• 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 either as: part of name.of.library; or as 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.

Strong Mode

Core library changes

  • dart:io

    • Unified backends for SecureSocket, SecurityContext, and X509Certificate to be consistent across all platforms. All SecureSocket, SecurityContext, and X509Certificate properties and methods are now supported on iOS and OSX.
    • Deprecated SecurityContext.alpnSupported as ALPN is now supported on all platforms.
    • Added ‘timeout’ parameter to ‘Socket.connect’, ‘RawSocket.connect’, ‘SecureSocket.connect’ and 'RawSecureSocket.connect. If a connection attempt takes longer than the duration specified in ‘timeout’, a ‘SocketException’ will be thrown. Note: if the duration specified in ‘timeout’ is greater than the system level timeout duration, a timeout may occur sooner than specified in ‘timeout’.
    • Added Platform.operatingSystemVersion that gives a platform-specific String describing the version of the operating system.
  • dart:core

    • The Uri class now correctly handles paths while running on Node.js on Windows.
    • Deprecated the proxy annotation.
  • dart:developer

    • Timeline.startSync and Timeline.timeSync now accept an optional parameter flow of type Flow. The flow parameter is used to generate flow timeline events that are enclosed by the slice described by Timeline.{start,finish}Sync and Timeline.timeSync.

Dart VM

  • Support for MIPS has been removed.

Tool Changes

  • Pub

    • Git dependencies may now include a path parameter, indicating that the package exists in a subdirectory of the Git repository. For example:

            url: git://github.com/dart-lang/multi_package_repo
            path: pkg/foobar
    • pub get and pub upgrade properly produce an error message and exit code when no network is present.

    • pub serve now waits for file watcher events to stabilize before scheduling new builds. This helps specifically with safe-write features in editors, as well as other situations such as save all which cause many fast edits.

    • Added the --build-delay argument to pub serve which sets the amount of time (in ms) to wait between file watcher events before scheduling a build. Defaults to 50.

    • Removed require.js module loading timeout for dartdevc, which resolves an issue where the initial load of an app might give a timeout error.

  • dartfmt

    • Support assert in const constructor initializer lists.
    • Better formatting for multi-line strings in argument lists. wasn't in a Git repository.
  • Dart Dev Compiler

    • dartdevc will no longer throw an error from is checks that return a different result in weak mode (SDK issue 28988). For example:
      main() {
        List l = [];
        // Prints "false", does not throw.
        print(l is List<String>);

1.24.2 - 22-06-2017

1.24.1 - 14-06-2017

  • Bug fixes for dartdevc support in pub serve.
    • Fixed module config invalidation logic so modules are properly recalculated when package layout changes.
    • Fixed exception when handling require.js errors that aren't script load errors.
    • Fixed an issue where requesting the bootstrap.js file before the dart.js file would result in a 404.
    • Fixed a Safari issue during bootstrapping (note that Safari is still not officially supported but does work for trivial examples).
  • Fix for a Dartium issue where there was no sound in checked mode (https://github.com/dart-lang/sdk/issues/29810).

1.24.0 - 12-06-2017


  • During a dynamic type check, void is not required to be null anymore. In practice, this makes overriding void functions with non-void functions safer.

  • During static analysis, a function or setter declared using => with return type void now allows the returned expression to have any type. For example, assuming the declaration int x;, it is now type correct to have void f() => ++x;.

  • A new function-type syntax has been added to the language. Intuitively, the type of a function can be constructed by textually replacing the function's name with Function in its declaration. For instance, the type of void foo() {} would be void Function(). The new syntax may be used wherever a type can be written. It is thus now possible to declare fields containing functions without needing to write typedefs: void Function() x;. The new function type has one restriction: it may not contain the old-style function-type syntax for its parameters. The following is thus illegal: void Function(int f()). typedefs have been updated to support this new syntax.


    typedef F = void Function();  // F is the name for a `void` callback.
    int Function(int) f;  // A field `f` that contains an int->int function.
    class A<T> {
      // The parameter `callback` is a function that takes a `T` and returns
      // `void`.
      void forEach(void Function(T) callback);
    // The new function type supports generic arguments.
    typedef Invoker = T Function<T>(T Function() callback);

Core library changes

  • dart:async, dart:core, dart:io

    • Adding to a closed sink, including IOSink, is no longer not allowed. In 1.24, violations are only reported (on stdout or stderr), but a future version of the Dart SDK will change this to throwing a StateError.
  • dart:convert

    • BREAKING Removed the deprecated ChunkedConverter class.
    • JSON maps are now typed as Map<String, dynamic> instead of Map<dynamic, dynamic>. A JSON-map is not a HashMap or LinkedHashMap anymore (but just a Map).
  • dart:io

    • Added Platform.localeName, needed for accessing the locale on platforms that don't store it in an environment variable.
    • Added ProcessInfo.currentRss and ProcessInfo.maxRss for inspecting the Dart VM process current and peak resident set size.
    • Added RawSynchronousSocket, a basic synchronous socket implementation.
  • dart: web APIs have been updated to align with Chrome v50. This change includes a large number of changes, many of which are breaking. In some cases, new class names may conflict with names that exist in existing code.

  • dart:html

    • REMOVED classes: Bluetooth, BluetoothDevice, BluetoothGattCharacteristic, BluetoothGattRemoteServer, BluetoothGattService, BluetoothUuid, CrossOriginConnectEvent, DefaultSessionStartEvent, DomSettableTokenList, MediaKeyError, PeriodicSyncEvent, PluginPlaceholderElement, ReadableStream, StashedMessagePort, SyncRegistration

    • REMOVED members:

      • texImage2DCanvas was removed from RenderingContext.
      • endClip and startClip were removed from Animation.
      • after and before were removed from CharacterData, ChildNode and Element.
      • keyLocation was removed from KeyboardEvent. Use location instead.
      • generateKeyRequest, keyAddedEvent, keyErrorEvent, keyMessageEvent, mediaGroup, needKeyEvent, onKeyAdded, onKeyError, onKeyMessage, and onNeedKey were removed from MediaElement.
      • getStorageUpdates was removed from Navigator
      • status was removed from PermissionStatus
      • getAvailability was removed from PreElement
    • Other behavior changes:

      • URLs returned in CSS or html are formatted with quoted string. Like url("http://google.com") instead of url(http://google.com).
      • Event timestamp property type changed from int to num.
      • Chrome introduced slight layout changes of UI objects. In addition many height/width dimensions are returned in subpixel values (num instead of whole numbers).
      • setRangeText with a selectionMode value of ‘invalid’ is no longer valid. Only “select”, “start”, “end”, “preserve” are allowed.
  • dart:svg

    • A large number of additions and removals. Review your use of dart:svg carefully.
  • dart:web_audio

    • new method on AudioContext – createIirFilter returns a new class IirFilterNode.
  • dart:web_gl

    • new classes: CompressedTextureAstc, ExtColorBufferFloat, ExtDisjointTimerQuery, and TimerQueryExt.

    • ExtFragDepth added: readPixels2 and texImage2D2.

Strong Mode

  • Removed ad hoc Future.then inference in favor of using FutureOr. Prior to adding FutureOr to the language, the analyzer implented an ad hoc type inference for Future.then (and overrides) treating it as if the onValue callback was typed to return FutureOr for the purposes of inference. This ad hoc inference has been removed now that FutureOr has been added.

