaking change** [#45071][]: `Dart_NewWeakPersistentHandle`'s and
`Dart_NewFinalizableHandle`'s `object` parameter no longer accepts `Pointer`s
and subtypes of `Struct`. Expandos no longer accept `Pointer`s and subtypes of
`Struct`s.
[#45071]: https://github.com/dart-lang/sdk/issues/45071
### Tools
#### Dart command line
- **Breaking change** [#46100][]: The standalone `dart2native` tool has been
marked deprecated, and now prints a warning message. Its replacements are the
`dart compile exe` and `dart compile aot-snapshot` commands, which offer the
same functionality. The `dart2native` tool will be removed from the Dart SDK
in Dart 2.15.
- **Breaking change**: The standalone `dartfmt` tool has been marked deprecated,
and now prints a warning message. Instead, use `dart format`. The `dartfmt`
tool will be removed from the Dart SDK in Dart 2.15.
Note that `dart format` has [a different set of options and
defaults][dartfmt cli] than `dartfmt`.
- The `dart create` command has been updated to create projects that use the new
'recommended' set of lints from `package:lints`. See
https://dart.dev/go/core-lints for more information about these lints.
[#46100]: https://github.com/dart-lang/sdk/issues/46100
[dartfmt cli]: https://github.com/dart-lang/dart_style/wiki/CLI-Changes
- The `dart analyze` command has been extended to support specifying multiple
files or directories to analyze; see also
https://github.com/dart-lang/sdk/issues/45352.
- The `dartanalyzer` command's JSON output mode has been changed to emit the
JSON output on stdout instead of stderr.
#### dart format
- Simplify and optimize cascade formatting. See:
https://github.com/dart-lang/dart_style/pull/1033
- Don't unnecessarily split argument lists with `/* */` comments.
- Return correct exit code from `FormatCommand` when formatting stdin.
- Split empty catch blocks with finally clauses or catches after them.
#### Linter
Updated the Linter to `1.8.0`, which includes changes that
- improve performance for `prefer_is_not_empty`.
- fix false positives in `no_logic_in_create_state`.
- improve `package_names` to allow dart identifiers as package names.
- fix a false-positive in `package_names` (causing keywords to wrongly get flagged).
- fix `avoid_classes_with_only_static_member` to check for inherited members and also
flag classes with only methods.
- fix `curly_braces_in_flow_control_structures` to properly flag terminating `else-if`
blocks.
- improve `always_specify_types` to support type aliases.
- fix a false positive in `unnecessary_string_interpolations` w/ nullable interpolated
strings
- fix a false positive in `avoid_function_literals_in_foreach_calls` for nullable
iterables.
- fix false positives in `avoid_returning_null` w/ NNBD
- fix false positives in `use_late_for_private_fields_and_variables` in the presence
of const constructors.
- adds a new lint: `eol_at_end_of_file`.
- fix case-sensitive false positive in `use_full_hex_values_for_flutter_colors`.
- improve try-block and switch statement flow analysis for
`use_build_context_synchronously`.
- update `use_setters_to_change_properties` to only highlight a method name, not
the entire body and doc comment.
- update `unnecessary_getters_setters` to allow otherwise "unnecessary" getters
and setters with annotations.
- update `missing_whitespace_between_adjacent_strings` to allow String
interpolations at the beginning and end of String literals.
- update `unnecessary_getters_setters` to allow for setters with non-basic
assignments (for example, `??=` or `+=`).
- relax `non_constant_identifier_names` to allow for a trailing underscore.
- fix false negative in `prefer_final_parameters` where first parameter is
final.
- improve `directives_ordering` sorting of directives with dot paths and
dot-separated package names.
- (internal) migrate to `SecurityLintCode` instead of deprecated
`SecurityLintCodeWithUniqueName`.
- (internal) fix `avoid_types_as_parameter_names` to skip field formal
parameters.
- fix false positives in `prefer_interpolation_to_compose_strings` where the
left operand is not a String.
- fix false positives in `only_throw_errors` for misidentified type variables.
- add new lint: `depend_on_referenced_packages`.
- update `avoid_returning_null_for_future` to skip checks for null-safe
libraries.
- add new lint: `use_test_throws_matchers`.
- relax `sort_child_properties_last` to accept closures after child.
- improve performance for `prefer_contains` and `prefer_is_empty`.
- add new lint: `noop_primitive_operations`.
- mark `avoid_web_libraries_in_flutter` as stable.
- add new lint: `prefer_final_parameters`.
- update `prefer_initializing_formals` to allow assignments where identifier
names don't match.
- update `directives_ordering` to checks ordering of `package:` imports in code
outside pub packages.
- add simple reachability analysis to `use_build_context_synchronously` to
short-circuit await-discovery in terminating blocks.
- update `use_build_context_synchronously` to recognize nullable types when
accessed from legacy libraries.
#### Pub
- `dart pub publish` now respects `.pubignore` files with gitignore-style rules.
`.gitignore` files in the repo are still respected if they are not overridden
by a `.pubignore` in the same directory.
pub no longer queries git for listing the files. This implies:
- Checked in files will now be ignored if they are included by a `.gitignore`
rule.
- Global ignores are no longer taken into account.
- Even packages that are not in git source control will have their
`.gitignore` files respected.
- `.gitignore` and `.pubignore` is always case-insensitive on MacOs and
Windows (as is default for `git` repositories).
- New flag `dart pub deps --json` gives a machine parsable overview of the
current dependencies.
- New command: `dart pub cache clean`. Will delete everything in your current
pub cache.
- Commands related to a single package now takes a `--directory` option to
operate on a package in the given directory instead of the working directory.
- git dependencies with a relative repo url would previously be interpreted
relative to the current package, even for transitive dependencies. This now
fails instead.
- Pub now uses a Dart library to read and write tar files. This should fix
several issues we had with incompatibilities between different system `tar`s.
- `PUB_HOSTED_URL` can now include a trailing slash.
- Incremental compilation is now used for compilation of executables from
dependencies when using `dart run <package>:<command>`.
#### Dart2JS
* **Breaking change** [#46545][]: Dart2JS emits ES6+ JavaScript by default,
thereby no longer supporting legacy browsers. Passing the
`--legacy-javascript` flag will let you opt out of this update, but this
flag will be removed in a future release. Modern browsers will not be
affected, as Dart2JS continues to support [last two major releases][1] of
Edge, Safari, Firefox, and Chrome.
[#46545]: https://github.com/dart-lang/sdk/issues/46545
[1]: https://dart.dev/faq#q-what-browsers-do-you-support-as-javascript-compilation-targets
#### Dart Dev Compiler (DDC)
- **Breaking change** [#44154][]: Subtyping relations of `package:js` classes
have been changed to be more correct and consistent with Dart2JS.
Like `anonymous` classes, non-`anonymous` classes will no longer check the
underlying type in DDC. The internal type representation of these objects have
changed as well, which will affect the `toString` value of these types.
[#44154]: https://github.com/dart-lang/sdk/issues/44154
## 2.13.4 - 2021-06-28
This is a patch release that fixes:
- a Dart VM compiler crash (issue [flutter/flutter#84212][]).
- a DDC compiler crash (issue [flutter/flutter#82838][]).
[flutter/flutter#84212]: https://github.com/flutter/flutter/issues/84212
[flutter/flutter#82838]: https://github.com/flutter/flutter/issues/82838
## 2.13.3 - 2021-06-10
This is a patch release that fixes:
- a Dart compiler crash (issue [flutter/flutter#83094][]).
- an analysis server deadlock causing it to stop responding to IDE requests
(issue [#45996][]).
- an analyzer crash when analyzing against `package:meta` `v1.4.0` (issue
[#46183][]).
[flutter/flutter#83094]: https://github.com/flutter/flutter/issues/83094
[#45996]: https://github.com/dart-lang/sdk/issues/45996
[#46183]: https://github.com/dart-lang/sdk/issues/46183
## 2.13.1 - 2021-05-25
This is a patch release that fixes:
- incorrect behavior in CastMap (issue [#45473][]).
- missing nullability from recursive type hierarchies in DDC (issue [#45767][]).
[#45473]: https://github.com/dart-lang/sdk/issues/45473
[#45767]: https://github.com/dart-lang/sdk/issues/45767
## 2.13.0 - 2021-05-18
### Language
- **Type aliases** [Non-function type aliases][]: Type aliases (names for types
introduced via the `typedef` keyword) were previously restricted to only
introduce names for function types. In this release, we remove this
restriction and allow type aliases to name any kind of type.
```dart
import 'dart:convert';
typedef JsonMap = Map<String, dynamic>;
JsonMap parseJsonMap(String input) => json.decode(input) as JsonMap;
```
In addition to being usable as type annotations, type aliases that name class
types can now also be used anywhere that the underlying class could be used,
allowing type aliases to be used to safely rename existing classes.
```dart
class NewClassName<T> {
NewClassName.create(T x);
static NewClassName<T> mkOne<T>(T x) => NewClassName<T>.create(x);
}
@Deprecated("Use NewClassName instead")
typedef OldClassName<T> = NewClassName<T>;
class LegacyClass extends OldClassName<int> {
LegacyClass() : super.create(3);
}
OldClassName<int> legacyCode() {
var one = OldClassName.create(1);
var two = OldClassName.mkOne(2);
return LegacyClass();
}
```
The new type alias feature is only available as part of the 2.13
[language version](https://dart.dev/guides/language/evolution). To use this
feature, you must set the lower bound on the sdk constraint for your package
to 2.13 or greater.
[non-function type aliases]:
https://github.com/dart-lang/language/blob/master/accepted/2.13/nonfunction-type-aliases/feature-specification.md
### Core libraries
#### `dart:collection`
- The `SplayTreeMap` was changed to allow `null` as key if the `compare`
function allows it. It now checks that a new key can be used as an argument to
the `compare` function when the member is added, _even if the map is empty_
(in which case it just compares the key to itself).
- The `SplayTreeSet` was changed to checks that a new element can be used as an
argument to the `compare` function when the member is added, _even if the set
is empty_ (in which case it just compares the element to itself).
#### `dart:developer`
- Added `serverWebSocketUri` property to `ServiceProtocolInfo`.
### Dart VM
### Tools
#### Analyzer
- Static analyses with "error" severity can once again be ignored with comments
like `// ignore: code` and `// ignore_for_file: code`. To declare that certain
analysis codes, or codes with certain severities ("error", "warning", and
"info") cannot be ignored with such comments, list them in
`analysis_options.yaml`, under the `analyzer` heading, with a new YAML key,
`cannot-ignore`. For example, to declare that "error" codes and
`unused_import` cannot be ignored, write the following into
`analysis_options.yaml`:
```yaml
analyzer:
cannot-ignore:
- error
- unused_import
```
#### dart format
- Correct constructor initializer indentation after `required` named parameters.
#### Linter
Updated the Linter to `1.2.1`, which includes:
- Improved `iterable_contains_unrelated_type` to better support `List` content
checks.
- Fixed `camel_case_types` and `prefer_mixin` to support non-function type
aliases.
- Fixed `prefer_mixin` to properly make exceptions for `dart.collection` legacy
mixins.
- Added new lints `avoid_multiple_declarations_per_line`,
`use_if_null_to_convert_nulls_to_bools`, `deprecated_consistency`,
`use_named_constants`, `use_build_context_synchronously` (experimental).
- Deprecated `avoid_as`.
- Migrated library to null-safety.
### Other libraries
#### `package:js`
- **Breaking change:** It is no longer valid to use `String`s that match an
`@Native` annotation in an `@JS()` annotation for a non-anonymous JS interop
class. This led to erroneous behavior due to the way interceptors work. If you
need to work with a native class, prefer `dart:html`, an `@anonymous` class,
or `js_util`. See issue [#44211][] for more details.
[#44211]: https://github.com/dart-lang/sdk/issues/44211
## 2.12.4 - 2021-04-15
This is a patch release that fixes a Dart VM compiler crashes when compiling
initializers containing async closures (issue [#45306][]).
[#45306]: https://github.com/dart-lang/sdk/issues/45306
## 2.12.3 - 2021-04-14
**Security advisory**: This is a patch release that fixes a vulnerability in
`dart:html` related to DOM clobbering. See the security advisory
[CVE-2021-22540][cve-2021-22540] for more details. Thanks again to **Vincenzo di
Cicco** for finding and reporting this vulnerability.
[cve-2021-22540]:
https://github.com/dart-lang/sdk/security/advisories/GHSA-3rfv-4jvg-9522
## 2.12.2 - 2021-03-17
This is a patch release that fixes crashes reported by Flutter 2 users (issue
[flutter/flutter#78167][]).
[flutter/flutter#78167]: https://github.com/flutter/flutter/issues/78167
## 2.12.1 - 2021-03-10
This is a patch release that fixes:
- an unhandled exception in HTTPS connections (issue [#45047][]).
- a typing issue in the typed_data `+` operator (issue [#45140][]).
[#45047]: https://github.com/dart-lang/sdk/issues/45047
[#45140]: https://github.com/dart-lang/sdk/issues/45140
## 2.12.0 - 2021-03-03
### Language
- **Breaking change** [Null safety][] is now enabled by default in all code that
has not opted out. With null safety, types in your code are non-nullable by
default. Null can only flow into parts of your program where you want it. With
null safety, your runtime null-dereference bugs turn into edit-time analysis
errors.
You can opt out of null safety and preserve your code's previous behavior by
setting the lower bound of the SDK constraint in your pubspec to 2.11.0 or
earlier to request an earlier [language version][]. You can opt out individual
Dart files by adding `// @dart=2.11` to the beginning of the file.
Files that are opted in to null safety may report new compile-time errors.
Opting in to null safety also gives you access to other new language features:
- Smarter flow analysis and type promotion
- `required` named parameters
- `late` variables
- The postfix `!` null assertion operator
- The `?..` and `?[]` null-aware operators
- **Breaking change** [#44660][]: Fixed an implementation bug where `this` would
sometimes undergo type promotion in extensions.
[null safety]: https://dart.dev/null-safety/understanding-null-safety
[language version]:
https://dart.dev/guides/language/evolution#language-versioning
[#44660]: https://github.com/dart-lang/sdk/issues/44660
### Core libraries
#### `dart:async`
- Add extension method `onError()` on `Future` to allow better typing of error
callbacks.
#### `dart:collection`
- Add `UnmodifiableSetView` class, which allows users to guarantee that methods
that could change underlying `Set` instance can not be invoked.
- Make it explicit that `LinkedList` compares elements by identity, and update
`contains()` to take advantage of this.
#### `dart:core`
- Add `Set.unmodifiable()` constructor, which allows users to create
unmodifiable `Set` instances.
#### `dart:io`
- `HttpRequest` now correctly follows HTTP 308 redirects
(`HttpStatus.permanentRedirect`).
