Getting builders onto 3.0.0 --> analyzer element2 model

[davidmorgan]

Please note I'll be away/unavailable 28th June - 6th July, happy to help when I'm back on the 7th! -- Morgan

The analyzer's new element2 APIs are a prerequisite for adding augmentations to the language, which is a feature I'm sure we're all looking forward to :)

Unfortunately for builder maintainers it does mean a breaking change, if you use resolvers/analysis.

Here's the migration guide.

Some example migrations:

google/built_value.dart#1369
google/json_serializable.dart#1504
dart-lang/mockito#817

I've released the build element2 version as a prerelease 3.0.0-dev.

For those using source_gen, the element2 version is merged and pending release, so for now you'll need a git dependency to use it.

Of course we'll be taking any feedback and tweaking/fixing as needed for the full release.

FAQ

What min Dart/Flutter version does my package work with if I switch to 3.0.0 / element2?

Dart >= 3.7, which means Flutter stable releases 3.29 (Feb 12th 2025) and 3.32 (May 20th 2025). This is with analyzer 7.4.0.

Will APIs break again with analyzer 8.0.0?

The current element2 APIs will continue to work until 9.0.0.

Analyzer 8.0.0 will remove the element1 names, such as LibraryElement, but will not remove element2 names, such as LibraryElement2. Then during version 8, they will be renamed in a non-breaking way by adding aliases, e.g. LibraryElement now as an alias of LibraryElement2, and deprecating LibraryElement2. Then LibraryElement2 will be removed only in 9.0.0.