    Packages that implement Future must either type the onValue parameter to .then as returning FutureOr<T>, or else must leave the type of the parameter entirely to allow inference to fill in the type.

  • During static analysis, a function or setter declared using => with return type void now allows the returned expression to have any type.

Tool Changes

  • Dartium

    Dartium is now based on Chrome v50. See Core library changes above for details on the changed APIs.

  • Pub

    • pub build and pub serve

      • Added support for the Dart Development Compiler.

        Unlike dart2js, this new compiler is modular, which allows pub to do incremental re-builds for pub serve, and potentially pub build in the future.

        In practice what that means is you can edit your Dart files, refresh in Chrome (or other supported browsers), and see your edits almost immediately. This is because pub is only recompiling your package, not all packages that you depend on.

        There is one caveat with the new compiler, which is that your package and your dependencies must all be strong mode clean. If you are getting an error compiling one of your dependencies, you will need to file bugs or send pull requests to get them strong mode clean.

        There are two ways of opting into the new compiler:

        • Use the new --web-compiler flag, which supports dartdevc, dart2js or none as options. This is the easiest way to try things out without changing the default.

        • Add config to your pubspec. There is a new web key which supports a single key called compiler. This is a map from mode names to compiler to use. For example, to default to dartdevc in debug mode you can add the following to your pubspec:

              debug: dartdevc

        You can also use the new compiler to run your tests in Chrome much more quickly than you can with dart2js. In order to do that, run pub serve test --web-compiler=dartdevc, and then run pub run test -p chrome --pub-serve=8080.

      • The --no-dart2js flag has been deprecated in favor of --web-compiler=none.

      • pub build will use a failing exit code if there are errors in any transformer.

    • pub publish

      • Added support for the UNLICENSE file.

      • Packages that depend on the Flutter SDK may be published.

    • pub get and pub upgrade

      • Don't dump a stack trace when a network error occurs while fetching packages.
  • dartfmt

    • Preserve type parameters in new generic function typedef syntax.
    • Add self-test validation to ensure formatter bugs do not cause user code to be lost.

Infrastructure changes

  • As of this release, we‘ll show a warning when using the MIPS architecture. Unless we learn about any critical use of Dart on MIPS in the meantime, we’re planning to deprecate support for MIPS starting with the next stable release.

1.23.0 - 2017-04-21

Strong Mode

  • Breaking change - it is now a strong mode error if a mixin causes a name conflict between two private members (field/getter/setter/method) from a different library. (SDK issue 28809).


class A {
  int _x;

class B {
  int _x;


import 'lib1.dart';

class C extends A with B {}
    error • The private name _x, defined by B, conflicts with the same name defined by A at tmp/lib2.dart:3:24 • private_collision_in_mixin_application
  • Breaking change - strong mode will prefer the expected type to infer generic types, functions, and methods (SDK issue 27586).

    main() {
      List<Object> foo = /*infers: <Object>*/['hello', 'world'];
      var bar = /*infers: <String>*/['hello', 'world'];
  • Strong mode inference error messages are improved (SDK issue 29108).

    import 'dart:math';
    test(Iterable/* fix is to add <num> here */ values) {
      num n = values.fold(values.first as num, max);

    Now produces the error on the generic function “max”:

    Couldn't infer type parameter 'T'.
    Tried to infer 'dynamic' for 'T' which doesn't work:
      Function type declared as '<T extends num>(T, T) → T'
                    used where  '(num, dynamic) → num' is required.
    Consider passing explicit type argument(s) to the generic.
  • Strong mode supports overriding fields, @virtual is no longer required (SDK issue 28120).

    class C {
      int x = 42;
    class D extends C {
      get x {
        print("x got called");
        return super.x;
    main() {
      print(new D().x);
  • Strong mode down cast composite warnings are no longer issued by default. (SDK issue 28588).

void test() {
  List untyped = [];
  List<int> typed = untyped; // No down cast composite warning

To opt back into the warnings, add the following to the .analysis_options file for your project.

    strong_mode_down_cast_composite: warning

Core library changes

  • dart:core
    • Added Uri.isScheme function to check the scheme of a URI. Example: uri.isScheme("http"). Ignores case when comparing.
    • Make UriData.parse validate its input better. If the data is base-64 encoded, the data is normalized wrt. alphabet and padding, and it contains invalid base-64 data, parsing fails. Also normalizes non-base-64 data.
  • dart:io
    • Added functions File.lastAccessed, File.lastAccessedSync, File.setLastModified, File.setLastModifiedSync, File.setLastAccessed, and File.setLastAccessedSync.
    • Added {Stdin,Stdout}.supportsAnsiEscapes.

Dart VM

  • Calls to print() and Stdout.write*() now correctly print unicode characters to the console on Windows. Calls to Stdout.add*() behave as before.

Tool changes

  • Analysis

    • dartanalyzer now follows the same rules as the analysis server to find an analysis options file, stopping when an analysis options file is found:
      • Search up the directory hierarchy looking for an analysis options file.
      • If analyzing a project referencing the Flutter package, then use the default Flutter analysis options found in package:flutter.
      • If in a Bazel workspace, then use the analysis options in package:dart.analysis_options/default.yaml if it exists.
      • Use the default analysis options rules.
    • In addition, specific to dartanalyzer:
      • an analysis options file can be specified on the command line via --options and that file will be used instead of searching for an analysis options file.
      • any analysis option specified on the command line (e.g. --strong or --no-strong) takes precedence over any corresponding value specified in the analysis options file.
  • Dartium, dart2js, and DDC

    • Imports to dart:io are allowed, but the imported library is not supported and will likely fail on most APIs at runtime. This change was made as a stopgap measure to make it easier to write libraries that share code between platforms (like package http). This might change again when configuration specific imports are supported.
  • Pub

    • Now sends telemetry data to pub.dartlang.org to allow better understanding of why a particular package is being accessed.
    • pub publish
      • Warns if a package imports a package that‘s not a dependency from within lib/ or bin/, or a package that’s not a dev dependency from within benchmark/, example/, test/ or tool/.
      • No longer produces “UID too large” errors on OS X. All packages are now uploaded with the user and group names set to “pub”.
      • No longer fails with a stack overflow when uploading a package that uses Git submodules.
    • pub get and pub upgrade
      • Produce more informative error messages if they're run directly in a package that uses Flutter.
      • Properly unlock SDK and path dependencies if they have a new version that‘s also valid according to the user’s pubspec.
  • dartfmt

    • Support new generic function typedef syntax.
    • Make the precedence of cascades more visible.
    • Fix a couple of places where spurious newlines were inserted.
    • Correctly report unchanged formatting when reading from stdin.
    • Ensure space between - and --. Code that does this is pathological, but it technically meant dartfmt could change the semantics of the code.
    • Preserve a blank line between enum cases.
    • Other small formatting tweaks.

1.22.1 - 2017-02-22

Patch release, resolves two issues:

1.22.0 - 2017-02-14


  • Breaking change: ‘Generalized tear-offs’ are no longer supported, and will cause errors. We updated the language spec and added warnings in 1.21, and are now taking the last step to fully de-support them. They were previously only supported in the VM, and there are almost no known uses of them in the wild.

  • The assert() statement has been expanded to support an optional second message argument (SDK issue 27342).