#### `dart:isolate`
- Add `debugName` positional parameter to `ReceivePort` and `RawReceivePort`
constructors, a name which can be associated with the port and displayed in
tooling.
- Introduce `Isolate.exit([port, message])` which terminates current isolate
and, if `port` is specified, as a last action sends out the `message` out to
that `port`.
#### `dart:html`
- `EventStreamSubscription.cancel` has been updated to retain its synchronous
timing when running in both sound and unsound null safety modes. See issue
[#44157][] for more details.
[#44157]: https://github.com/dart-lang/sdk/issues/44157
### Dart VM
- **Breaking change** [#42312][]: `Dart_WeakPersistentHandle`s no longer
auto-delete themselves when the referenced object is garbage collected to
avoid race conditions, but they are still automatically deleted when the
isolate group shuts down.
- **Breaking change** [#42312][]: `Dart_WeakPersistentHandleFinalizer` is
renamed to `Dart_HandleFinalizer` and had its `handle` argument removed. All
API functions using that type have been updated.
[#42312]: https://github.com/dart-lang/sdk/issues/42312
### Foreign Function Interface (`dart:ffi`)
- **Breaking change** [#44621][]: Invocations with a generic `T` of `sizeOf<T>`,
`Pointer<T>.elementAt()`, `Pointer<T extends Struct>.ref`, and
`Pointer<T extends Struct>[]` are being deprecated in the current stable
release (2.12), and are planned to be fully removed in the following stable
release (2.13). Consequently, `allocate` in `package:ffi` will no longer be
able to invoke `sizeOf<T>` generically, and will be deprecated as well.
Instead, the `Allocator` it is introduced to `dart:ffi`, and also requires a
constant `T` on invocations. For migration notes see the breaking change
request.
- **Breaking change** [#44622][]: Subtypes of `Struct` without any native member
are being deprecated in the current stable release (2.12), and are planned to
be fully removed in the following stable release (2.13). Migrate opaque types
to extend `Opaque` rather than `Struct`.
[#44621]: https://github.com/dart-lang/sdk/issues/44621
[#44622]: https://github.com/dart-lang/sdk/issues/44622
### Dart2JS
- Remove `--no-defer-class-types` and `--no-new-deferred-split`.
### Tools
#### Analyzer
- Remove the `--use-fasta-parser`, `--preview-dart-2`, and
`--enable-assert-initializers` command line options. These options haven't
been supported in a while and were no-ops.
- Report diagnostics regarding the
[`@internal`](https://pub.dev/documentation/meta/latest/meta/internal-constant.html)
annotation.
- Improve diagnostic-reporting regarding the
[`@doNotStore`](https://pub.dev/documentation/meta/latest/meta/doNotStore-constant.html)
annotation.
- Introduce a diagnostic which is reported when a library member named `main` is
not a function.
- Introduce a diagnostic which is reported when a `main` function's first
parameter is not a supertype of `List<String>`.
- Introduce diagnostics for when an `// ignore` comment contains an error code
which is not being reported, cannot be ignored, or is already being ignored.
- Report diagnostics when using
[`@visibleForTesting`](https://pub.dev/documentation/meta/latest/meta/
visibleForTesting-constant.html) on top-level variables.
- Fix false positive reports of "unused element" for top-level setters and
getters.
- Fix false positive reports regarding `@deprecated` field formal parameters at
their declaration.
- For null safety, introduce a diagnostic which reports when a null-check will
always fail.
- Fix false positive reports regarding optional parameters on private
constructors being unused.
- Introduce a diagnostic which is reported when a constructor includes duplicate
field formal parameters.
- Improve the "unused import" diagnostic when multiple import directives share a
common prefix.
- Fix false positive "unused import" diagnostic regarding an import which
provides an extension method which is used.
- For null safety, improve the messaging of "use of nullable value" diagnostics
for eight different contexts.
- Fix false positive reports regarding `@visibleForTesting` members in a "hide"
combinator of an import or export directive.
- Improve the messaging of "invalid override" diagnostics.
- Introduce a diagnostic which is reported when `Future<T>.catchError` is called
with an `onError` callback which does not return `FutureOr<T>`.
#### dartfmt
- Don't duplicate comments on chained if elements.
- Preserve `?` in initializing formal function-typed parameters.
- Fix performance issue with constructors that have no initializer list.
#### Linter
Updated the Linter to `0.1.129`, which includes:
- New lints: `avoid_dynamic_calls`, `cast_nullable_to_non_nullable`,
`null_check_on_nullable_type_parameter`,
`tighten_type_of_initializing_formals`, `unnecessary_null_checks`, and
`avoid_type_to_string`.
- Fix crash in `prefer_collection_literals` when there is no static parameter
element.
- Fix false negatives for `prefer_collection_literals` when a LinkedHashSet or
LinkedHashMap instantiation is passed as the argument to a function in any
position other than the first.
- Fix false negatives for `prefer_collection_literals` when a LinkedHashSet or
LinkedHashMap instantiation is used in a place with a static type other than
Set or Map.
- Update to `package_names` to allow leading underscores.
- Fix crashes in `unnecessary_null_checks` and
`missing_whitespace_between_adjacent_strings`.
- Update to `void_checks` for null safety.
- Fix range error in `unnecessary_string_escapes`.
- Fix false positives in `unnecessary_null_types`.
- Fix to `prefer_constructors_over_static_methods` to respect type parameters.
- Update to `always_require_non_null_named_parameters` to be null safety-aware.
- Update to `unnecessary_nullable_for_final_variable_declarations` to allow
dynamic.
- Update `overridden_fields` to not report on abstract parent fields.
- Fix to `unrelated_type_equality_checks` for null safety.
- Improvements to `type_init_formals`to allow types not equal to the field type.
- Updates to `public_member_apis` to check generic type aliases.
- Fix `close_sinks` to handle `this`-prefixed property accesses.
- Fix `unawaited_futures` to handle `Future` subtypes.
- Performance improvements to `always_use_package_imports`,
`avoid_renaming_method_parameters`, `prefer_relative_imports` and
`public_member_api_docs`.
#### Pub
- **Breaking**: The Dart SDK constraint is now **required** in `pubspec.yaml`.
You must include a section like:
```yaml
environment:
sdk: ">=2.10.0 <3.0.0"
```
See [#44072][].
For legacy dependencies without an SDK constraint, pub will now assume a
default language version of 2.7.
- The top level `pub` executable has been deprecated. Use `dart pub` instead.
See [dart tool][].
- New command `dart pub add` that adds new dependencies to your `pubspec.yaml`,
and a corresponding `dart pub remove` that removes dependencies.
- New option `dart pub upgrade --major-versions` will update constraints in your
`pubspec.yaml` to match the _resolvable_ column reported in
`dart pub outdated`. This allows users to easily upgrade to latest version for
all dependencies where this is possible, even if such upgrade requires an
update to the version constraint in `pubspec.yaml`.
It is also possible to only upgrade the major version for a subset of your
dependencies using `dart pub upgrade --major-versions <dependencies...>`.
- New option `dart pub upgrade --null-safety` will attempt to update constraints
in your `pubspec.yaml`, such that only null-safety migrated versions of
dependencies are allowed.
- New option `dart pub outdated --mode=null-safety` that will analyze your
dependencies for null-safety.
- `dart pub get` and `dart pub upgrade` will highlight dependencies that have
been [discontinued](https://dart.dev/tools/pub/publishing#discontinue) on
pub.dev.
- `dart pub publish` will now check your pubspec keys for likely typos.
- `dart pub upgrade package_foo` fetchs dependencies but ignores the
`pubspec.lock` for `package_foo`, allowing users to only upgrade a subset of
dependencies.
- New command `dart pub login` that logs in to pub.dev.
- The `--server` option to `dart pub publish` and `dart pub uploader` are
deprecated. Use `publish_to` in your `pubspec.yaml` or set the
`$PUB_HOSTED_URL` environment variable.
- `pub global activate` no longer re-precompiles if the current global
installation was same version.
- The Flutter SDK constraint upper bound is now ignored in pubspecs and
deprecated when publishing. See: [flutter-upper-bound-deprecation][].
[flutter-upper-bound-deprecation]:
https://dart.dev/go/flutter-upper-bound-deprecation
[#44072]: https://github.com/dart-lang/sdk/issues/44072
[dart tool]: https://dart.dev/tools/dart-tool
## 2.10.5 - 2021-01-21
This is a patch release that fixes a crash in the Dart VM. (issue [#44563][]).
[#44563]: https://github.com/dart-lang/sdk/issues/44563
## 2.10.4 - 2020-11-12
This is a patch release that fixes a crash in the Dart VM (issues [#43941][],
[flutter/flutter#43620][], and [Dart-Code/Dart-Code#2814][]).
[#43941]: https://github.com/dart-lang/sdk/issues/43941
[flutter/flutter#43620]: https://github.com/flutter/flutter/issues/43620
[dart-code/dart-code#2814]: https://github.com/Dart-Code/Dart-Code/issues/2814
## 2.10.3 - 2020-10-29
This is a patch release that fixes the following issues:
- breaking changes in Chrome 86 that affect DDC (issues [#43750][] and
[#43193][]).
- compiler error causing incorrect use of positional parameters when named
parameters should be used instead (issues [flutter/flutter#65324][] and
[flutter/flutter#68092][]).
- crashes and/or undefined behavor in AOT compiled code (issues [#43770][] and
[#43786][]).
- AOT compilation of classes with more than 64 unboxed fields (issue
[flutter/flutter#67803][]).
[#43750]: https://github.com/dart-lang/sdk/issues/43750
[#43193]: https://github.com/dart-lang/sdk/issues/43193
[flutter/flutter#65324]: https://github.com/flutter/flutter/issues/65324
[flutter/flutter#68092]: https://github.com/flutter/flutter/issues/68092
[#43770]: https://github.com/dart-lang/sdk/issues/43770
[#43786]: https://github.com/dart-lang/sdk/issues/43786
[flutter/flutter#67803]: https://github.com/flutter/flutter/issues/67803
## 2.10.2 - 2020-10-15
This is a patch release that fixes a DDC compiler crash (issue [#43589]).
[#43589]: https://github.com/dart-lang/sdk/issues/43589
## 2.10.1 - 2020-10-06
This is a patch release that fixes the following issues:
- crashes when developing Flutter applications (issue [#43464][]).
- non-deterministic incorrect program behaviour and/or crashes (issue
[flutter/flutter#66672][]).
- uncaught TypeErrors in DDC (issue [#43661][]).
[#43464]: https://github.com/dart-lang/sdk/issues/43464
[flutter/flutter#66672]: https://github.com/flutter/flutter/issues/66672
[#43661]: https://github.com/dart-lang/sdk/issues/43661
## 2.10.0 - 2020-09-28
### Core libraries
#### `dart:io`
- Adds `Abort` method to class `HttpClientRequest`, which allows users to cancel
outgoing HTTP requests and stop following IO operations.
- A validation check is added to `path` of class `Cookie`. Having characters
ranging from 0x00 to 0x1f and 0x3b (";") will lead to a `FormatException`.
- The `HttpClient` and `HttpServer` classes now have a 1 MiB limit for the total
size of the HTTP headers when parsing a request or response, instead of the
former 8 KiB limit for each header name and value. This limit cannot be
configured at this time.
#### `dart:typed_data`
- Class `BytesBuilder` is moved from `dart:io` to `dart:typed_data`. It's
temporarily being exported from `dart:io` as well.
### `dart:uri`
- [#42564]: Solved inconsistency in `Uri.https` and `Uri.http` constructors'
`queryParams` type.
### Dart VM
- **Breaking change** [#42982][]: `dart_api_dl.cc` is renamed to `dart_api_dl.c`
and changed to a pure C file.
- Introduces `Dart_FinalizableHandle`s. They do auto-delete, and the weakly
referred object cannot be accessed through them.
### Dart2JS
- Adds support for deferred loading of types seperately from classes. This
enables dart2js to make better optimization choices when deferred loading.
This work is necessary to address unsoundness in the deferred loading
algorithm. Currently, fixing this unsoundness would result in code bloat, but
loading types seperately from classes will allow us to fix the unsoundness
with only a minimal regression. To explicitly disable deferred loading of
types, pass `--no-defer-class-types`. See the original post on the
[unsoundness in the deferred loading algorithm][].
- Enables a new sound deferred splitting algorithm. To explicitly disable the
new deferred splitting algorithm, pass `--no-new-deferred-split`. See the
original post on the [unsoundness in the deferred loading algorithm][].
[#42982]: https://github.com/dart-lang/sdk/issues/42982
[unsoundness in the deferred loading algorithm]:
https://github.com/dart-lang/sdk/blob/302ad7ab2cd2de936254850550aad128ae76bbb7/CHANGELOG.md#dart2js-3
### Tools
#### dartfmt
- Don't crash when non-ASCII whitespace is trimmed.
- Split all conditional expressions (`?:`) when they are nested.
- Handle `external` and `abstract` fields and variables.
#### Linter
Updated the Linter to `0.1.118`, which includes:
- New lint: `unnecessary_nullable_for_final_variable_declarations`.
- Fixed NPE in `prefer_asserts_in_initializer_lists`.
- Fixed range error in `unnecessary_string_escapes`.
- `unsafe_html` updated to support unique error codes.
- Updates to `diagnostic_describe_all_properties` to check for `Diagnosticable`s
(not `DiagnosticableMixin`s).
- New lint: `use_late`.
- Fixed `unnecessary_lambdas` to respect deferred imports.
- Updated `public_member_api_docs` to check mixins.
- Updated `unnecessary_statements` to skip `as` expressions.
- Fixed `prefer_relative_imports` to work with path dependencies.
#### Pub
- `pub run` and `pub global run` accepts a `--(no-)-sound-null-safety` flag,
that is passed to the VM.
- Fix: Avoid multiple recompilation of binaries in global packages.
- Fix: Avoid exponential behaviour of error reporting from the solver.
- Fix: Refresh binstubs after recompile in global run.
## 2.9.3 - 2020-09-08
This is a patch release that fixes DDC to handle a breaking change in Chrome
(issue [#43193][]).
[#43193]: https://github.com/dart-lang/sdk/issues/43193
## 2.9.2 - 2020-08-26
This is a patch release that fixes transient StackOverflow exceptions when
building Flutter applications (issue [flutter/flutter#63560][]).
[flutter/flutter#63560]: https://github.com/flutter/flutter/issues/63560
## 2.9.1 - 2020-08-12
This is a patch release that fixes unhandled exceptions in some Flutter
applications (issue [flutter/flutter#63038][]).
