Johnni Winther
eb8156415c
Change-Id: Iac3850696fb5e48dff847d17f7110644e8b8bd03 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/395920 Reviewed-by: Jens Johansen <jensj@google.com> Commit-Queue: Johnni Winther <johnniwinther@google.com> Reviewed-by: Slava Egorov <vegorov@google.com>
26 lines
1.1 KiB
Markdown
26 lines
1.1 KiB
Markdown
# Experiment flags
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If you're implementing a language feature, then it needs to have an accompanying
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experiment flag. (Or multiple experiments if it's going to be enabled over the
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course of multiple releases.)
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## Adding an experiment flag
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Experiment flags are shared across all of the tools, so they are defined in a
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single location. To add a new flag, edit
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[`experimental_features.yaml`](https://github.com/dart-lang/sdk/blob/main/tools/experimental_features.yaml).
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The initial commit is only required to define the name and to include a `help:`
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key.
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To generate the declarations used by the analyzer, run
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`dart pkg/analyzer/tool/experiments/generate.dart`.
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To generate the declarations used by the front-end, run
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`dart pkg/front_end/tool/cfe.dart generate-experimental-flags`.
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## Summary representation
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The set of (the indexes of) enabled experiments is used to build the hash for
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[summary files](summaries.md). If defining the new experiment flag changes the
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indexes of existing experiment flags, then the value of the static field
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`AnalysisDriver.DATA_VERSION` needs to be incremented. |