    The message is displayed if the assert fails. It can be any object, and it is accessible as AssertionError.message. It can be used to provide more user friendly exception outputs. As an example, the following assert:

    assert(configFile != null, "Tool config missing. Please see https://goo.gl/k8iAi for details.");

    would produce the following exception output:

    Unhandled exception:
    'file:///Users/mit/tmp/tool/bin/main.dart': Failed assertion: line 9 pos 10:
    'configFile != null': Tool config missing. Please see https://goo.gl/k8iAi for details.
    #0      _AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:33)
    #1      _AssertionError._throwNew (dart:core-patch/errors_patch.dart:29)
    #2      main (file:///Users/mit/tmp/tool/bin/main.dart:9:10)
  • The Null type has been moved to the bottom of the type hierarchy. As such, it is considered a subtype of every other type. The null literal was always treated as a bottom type. Now the named class Null is too:

    const empty = <Null>[];
    String concatenate(List<String> parts) => parts.join();
    int sum(List<int> numbers) => numbers.fold(0, (sum, n) => sum + n);
    concatenate(empty); // OK.
    sum(empty); // OK.
  • Introduce covariant modifier on parameters. It indicates that the parameter (and the corresponding parameter in any method that overrides it) has looser override rules. In strong mode, these require a runtime type check to maintain soundness, but enable an architectural pattern that is useful in some code.

    It lets you specialize a family of classes together, like so:

    abstract class Predator {
      void chaseAndEat(covariant Prey p);
    abstract class Prey {}
    class Mouse extends Prey {}
    class Seal extends Prey {}
    class Cat extends Predator {
      void chaseAndEat(Mouse m) => ...
    class Orca extends Predator {
      void chaseAndEat(Seal s) => ...

    This isn't statically safe, because you could do:

    Predator predator = new Cat(); // Upcast.
    predator.chaseAndEat(new Seal()); // Cats can't eat seals!

    To preserve soundness in strong mode, in the body of a method that uses a covariant override (here, Cat.chaseAndEat()), the compiler automatically inserts a check that the parameter is of the expected type. So the compiler gives you something like:

    class Cat extends Predator {
      void chaseAndEat(o) {
        var m = o as Mouse;

    Spec mode allows this unsound behavior on all parameters, even though users rarely rely on it. Strong mode disallowed it initially. Now, strong mode lets you opt into this behavior in the places where you do want it by using this modifier. Outside of strong mode, the modifier is ignored.

  • Change instantiate-to-bounds rules for generic type parameters when running in strong mode. If you leave off the type parameters from a generic type, we need to decide what to fill them in with. Dart 1.0 says just use dynamic, but that isn't sound:

    class Abser<T extends num> {
       void absThis(T n) { n.abs(); }
    var a = new Abser(); // Abser<dynamic>.
    a.absThis("not a num");

    We want the body of absThis() to be able to safely assume n is at least a num -- that‘s why there’s a constraint on T, after all. Implicitly using dynamic as the type parameter in this example breaks that.

    Instead, strong mode uses the bound. In the above example, it fills it in with num, and then the second line where a string is passed becomes a static error.

    However, there are some cases where it is hard to figure out what that default bound should be:

    class RuhRoh<T extends Comparable<T>> {}

    Strong mode‘s initial behavior sometimes produced surprising, unintended results. For 1.22, we take a simpler approach and then report an error if a good default type argument can’t be found.

Core libraries

  • Define FutureOr<T> for code that works with either a future or an immediate value of some type. For example, say you do a lot of text manipulation, and you want a handy function to chain a bunch of them:

    typedef String StringSwizzler(String input);
    String swizzle(String input, List<StringSwizzler> swizzlers) {
      var result = input;
      for (var swizzler in swizzlers) {
        result = swizzler(result);
      return result;

    This works fine:

    main() {
      var result = swizzle("input", [
        (s) => s.toUpperCase(),
        (s) => () => s * 2)
      print(result); // "INPUTINPUT".

    Later, you realize you'd also like to support swizzlers that are asynchronous (maybe they look up synonyms for words online). You could make your API strictly asynchronous, but then users of simple synchronous swizzlers have to manually wrap the return value in a Future.value(). Ideally, your swizzle() function would be “polymorphic over asynchrony”. It would allow both synchronous and asynchronous swizzlers. Because await accepts immediate values, it is easy to implement this dynamically:

    Future<String> swizzle(String input, List<StringSwizzler> swizzlers) async {
      var result = input;
      for (var swizzler in swizzlers) {
        result = await swizzler(result);
      return result;
    main() async {
      var result = swizzle("input", [
        (s) => s.toUpperCase(),
        (s) => new Future.delayed(new Duration(milliseconds: 40), () => s * 2)
      print(await result);

    What should the declared return type on StringSwizzler be? In the past, you had to use dynamic or Object, but that doesn't tell the user much. Now, you can do:

    typedef FutureOr<String> StringSwizzler(String input);

    Like the name implies, FutureOr<String> is a union type. It can be a String or a Future<String>, but not anything else. In this case, that's not super useful beyond just stating a more precise type for readers of the code. It does give you a little better error checking in code that uses the result of that.

    FutureOr<T> becomes really important in generic methods like Future.then(). In those cases, having the type system understand this magical union type helps type inference figure out the type argument of then() based on the closure you pass it.

    Previously, strong mode had hard-coded rules for handling Future.then() specifically. FutureOr<T> exposes that functionality so third-party APIs can take advantage of it too.

Tool changes

  • Dart2Js

    • Remove support for (long-time deprecated) mixin typedefs.
  • Pub

    • Avoid using a barback asset server for executables unless they actually use transformers. This makes precompilation substantially faster, produces better error messages when precompilation fails, and allows globally-activated executables to consistently use the Isolate.resolvePackageUri() API.

    • On Linux systems, always ignore packages' original file owners and permissions when extracting those packages. This was already the default under most circumstances.

    • Properly close the standard input stream of child processes started using pub run.

    • Handle parse errors from the package cache more gracefully. A package whose pubspec can't be parsed will now be ignored by pub get --offline and deleted by pub cache repair.

    • Make pub run run executables in spawned isolates. This lets them handle signals and use standard IO reliably.

    • Fix source-maps produced by dart2js when running in pub serve: URL references to assets from packages match the location where pub serve serves them (packages/package_name/ instead of ../packages/package_name/).

Infrastructure changes

  • The SDK now uses GN rather than gyp to generate its build files, which will now be exclusively ninja flavored. Documentation can be found on our wiki. Also see the help message of tools/gn.py. This change is in response to the deprecation of gyp. Build file generation with gyp will continue to be available in this release by setting the environment variable DART_USE_GYP before running gclient sync or gclient runhooks, but this will be removed in a future release.

1.21.1 - 2017-01-13

Patch release, resolves one issue:

  • Dart VM: Snapshots of generic functions fail. Issue 28072

1.21.0 - 2016-12-07


  • Support generic method syntax. Type arguments are not available at runtime. For details, check the informal specification.

  • Support access to initializing formals, e.g., the use of x to initialize y in class C { var x, y; C(this.x): y = x; }. Please check the informal specification for details.

  • Don't warn about switch case fallthrough if the case ends in a rethrow statement. (SDK issue 27650)

  • Also don't warn if the entire switch case is wrapped in braces - as long as the block ends with a break, continue, rethrow, return or throw.