[flutter/flutter#63038]: https://github.com/flutter/flutter/issues/63038
## 2.9.0 - 2020-08-05
### Language
### Core libraries
#### `dart:async`
- Adds `Stream.multi` constructor creating streams which can be listened to more
than once, and where each individual listener can be controlled independently.
#### `dart:convert`
- **Breaking change** [#41100][]: When encoding a string containing unpaired
surrogates as UTF-8, the unpaired surrogates will be encoded as replacement
characters (`U+FFFD`). When decoding UTF-8, encoded surrogates will be treated
as malformed input. When decoding UTF-8 with `allowMalformed: true`, the
number of replacement characters emitted for malformed input sequences has
been changed to match the [WHATWG encoding standard][].
[#41100]: https://github.com/dart-lang/sdk/issues/41100
[whatwg encoding standard]: https://encoding.spec.whatwg.org/#utf-8-decoder
#### `dart:io`
- [#42006][]: The signature of `exit` has been changed to return the `Never`type
instead of `void`. since no code will run after it,
- Class `OSError` now implements `Exception`. This change means `OSError` will
now be caught in catch clauses catching `Exception`s.
- Added `InternetAddress.tryParse`.
- [Abstract Unix Domain Socket][] is supported on Linux/Android now. Using an
`InternetAddress` with `address` starting with '@' and type being
`InternetAddressType.Unix` will create an abstract Unix Domain Socket.
- On Windows, file APIs can now handle files and directories identified by long
paths (greater than 260 characters). It complies with all restrictions from
[Long Path on Windows][]. Note that `Directory.current` does not work with
long path.
[#42006]: https://github.com/dart-lang/sdk/issues/42006
[abstract unix domain socket]: http://man7.org/linux/man-pages/man7/unix.7.html
[long path on windows]:
https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#maximum-path-length-limitation
#### `dart:html`
- **Breaking change**: `CssClassSet.add()` previously returned `null` if the
`CssClassSet` corresponded to multiple elements. In order to align with the
null-safe changes in the `Set` interface, it will now return `false` instead.
The same applies for `CssClassSet.toggle`.
- `EventStreamSubscription.cancel` method used to return `null`, but since
`StreamSubscription.cancel` has changed to be non-nullable, this method
returns an empty `Future` instead. Due to an optimization on `null` `Future`s,
this method used to complete synchronously, but now that the `Future` is empty
instead, it completes asynchronously, therefore potentially invalidating code
that relied on the synchronous side-effect. This change will only affect code
using sound null-safety. See issue [#41653][] for more details.
- Methods in `Console` have been updated to better reflect the modern Console
specification. Particularly of interest are `dir` and `table` which take in
extra optional arguments.
[#41653]: https://github.com/dart-lang/sdk/issues/41653
#### `dart:mirrors`
- **Breaking change** [#42714][]: web compilers (dart2js and DDC) now produce a
compile-time error if `dart:mirrors` is imported.
Most projects should not be affected. Since 2.0.0 this library was unsupported
and produced runtime errors on all its APIs. Since then several tools already
reject code that use `dart:mirrors` including webdev and flutter tools, we
expect few projects to run into this problem.
[#42714]: https://github.com/dart-lang/sdk/issues/42714
### Tools
#### dartfmt
- Add `--fix-single-cascade-statements`.
- Correctly handle `var` in `--fix-function-typedefs`.
- Preserve leading indentation in fixed doc comments.
- Split outer nested control flow elements.
- Always place a blank line after script tags.
- Don't add unneeded splits on if elements near comments.
- Indent blocks in initializers of multiple-variable declarations.
- Update the null-aware subscript syntax from `?.[]` to `?[]`.
#### Analyzer
- Static analyses with a severity of "error" can no longer be ignored with
comments (`// ignore: code` and `// ignore_for_file: code`).
#### Linter
Updated the Linter to `0.1.117`, which includes:
- New lint: `do_not_use_environment`.
- New lint: `exhaustive_cases`.
- New lint: `no_default_cases` (experimental).
- New lint: `sized_box_for_whitespace`.
- New lint: `use_is_even_rather_than_modulo`.
- Updated `directives_ordering` to remove third party package special-casing.
- Updated `prefer_is_empty` to special-case assert initializers and const
contexts.
- Updated `prefer_mixin` to allow "legacy" SDK abstract class mixins.
- Updated `sized_box_for_whitespace` to address false-positives.
- Updated `type_annotate_public_apis` to allow inferred types in final field
assignments.
- Updated `unnecessary_lambdas` to check for tear-off assignability.
- Updated `unsafe_html` to use a `SecurityLintCode` (making it un-ignorable) and
to include `Window.open`, `Element.html` and `DocumentFragment.html` in unsafe
API checks. Also added checks for attributes and methods on extensions.
### Dart VM
- **Breaking change** [#41100][]: When printing a string using the `print`
function, the default implementation (used when not overridden by the embedder
or the current zone) will print any unpaired surrogates in the string as
replacement characters (`U+FFFD`). Similarly, the `Dart_StringToUTF8` function
in the Dart API will convert unpaired surrogates into replacement characters.
### Pub
- `pub run` and `pub global run` accepts a `--enable-experiment` flag enabling
experiments in the Dart VM (and language).
- Warn when publishing the first null-safe version of a package.
- `pub outdated`:
- If the current version of a dependency is a prerelease version, use
prereleases for latest if there is no newer stable.
- Don't require a `pubspec.lock` file. When the lockfile is missing, the
**Current** column is empty.
- `pub upgrade`: Show summary count of outdated packages after running. It will
also only show newer packages if they are not prereleases or the package is
already a prerelease.
- Publishing Flutter plugins using the old plugin format is no longer allowed.
Plugins using the old plugin format can still be consumed.
- `pub run`: Fix precompilation with relative `PUB_CACHE` paths
([#2486](https://github.com/dart-lang/pub/pull/2486)).
- Preserve Windows line endings in `pubspec.lock` if they are already there
([#2489](https://github.com/dart-lang/pub/pull/2489)).
- Better terminal color-detection. Use colors in terminals on Windows.
- Fix git folder names in cache, allowing for ssh-style git dependencies.
- Fix: Avoid precompilation of dependencies of global packages.
## 2.8.4 - 2020-06-04
This is a patch release that fixes potential memory leaks in the Dart front-end
(issues [#42111][] and [#42112][]).
[#42111]: https://github.com/dart-lang/sdk/issues/42111
[#42112]: https://github.com/dart-lang/sdk/issues/42112
## 2.8.3 - 2020-05-28
This is a patch release that fixes the following issues:
- crashes in Flutter apps (issue [flutter/flutter#57318][]).
- a regression in stack traces (issue [#41907][]).
- re-canonicalization of constants with unboxed fields (issue
[flutter/flutter#57190][]).
[flutter/flutter#57318]: https://github.com/flutter/flutter/issues/57318
[#41907]: https://github.com/dart-lang/sdk/issues/41907
[flutter/flutter#57190]: https://github.com/flutter/flutter/issues/57190
## 2.8.2 - 2020-05-13
This is a patch release that fixes an AOT compilation bug in global
transformations which manifests as a NoSuchMethod exception (issue
[flutter/flutter#56479][]).
[flutter/flutter#56479]: https://github.com/flutter/flutter/issues/56479
## 2.8.1 - 2020-05-06
Much of the changes in this release are in preparation for non-nullable types,
which will arrive in a future version. In anticipation of that, we have made a
number of small but technically breaking changes to several core library APIs in
order to make them easier to use in a world with non-nullable types. Almost all
existing Dart code will be unaffected by these changes, but if you see
unexpected failures, note the breaking changes listed below.
### Language
There are no new language features in this release. There are only two minor
breaking changes:
- **Breaking change** [#40675][]: Fixed an implementation bug where local
variable inference would incorrectly use the promoted type of a type variable.
- **Breaking change** [#41362][]: Dart 2.0.0 made the clauses
`implements Function`, `extends Function`, or `with Function` have no effect
(spec section 19.6). We fixed an implementation bug that may be visible on
some rare scenarios.
[#40675]: https://github.com/dart-lang/sdk/issues/40675
[#41362]: https://github.com/dart-lang/sdk/issues/41362
### Core libraries
#### `dart:async`
- **Breaking change** [#40676][]: Changed the return type of
`StreamSubscription.cancel()` to `Future<void>`. Previously, it was declared
to return `Future` and was allowed to return `null` at runtime.
- **Breaking change** [#40681][]: The `runZoned()` function is split into two
functions: `runZoned()` and `runZonedGuarded()`, where the latter has a
required `onError` parameter, and the former has none. This prepares the
functions for null safety where the two functions will differ in the
nullability of their return types.
- **Breaking change** [#40683][]: Errors passed to `Completer.completeError()`,
`Stream.addError()`, `Future.error()`, etc. can no longer be `null`. These
operations now _synchronously_ throw an exception if passed a `null` error.
- Make stack traces non-null [#40130][]. Where methods like
`completer.completeError()` allow omitting a stack trace, the platform will
now insert a default stack trace rather than propagate a `null` value.
Error handling functions need no longer be prepared for `null` stack traces.
[#40676]: https://github.com/dart-lang/sdk/issues/40676
[#40681]: https://github.com/dart-lang/sdk/issues/40681
[#40683]: https://github.com/dart-lang/sdk/issues/40683
[#40130]: https://github.com/dart-lang/sdk/issues/40130
#### `dart:core`
- **Breaking change** [#40674][]: Three members on `RuneIterator` no longer
return `null` when accessed before the first call to `moveNext()`. Instead,
`current` and `rawIndex` return `-1` and `currentAsString` returns an empty
string.
- **Breaking change** [#40678][]: The `String.fromEnvironment()` default value
for `defaultValue` is now an empty string instead of `null`. Likewise, the
default value for `int.fromEnvironment()`'s `defaultValue` parameter is zero.
Under null safety, a constructor cannot return `null`, so this prepares these
APIs for that.
- The class `CastError` is deprecated, and all implementation specific classes
implementing `TypeError` or `CastError` now implement both. In a future
release, `CastError` will be removed. See issue [40763][] for details.
- Adds `StackTrace.empty` constant which is the stack trace used as default
stack trace when no better alternative is available.
- The class `TypeError` no longer extends `AssertionError`. This also means that
it no longer inherits the spurious `message` getter which was added to
`AssertionError` when the second operand to `assert` was allowed. The value of
that getter on a `TypeError` was the same string as returned by `toString()`,
so it is still available.
- `ArgumentError.checkNotNull()` and the `RangeError` static methods
`checkValueInInterval()`, `checkValidIndex()` and `checkNotNegative()` all
return their first argument on success. This makes these functions more
convenient to use in-line in, for example, `=>` function bodies or constructor
initialization lists.
[#40674]: https://github.com/dart-lang/sdk/issues/40674
[#40678]: https://github.com/dart-lang/sdk/issues/40678
[40763]: https://github.com/dart-lang/sdk/issues/40763
#### `dart:developer`
- The constructors for `TimelineTask` now accept an optional `filterKey`
parameter. If provided, the arguments for all events associated with the task
will contain an entry named `filterKey`, set to the value of the `filterKey`
parameter provided in the constructor. This will be used by tooling to allow
for better filtering of timeline events.
#### `dart:html`
- **Breaking change** [#39627][]: Changed the return type of several HTML native
methods involving futures. In return types that matched `Future<List<T>>`,
`T was` changed to `dynamic`. These methods would have resulted in a runtime
error if they were used.
- **Breaking change**: `Node.insertAllBefore()` erroneously had a return type of
`Node`, even though it was not returning anything. This has been corrected to
`void`.
[#39627]: https://github.com/dart-lang/sdk/issues/39627
#### `dart:io`
- Class `HttpParser` will no longer throw an exception when a HTTP response
status code is within [0, 999]. Customized status codes in this range are now
valid.
- **Breaking change** [#33501][]: The signature of `HttpHeaders` methods `add()`
and `set` have been changed to:
```dart
void add(String name, Object value, {bool preserveHeaderCase: false})
void set(String name, Object value, {bool preserveHeaderCase: false})
```
Setting `preserveHeaderCase` to `true` preserves the case of the `name`
parameter instead of converting it to lowercase. The `HttpHeader.forEach()`
method provides the current case of each header.
This is breaking only for classes extending or implementing `HttpHeaders` and
having their own `add` or `set` methods without the `bool preserveHeaderCase`
named parameter.
- **Breaking change** [#40702][]: The `Socket` class now throws a
`SocketException` if the socket has been explicitly destroyed or upgraded to a
secure socket upon setting or getting socket options. Previously, setting a
socket option would be ignored and getting a socket option would return
`null`.
- **Breaking change** [#40483][]: The `Process` class now throws a `StateError`
if the process is detached (`ProcessStartMode.detached` and
`ProcessStartMode.detachedWithStdio`) upon accessing the `exitCode` getter. It
now also throws when not connected to the child process's stdio
(`ProcessStartMode.detached` and `ProcessStartMode.inheritStdio`) upon
accessing the `stdin`, `stdout`, and `stderr` getters. Previously, these
getters would all return `null`.
- **Breaking change** [#40706][]: The dummy object returned if `FileStat.stat()`
or `FileStat.statSync()` fail now contains Unix epoch timestamps instead of
`null` for the `accessed`, `changed`, and `modified` getters.
- **Breaking change** [#40709][]: The `HeaderValue` class now parses more
strictly in two invalid edge cases. This is the class used to parse the
semicolon delimited parameters used in the `Accept`, `Authorization`,
`Content-Type`, and other such HTTP headers.
The empty parameter value without double quotes (which is not allowed by the
standards) is now parsed as the empty string rather than `null`. E.g.
`HeaderValue.parse("v;a=").parameters` now gives `{"a": ""}` rather than
`{"a": null}`.
Invalid inputs with unbalanced double quotes are now rejected. E.g.
`HeaderValue.parse('v;a="b').parameters` will now throw a `HttpException`
instead of giving `{"a": "b"}`.
- The `HeaderValue.toString()` method now supports parameters with `null` values
by omitting the value. `HeaderValue("v", {"a": null, "b": "c"}).toString()`
now gives `v; a; b=c`. This behavior can be used to implement some features in
the `Accept` and `Sec-WebSocket-Extensions` headers.
Likewise the empty value and values using characters outside of [RFC 7230
tokens][] are now correctly implemented by double quoting such values with
escape sequences. For example:
```dart
HeaderValue("v",
{"a": "A", "b": "(B)", "c": "", "d": "ø", "e": "\\\""}).toString()
```
Gives: `v;a=A;b="(B)";c="";d="ø";e="\\\""`.
- [Unix domain sockets][] are now supported on Linux, Android and MacOS, which
can be used by passing a `InternetAddress` of `InternetAddressType.Unix` into
the `connect()`, `startConnect()` and `bind()` methods. The `port` argument in
those methods will be ignored. The `port` getter always returns 0 for Unix
domain sockets.
