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Upgrading source_gen 2 to 3

Breaking2.0.0 → 3.1.0Breaking1Platform2Deprecated1New2Changed4

Full comparisonBack to source_gen
BreakingUpgrade verdict

1 breaking change and 2 platform requirement changes.

In plain terms
  • Code generators that look up type information must be updated to the analyzer's new element model.
  • You need Dart SDK 3.7.0 or newer to use this version.
  • You need Dart 3.7.0 or newer to use this version.
  • A way of looking up types that relies on runtime reflection is being retired. Use the new lookup method instead.
Must act 4 items need code or config changes

source_gen publishes an official migration guide for version 3. It covers more than the release notes do.

Migration guide ↗

Dart SDK requirement changed in 3.0.0-dev: ^3.6.0 → ^3.7.0.

What you must change

Breaking1
Uses the new element2 APIs in analyzer; builders that do resolution must switch to the new API.
element2
3.0.0GitHub ReleaseSummarizedView source
Platform2
Requires Dart 3.7.0.
3.0.0GitHub ReleaseSummarizedView source
Requires Dart 3.7.0.
3.0.0-devGitHub ReleaseSummarizedView source

Deprecations to plan for

Deprecated1
Deprecates TypeChecker.fromRuntime ahead of removal in 4.0.0 and adds TypeChecker.typeNamed as the recommended replacement.
TypeChecker.fromRuntimeTypeChecker.typeNameddart:mirrors
3.1.0CHANGELOG.mdSummarizedView source