  • Allow = as well as : as separator for named parameter default values.

    enableFlags({bool hidden: false}) {}

    can now be replaced by

    enableFlags({bool hidden = false}) {}

    (SDK issue 27559)

Core library changes

  • dart:core: Set.difference now takes a Set<Object> as argument. (SDK issue 27573)

  • dart:developer

    • Added Service class.
      • Allows inspecting and controlling the VM service protocol HTTP server.
      • Provides an API to access the ID of an Isolate.

Tool changes

  • Dart Dev Compiler

    • Support calls to loadLibrary() on deferred libraries. Deferred libraries are still loaded eagerly. (SDK issue 27343)

1.20.1 - 2016-10-13

Patch release, resolves one issue:

  • Dartium: Fixes a bug that caused crashes. No issue filed.

Strong Mode

  • It is no longer a warning when casting from dynamic to a composite type (SDK issue 27766).

    main() {
      dynamic obj = <int>[1, 2, 3];
      // This is now allowed without a warning.
      List<int> list = obj;

1.20.0 - 2016-10-11

Dart VM

  • We have improved the way that the VM locates the native code library for a native extension (e.g. dart-ext: import). We have updated this article on native extensions to reflect the VM's improved behavior.

  • Linux builds of the VM will now use the tcmalloc library for memory allocation. This has the advantages of better debugging and profiling support and faster small allocations, with the cost of slightly larger initial memory footprint, and slightly slower large allocations.

  • We have improved the way the VM searches for trusted root certificates for secure socket connections on Linux. First, the VM will look for trusted root certificates in standard locations on the file system (/etc/pki/tls/certs/ca-bundle.crt followed by /etc/ssl/certs), and only if these do not exist will it fall back on the builtin trusted root certificates. This behavior can be overridden on Linux with the new flags --root-certs-file and --root-certs-cache. The former is the path to a file containing the trusted root certificates, and the latter is the path to a directory containing root certificate files hashed using c_rehash.

  • The VM now throws a catchable Error when method compilation fails. This allows easier debugging of syntax errors, especially when testing. (SDK issue 23684)

Core library changes

  • dart:core: Remove deprecated Resource class. Use the class in package:resource instead.
  • dart:async
    • Future.wait now catches synchronous errors and returns them in the returned Future. (SDK issue 27249)
    • More aggressively returns a Future on Stream.cancel operations. Discourages to return null from cancel. (SDK issue 26777)
    • Fixes a few bugs where the cancel future wasn't passed through transformations.
  • dart:io
    • Added WebSocket.addUtf8Text to allow sending a pre-encoded text message without a round-trip UTF-8 conversion. (SDK issue 27129)

Strong Mode

  • Breaking change - it is an error if a generic type parameter cannot be inferred (SDK issue 26992).

    class Cup<T> {
      Cup(T t);
    main() {
      // Error because:
      // - if we choose Cup<num> it is not assignable to `cOfInt`,
      // - if we choose Cup<int> then `n` is not assignable to int.
      num n;
      C<int> cOfInt = new C(n);
  • New feature - use @checked to override a method and tighten a parameter type (SDK issue 25578).

    import 'package:meta/meta.dart' show checked;
    class View {
      addChild(View v) {}
    class MyView extends View {
      // this override is legal, it will check at runtime if we actually
      // got a MyView.
      addChild(@checked MyView v) {}
    main() {
      dynamic mv = new MyView();
      mv.addChild(new View()); // runtime error
  • New feature - use @virtual to allow field overrides in strong mode (SDK issue 27384).

    import 'package:meta/meta.dart' show virtual;
    class Base {
      @virtual int x;
    class Derived extends Base {
      int x;
      // Expose the hidden storage slot:
      int get superX => super.x;
      set superX(int v) { super.x = v; }
  • Breaking change - infer list and map literals from the context type as well as their values, consistent with generic methods and instance creation (SDK issue 27151).

    import 'dart:async';
    main() async {
      var b = new Future<B>.value(new B());
      var c = new Future<C>.value(new C());
      var/*infer List<Future<A>>*/ list = [b, c];
      var/*infer List<A>*/ result = await Future.wait(list);
    class A {}
    class B extends A {}
    class C extends A {}

Tool changes

  • dartfmt - upgraded to v0.2.10

    • Don't crash on annotations before parameters with trailing commas.
    • Always split enum declarations if they end in a trailing comma.
    • Add --set-exit-if-changed to set the exit code on a change.
  • Pub

    • Pub no longer generates a packages/ directory by default. Instead, it generates a .packages file, called a package spec. To generate a packages/ directory in addition to the package spec, use the --packages-dir flag with pub get, pub upgrade, and pub downgrade. See the Good-bye symlinks article for details.

1.19.1 - 2016-09-08

Patch release, resolves one issue:

  • Dartdoc: Fixes a bug that prevented generation of docs. (Dartdoc issue 1233)

1.19.0 - 2016-08-26

Language changes

  • The language now allows a trailing comma after the last argument of a call and the last parameter of a function declaration. This can make long argument or parameter lists easier to maintain, as commas can be left as-is when reordering lines. For details, see SDK issue 26644.

Tool Changes

  • dartfmt - upgraded to v0.2.9+1

    • Support trailing commas in argument and parameter lists.
    • Gracefully handle read-only files.
    • About a dozen other bug fixes.
  • Pub

    • Added a --no-packages-dir flag to pub get, pub upgrade, and pub downgrade. When this flag is passed, pub will not generate a packages/ directory, and will remove that directory and any symlinks to it if they exist. Note that this replaces the unsupported --no-package-symlinks flag.

    • Added the ability for packages to declare a constraint on the Flutter SDK:

        flutter: ^0.1.2
        sdk: >=1.19.0 <2.0.0

      A Flutter constraint will only be satisfiable when pub is running in the context of the flutter executable, and when the Flutter SDK version matches the constraint.

    • Added sdk as a new package source that fetches packages from a hard-coded SDK. Currently only the flutter SDK is supported:

          sdk: flutter
          version: ^0.0.1

      A Flutter sdk dependency will only be satisfiable when pub is running in the context of the flutter executable, and when the Flutter SDK contains a package with the given name whose version matches the constraint.

    • tar files on Linux are now created with 0 as the user and group IDs. This fixes a crash when publishing packages while using Active Directory.

    • Fixed a bug where packages from a hosted HTTP URL were considered the same as packages from an otherwise-identical HTTPS URL.

    • Fixed timer formatting for timers that lasted longer than a minute.

    • Eliminate some false negatives when determining whether global executables are on the user's executable path.

  • dart2js

    • dart2dart (aka dart2js --output-type=dart) has been removed (this was deprecated in Dart 1.11).

Dart VM

  • The dependency on BoringSSL has been rolled forward. Going forward, builds of the Dart VM including secure sockets will require a compiler with C++11 support. For details, see the Building wiki page.

Strong Mode

  • New feature - an option to disable implicit casts (SDK issue 26583), see the documentation for usage instructions and examples.

  • New feature - an option to disable implicit dynamic (SDK issue 25573), see the documentation for usage instructions and examples.