- Class `InternetAddressType` gains one more option `Unix`, which represents a
Unix domain address.
- Class `InternetAddress`:
- `InternetAddress` constructor gains an optional `type` parameter. To create
a Unix domain address, `type` is set to `InternetAddressType.Unix` and
`address` is a file path.
- `InternetAddress` gains a new constructor `fromRawAddress()` that takes an
address in byte format for Internet addresses or raw file path for Unix
domain addresses.
- **Breaking change** [#40681][]: The static methods `runZoned()` and
`runWithHttpOverrides()` on `HttpOverrides` no longer accept
`zoneSpecification` and `onError` parameters. Use the `runZoned()` or
`runZonedGuarded()` functions from `dart:async` directly if needing to specify
those.
- Class `HttpClient` and `HttpServer`, when receiving `HttpRequest` or
`HttpClientResponse`, will now put a 8K size limit on its header fields and
values.
[#33501]: https://github.com/dart-lang/sdk/issues/33501
[#40702]: https://github.com/dart-lang/sdk/issues/40702
[#40483]: https://github.com/dart-lang/sdk/issues/40483
[#40706]: https://github.com/dart-lang/sdk/issues/40706
[#40709]: https://github.com/dart-lang/sdk/issues/40709
[rfc 7230 tokens]: https://tools.ietf.org/html/rfc7230#section-3.2.6
[unix domain sockets]: https://en.wikipedia.org/wiki/Unix_domain_socket
#### `dart:mirrors`
- Added `MirrorSystem.neverType`.
### Dart VM
- Added `Dart_TypeDynamic`, `Dart_TypeVoid` and `Dart_TypeNever`. Type `dynamic`
can no longer by reached using `Dart_GetType(dart:core, dynamic)`.
- Added the following methods to the VM embedding API:
- `Dart_GetNonNullableType()`
- `Dart_GetNullableType()`
- `Dart_TypeToNonNullable()`
- `Dart_TypeToNullable()`
- `Dart_IsLegacyType()`
- `Dart_IsNonNullableType()`
- `Dart_IsNullableType()`
### Foreign Function Interface (`dart:ffi`)
- **Breaking change**: Changed `Pointer.asFunction()` and
`DynamicLibrary.lookupFunction()` to extension methods. Invoking them
dynamically previously already threw an exception, so the runtime behavior
stays the same. However, the extension methods are only visible if `dart:ffi`
is imported directly. This breaks code where `dart:ffi` is not directly
imported. To fix, add:
```dart
import 'dart:ffi';
```
### Tools
#### Dart Dev Compiler (DDC)
We fixed several inconsistencies between DDC and Dart2JS so that users less
frequently encounter code that is accepted by one compiler but then fails in the
other.
- **Breaking change**: Deleted the legacy (analyzer based) version of DDC. For
additional details see the [announcement][ddc].
- The `--kernel` option is now ignored and defaults to true. There is no
longer any way to invoke the legacy (analyzer based) version of DDC.
- Command line arguments that were only used for the legacy DDC have been
removed.
- The pre-compiled `dart_sdk.js` artifacts generated by legacy DDC have been
deleted from `dart-sdk/lib/dev_compiler` in favor of the versions located at
`dart-sdk/lib/dev_compiler/kernel`.
- **Breaking change**: Functions passed to JavaScript using the recommended
`package:js` interop specification must now be wrapped with a call to
`allowInterop`. This behavior was always enforced by Dart2JS, but was not
enforced consistently by DDC. It is now enforced by both.
- **Breaking change**: Constructors in `@JS()` classes must be marked with
`external`. Previously the `external` could be omitted in some cases with DDC
but doing so would cause incorrect behavior with Dart2JS.
- JS interop classes with an index operator are now static errors.
- All remaining support from the `dart:mirrors` library has been removed. Use of
this library on the web has been unsupported and prevented by the Dart build
systems since Dart v2.0.0. All known exception cases have been cleaned up.
This change makes DDC and Dart2JS now behave consistently.
The library can still be imported on web apps, but all APIs throw. In a future
breaking change release, imports to this library will likely become a
compile-time error.
[ddc]: https://github.com/dart-lang/sdk/issues/38994
#### Dart2JS
A new representation of runtime types is enabled by default.
This change is part of a long term goal of making runtime checks cheaper and
more flexible for upcoming changes in the language. The new representation
disentangles how types and classes are represented and makes types first-class
to the compiler. This makes it possible to do certain kind of optimizations on
type checks that were not possible before and will enable us to model
non-nullable types in the near future.
This change should not affect the semantics of your application, but it has some
relatively small visible effects that we want to highlight:
- Types are now canonicalized, this fixes a long standing bug that Types could
not be used in switch cases (issue [17207][]).
- Code-size changes may be visible, but the difference is small overall. It is
more visible on smaller apps because the new implementation includes more
helper methods. On large apps we have even seen an overall code-size
reduction.
- Certain checks are a lot faster. This is less noticeable if you are compiling
apps with `-O3` where checks are omitted altogether. Even with `-O3`, the
performance of some `is` checks used by your app may improve.
- When using `-O3` and `-O4` incorrect type annotations could surface as errors.
The old type representation was accidentally lenient on some invalid type
annotations. We have only encountered this issue on programs that were not
tested properly at the js-interop program boundary.
- `Type.toString()` has a small change that is rarely visible. For a long time,
Dart2JS has had support to erase unused type variables. Today, when Dart2JS is
given `--lax-runtime-type-to-string` (currently included in `-O2`, `-O3`, and
`-O4`) and it decides to erase the type variable of a class `Foo<T>`, then it
compiles expressions like `foo.runtimeType.toString()` to print `Foo`. With
the new representation, this will show `Foo<erased>` instead. This change may
be visible in error messages produced by type checks involving erased types.
Because types and classes are represented separately, we will likely reevaluate
restrictions of deferred libraries in the near future. For example, we could
support referring to deferred types because types can be downloaded while
classes are not.
In the unlikely case you run into any issues, please file a bug so we can
investigate. You can temporarily force the old type representation by passing
`--use-old-rti` to Dart2JS if necessary, but our goal is to delete the old type
representation soon.
In addition, we fixed some inconsistencies between Dart2JS and DDC:
- JS interop classes with an index operator are now static errors instead of
causing invalid code in Dart2JS.
- **Breaking change**: The subtyping rule for generic functions is now more
forgiving. Corresponding type parameter bounds now only need to be mutual
subtypes rather than structurally equal up to renaming of bound type variables
and equating all top types.
- **Breaking change**: Types are now normalized. See [normalization][] for the
full specification. Types will now be printed in their normal form, and mutual
subtypes with the same normal form will now be considered equal.
- **Breaking change**: Constructors in `@JS()` classes must be marked with
`external`. Previously, the external could be omitted for unused constructors.
Omitting `external` for a constructor which is used would cause incorrect
behavior at runtime, now omitting it on any constructor is a static error.
[17207]: https://github.com/dart-lang/sdk/issues/17207
[normalization]:
https://github.com/dart-lang/language/blob/master/resources/type-system/normalization.md
Other dart2js changes:
- **Breaking change**: The `--package-root` flag, which was hidden and disabled
in Dart 2.0.0, has been completely removed. Passing this flag will now cause
`dart2js` to fail.
#### Linter
Updated the Linter to `0.1.114`, which includes:
- Fixed `avoid_shadowing_type_parameters` to support extensions and mixins.
- Updated `non_constant_identifier_names` to allow named constructors made up of
only underscores (`_`).
- Updated `avoid_unused_constructor_parameters` to ignore unused params named in
all underscores (`_`).
#### Analyzer
- Removed support for the deprecated analysis options file name
`.analysis_options`.
#### Pub
- Added `pub outdated` command which lists outdated package dependencies, and
gives advice on how to upgrade.
- `pub get` and `pub upgrade` now fetch version information about hosted
dependencies in parallel, improving the time package resolution performance.
- `pub get` and `pub upgrade` no longer precompile executables from dependencies
by default. Instead they are precompiled on first `pub run`. Use
`pub get --precompile` to get the previous behavior.
- Fixed missing retries of DNS failures during `pub get`.
- If code contains imports for packages not listed in the package's
`pubspec.yaml` then `pub publish` will reject the package.
- `pub publish` no longer requires the presence of a `homepage` field, if the
`repository` field is provided.
- `pub publish` warns if non-pre-release packages depends on pre-release
packages or pre-release Dart SDKs.
- Relative paths in `pubspec.lock` now use `/` also on Windows to make the file
sharable between machines.
- Fixed language version in [`.dart_tool/package_config.json`][package config]
for packages without an explicit SDK constraint. Pub now writes an empty
language version where before the language version of the current SDK would be
used.
- `%LOCALAPPDATA%` is now preferred over `%APPDATA%` when creating a pub cache
directory on Windows. `%LOCALAPPDATA%` is not copied when users roam between
devices.
- `pub publish` warns if LICENSE and README.md files are not called those exact
names.
- `pub repair cache` downloads hosted packages in parallel.
[package config]:
https://github.com/dart-lang/language/blob/master/accepted/future-releases/language-versioning/package-config-file-v2.md
## 2.7.2 - 2020-03-23
**Security advisory**: This is a patch release that addresses a vulnerability in
`dart:html` [NodeValidator][] related to DOM clobbering of `previousSibling`.
See the security advisory [CVE-2020-8923][cve-2020-8923] for more details.
Thanks to **Vincenzo di Cicco** for finding and reporting this issue.
This release also improves compatibility with ARMv8 processors (issue [40001][])
and dart:io stability (issue [40589][]).
[nodevalidator]: https://api.dart.dev/stable/dart-html/NodeValidator-class.html
[cve-2020-8923]:
https://github.com/dart-lang/sdk/security/advisories/GHSA-hfq3-v9pv-p627
[40001]: https://github.com/dart-lang/sdk/issues/40001
[40589]: https://github.com/dart-lang/sdk/issues/40589
## 2.7.1 - 2020-01-23
This is a patch release that improves dart2js compile-time (issue [40217][]).
[40217]: https://github.com/dart-lang/sdk/issues/40217
**Breaking change**: The Dart SDK for macOS is now only available for x64 (issue
[39810][]).
[39810]: https://github.com/dart-lang/sdk/issues/39810
## 2.7.0 - 2019-12-11
**Extension methods** -- which we shipped in preview in 2.6.0 -- are no longer
in preview, and are now officially supported as of 2.7.0. Learn more about them
here:
https://medium.com/dartlang/extension-methods-2d466cd8b308
### Language
- **Breaking change**: [Static extension members][] are accessible when imported
with a prefix (issue [671][]). In the extension method **preview** launch,
importing a library with a prefix hid all extension members in addition to
hiding the extension name, thereby making them inaccessible in the importing
library except via the explicit override syntax. Based on user feedback, we
have changed this to make extensions methods accessible even when imported
with a prefix.
```dart
// "thing.dart"
class Thing {
}
extension Show on Thing {
void show() {
print("This is a thing");
}
}
// "client.dart"
import "thing.dart" as p;
void test() {
p.Thing().show(); // Previously an error, now resolves to Show.show
}
```
[static extension members]:
https://github.com/dart-lang/language/blob/master/accepted/2.6/static-extension-members/feature-specification.md
[671]: https://github.com/dart-lang/language/issues/671
### Core libraries
#### `dart:io`
- **Breaking change**: Added `IOOverrides.serverSocketBind` to aid in writing
tests that wish to mock `ServerSocket.bind`.
#### `dart:typed_data`
- Added new constructors, `.sublistView(TypedData, [start, end])` to all
`TypedData` classes. The constructor makes it easier, and less error-prone, to
create a view of (a slice of) another `TypedData` object.
### Dart VM
- New fields added to existing instances by a reload will now be initialized
lazily, as if the field was a late field. This makes the initialization order
program-defined, whereas previously it was undefined.
### Tools
#### Linter
The Linter was updated to `0.1.104`, which includes:
- updated `unnecessary_overrides` to allow overrides when annotations (besides
`@override` are specified)
- updated `file_names` to allow names w/ leading `_`'s (and improved
performance)
- new lint: `unnecessary_final`
#### Pub
- `pub get` generates
[`.dart_tool/package_config.json`](https://github.com/dart-lang/language/blob/62c036cc41b10fb543102d2f73ee132d1e2b2a0e/accepted/future-releases/language-versioning/package-config-file-v2.md)
in addition to `.packages` to support language versioning.
- `pub publish` now warns about the old flutter plugin registration format.
- `pub publish` now warns about the `author` field in pubspec.yaml being.
obsolete.
- Show a proper error message when `git` is not installed.
## 2.6.1 - 2019-11-11
This is a patch release that reduces dart2js memory usage (issue [27883][]),
improves stability on arm64 (issue [39090][]) and updates the Dart FFI
documentation.
[27883]: https://github.com/dart-lang/sdk/issues/27883
[39090]: https://github.com/dart-lang/sdk/issues/39090
## 2.6.0 - 2019-11-05
### Language
- **[IN PREVIEW]** [Static extension members][]: A new language feature allowing
specially declared static functions to be invoked like instance members on
expressions of appropriate static types is available in preview.
Static extension members are declared using a new `extension` declaration.
Example:
```dart
extension MyFancyList<T> on List<T> {
/// Whether this list has an even length.
bool get isLengthEven => this.length.isEven;
/// Whether this list has an odd length.
bool get isLengthOdd => !isLengthEven;
/// List of values computed for each pairs of adjacent elements.
///
/// The result always has one element less than this list,
/// if this list has any elements.
List<R> combinePairs<R>(R Function(T, T) combine) =>
[for (int i = 1; i < this.length; i++)
combine(this[i - 1], this[i])];
}
```
Extension declarations cannot declare instance fields or constructors.
Extension members can be invoked explicitly,
`MyFancyList(intList).isLengthEven)`, or implicitly, `intList.isLengthEven`,
where the latter is recognized by `intList` matching the `List<T>` "on" type
of the declaration. An extension member cannot be called implicitly on an
expression whose static type has a member with the same base-name. In that
case, the interface member takes precedence. If multiple extension members
apply to the same implicit invocation, the most specific one is used, if there
is one such.
Extensions can be declared on any type, not just interface types.
```dart
extension IntCounter on int {
/// The numbers from this number to, but not including, [end].
Iterable<int> to(int end) sync* {
int step = end < this ? -1 : 1;
for (int i = this; i != end; i += step) yield i;
}
}
extension CurryFunction<R, S, T> on R Function(S, T) {
/// Curry a binary function with its first argument.
