[analyzer] Don't find the same "fixes for all" multiple times

Before this CL, if one has a file like

```
Map<String, String> foo = {
  "1": "1",
  "2": "2",
  "3": "3",
[...]
```

with many violations of the prefer_single_quotes lint, using VSCode and
selecting all would lock up the analysis server, e.g. in
https://dart-review.googlesource.com/c/sdk/+/425503 I showed 400 such
lines taking ~36 seconds on my machine (and 800 such lines taking ~247
seconds).

This is because for each error (lint) in range (i.e. all of them) it
calculates fixes for all of them. Once it's done with that it
deduplicates and throws most of the data away again.

This CL instead only calculates the "fixes for all" for each
combination of error-type and generator, skipping lots of work,
making the whole thing be much faster.

In the data send to the client (VSCode in this instance) the
"diagnostics" for
"Convert to single quoted strings everywhere in file"
contains fewer elements (only 1, vs all before), but it's unclear when
(or if) this is used. Note that the "edit"s does contain all, and
applying it still changes all instances.

I now get these runtimes for the select all case (via the benchmark)
(with cpu governor "performance" which likely wasn't the case for
the ~36 seconds and ~247 seconds above, although it doesn't matter
much with these differences):

400: 0.736783
800: 1.502978
1600: 3.704314
3200: 10.701988

Change-Id: I2b69a77525c0e1ed720c2b3d1de70ccc1fc5e94c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/425861
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>
7 files changed
tree: c315bf98ab476957db1e39a5b8d8fccf78899cc9
  1. .dart_tool/
  2. .github/
  3. benchmarks/
  4. build/
  5. docs/
  6. pkg/
  7. runtime/
  8. samples/
  9. sdk/
  10. tests/
  11. third_party/
  12. tools/
  13. utils/
  14. .clang-format
  15. .gitattributes
  16. .gitconfig
  17. .gitignore
  18. .gn
  19. .mailmap
  20. .style.yapf
  21. AUTHORS
  22. BUILD.gn
  23. CHANGELOG.md
  24. codereview.settings
  25. CONTRIBUTING.md
  26. DEPS
  27. LICENSE
  28. OWNERS
  29. PATENT_GRANT
  30. PRESUBMIT.py
  31. pubspec.yaml
  32. README.dart-sdk
  33. README.md
  34. sdk.code-workspace
  35. sdk_args.gni
  36. sdk_packages.yaml
  37. SECURITY.md
  38. WATCHLISTS
README.md

Dart

An approachable, portable, and productive language for high-quality apps on any platform

Dart is:

  • Approachable: Develop with a strongly typed programming language that is consistent, concise, and offers modern language features like null safety and patterns.

  • Portable: Compile to ARM, x64, or RISC-V machine code for mobile, desktop, and backend. Compile to JavaScript or WebAssembly for the web.

  • Productive: Make changes iteratively: use hot reload to see the result instantly in your running app. Diagnose app issues using DevTools.

Dart's flexible compiler technology lets you run Dart code in different ways, depending on your target platform and goals:

  • Dart Native: For programs targeting devices (mobile, desktop, server, and more), Dart Native includes both a Dart VM with JIT (just-in-time) compilation and an AOT (ahead-of-time) compiler for producing machine code.

  • Dart Web: For programs targeting the web, Dart Web includes both a development time compiler (dartdevc) and a production time compiler (dart2js).

Dart platforms illustration

License & patents

Dart is free and open source.

See LICENSE and PATENT_GRANT.

Using Dart

Visit dart.dev to learn more about the language, tools, and to find codelabs.

Browse pub.dev for more packages and libraries contributed by the community and the Dart team.

Our API reference documentation is published at api.dart.dev, based on the stable release. (We also publish docs from our beta and dev channels, as well as from the primary development branch).

Building Dart

If you want to build Dart yourself, here is a guide to getting the source, preparing your machine to build the SDK, and building.

There are more documents in our repo at docs.

Contributing to Dart

The easiest way to contribute to Dart is to file issues.

You can also contribute patches, as described in Contributing.

Roadmap

Future plans for Dart are included in the combined Dart and Flutter roadmap on the Flutter wiki.