  • Breaking change - infer generic type arguments from the constructor invocation arguments (SDK issue 25220).

    var map = new Map<String, String>();
    // infer: Map<String, String>
    var otherMap = new Map.from(map);
  • Breaking change - infer local function return type (SDK issue 26414).

    void main() {
      // infer: return type is int
      f() { return 40; }
      int y = f() + 2; // type checks
  • Breaking change - allow type promotion from a generic type parameter (SDK issue 26414).

    void fn/*<T>*/(/*=T*/ object) {
      if (object is String) {
        // Treat `object` as `String` inside this block.
        // But it will require a cast to pass it to something that expects `T`.
  • Breaking change - smarter inference for Future.then (SDK issue 25944). Previous workarounds that use async/await or .then/*<Future<SomeType>>*/ should no longer be necessary.

    // This will now infer correctly.
    Future<List<int>> t2 = f.then((_) => [3]);
    // This infers too.
    Future<int> t2 = f.then((_) => new Future.value(42));
  • Breaking change - smarter inference for async functions (SDK issue 25322).

    void test() async {
      List<int> x = await [4]; // was previously inferred
      List<int> y = await new Future.value([4]); // now inferred too
  • Breaking change - sideways casts are no longer allowed (SDK issue 26120).

1.18.1 - 2016-08-02

Patch release, resolves two issues and improves performance:

1.18.0 - 2016-07-27

Core library changes

  • dart:core
    • Improved performance when parsing some common URIs.
    • Fixed bug in Uri.resolve (SDK issue 26804).
  • dart:io
    • Adds file locking modes FileLock.BLOCKING_SHARED and FileLock.BLOCKING_EXCLUSIVE.

1.17.1 - 2016-06-10

Patch release, resolves two issues:

1.17.0 - 2016-06-08

Core library changes

  • dart:convert

    • Deprecate ChunkedConverter which was erroneously added in 1.16.
  • dart:core

    • Uri.replace supports iterables as values for the query parameters.
    • Uri.parseIPv6Address returns a Uint8List.
  • dart:io

    • Added NetworkInterface.listSupported, which is true when NetworkInterface.list is supported, and false otherwise. Currently, NetworkInterface.list is not supported on Android.

Tool Changes

  • Pub

    • TAR files created while publishing a package on Mac OS and Linux now use a more portable format.

    • Errors caused by invalid arguments now print the full usage information for the command.

    • SDK constraints for dependency overrides are no longer considered when determining the total SDK constraint for a lockfile.

    • A bug has been fixed in which a lockfile was considered up-to-date when it actually wasn't.

    • A bug has been fixed in which pub get --offline would crash when a prerelease version was selected.

  • Dartium and content shell

    • Debugging Dart code inside iframes improved, was broken.

1.16.1 - 2016-05-24

Patch release, resolves one issue:

  • VM: Fixes a bug that caused intermittent hangs on Windows. (SDK issue 26400)

1.16.0 - 2016-04-26

Core library changes

  • dart:convert

    • Added BASE64URL codec and corresponding Base64Codec.urlSafe constructor.

    • Introduce ChunkedConverter and deprecate chunked methods on Converter.

  • dart:html

    There have been a number of BREAKING changes to align APIs with recent changes in Chrome. These include:

    • Chrome's ShadowRoot interface no longer has the methods getElementById, getElementsByClassName, and getElementsByTagName, e.g.,


      should become:

    • The clipboardData property has been removed from KeyEvent and Event. It has been moved to the new ClipboardEvent class, which is now used by copy, cut, and paste events.

    • The layer property has been removed from KeyEvent and UIEvent. It has been moved to MouseEvent.

    • The Point get page property has been removed from UIEvent. It still exists on MouseEvent and Touch.

    There have also been a number of other additions and removals to dart:html, dart:indexed_db, dart:svg, dart:web_audio, and dart:web_gl that correspond to changes to Chrome APIs between v39 and v45. Many of the breaking changes represent APIs that would have caused runtime exceptions when compiled to Javascript and run on recent Chrome releases.

  • dart:io

    • Added SecurityContext.alpnSupported, which is true if a platform supports ALPN, and false otherwise.

JavaScript interop

For performance reasons, a potentially BREAKING change was added for libraries that use JS interop. Any Dart file that uses @JS annotations on declarations (top-level functions, classes or class members) to interop with JavaScript code will require that the file have the annotation @JS() on a library directive.

library my_library;

The analyzer will enforce this by generating the error:

The @JS() annotation can only be used if it is also declared on the library directive.

If part file uses the @JS() annotation, the library that uses the part should have the @JS() annotation e.g.,

// library_1.dart
library library_1;

import 'package:js/js.dart';

part 'part_1.dart';
// part_1.dart
part of library_1;

external List<FrameworkStabilizer> get frameworkStabilizers;

If your library already has a JS module e.g.,

library my_library;

Then your library will work without any additional changes.


  • Static checking of for in statements. These will now produce static warnings:

    // Not Iterable.
    for (var i in 1234) { ... }
    // String cannot be assigned to int.
    for (int n in <String>["a", "b"]) { ... }

Tool Changes

  • Pub

    • pub serve now provides caching headers that should improve the performance of requesting large files multiple times.

    • Both pub get and pub upgrade now have a --no-precompile flag that disables precompilation of executables and transformed dependencies.

    • pub publish now resolves symlinks when publishing from a Git repository. This matches the behavior it always had when publishing a package that wasn't in a Git repository.

  • Dart Dev Compiler

    • The experimental dartdevc executable has been added to the SDK.

    • It will help early adopters validate the implementation and provide feedback. dartdevc is not yet ready for production usage.

    • Read more about the Dart Dev Compiler here.

1.15.0 - 2016-03-09

Core library changes

  • dart:async

    • Made StreamView class a const class.
  • dart:core

    • Added Uri.queryParametersAll to handle multiple query parameters with the same name.
  • dart:io

    • Added SecurityContext.usePrivateKeyBytes, SecurityContext.useCertificateChainBytes, SecurityContext.setTrustedCertificatesBytes, and SecurityContext.setClientAuthoritiesBytes.
    • Breaking The named directory argument of SecurityContext.setTrustedCertificates has been removed.
    • Added support to SecurityContext for PKCS12 certificate and key containers.
    • All calls in SecurityContext that accept certificate data now accept an optional named parameter password, similar to SecurityContext.usePrivateKeyBytes, for use as the password for PKCS12 data.

Tool changes

  • Dartium and content shell

    • The Chrome-based tools that ship as part of the Dart SDK – Dartium and content shell – are now based on Chrome version 45 (instead of Chrome 39).
    • Dart browser libraries (dart:html, dart:svg, etc) have not been updated.
      • These are still based on Chrome 39.
      • These APIs will be updated in a future release.
    • Note that there are experimental APIs which have changed in the underlying browser, and will not work with the older libraries. For example, Element.animate.
  • dartfmt - upgraded to v0.2.4

    • Better handling for long collections with comments.
    • Always put member metadata annotations on their own line.
    • Indent functions in named argument lists with non-functions.
    • Force the parameter list to split if a split occurs inside a function-typed parameter.
    • Don't force a split for before a single named argument if the argument itself splits.

Service protocol changes

  • Fixed a documentation bug where the field extensionRPCs in Isolate was not marked optional.

Experimental language features

  • Added support for configuration-specific imports. On the VM and dart2js, they can be enabled with --conditional-directives.

    The analyzer requires additional configuration:

        enableConditionalDirectives: true

    Read about configuring the analyzer for more details.