R Function(T) curry(S first) => (T second) => this(first, second);
}
```
[static extension members]:
https://github.com/dart-lang/language/blob/master/accepted/2.6/static-extension-members/feature-specification.md
- **Breaking change** [#37985](https://github.com/dart-lang/sdk/issues/37985):
Inference is changed when using `Null` values in a `FutureOr` context. Namely,
constraints of the forms similar to `Null` <: `FutureOr<T>` now yield `Null`
as the solution for `T`. For example, the following code will now print
"Null", and it was printing "dynamic" before (note that the anonymous closure
`() {}` in the example has `Null` as its return type):
```dart
import 'dart:async';
void foo<T>(FutureOr<T> Function() f) { print(T); }
main() { foo(() {}); }
```
### Core libraries
- Default values of parameters of abstract methods are no longer available via
`dart:mirrors`.
#### `dart:developer`
- Added optional `parent` parameter to `TimelineTask` constructor to allow for
linking of asynchronous timeline events in the DevTools timeline view.
#### `dart:io`
- Added `enableTimelineLogging` property to `HttpClient` which, when enabled,
will post HTTP connection and request information to the developer timeline
for all `HttpClient` instances.
### Dart VM
- Added a new tool for AOT compiling Dart programs to native, self-contained
executables. See https://dart.dev/tools/dart2native for additional details.
### Foreign Function Interface (`dart:ffi`)
- **Breaking change**: The API now makes use of static extension members. Static
extension members enable the `dart:ffi` API to be more precise with types, and
provide convenient access to memory through extension getters and setters. The
extension members on `Pointer` provide `.value` and `.value =` for accessing
the value in native memory and `[]` and `[]=` for indexed access. The method
`asExternalTypedData` has been replaced with `asTypedList` extension methods.
And finally, `Structs` do no longer have a type argument and are accessed
using the extension member `.ref` on `Pointer`. These changes makes the code
using `dart:ffi` much more concise.
- **Breaking change**: The memory management has been removed
(`Pointer.allocate` and `Pointer.free`). Instead, memory management is
available in [package:ffi](https://pub.dev/packages/ffi).
- **Breaking change**: `Pointer.offsetBy` was removed, use `cast` and
`elementAt` instead.
- Faster memory load and stores.
- The dartanalyzer (commandline and IDEs) now reports `dart:ffi` static errors.
- Callbacks are now supported in AOT (ahead-of-time) compiled code.
### Dart for the Web
#### Dart Dev Compiler (DDC)
- Kernel DDC will no longer accept non-dill files as summary inputs.
- Removed support for the deprecated web extension.
### Tools
#### Linter
The Linter was updated to `0.1.101`, which includes:
- fixed `diagnostic_describe_all_properties` to flag properties in
`Diagnosticable`s with no debug methods defined
- fixed `noSuchMethod` exception in `camel_case_extensions` when analyzing
unnamed extensions
- fixed `avoid_print` to catch tear-off usage
- new lint: `avoid_web_libraries_in_flutter` (experimental)
- (internal) prepare `unnecessary_lambdas` for coming `MethodInvocation` vs.
`FunctionExpressionInvocation` changes
## 2.5.2 - 2019-10-08
This is a patch release with properly signed binaries required for macOS
Catalina (Issue [38765][]).
[38765]: https://github.com/dart-lang/sdk/issues/38765
## 2.5.1 - 2019-09-27
This is a patch release that prevents type inference failures in the analyzer
(Issue [38365][]).
[38365]: https://github.com/dart-lang/sdk/issues/38365
## 2.5.0 - 2019-09-10
### Language
The set of operations allowed in constant expressions has been expanded as
described in the
[constant update proposal](https://github.com/dart-lang/language/issues/61). The
control flow and spread collection features shipped in Dart 2.3 are now also
supported in constants as
[described in the specification here](https://github.com/dart-lang/language/blob/master/accepted/2.3/unified-collections/feature-specification.md#constant-semantics).
Specifically, it is now valid to use the following operations in constant
expressions under the appropriate conditions:
- Casts (`e as T`) and type tests (`e is T`).
- Comparisons to `null`, even for types which override the `==` operator.
- The `&`, `|`, and `^` binary operators on booleans.
- The spread operators (`...` and `...?`).
- An `if` element in a collection literal.
```dart
// Example: these are now valid constants.
const Object i = 3;
const list = [i as int];
const set = {if (list is List<int>) ...list};
const map = {if (i is int) i : "int"};
```
In addition, the semantics of constant evaluation has been changed as follows:
- The `&&` operator only evaluates its second operand if the first evaluates to
true.
- The `||` operator only evaluates its second operand if the first evaluates to
false.
- The `??` operator only evaluates its second operand if the first evaluates to
null.
- The conditional operator (`e ? e1 : e2`) only evaluates one of the two
branches, depending on the value of the first operand.
```dart
// Example: x is now a valid constant definition.
const String s = null;
const int x = (s == null) ? 0 : s.length;
```
### Core libraries
- **Breaking change** [#36900](https://github.com/dart-lang/sdk/issues/36900):
The following methods and properties across various core libraries, which used
to declare a return type of `List<int>`, were updated to declare a return type
of `Uint8List`:
- `BytesBuilder.takeBytes()`
- `BytesBuilder.toBytes()`
- `Datagram.data`
- `File.readAsBytes()` (`Future<Uint8List>`)
- `File.readAsBytesSync()`
- `InternetAddress.rawAddress`
- `RandomAccessFile.read()` (`Future<Uint8List>`)
- `RandomAccessFile.readSync()`
- `RawSocket.read()`
- `Utf8Codec.encode()` (and `Utf8Encoder.convert()`)
In addition, the following classes were updated to implement
`Stream<Uint8List>` rather than `Stream<List<int>>`:
- `HttpRequest`
- `Socket`
**Possible errors and how to fix them**
- > The argument type 'Utf8Decoder' can't be assigned to the parameter type
> 'StreamTransformer<Uint8List, dynamic>'
> type 'Utf8Decoder' is not a subtype of type 'StreamTransformer' of
> 'streamTransformer'"
You can fix these call sites by updating your code to use
`StreamTransformer.bind()` instead of `Stream.transform()`, like so:
_Before:_ `stream.transform(utf8.decoder)` _After:_
`utf8.decoder.bind(stream)`
- > The argument type 'IOSink' can't be assigned to the parameter type
> 'StreamConsumer<Uint8List>'
> type '\_IOSinkImpl' is not a subtype of type 'StreamConsumer<Uint8List>'
> of 'streamConsumer'
You can fix these call sites by casting your stream instance to a
`Stream<List<int>>` before calling `.pipe()` on the stream, like so:
_Before:_ `stream.pipe(consumer)` _After:_
`stream.cast<List<int>>().pipe(consumer)`
Finally, the following typed lists were updated to have their `sublist()`
methods declare a return type that is the same as the source list:
- `Int8List.sublist()` → `Int8List`
- `Int16List.sublist()` → `Int16List`
- `Int32List.sublist()` → `Int32List`
- `Int64List.sublist()` → `Int64List`
- `Int32x4List.sublist()` → `Int32x4List`
- `Float32List.sublist()` → `Float32List`
- `Float64List.sublist()` → `Float64List`
- `Float32x4List.sublist()` → `Float32x4List`
- `Float64x2List.sublist()` → `Float64x2List`
- `Uint8List.sublist()` → `Uint8List`
- `Uint8ClampedList.sublist()` → `Uint8ClampedList`
- `Uint16List.sublist()` → `Uint16List`
- `Uint32List.sublist()` → `Uint32List`
- `Uint64List.sublist()` → `Uint64List`
#### `dart:async`
- Add `value` and `error` constructors on `Stream` to allow easily creating
single-value or single-error streams.
#### `dart:core`
- Update `Uri` class to support [RFC6874](https://tools.ietf.org/html/rfc6874):
"%25" or "%" can be appended to the end of a valid IPv6 representing a Zone
Identifier. A valid zone ID consists of unreversed character or Percent
encoded octet, which was defined in RFC3986. IPv6addrz = IPv6address "%25"
ZoneID
[29456]: https://github.com/dart-lang/sdk/issues/29456
#### `dart:io`
- **Breaking change** [#37192](https://github.com/dart-lang/sdk/issues/37192):
The `Cookie` class's constructor's `name` and `value` optional positional
parameters are now mandatory. The signature changes from:
Cookie([String name, String value])
to
Cookie(String name, String value)
However, it has not been possible to set `name` and `value` to null since Dart
1.3.0 (2014) where a bug made it impossible. Any code not using both
parameters or setting any to null would necessarily get a noSuchMethod
exception at runtime. This change catches such erroneous uses at compile time.
Since code could not previously correctly omit the parameters, this is not
really a breaking change.
- **Breaking change** [#37192](https://github.com/dart-lang/sdk/issues/37192):
The `Cookie` class's `name` and `value` setters now validates that the strings
are made from the allowed character set and are not null. The constructor
already made these checks and this fixes the loophole where the setters didn't
also validate.
### Dart VM
### Tools
#### Pub
- Clean-up invalid git repositories in cache when fetching from git.
- **Breaking change** [#36765](https://github.com/dart-lang/sdk/issues/36765):
Packages published to [pub.dev](https://pub.dev) can no longer contain git
dependencies. These packages will be rejected by the server.
#### Linter
The Linter was updated to `0.1.96`, which includes:
- fixed false positives in `unnecessary_parens`
- various changes to migrate to preferred analyzer APIs
- rule test fixes
#### Dartdoc
Dartdoc was updated to `0.28.4`; this version includes several fixes and is
based on a newer version of the analyzer package.
## 2.4.1 - 2019-08-07
This is a patch release that fixes a performance regression in JIT mode, as well
as a potential crash of our AOT compiler.
### Dart VM
- Fixed a performance regression where usage of `Int32List` could trigger
repeated deoptimizations in JIT mode (Issue [37551][]).
- Fixed a bug where usage of a static getter with name `length` could cause a
crash in our AOT compiler (Issue [35121][]).
[37551]: https://github.com/dart-lang/sdk/issues/37551
[35121]: https://github.com/dart-lang/sdk/issues/35121
### Dart Dev Compiler (DDC)
Callbacks passed to JS and wrapped with `allowInterop` or
`allowInteropCaptureThis` are now strict about argument counts and argument
types. This may mean that tests which were previously passing and relying on
loose argument checking (too many or too few arguments, or arguments with too
specific types like `List<Something>` instead of `List<dynamic>`) may start
failing. This changes makes DDC behave more like dart2js with the default flags.
## 2.4.0 - 2019-06-27
### Core libraries
#### `dart:isolate`
- `TransferableTypedData` class was added to facilitate faster cross-isolate
communication of `Uint8List` data.
- **Breaking change**: `Isolate.resolvePackageUri` will always throw an
`UnsupportedError` when compiled with dart2js or DDC. This was the only
remaining API in `dart:isolate` that didn't automatically throw since we
dropped support for this library in [Dart 2.0.0][1]. Note that the API already
throws in dart2js if the API is used directly without manually setting up a
`defaultPackagesBase` hook.
[1]: https://github.com/dart-lang/sdk/blob/main/CHANGELOG.md#200---2018-08-07
#### `dart:developer`
- Exposed `result`, `errorCode` and `errorDetail` getters in
`ServiceExtensionResponse` to allow for better debugging of VM service
extension RPC results.
#### `dart:io`
- Fixed `Cookie` class interoperability with certain websites by allowing the
cookie values to be the empty string (Issue [35804][]) and not stripping
double quotes from the value (Issue [33327][]) in accordance with RFC 6265.
[33327]: https://github.com/dart-lang/sdk/issues/33327
[35804]: https://github.com/dart-lang/sdk/issues/35804
- [#36971](https://github.com/dart-lang/sdk/issues/36971): The
`HttpClientResponse` interface has been extended with the addition of a new
`compressionState` getter, which specifies whether the body of a response was
compressed when it was received and whether it has been automatically
uncompressed via `HttpClient.autoUncompress`.
As part of this change, a corresponding new enum was added to `dart:io`:
`HttpClientResponseCompressionState`.
This is a **breaking change** for those implementing the `HttpClientResponse`
interface as subclasses will need to implement the new getter.
#### `dart:async`
- **Breaking change** [#36382](https://github.com/dart-lang/sdk/issues/36382):
The `await for` allowed `null` as a stream due to a bug in `StreamIterator`
class. This bug has now been fixed.
#### `dart:core`
- [#36171](https://github.com/dart-lang/sdk/issues/36171): The `RegExp`
interface has been extended with two new constructor named parameters:
- `unicode:` (`bool`, default: `false`), for Unicode patterns
- `dotAll:` (`bool`, default: `false`), to change the matching behavior of '.'
to also match line terminating characters.
Appropriate properties for these named parameters have also been added so
their use can be detected after construction.
In addition, `RegExp` methods that originally returned `Match` objects now
return a more specific subtype, `RegExpMatch`, which adds two features:
- `Iterable<String> groupNames`, a property that contains the names of all
named capture groups
- `String namedGroup(String name)`, a method that retrieves the match for the
given named capture group
This is a **breaking change** for implementers of the `RegExp` interface.
Subclasses will need to add the new properties and may have to update the
return types on overridden methods.
### Language
- **Breaking change** [#35097](https://github.com/dart-lang/sdk/issues/35097):
Covariance of type variables used in super-interfaces is now enforced. For
example, the following code was previously accepted and will now be rejected:
```dart
class A<X> {};
class B<X> extends A<void Function(X)> {};
```
- The identifier `async` can now be used in asynchronous and generator
functions.
### Dart for the Web
#### Dart Dev Compiler (DDC)
- Improve `NoSuchMethod` errors for failing dynamic calls. Now they include
specific information about the nature of the error such as:
- Attempting to call a null value.
- Calling an object instance with a null `call()` method.
- Passing too few or too many arguments.
- Passing incorrect named arguments.
- Passing too few or too many type arguments.
- Passing type arguments to a non-generic method.
### Tools
#### Linter
The Linter was updated to `0.1.91`, which includes the following changes:
- Fixed missed cases in `prefer_const_constructors`
- Fixed `prefer_initializing_formals` to no longer suggest API breaking changes
- Updated `omit_local_variable_types` to allow explicit `dynamic`s
- Fixed null-reference in `unrelated_type_equality_checks`
- New lint: `unsafe_html`
- Broadened `prefer_null_aware_operators` to work beyond local variables.
- Added `prefer_if_null_operators`.
- Fixed `prefer_contains` false positives.
- Fixed `unnecessary_parenthesis` false positives.
- Fixed `prefer_asserts_in_initializer_lists` false positives
- Fixed `curly_braces_in_flow_control_structures` to handle more cases
- New lint: `prefer_double_quotes`
- New lint: `sort_child_properties_last`
- Fixed `type_annotate_public_apis` false positive for `static const`
initializers
#### Pub
- `pub publish` will no longer warn about missing dependencies for import
statements in `example/`.