1.14.2 - 2016-02-10

Patch release, resolves three issues:

  • VM: Fixed a code generation bug on x64. (SDK commit 834b3f02)

  • dart:io: Fixed EOF detection when reading some special device files. (SDK issue 25596)

  • Pub: Fixed an error using hosted dependencies in SDK version 1.14. (Pub issue 1386)

1.14.1 - 2016-02-04

Patch release, resolves one issue:

  • Debugger: Fixes a VM crash when a debugger attempts to set a break point during isolate initialization. (SDK issue 25618)

1.14.0 - 2016-01-28

Core library changes

  • dart:async

    • Added Future.any static method.
    • Added Stream.fromFutures constructor.
  • dart:convert

    • Base64Decoder.convert now takes optional start and end parameters.
  • dart:core

    • Added current getter to StackTrace class.
    • Uri class added support for data URIs
      • Added two new constructors: dataFromBytes and dataFromString.
      • Added a data getter for data: URIs with a new UriData class for the return type.
    • Added growable parameter to List.filled constructor.
    • Added microsecond support to DateTime: DateTime.microsecond, DateTime.microsecondsSinceEpoch, and new DateTime.fromMicrosecondsSinceEpoch.
  • dart:math

    • Random added a secure constructor returning a cryptographically secure random generator which reads from the entropy source provided by the embedder for every generated random value.
  • dart:io

    • Platform added a static isIOS getter and Platform.operatingSystem may now return ios.
    • Platform added a static packageConfig getter.
    • Added support for WebSocket compression as standardized in RFC 7692.
    • Compression is enabled by default for all WebSocket connections.
      • The optionally named parameter compression on the methods WebSocket.connect, WebSocket.fromUpgradedSocket, and WebSocketTransformer.upgrade and the WebSocketTransformer constructor can be used to modify or disable compression using the new CompressionOptions class.
  • dart:isolate

    • Added experimental support for Package Resolution Configuration.
      • Added packageConfig and packageRoot instance getters to Isolate.
      • Added a resolvePackageUri method to Isolate.
      • Added named arguments packageConfig and automaticPackageResolution to the Isolate.spawnUri constructor.

Tool changes

  • dartfmt

    • Better line splitting in a variety of cases.

    • Other optimizations and bug fixes.

  • Pub

    • Breaking: Pub now eagerly emits an error when a pubspec's “name” field is not a valid Dart identifier. Since packages with non-identifier names were never allowed to be published, and some of them already caused crashes when being written to a .packages file, this is unlikely to break many people in practice.

    • Breaking: Support for barback versions prior to 0.15.0 (released July 2014) has been dropped. Pub will no longer install these older barback versions.

    • pub serve now GZIPs the assets it serves to make load times more similar to real-world use-cases.

    • pub deps now supports a --no-dev flag, which causes it to emit the dependency tree as it would be if no dev_dependencies were in use. This makes it easier to see your package's dependency footprint as your users will experience it.

    • pub global run now detects when a global executable's SDK constraint is no longer met and errors out, rather than trying to run the executable anyway.

    • Pub commands that check whether the lockfile is up-to-date (pub run, pub deps, pub serve, and pub build) now do additional verification. They ensure that any path dependencies' pubspecs haven't been changed, and they ensure that the current SDK version is compatible with all dependencies.

    • Fixed a crashing bug when using pub global run on a global script that didn't exist.

    • Fixed a crashing bug when a pubspec contains a dependency without a source declared.

1.13.2 - 2016-01-06

Patch release, resolves one issue:

1.13.1 - 2015-12-17

Patch release, resolves three issues:

1.13.0 - 2015-11-18

Core library changes

  • dart:async

    • StreamController added getters for onListen, onPause, and onResume with the corresponding new typedef void ControllerCallback().
    • StreamController added a getter for onCancel with the corresponding new typedef ControllerCancelCallback();
    • StreamTransformer instances created with fromHandlers with no handleError callback now forward stack traces along with errors to the resulting streams.
  • dart:convert

    • Added support for Base-64 encoding and decoding.
      • Added new classes Base64Codec, Base64Encoder, and Base64Decoder.
      • Added new top-level const Base64Codec BASE64.
  • dart:core

    • Uri added removeFragment method.
    • String.allMatches (implementing Pattern.allMatches) is now lazy, as all allMatches implementations are intended to be.
    • Resource is deprecated, and will be removed in a future release.
  • dart:developer

    • Added Timeline class for interacting with Observatory's timeline feature.
    • Added ServiceExtensionHandler, ServiceExtensionResponse, and registerExtension which enable developers to provide their own VM service protocol extensions.
  • dart:html, dart:indexed_db, dart:svg, dart:web_audio, dart:web_gl, dart:web_sql

    • The return type of some APIs changed from double to num. Dartium is now using JS interop for most operations. JS does not distinguish between numeric types, and will return a number as an int if it fits in an int. This will mostly cause an error if you assign to something typed double in checked mode. You may need to insert a toDouble() call or accept num. Examples of APIs that are affected include Element.getBoundingClientRect and TextMetrics.width.
  • dart:io

    • Breaking: Secure networking has changed, replacing the NSS library with the BoringSSL library. SecureSocket, SecureServerSocket, RawSecureSocket,RawSecureServerSocket, HttpClient, and HttpServer now all use a SecurityContext object which contains the certificates and keys used for secure TLS (SSL) networking.

      This is a breaking change for server applications and for some client applications. Certificates and keys are loaded into the SecurityContext from PEM files, instead of from an NSS certificate database. Information about how to change applications that use secure networking is at https://www.dartlang.org/server/tls-ssl.html

    • HttpClient no longer sends URI fragments in the request. This is not allowed by the HTTP protocol. The HttpServer still gracefully receives fragments, but discards them before delivering the request.

    • To allow connections to be accepted on the same port across different isolates, set the shared argument to true when creating server socket and HttpServer instances.

      • The deprecated ServerSocketReference and RawServerSocketReference classes have been removed.
      • The corresponding reference properties on ServerSocket and RawServerSocket have been removed.
  • dart:isolate

    • spawnUri added an environment named argument.

Tool changes

  • dart2js and Dartium now support improved Javascript Interoperability via the js package.

  • docgen and dartdocgen no longer ship in the SDK. The docgen sources have been removed from the repository.

  • This is the last release to ship the VM's “legacy debug protocol”. We intend to remove the legacy debug protocol in Dart VM 1.14.

  • The VM's Service Protocol has been updated to version 3.0 to take care of a number of issues uncovered by the first few non-observatory clients. This is a potentially breaking change for clients.

  • Dartium has been substantially changed. Rather than using C++ calls into Chromium internals for DOM operations it now uses JS interop. The DOM objects in dart:html and related libraries now wrap a JavaScript object and delegate operations to it. This should be mostly transparent to users. However, performance and memory characteristics may be different from previous versions. There may be some changes in which DOM objects are wrapped as Dart objects. For example, if you get a reference to a Window object, even through JS interop, you will always see it as a Dart Window, even when used cross-frame. We expect the change to using JS interop will make it much simpler to update to new Chrome versions.

1.12.2 - 2015-10-21

Core library changes

  • dart:io

    • A memory leak in creation of Process objects is fixed.

1.12.1 - 2015-09-08

Tool changes

  • Pub

    • Pub will now respect .gitignore when validating a package before it's published. For example, if a LICENSE file exists but is ignored, that is now an error.

    • If the package is in a subdirectory of a Git repository and the entire subdirectory is ignored with .gitignore, pub will act as though nothing was ignored instead of uploading an empty package.

    • The heuristics for determining when pub get needs to be run before various commands have been improved. There should no longer be false positives when non-dependency sections of the pubspec have been modified.

1.12.0 - 2015-08-31

Language changes

  • Null-aware operators
    • ??: if null operator. expr1 ?? expr2 evaluates to expr1 if not null, otherwise expr2.
    • ??=: null-aware assignment. v ??= expr causes v to be assigned expr only if v is null.
    • x?.p: null-aware access. x?.p evaluates to x.p if x is not null, otherwise evaluates to null.
    • x?.m(): null-aware method invocation. x?.m() invokes m only if x is not null.

Core library changes

  • dart:async

    • StreamController added setters for the onListen, onPause, onResume and onCancel callbacks.
  • dart:convert

    • LineSplitter added a split static method returning an Iterable.
  • dart:core

    • Uri class now perform path normalization when a URI is created. This removes most .. and . sequences from the URI path. Purely relative paths (no scheme or authority) are allowed to retain some leading “dot” segments. Also added hasAbsolutePath, hasEmptyPath, and hasScheme properties.
  • dart:developer

    • New log function to transmit logging events to Observatory.
  • dart:html

    • NodeTreeSanitizer added the const trusted field. It can be used instead of defining a NullTreeSanitizer class when calling setInnerHtml or other methods that create DOM from text. It is also more efficient, skipping the creation of a DocumentFragment.
  • dart:io

    • Added two new file modes, WRITE_ONLY and WRITE_ONLY_APPEND for opening a file write only. eaeecf2
    • Change stdout/stderr to binary mode on Windows. 4205b29
  • dart:isolate

    • Added onError, onExit and errorsAreFatal parameters to Isolate.spawnUri.
  • dart:mirrors

    • InstanceMirror.delegate moved up to ObjectMirror.
    • Fix InstanceMirror.getField optimization when the selector is an operator.
    • Fix reflective NoSuchMethodErrors to match their non-reflective counterparts when due to argument mismatches. (VM only)

Tool changes

  • Documentation tools

    • dartdoc is now the default tool to generate static HTML for API docs. Learn more.

    • docgen and dartdocgen have been deprecated. Currently plan is to remove them in 1.13.

  • Formatter (dartfmt)

    • Over 50 bugs fixed.

    • Optimized line splitter is much faster and produces better output on complex code.

  • Observatory

    • Allocation profiling.

    • New feature to display output from logging.

    • Heap snapshot analysis works for 64-bit VMs.

    • Improved ability to inspect typed data, regex and compiled code.

    • Ability to break on all or uncaught exceptions from Observatory's debugger.

    • Ability to set closure-specific breakpoints.

    • ‘anext’ - step past await/yield.

    • Preserve when a variable has been expanded/unexpanded in the debugger.

    • Keep focus on debugger input box whenever possible.

    • Echo stdout/stderr in the Observatory debugger. Standalone-only so far.

    • Minor fixes to service protocol documentation.

  • Pub

    • Breaking: various commands that previously ran pub get implicitly no longer do so. Instead, they merely check to make sure the “.packages” file is newer than the pubspec and the lock file, and fail if it's not.

    • Added support for --verbosity=error and --verbosity=warning.

    • pub serve now collapses multiple GET requests into a single line of output. For full output, use --verbose.

    • pub deps has improved formatting for circular dependencies on the entrypoint package.

    • pub run and pub global run

      • Breaking: to match the behavior of the Dart VM, executables no longer run in checked mode by default. A --checked flag has been added to run them in checked mode manually.

      • Faster start time for executables that don't import transformed code.

      • Binstubs for globally-activated executables are now written in the system encoding, rather than always in UTF-8. To update existing executables, run pub cache repair.

    • pub get and pub upgrade

      • Pub will now generate a “.packages” file in addition to the “packages” directory when running pub get or similar operations, per the package spec proposal. Pub now has a --no-package-symlinks flag that will stop “packages” directories from being generated at all.

      • An issue where HTTP requests were sometimes made even though --offline was passed has been fixed.

      • A bug with --offline that caused an unhelpful error message has been fixed.

      • Pub will no longer time out when a package takes a long time to download.

    • pub publish

      • Pub will emit a non-zero exit code when it finds a violation while publishing.

      • .gitignore files will be respected even if the package isn't at the top level of the Git repository.

    • Barback integration

      • A crashing bug involving transformers that only apply to non-public code has been fixed.

      • A deadlock caused by declaring transformer followed by a lazy transformer (such as the built-in $dart2js transformer) has been fixed.

      • A stack overflow caused by a transformer being run multiple times on the package that defines it has been fixed.

      • A transformer that tries to read a non-existent asset in another package will now be re-run if that asset is later created.

VM Service Protocol Changes

  • BREAKING The service protocol now sends JSON-RPC 2.0-compatible server-to-client events. To reflect this, the service protocol version is now 2.0.

  • The service protocol now includes a "jsonrpc" property in its responses, as opposed to "json-rpc".

  • The service protocol now properly handles requests with non-string ids. Numeric ids are no longer converted to strings, and null ids now don't produce a response.

  • Some RPCs that didn't include a "jsonrpc" property in their responses now include one.

1.11.2 - 2015-08-03

Core library changes

  • Fix a bug where WebSocket.close() would crash if called after WebSocket.cancel().

1.11.1 - 2015-07-02

Tool changes

  • Pub will always load Dart SDK assets from the SDK whose pub executable was run, even if a DART_SDK environment variable is set.

1.11.0 - 2015-06-25

Core library changes

  • dart:core

    • Iterable added an empty constructor. dcf0286
    • Iterable can now be extended directly. An alternative to extending IterableBase from dart:collection.
    • List added an unmodifiable constructor. r45334
    • Map added an unmodifiable constructor. r45733
    • int added a gcd method. a192ef4
    • int added a modInverse method. f6f338c
    • StackTrace added a fromString constructor. 68dd6f6
    • Uri added a directory constructor. d8dbb4a
    • List iterators may not throw ConcurrentModificationError as eagerly in release mode. In checked mode, the modification check is still as eager as possible. r45198
  • dart:developer - NEW

    • Replaces the deprecated dart:profiler library.
    • Adds new functions debugger and inspect. 6e42aec
  • dart:io

    • FileSystemEntity added a uri property. 8cf32dc
    • Platform added a static resolvedExecutable property. c05c8c6
  • dart:html

    • Element methods, appendHtml and insertAdjacentHtml now take nodeValidator and treeSanitizer parameters, and the inputs are consistently sanitized. r45818 announcement
  • dart:isolate

    • BREAKING The positional priority parameter of Isolate.ping and Isolate.kill is now a named parameter named priority.
    • BREAKING Removed the Isolate.AS_EVENT priority.
    • Isolate methods ping and addOnExitListener now have a named parameter response. r45092
    • Isolate.spawnUri added a named argument checked.
    • Remove the experimental state of the API.
  • dart:profiler - DEPRECATED

    • This library will be removed in 1.12. Use dart:developer instead.