- OAuth2 authentication will explicitly ask for the `openid` scope.
## 2.3.2 - 2019-06-11
This is a patch version release with a security improvement.
### Security vulnerability
- **Security improvement:** On Linux and Android, starting a process with
`Process.run`, `Process.runSync`, or `Process.start` would first search the
current directory before searching `PATH` (Issue [37101][]). This behavior
effectively put the current working directory in the front of `PATH`, even if
it wasn't in the `PATH`. This release changes that behavior to only searching
the directories in the `PATH` environment variable. Operating systems other
than Linux and Android didn't have this behavior and aren't affected by this
vulnerability.
This vulnerability could result in execution of untrusted code if a command
without a slash in its name was run inside an untrusted directory containing
an executable file with that name:
```dart
Process.run("ls", workingDirectory: "/untrusted/directory")
```
This would attempt to run `/untrusted/directory/ls` if it existed, even though
it is not in the `PATH`. It was always safe to instead use an absolute path or
a path containing a slash.
This vulnerability was introduced in Dart 2.0.0.
[37101]: https://github.com/dart-lang/sdk/issues/37101
## 2.3.1 - 2019-05-21
This is a patch version release with bug fixes.
### Tools
#### dart2js
- Fixed a bug that caused the compiler to crash when it compiled UI-as-code
features within fields (Issue [36864][]).
[36864]: https://github.com/dart-lang/sdk/issues/36864
## 2.3.0 - 2019-05-08
The focus in this release is on the new "UI-as-code" language features which
make collections more expressive and declarative.
### Language
Flutter is growing rapidly, which means many Dart users are building UI in code
out of big deeply-nested expressions. Our goal with 2.3.0 was to [make that kind
of code easier to write and maintain][ui-as-code]. Collection literals are a
large component, so we focused on three features to make collections more
powerful. We'll use list literals in the examples below, but these features also
work in map and set literals.
[ui-as-code]:
https://medium.com/dartlang/making-dart-a-better-language-for-ui-f1ccaf9f546c
#### Spread
Placing `...` before an expression inside a collection literal unpacks the
result of the expression and inserts its elements directly inside the new
collection. Where before you had to write something like this:
```dart
CupertinoPageScaffold(
child: ListView(children: [
Tab2Header()
]..addAll(buildTab2Conversation())
..add(buildFooter())),
);
```
Now you can write this:
```dart
CupertinoPageScaffold(
child: ListView(children: [
Tab2Header(),
...buildTab2Conversation(),
buildFooter()
]),
);
```
If you know the expression might evaluate to null and you want to treat that as
equivalent to zero elements, you can use the null-aware spread `...?`.
#### Collection if
Sometimes you might want to include one or more elements in a collection only
under certain conditions. If you're lucky, you can use a `?:` operator to
selectively swap out a single element, but if you want to exchange more than one
or omit elements, you are forced to write imperative code like this:
```dart
Widget build(BuildContext context) {
var children = [
IconButton(icon: Icon(Icons.menu)),
Expanded(child: title)
];
if (isAndroid) {
children.add(IconButton(icon: Icon(Icons.search)));
}
return Row(children: children);
}
```
We now allow `if` inside collection literals to conditionally omit or (with
`else`) swap out an element:
```dart
Widget build(BuildContext context) {
return Row(
children: [
IconButton(icon: Icon(Icons.menu)),
Expanded(child: title),
if (isAndroid)
IconButton(icon: Icon(Icons.search)),
],
);
}
```
Unlike the existing `?:` operator, a collection `if` can be composed with
spreads to conditionally include or omit multiple items:
```dart
Widget build(BuildContext context) {
return Row(
children: [
IconButton(icon: Icon(Icons.menu)),
if (isAndroid) ...[
Expanded(child: title),
IconButton(icon: Icon(Icons.search)),
]
],
);
}
```
#### Collection for
In many cases, the higher-order methods on Iterable give you a declarative way
to modify a collection in the context of a single expression. But some
operations, especially involving both transforming and filtering, can be
cumbersome to express in a functional style.
To solve this problem, you can use `for` inside a collection literal. Each
iteration of the loop produces an element which is then inserted in the
resulting collection. Consider the following code:
```dart
var command = [
engineDartPath,
frontendServer,
...fileSystemRoots.map((root) => "--filesystem-root=$root"),
...entryPoints
.where((entryPoint) => fileExists("lib/$entryPoint.json"))
.map((entryPoint) => "lib/$entryPoint"),
mainPath
];
```
With a collection `for`, the code becomes simpler:
```dart
var command = [
engineDartPath,
frontendServer,
for (var root in fileSystemRoots) "--filesystem-root=$root",
for (var entryPoint in entryPoints)
if (fileExists("lib/$entryPoint.json")) "lib/$entryPoint",
mainPath
];
```
As you can see, all three of these features can be freely composed. For full
details of the changes, see [the official proposal][ui-as-code proposal].
[ui-as-code proposal]:
https://github.com/dart-lang/language/blob/master/accepted/future-releases/unified-collections/feature-specification.md
**Note: These features are not currently supported in _const_ collection
literals. In a future release, we intend to relax this restriction and allow
spread and collection `if` inside const collections.**
### Core library changes
#### `dart:isolate`
- Added `debugName` property to `Isolate`.
- Added `debugName` optional parameter to `Isolate.spawn` and
`Isolate.spawnUri`.
#### `dart:core`
- RegExp patterns can now use lookbehind assertions.
- RegExp patterns can now use named capture groups and named backreferences.
Currently, named group matches can only be retrieved in Dart either by the
implicit index of the named group or by downcasting the returned Match object
to the type RegExpMatch. The RegExpMatch interface contains methods for
retrieving the available group names and retrieving a match by group name.
### Dart VM
- The VM service now requires an authentication code by default. This behavior
can be disabled by providing the `--disable-service-auth-codes` flag.
- Support for deprecated flags '-c' and '--checked' has been removed.
### Dart for the Web
#### dart2js
A binary format was added to dump-info. The old JSON format is still available
and provided by default, but we are starting to deprecate it. The new binary
format is more compact and cheaper to generate. On some large apps we tested, it
was 4x faster to serialize and used 6x less memory.
To use the binary format today, use `--dump-info=binary`, instead of
`--dump-info`.
What to expect next?
- The [visualizer tool][visualizer] will not be updated to support the new
binary format, but you can find several command-line tools at
`package:dart2js_info` that provide similar features to those in the
visualizer.
- The command-line tools in `package:dart2js_info` also work with the old JSON
format, so you can start using them even before you enable the new format.
- In a future release `--dump-info` will default to `--dump-info=binary`. At
that point, there will be an option to fallback to the JSON format, but the
visualizer tool will be deprecated.
- A release after that, the JSON format will no longer be available from
dart2js, but may be available from a command-line tool in
`package:dart2js_info`.
[visualizer]: https://dart-lang.github.io/dump-info-visualizer/
### Tools
#### dartfmt
- Tweak set literal formatting to follow other collection literals.
- Add support for "UI as code" features.
- Properly format trailing commas in assertions.
- Improve indentation of adjacent strings in argument lists.
#### Linter
The Linter was updated to `0.1.86`, which includes the following changes:
- Added the following lints: `prefer_inlined_adds`,
`prefer_for_elements_to_map_fromIterable`,
`prefer_if_elements_to_conditional_expressions`,
`diagnostic_describe_all_properties`.
- Updated `file_names` to skip prefixed-extension Dart files (`.css.dart`,
`.g.dart`, etc.).
- Fixed false positives in `unnecessary_parenthesis`.
#### Pub
- Added a CHANGELOG validator that complains if you `pub publish` without
mentioning the current version.
- Removed validation of library names when doing `pub publish`.
- Added support for `pub global activate`ing package from a custom pub URL.
- Added subcommand: `pub logout`. Logs you out of the current session.
#### Dart native
Initial support for compiling Dart apps to native machine code has been added.
Two new tools have been added to the `bin` folder of the Dart SDK:
- `dart2aot`: AOT (ahead-of-time) compiles a Dart program to native machine
code. The tool is supported on Windows, macOS, and Linux.
- `dartaotruntime`: A small runtime used for executing an AOT compiled program.
## 2.2.0 - 2019-02-26
### Language
Sets now have a literal syntax like lists and maps do:
```dart
var set = {1, 2, 3};
```
Using curly braces makes empty sets ambiguous with maps:
```dart
var collection = {}; // Empty set or map?
```
To avoid breaking existing code, an ambiguous literal is treated as a map. To
create an empty set, you can rely on either a surrounding context type or an
explicit type argument:
```dart
// Variable type forces this to be a set:
Set<int> set = {};
// A single type argument means this must be a set:
var set2 = <int>{};
```
Set literals are released on all platforms. The `set-literals` experiment flag
has been disabled.
### Tools
#### Analyzer
- The `DEPRECATED_MEMBER_USE` hint was split into two hints:
- `DEPRECATED_MEMBER_USE` reports on usage of `@deprecated` members declared
in a different package.
- `DEPRECATED_MEMBER_USE_FROM_SAME_PACKAGE` reports on usage of `@deprecated`
members declared in the same package.
#### Linter
Upgraded the linter to `0.1.82` which adds the following improvements:
- Added `provide_deprecation_message`, and
`use_full_hex_values_for_flutter_colors`, `prefer_null_aware_operators`.
- Fixed `prefer_const_declarations` set literal false-positives.
- Updated `prefer_collection_literals` to support set literals.
- Updated `unnecessary_parenthesis` play nicer with cascades.
- Removed deprecated lints from the "all options" sample.
- Stopped registering "default lints".
- Fixed `hash_and_equals` to respect `hashCode` fields.
### Other libraries
#### `package:kernel`
- **Breaking change:** The `klass` getter on the `InstanceConstant` class in the
Kernel AST API has been renamed to `classNode` for consistency.
- **Breaking change:** Updated `Link` implementation to utilize true symbolic
links instead of junctions on Windows. Existing junctions will continue to
work with the new `Link` implementation, but all new links will create
symbolic links.
To create a symbolic link, Dart must be run with administrative privileges or
Developer Mode must be enabled, otherwise a `FileSystemException` will be
raised with errno set to `ERROR_PRIVILEGE_NOT_HELD` (Issue [33966]).
[33966]: https://github.com/dart-lang/sdk/issues/33966
## 2.1.1 - 2019-02-18
This is a patch version release. Again, the team's focus was mostly on improving
performance and stability after the large changes in Dart 2.0.0. In particular,
dart2js now always uses the "fast startup" emitter and the old emitter has been
removed.
There are a couple of very minor **breaking changes:**
- In `dart:io`, adding to a closed `IOSink` now throws a `StateError`.
- On the Dart VM, a soundness hole when using `dart:mirrors` to reflectively
invoke a method in an incorrect way that violates its static types has been
fixed (Issue [35611][]).
### Language
This release has no language changes.
### Core library
#### `dart:core`
- Made `DateTime.parse()` also recognize `,` as a valid decimal separator when
parsing from a string (Issue [35576][]).
[35576]: https://github.com/dart-lang/sdk/issues/35576
#### `dart:html`
- Added methods `Element.removeAttribute`, `Element.removeAttributeNS`,
`Element.hasAttribute` and `Element.hasAttributeNS`. (Issue [35655][]).
- Improved dart2js compilation of `element.attributes.remove(name)` to generate
`element.removeAttribute(name)`, so that there is no performance reason to
migrate to the above methods.
- Fixed a number of `dart:html` bugs:
- Fixed HTML API's with callback typedef to correctly convert Dart functions
to JS functions (Issue [35484]).
- HttpStatus constants exposed in `dart:html` (Issue [34318]).
- Expose DomName `ondblclick` and `dblclickEvent` for Angular analyzer.
- Fixed `removeAll` on `classes`; `elements` parameter should be
`Iterable<Object>` to match Set's `removeAll` not `Iterable<E>` (Issue
[30278]).
- Fixed a number of methods on DataTransferItem, Entry, FileEntry and
DirectoryEntry which previously returned NativeJavaScriptObject. This fixes
handling drag/drop of files/directories (Issue [35510]).
- Added ability to allow local file access from Chrome browser in ddb.
[35655]: https://github.com/dart-lang/sdk/issues/35655
[30278]: https://github.com/dart-lang/sdk/issues/30278
[34318]: https://github.com/dart-lang/sdk/issues/34318
[35484]: https://github.com/dart-lang/sdk/issues/35484
[35510]: https://github.com/dart-lang/sdk/issues/35510
#### `dart:io`
- **Breaking change:** Adding to a closed `IOSink` now throws a `StateError`.
- Added ability to get and set low level socket options.
[29554]: https://github.com/dart-lang/sdk/issues/29554
### Dart VM
In previous releases it was possible to violate static types using
`dart:mirrors`. This code would run without any TypeErrors and print
"impossible" output:
```dart
import 'dart:mirrors';
class A {
void method(int v) {
if (v != null && v is! int) {
print("This should be impossible: expected null or int got ${v}");
}
}
}
void main() {
final obj = A();
reflect(obj).invoke(#method, ['not-an-number']);
}
```
This bug is fixed now. Only code that already violates static typing will break.
See Issue [35611][] for more details.
[35611]: https://github.com/dart-lang/sdk/issues/35611
### Dart for the Web
#### dart2js
- The old "full emitter" back-end is removed and dart2js always uses the "fast
startup" back-end. The generated fast startup code is optimized to load
faster, even though it can be slightly larger. The `--fast-startup` and
`--no-fast-startup` are allowed but ignored. They will be removed in a future
version.
- We fixed a bug in how deferred constructor calls were incorrectly not marked
as deferred. The old behavior didn't cause breakages, but was imprecise and
pushed more code to the main output unit.
- A new deferred split algorithm implementation was added.
This implementation fixes a soundness bug and addresses performance issues of
the previous implementation, because of that it can have a visible impact on
apps. In particular:
- We fixed a performance issue which was introduced when we migrated to the
common front-end. On large apps, the fix can cut 2/3 of the time spent on
this task.
- We fixed a bug in how inferred types were categorized (Issue [35311][]). The
old behavior was unsound and could produce broken programs. The fix may
cause more code to be pulled into the main output unit.
This shows up frequently when returning deferred values from closures since
the closure's inferred return type is the deferred type. For example, if you
have:
```dart
() async {
await deferred_prefix.loadLibrary();
return new deferred_prefix.Foo();
}
```
The closure's return type is `Future<Foo>`. The old implementation defers
`Foo`, and incorrectly makes the return type `Future<dynamic>`. This may
break in places where the correct type is expected.