Tool changes

  • This is the first release that does not include the Eclipse-based Dart Editor. See dartlang.org/tools for alternatives.
  • This is the last release that ships the (unsupported) dart2dart (aka dart2js --output-type=dart) utility as part of dart2js

1.10.0 – 2015-04-29

Core library changes

  • dart:convert

    • POTENTIALLY BREAKING Fix behavior of HtmlEscape. It no longer escapes no-break space (U+00A0) anywhere or forward slash (/, U+002F) in element context. Slash is still escaped using HtmlEscapeMode.UNKNOWN. r45003, r45153, r45189
  • dart:core

    • Uri.parse added start and end positional arguments.
  • dart:html

    • POTENTIALLY BREAKING CssClassSet method arguments must now be ‘tokens’, i.e. non-empty strings with no white-space characters. The implementation was incorrect for class names containing spaces. The fix is to forbid spaces and provide a faster implementation. Announcement
  • dart:io

    • ProcessResult now exposes a constructor.
    • import and Isolate.spawnUri now supports the Data URI scheme on the VM.

Tool Changes


  • Running pub run foo within a package now runs the foo executable defined by the foo package. The previous behavior ran bin/foo. This makes it easy to run binaries in dependencies, for instance pub run test.

  • On Mac and Linux, signals sent to pub run and forwarded to the child command.

1.9.3 – 2015-04-14

This is a bug fix release which merges a number of commits from bleeding_edge.

  • dart2js: Addresses as issue with minified Javascript output with CSP enabled - r44453

  • Editor: Fixes accidental updating of files in the pub cache during rename refactoring - r44677

  • Editor: Fix for issue 23032 regarding skipped breakpoints on Windows - r44824

  • dart:mirrors: Fix MethodMirror.source when the method is on the first line in a script - r44957, r44976

  • pub: Fix for issue 23084: Pub can fail to load transformers necessary for local development - r44876

1.9.1 – 2015-03-25

Language changes

  • Support for async, await, sync*, async*, yield, yield*, and await for. See the the language tour for more details.

  • Enum support is fully enabled. See the language tour for more details.

Tool changes

  • The formatter is much more comprehensive and generates much more readable code. See its tool page for more details.

  • The analysis server is integrated into the IntelliJ plugin and the Dart editor. This allows analysis to run out-of-process, so that interaction remains smooth even for large projects.

  • Analysis supports more and better hints, including unused variables and unused private members.

Core library changes


  • There's a new model for shared server sockets with no need for a Socket reference.

  • A new, much faster regular expression engine.

  • The Isolate API now works across the VM and dart2js.


For more information on any of these changes, see the corresponding documentation on the Dart API site.

  • dart:async:

    • Future.wait added a new named argument, cleanUp, which is a callback that releases resources allocated by a successful Future.

    • The SynchronousStreamController class was added as an explicit name for the type returned when the sync argument is passed to new StreamController.

  • dart:collection: The new SplayTreeSet.from(Iterable) constructor was added.

  • dart:convert: Utf8Encoder.convert and Utf8Decoder.convert added optional start and end arguments.

  • dart:core:

    • RangeError added new static helper functions: checkNotNegative, checkValidIndex, checkValidRange, and checkValueInInterval.

    • int added the modPow function.

    • String added the replaceFirstMapped and replaceRange functions.

  • dart:io:

    • Support for locking files to prevent concurrent modification was added. This includes the File.lock, File.lockSync, File.unlock, and File.unlockSync functions as well as the FileLock class.

    • Support for starting detached processes by passing the named mode argument (a ProcessStartMode) to Process.start. A process can be fully attached, fully detached, or detached except for its standard IO streams.

    • HttpServer.bind and HttpServer.bindSecure added the v6Only named argument. If this is true, only IPv6 connections will be accepted.

    • HttpServer.bind, HttpServer.bindSecure, ServerSocket.bind, RawServerSocket.bind, SecureServerSocket.bind and RawSecureServerSocket.bind added the shared named argument. If this is true, multiple servers or sockets in the same Dart process may bind to the same address, and incoming requests will automatically be distributed between them.

    • Deprecation: the experimental ServerSocketReference and RawServerSocketReference classes, as well as getters that returned them, are marked as deprecated. The shared named argument should be used instead. These will be removed in Dart 1.10.

    • Socket.connect and RawSocket.connect added the sourceAddress named argument, which specifies the local address to bind when making a connection.

    • The static Process.killPid method was added to kill a process with a given PID.

    • Stdout added the nonBlocking instance property, which returns a non-blocking IOSink that writes to standard output.

  • dart:isolate:

    • The static getter Isolate.current was added.

    • The Isolate methods addOnExitListener, removeOnExitListener, setErrorsFatal, addOnErrorListener, and removeOnErrorListener now work on the VM.

    • Isolates spawned via Isolate.spawn now allow most objects, including top-level and static functions, to be sent between them.

1.8.5 – 2015-01-21

  • Code generation for SIMD on ARM and ARM64 is fixed.

  • A possible crash on MIPS with newer GCC toolchains has been prevented.

  • A segfault when using rethrow was fixed (issue 21795).

1.8.3 – 2014-12-10

  • Breakpoints can be set in the Editor using file suffixes (issue 21280).

  • IPv6 addresses are properly handled by HttpClient in dart:io, fixing a crash in pub (issue 21698).

  • Issues with the experimental async/await syntax have been fixed.

  • Issues with a set of number operations in the VM have been fixed.

  • ListBase in dart:collection always returns an Iterable with the correct type argument.

1.8.0 – 2014-11-28

  • dart:collection: SplayTree added the toSet function.

  • dart:convert: The JsonUtf8Encoder class was added.

  • dart:core:

    • The IndexError class was added for errors caused by an index being outside its expected range.

    • The new RangeError.index constructor was added. It forwards to new IndexError.

    • RangeError added three new properties. invalidProperty is the value that caused the error, and start and end are the minimum and maximum values that the value is allowed to assume.

    • new RangeError.value and new RangeError.range added an optional message argument.

    • The new String.fromCharCodes constructor added optional start and end arguments.

  • dart:io:

    • Support was added for the Application-Layer Protocol Negotiation extension to the TLS protocol for both the client and server.

    • SecureSocket.connect, SecureServerSocket.bind, RawSecureSocket.connect, RawSecureSocket.secure, RawSecureSocket.secureServer, and RawSecureServerSocket.bind added a supportedProtocols named argument for protocol negotiation.

    • RawSecureServerSocket added a supportedProtocols field.

    • RawSecureSocket and SecureSocket added a selectedProtocol field which contains the protocol selected during protocol negotiation.

1.7.0 – 2014-10-15

Tool changes

  • pub now generates binstubs for packages that are globally activated so that they can be put on the user's PATH and used as normal executables. See the pub global activate documentation.

  • When using dart2js, deferred loading now works with multiple Dart apps on the same page.

Core library changes

  • dart:async: Zone, ZoneDelegate, and ZoneSpecification added the errorCallback function, which allows errors that have been programmatically added to a Future or Stream to be intercepted.

  • dart:io:

    • Breaking change: HttpClient.close must be called for all clients or they will keep the Dart process alive until they time out. This fixes the handling of persistent connections. Previously, the client would shut down immediately after a request.

    • Breaking change: HttpServer no longer compresses all traffic by default. The new autoCompress property can be set to true to re-enable compression.

  • dart:isolate: Isolate.spawnUri added the optional packageRoot argument, which controls how it resolves package: URIs.