The new implementation will not defer `Foo`, and will place it in the main
output unit. If your intent is to defer it, then you need to ensure the
return type is not inferred to be `Foo`. For example, you can do so by
changing the code to a named closure with a declared type, or by ensuring
that the return expression has the type you want, like:
```dart
() async {
await deferred_prefix.loadLibrary();
return new deferred_prefix.Foo() as dynamic;
}
```
Because the new implementation might require you to inspect and fix your
app, we exposed two temporary flags:
- The `--report-invalid-deferred-types` causes dart2js to run both the old and
new algorithms and report any cases where an invalid type was detected.
- The `--new-deferred-split` flag enables this new algorithm.
- The `--categories=*` flag is being replaced. `--categories=all` was only used
for testing and it is no longer supported. `--categories=Server` continues to
work at this time but it is deprecated, please use `--server-mode` instead.
- The `--library-root` flag was replaced by `--libraries-spec`. This flag is
rarely used by developers invoking dart2js directly. It's important for
integrating dart2js with build systems. See `--help` for more details on the
new flag.
[35311]: https://github.com/dart-lang/sdk/issues/35311
### Tools
#### Analyzer
- Support for `declarations-casts` has been removed and the `implicit-casts`
option now has the combined semantics of both options. This means that users
that disable `implicit-casts` might now see errors that were not previously
being reported.
- New hints added:
- `NON_CONST_CALL_TO_LITERAL_CONSTRUCTOR` and
`NON_CONST_CALL_TO_LITERAL_CONSTRUCTOR_USING_NEW` inform you when a
`@literal` const constructor is called in a non-const context (or with
`new`).
- `INVALID_LITERAL_ANNOTATION` reports when something other than a const
constructor is annotated with `@literal`.
- `SUBTYPE_OF_SEALED_CLASS` reports when any class or mixin subclasses
(extends, implements, mixes in, or constrains to) a `@sealed` class, and the
two are declared in different packages.
- `MIXIN_ON_SEALED_CLASS` reports when a `@sealed` class is used as a
superclass constraint of a mixin.
#### dartdoc
Default styles now work much better on mobile. Simple browsing and searching of
API docs now work in many cases.
Upgraded the linter to `0.1.78` which adds the following improvements:
- Added `prefer_final_in_for_each`, `unnecessary_await_in_return`,
`use_function_type_syntax_for_parameters`, `avoid_returning_null_for_future`,
and `avoid_shadowing_type_parameters`.
- Updated `invariant_booleans` status to experimental.
- Fixed `type_annotate_public_apis` false positives on local functions.
- Fixed `avoid_shadowing_type_parameters` to report shadowed type parameters in
generic typedefs.
- Fixed `use_setters_to_change_properties` to not wrongly lint overriding
methods.
- Fixed `cascade_invocations` to not lint awaited targets.
- Fixed `prefer_conditional_assignment` false positives.
- Fixed `join_return_with_assignment` false positives.
- Fixed `cascade_invocations` false positives.
- Deprecated `prefer_bool_in_asserts` as it is redundant in Dart 2.
## 2.1.0 - 2018-11-15
This is a minor version release. The team's focus was mostly on improving
performance and stability after the large changes in Dart 2.0.0. Notable
changes:
- We've introduced a dedicated syntax for declaring a mixin. Instead of the
`class` keyword, it uses `mixin`:
```dart
mixin SetMixin<E> implements Set<E> {
...
}
```
The new syntax also enables `super` calls inside mixins.
- Integer literals now work in double contexts. When passing a literal number to
a function that expects a `double`, you no longer need an explicit `.0` at the
end of the number. In releases before 2.1, you need code like this when
setting a double like `fontSize`:
```dart
TextStyle(fontSize: 18.0)
```
Now you can remove the `.0`:
```dart
TextStyle(fontSize: 18)
```
In releases before 2.1, `fontSize : 18` causes a static error. This was a
common mistake and source of friction.
- **Breaking change:** A number of static errors that should have been detected
and reported were not supported in 2.0.0. These are reported now, which means
existing incorrect code may show new errors.
- `dart:core` now exports `Future` and `Stream`. You no longer need to import
`dart:async` to use those very common types.
### Language
- Introduced a new syntax for mixin declarations.
```dart
mixin SetMixin<E> implements Set<E> {
...
}
```
Most classes that are intended to be used as mixins are intended to _only_ be
used as mixins. The library author doesn't want users to be able to construct
or subclass the class. The new syntax makes that intent clear and enforces it
in the type system. It is an error to extend or construct a type declared
using `mixin`. (You can implement it since mixins expose an implicit
interface.)
Over time, we expect most mixin declarations to use the new syntax. However,
if you have a "mixin" class where users _are_ extending or constructing it,
note that moving it to the new syntax is a breaking API change since it
prevents users from doing that. If you have a type like this that is a mixin
as well as being a concrete class and/or superclass, then the existing syntax
is what you want.
If you need to use a `super` inside a mixin, the new syntax is required. This
was previously only allowed with the experimental `--supermixins` flag because
it has some complex interactions with the type system. The new syntax
addresses those issues and lets you use `super` calls by declaring the
superclass constraint your mixin requires:
```dart
class Superclass {
superclassMethod() {
print("in superclass");
}
}
mixin SomeMixin on Superclass {
mixinMethod() {
// This is OK:
super.superclassMethod();
}
}
class GoodSub extends Superclass with SomeMixin {}
class BadSub extends Object with SomeMixin {}
// Error: Since the super() call in mixinMethod() can't find a
// superclassMethod() to call, this is prohibited.
```
Even if you don't need to use `super` calls, the new mixin syntax is good
because it clearly expresses that you intend the type to be mixed in.
- Allow integer literals to be used in double contexts. An integer literal used
in a place where a double is required is now interpreted as a double value.
The numerical value of the literal needs to be precisely representable as a
double value.
- Integer literals compiled to JavaScript are now allowed to have any value that
can be exactly represented as a JavaScript `Number`. They were previously
limited to such numbers that were also representable as signed 64-bit
integers.
**(Breaking)** A number of static errors that should have been detected and
reported were not supported in 2.0.0. These are reported now, which means
existing incorrect code may show new errors:
- **Setters with the same name as the enclosing class aren't allowed.** (Issue
[34225][].) It is not allowed to have a class member with the same name as the
enclosing class:
```dart
class A {
set A(int x) {}
}
```
Dart 2.0.0 incorrectly allows this for setters (only). Dart 2.1.0 rejects it.
_To fix:_ This is unlikely to break anything, since it violates all style
guides anyway.
- **Constant constructors cannot redirect to non-constant constructors.** (Issue
[34161][].) It is not allowed to have a constant constructor that redirects to
a non-constant constructor:
```dart
class A {
const A.foo() : this(); // Redirecting to A()
A() {}
}
```
Dart 2.0.0 incorrectly allows this. Dart 2.1.0 rejects it.
_To fix:_ Make the target of the redirection a properly const constructor.
- **Abstract methods may not unsoundly override a concrete method.** (Issue
[32014][].) Concrete methods must be valid implementations of their
interfaces:
```dart
class A {
num get thing => 2.0;
}
abstract class B implements A {
int get thing;
}
class C extends A with B {}
// 'thing' from 'A' is not a valid override of 'thing' from 'B'.
main() {
print(new C().thing.isEven); // Expects an int but gets a double.
}
```
Dart 2.0.0 allows unsound overrides like the above in some cases. Dart 2.1.0
rejects them.
_To fix:_ Relax the type of the invalid override, or tighten the type of the
overridden method.
- **Classes can't implement FutureOr.** (Issue [33744][].) Dart doesn't allow
classes to implement the FutureOr type:
```dart
class A implements FutureOr<Object> {}
```
Dart 2.0.0 allows classes to implement FutureOr. Dart 2.1.0 does not.
_To fix:_ Don't do this.
- **Type arguments to generic typedefs must satisfy their bounds.** (Issue
[33308][].) If a parameterized typedef specifies a bound, actual arguments
must be checked against it:
```dart
class A<X extends int> {}
typedef F<Y extends int> = A<Y> Function();
F<num> f = null;
```
Dart 2.0.0 allows bounds violations like `F<num>` above. Dart 2.1.0 rejects
them.
_To fix:_ Either remove the bound on the typedef parameter, or pass a valid
argument to the typedef.
- **Constructor invocations must use valid syntax, even with optional `new`.**
(Issue [34403][].) Type arguments to generic named constructors go after the
class name, not the constructor name, even when used without an explicit
`new`:
```dart
class A<T> {
A.foo() {}
}
main() {
A.foo<String>(); // Incorrect syntax, was accepted in 2.0.0.
A<String>.foo(); // Correct syntax.
}
```
Dart 2.0.0 accepts the incorrect syntax when the `new` keyword is left out.
Dart 2.1.0 correctly rejects this code.
_To fix:_ Move the type argument to the correct position after the class name.
- **Instance members should shadow prefixes.** (Issue [34498][].) If the same
name is used as an import prefix and as a class member name, then the class
member name takes precedence in the class scope.
```dart
import 'dart:core';
import 'dart:core' as core;
class A {
core.List get core => null; // "core" refers to field, not prefix.
}
```
Dart 2.0.0 incorrectly resolves the use of `core` in `core.List` to the prefix
name. Dart 2.1.0 correctly resolves this to the field name.
_To fix:_ Change the prefix name to something which does not clash with the
instance member.
- **Implicit type arguments in extends clauses must satisfy the class bounds.**
(Issue [34532][].) Implicit type arguments for generic classes are computed if
not passed explicitly, but when used in an `extends` clause they must be
checked for validity:
```dart
class Foo<T> {}
class Bar<T extends Foo<T>> {}
class Baz extends Bar {} // Should error because Bar completes to Bar<Foo>
```
Dart 2.0.0 accepts the broken code above. Dart 2.1.0 rejects it.
_To fix:_ Provide explicit type arguments to the superclass that satisfy the
bound for the superclass.
- **Mixins must correctly override their superclasses.** (Issue [34235][].) In
some rare cases, combinations of uses of mixins could result in invalid
overrides not being caught:
```dart
class A {
num get thing => 2.0;
}
class M1 {
int get thing => 2;
}
class B = A with M1;
class M2 {
num get thing => 2.0;
}
class C extends B with M2 {} // 'thing' from 'M2' not a valid override.
main() {
M1 a = new C();
print(a.thing.isEven); // Expects an int but gets a double.
}
```
Dart 2.0.0 accepts the above example. Dart 2.1.0 rejects it.
_To fix:_ Ensure that overriding methods are correct overrides of their
superclasses, either by relaxing the superclass type, or tightening the
subclass/mixin type.
[32014]: https://github.com/dart-lang/sdk/issues/32014
[33308]: https://github.com/dart-lang/sdk/issues/33308
[33744]: https://github.com/dart-lang/sdk/issues/33744
[34161]: https://github.com/dart-lang/sdk/issues/34161
[34225]: https://github.com/dart-lang/sdk/issues/34225
[34235]: https://github.com/dart-lang/sdk/issues/34235
[34403]: https://github.com/dart-lang/sdk/issues/34403
[34498]: https://github.com/dart-lang/sdk/issues/34498
[34532]: https://github.com/dart-lang/sdk/issues/34532
### Core libraries
#### `dart:async`
- Fixed a bug where calling `stream.take(0).drain(value)` would not correctly
forward the `value` through the returned `Future`.
- Added a `StreamTransformer.fromBind` constructor.
- Updated `Stream.fromIterable` to send a done event after the error when the
iterator's `moveNext` throws, and handle if the `current` getter throws (issue
[33431][]).
[33431]: http://dartbug.com/33431
#### `dart:core`
- Added `HashMap.fromEntries` and `LinkedHashmap.fromEntries` constructors.
- Added `ArgumentError.checkNotNull` utility method.
- Made `Uri` parsing more permissive about `[` and `]` occurring in the path,
query or fragment, and `#` occurring in fragment.
- Exported `Future` and `Stream` from `dart:core`.
- Added operators `&`, `|` and `^` to `bool`.
- Added missing methods to `UnmodifiableMapMixin`. Some maps intended to be
unmodifiable incorrectly allowed new methods added in Dart 2 to succeed.
- Deprecated the `provisional` annotation and the `Provisional` annotation
class. These should have been removed before releasing Dart 2.0, and they have
no effect.
#### `dart:html`
Fixed Service Workers and any Promise/Future API with a Dictionary parameter.
APIs in dart:html (that take a Dictionary) will receive a Dart Map parameter.
The Map parameter must be converted to a Dictionary before passing to the
browser's API. Before this change, any Promise/Future API with a Map/Dictionary
parameter never called the Promise and didn't return a Dart Future - now it
does.
This caused a number of breaks especially in Service Workers (register, etc.).
Here is a complete list of the fixed APIs:
- BackgroundFetchManager
- `Future<BackgroundFetchRegistration> fetch(String id, Object requests, [Map options])`
- CacheStorage
- `Future match(/*RequestInfo*/ request, [Map options])`
- CanMakePayment
- `Future<List<Client>> matchAll([Map options])`
- CookieStore
- `Future getAll([Map options])`
- `Future set(String name, String value, [Map options])`
- CredentialsContainer
- `Future get([Map options])`
- `Future create([Map options])`
- ImageCapture
- `Future setOptions(Map photoSettings)`
- MediaCapabilities
- `Future<MediaCapabilitiesInfo> decodingInfo(Map configuration)`
- `Future<MediaCapabilitiesInfo> encodingInfo(Map configuration)`
- MediaStreamTrack
- `Future applyConstraints([Map constraints])`
- Navigator
- `Future requestKeyboardLock([List<String> keyCodes])`
- `Future requestMidiAccess([Map options])`
- `Future share([Map data])`
- OffscreenCanvas
- `Future<Blob> convertToBlob([Map options])`
- PaymentInstruments
- `Future set(String instrumentKey, Map details)`
- Permissions
- `Future<PermissionStatus> query(Map permission)`
- `Future<PermissionStatus> request(Map permissions)`
- `Future<PermissionStatus> revoke(Map permission)`
- PushManager
- `Future permissionState([Map options])`
- `Future<PushSubscription> subscribe([Map options])`
- RtcPeerConnection
- Changed:
```dart
Future createAnswer([options_OR_successCallback,
RtcPeerConnectionErrorCallback failureCallback,
Map mediaConstraints])
```
to:
```dart
Future<RtcSessionDescription> createAnswer([Map options])
```
- Changed:
```dart
Future createOffer([options_OR_successCallback,
RtcPeerConnectionErrorCallback failureCallback,
Map rtcOfferOptions])
```
to:
```dart
Future<RtcSessionDescription> createOffer([Map options])
```
- Changed:
```dart
Future setLocalDescription(Map description,
VoidCallback successCallback,
[RtcPeerConnectionErrorCallback failureCallback])
```
to:
```dart
Future setLocalDescription(Map description)
```
- Changed:
```dart
Future setLocalDescription(Map description,
VoidCallback successCallback,
[RtcPeerConnectionErrorCallback failureCallback])
```
to:
```dart
Future setRemoteDescription(Map description)
```
- ServiceWorkerContainer
- `Future<ServiceWorkerRegistration> register(String url, [Map options])`
- ServiceWorkerRegistration
- `Future<List<Notification>> getNotifications([Map filter])`
- `Future showNotification(String title, [Map options])`
- VRDevice
- `Future requestSession([Map options])`
- `Future supportsSession([Map options])`
- VRSession
- `Future requestFrameOfReference(String type, [Map options])`
- Window
- `Future fetch(/*RequestInfo*/ input, [Map init])`
- WorkerGlobalScope
- `Future fetch(/*RequestInfo*/ input, [Map init])`
In addition, exposed Service Worker "self" as a static getter named "instance".
The instance is exposed on four different Service Worker classes and can throw a
InstanceTypeError if the instance isn't of the class expected
(WorkerGlobalScope.instance will always work and not throw):
- `SharedWorkerGlobalScope.instance`
- `DedicatedWorkerGlobalScope.instance`
- `ServiceWorkerGlobalScope.instance`
- `WorkerGlobalScope.instance`
#### `dart:io`
- Added new HTTP status codes.
### Dart for the Web
#### dart2js
- **(Breaking)** Duplicate keys in a const map are not allowed and produce a
compile-time error. Dart2js used to report this as a warning before. This was
already an error in dartanalyzer and DDC and will be an error in other tools
in the future as well.
- Added `-O` flag to tune optimization levels. For more details run
`dart2js -h -v`.
We recommend to enable optimizations using the `-O` flag instead of individual
flags for each optimization. This is because the `-O` flag is intended to be
stable and continue to work in future versions of dart2js, while individual
flags may come and go.
At this time we recommend to test and debug with `-O1` and to deploy with
`-O3`.
### Tool Changes
#### dartfmt
- Addressed several dartfmt issues when used with the new CFE parser.
#### Linter
Bumped the linter to `0.1.70` which includes the following new lints:
- `avoid_returning_null_for_void`
- `sort_pub_dependencies`
- `prefer_mixin`
- `avoid_implementing_value_types`
- `flutter_style_todos`
- `avoid_void_async`
- `prefer_void_to_null`
and improvements:
- Fixed NPE in `prefer_iterable_whereType`.
- Improved message display for `await_only_futures`
- Performance improvements for `null_closures`
- Mixin support
- Updated `sort_constructors_first` to apply to all members.
- Updated `unnecessary_this` to work on field initializers.
- Updated `unawaited_futures` to ignore assignments within cascades.
- Improved handling of constant expressions with generic type params.
- NPE fix for `invariant_booleans`.
- Improved docs for `unawaited_futures`.
- Updated `unawaited_futures` to check cascades.
- Relaxed `void_checks` (allowing `T Function()` to be assigned to
`void Function()`).
- Fixed false positives in `lines_longer_than_80_chars`.
#### Pub
- Renamed the `--checked` flag to `pub run` to `--enable-asserts`.
- Pub will no longer delete directories named "packages".
- The `--packages-dir` flag is now ignored.
## 2.0.0 - 2018-08-07
This is the first major version release of Dart since 1.0.0, so it contains many
significant changes across all areas of the platform. Large changes include:
- **(Breaking)** The unsound optional static type system has been replaced with
a sound static type system using type inference and runtime checks. This was
formerly called "[strong mode][]" and only used by the Dart for web products.
Now it is the one official static type system for the entire platform and
replaces the previous "checked" and "production" modes.
- **(Breaking)** Functions marked `async` now run synchronously until the first
`await` statement. Previously, they would return to the event loop once at the
top of the function body before any code runs ([issue 30345][]).
- **(Breaking)** Constants in the core libraries have been renamed from
`SCREAMING_CAPS` to `lowerCamelCase`.
- **(Breaking)** Many new methods have been added to core library classes. If
you implement the interfaces of these classes, you will need to implement the
new methods.
- **(Breaking)** "dart:isolate" and "dart:mirrors" are no longer supported when
using Dart for the web. They are still supported in the command-line VM.
- **(Breaking)** Pub's transformer-based build system has been replaced by a
[new build system][build system].
- The `new` keyword is optional and can be omitted. Likewise, `const` can be
omitted inside a const context ([issue 30921][]).
- Dartium is no longer maintained or supported.
[issue 30345]: https://github.com/dart-lang/sdk/issues/30345
[issue 30921]: https://github.com/dart-lang/sdk/issues/30921
[strong mode]: https://dart.dev/guides/language/type-system
[build system]: https://github.com/dart-lang/build
### Language
- "[Strong mode][]" is now the official type system of the language.
- The `new` keyword is optional and can be omitted. Likewise, `const` can be
omitted inside a const context.
- A string in a `part of` declaration may now be used to refer to the library
this file is part of. A library part can now declare its library as either:
```dart
part of name.of.library;
```
Or:
```dart
part of "uriReferenceOfLibrary.dart";
```
This allows libraries with no library declarations (and therefore no name) to
have parts, and it allows tools to easily find the library of a part file. The
Dart 1.0 syntax is supported but deprecated.
- Functions marked `async` now run synchronously until the first `await`
statement. Previously, they would return to the event loop once at the top of
the function body before any code runs ([issue 30345][]).
- The type `void` is now a Top type like `dynamic`, and `Object`. It also now
has new errors for being used where not allowed (such as being assigned to any
non-`void`-typed parameter). Some libraries (importantly, mockito) may need to
be updated to accept void values to keep their APIs working.
- Future flattening is now done only as specified in the Dart 2.0 spec, rather
than more broadly. This means that the following code has an error on the
assignment to `y`.
```dart
test() {
Future<int> f;
var x = f.then<Future<List<int>>>((x) => []);
Future<List<int>> y = x;
}
```
- Invocations of `noSuchMethod()` receive default values for optional args. The
following program used to print "No arguments passed", and now prints "First
argument is 3".
```dart
abstract class B {
void m([int x = 3]);
}
class A implements B {
noSuchMethod(Invocation i) {
if (i.positionalArguments.length == 0) {
print("No arguments passed");
} else {
print("First argument is ${i.positionalArguments[0]}");
}
}
}
void main() {
A().m();
}
```
- Bounds on generic functions are invariant. The following program now issues an
invalid override error ([issue 29014][sdk#29014]):
```dart
class A {
void f<T extends int>() {}
}
class B extends A {
@override
void f<T extends num>() {}
}
```
- Numerous corner case bugs around return statements in synchronous and
asynchronous functions fixed. Specifically:
- Issues [31887][issue 31887], [32881][issue 32881]. Future flattening should
not be recursive.
- Issues [30638][issue 30638], [32233][issue 32233]. Incorrect downcast errors
with `FutureOr`.
- Issue [32233][issue 32233]. Errors when returning `FutureOr`.
- Issue [33218][issue 33218]. Returns in functions with void related types.
- Issue [31278][issue 31278]. Incorrect hint on empty returns in async.
functions.
- An empty `return;` in an async function with return type `Future<Object>` does
not report an error.
- `return exp;` where `exp` has type `void` in an async function is now an error
unless the return type of the function is `void` or `dynamic`.
- Mixed return statements of the form `return;` and `return exp;` are now
allowed when `exp` has type `void`.
- A compile time error is emitted for any literal which cannot be exactly
represented on the target platform. As a result, dart2js and DDC report errors
if an integer literal cannot be represented exactly in JavaScript ([issue
33282][]).
- New member conflict rules have been implemented. Most cases of conflicting
members with the same name are now static errors ([issue 33235][]).
[sdk#29014]: https://github.com/dart-lang/sdk/issues/29014
[issue 30638]: https://github.com/dart-lang/sdk/issues/30638
[issue 31278]: https://github.com/dart-lang/sdk/issues/31278
[issue 31887]: https://github.com/dart-lang/sdk/issues/31887
[issue 32233]: https://github.com/dart-lang/sdk/issues/32233
[issue 32881]: https://github.com/dart-lang/sdk/issues/32881
[issue 33218]: https://github.com/dart-lang/sdk/issues/33218
[issue 33235]: https://github.com/dart-lang/sdk/issues/33235
[issue 33282]: https://github.com/dart-lang/sdk/issues/33282
[issue 33341]: https://github.com/dart-lang/sdk/issues/33341
### Core libraries
- Replaced `UPPER_CASE` constant names with `lowerCamelCase`. For example,
`HTML_ESCAPE` is now `htmlEscape`.
- The Web libraries were re-generated using Chrome 63 WebIDLs ([details][idl]).
[idl]: https://github.com/dart-lang/sdk/wiki/Chrome-63-Dart-Web-Libraries
#### `dart:async`
- `Stream`:
- Added `cast` and `castFrom`.
- Changed `firstWhere`, `lastWhere`, and `singleWhere` to return `Future<T>`
and added an optional `T orElse()` callback.
- `StreamTransformer`: added `cast` and `castFrom`.
- `StreamTransformerBase`: new class.
- `Timer`: added `tick` property.
- `Zone`
- changed to be strong-mode clean. This required some breaking API changes.
See https://goo.gl/y9mW2x for more information.
- Added `bindBinaryCallbackGuarded`, `bindCallbackGuarded`, and
`bindUnaryCallbackGuarded`.
- Renamed `Zone.ROOT` to `Zone.root`.
- Removed the deprecated `defaultValue` parameter on `Stream.firstWhere` and
`Stream.lastWhere`.
- Changed an internal lazily-allocated reusable "null future" to always belong
to the root zone. This avoids race conditions where the first access to the
future determined which zone it would belong to. The zone is only used for
_scheduling_ the callback of listeners, the listeners themselves will run in
the correct zone in any case. Issue [#32556](http://dartbug.com/32556).
#### `dart:cli`
- _New_ "provisional" library for CLI-specific features.
- `waitFor`: function that suspends a stack to wait for a `Future` to complete.
#### `dart:collection`
- `MapBase`: added `mapToString`.
- `LinkedHashMap` no longer implements `HashMap`
- `LinkedHashSet` no longer implements `HashSet`.
- Added `of` constructor to `Queue`, `ListQueue`, `DoubleLinkedQueue`,
`HashSet`, `LinkedHashSet`, `SplayTreeSet`, `Map`, `HashMap`, `LinkedHashMap`,
`SplayTreeMap`.
- Removed `Maps` class. Extend `MapBase` or mix in `MapMixin` instead to provide
map method implementations for a class.
- Removed experimental `Document` method `getCSSCanvasContext` and property
`supportsCssCanvasContext`.
- Removed obsolete `Element` property `xtag` no longer supported in browsers.
- Exposed `ServiceWorker` class.
- Added constructor to `MessageChannel` and `MessagePort` `addEventListener`
automatically calls `start` method to receive queued messages.
#### `dart:convert`
- `Base64Codec.decode` return type is now `Uint8List`.
- `JsonUnsupportedObjectError`: added `partialResult` property
- `LineSplitter` now implements `StreamTransformer<String, String>` instead of
`Converter`. It retains `Converter` methods `convert` and
`startChunkedConversion`.
- `Utf8Decoder` when compiled with dart2js uses the browser's `TextDecoder` in
some common cases for faster decoding.
- Renamed `ASCII`, `BASE64`, `BASE64URI`, `JSON`, `LATIN1` and `UTF8` to
`ascii`, `base64`, `base64Uri`, `json`, `latin1` and `utf8`.
- Renamed the `HtmlEscapeMode` constants `UNKNOWN`, `ATTRIBUTE`, `SQ_ATTRIBUTE`
and `ELEMENT` to `unknown`, `attribute`, `sqAttribute` and `elements`.
- Added `jsonEncode`, `jsonDecode`, `base64Encode`, `base64UrlEncode` and
`base64Decode` top-level functions.
- Changed return type of `encode` on `AsciiCodec` and `Latin1Codec`, and
`convert` on `AsciiEncoder`, `Latin1Encoder`, to `Uint8List`.
- Allow `utf8.decoder.fuse(json.decoder)` to ignore leading Unicode BOM.
#### `dart:core`
- `BigInt` class added to support integers greater than 64-bits.
- Deprecated the `proxy` annotation.
- Added `Provisional` class and `provisional` field.
- Added `pragma` annotation.
- `RegExp` added static `escape` function.
- The `Uri` class now correctly handles paths while running on Node.js on
Windows.
- Core collection changes:
- `Iterable` added members `cast`, `castFrom`, `followedBy` and `whereType`.
- `Iterable.singleWhere` added `orElse` parameter.
- `List` added `+` operator, `first` and `last` setters, and `indexWhere` and
`lastIndexWhere` methods, and static `copyRange` and `writeIterable`
methods.
- `Map` added `fromEntries` constructor.
- `Map` added `addEntries`, `cast`, `entries`, `map`, `removeWhere`, `update`
and `updateAll` members.
- `MapEntry`: new class used by `Map.entries`.
- _Note_: if a class extends `IterableBase`, `ListBase`, `SetBase` or
`MapBase` (or uses the corresponding mixins) from `dart:collection`, the new
members are implemented automatically.
- Added `of` constructor to `List`, `Set`, `Map`.
- Renamed `double.INFINITY`, `double.NEGATIVE_INFINITY`, `double.NAN`,
`double.MAX_FINITE` and `double.MIN_POSITIVE` to `double.infinity`,
`double.negativeInfinity`, `double.nan`, `double.maxFinite` and
`double.minPositive`.
- Renamed the following constants in `DateTime` to lower case: `MONDAY` through
`SUNDAY`, `DAYS_PER_WEEK` (as `daysPerWeek`), `JANUARY` through `DECEMBER` and
`MONTHS_PER_YEAR` (as `monthsPerYear`).
- Renamed the following constants in `Duration` to lower case:
`MICROSECONDS_PER_MILLISECOND` to `microsecondsPerMillisecond`,
`MILLISECONDS_PER_SECOND` to `millisecondsPerSecond`, `SECONDS_PER_MINUTE` to
`secondsPerMinute`, `MINUTES_PER_HOUR` to `minutesPerHour`, `HOURS_PER_DAY` to
`hoursPerDay`, `MICROSECONDS_PER_SECOND` to `microsecondsPerSecond`,
`MICROSECONDS_PER_MINUTE` to `microsecondsPerMinute`, `MICROSECONDS_PER_HOUR`
to `microsecondsPerHour`, `MICROSECONDS_PER_DAY` to `microsecondsPerDay`,
`MILLISECONDS_PER_MINUTE` to `millisecondsPerMinute`, `MILLISECONDS_PER_HOUR`
to `millisecondsPerHour`, `MILLISECONDS_PER_DAY` to `millisecondsPerDay`,
<