feat: add preamble for dart generated files

[Krysl]

Changes

Fixes #1948

Checklist

• An issue to be fixed by this PR is listed above.
• New tests are added to ensure new features are working. Please refer to this page to see how to add a test.
• ./frb_internal precommit --mode slow (or fast) is run (it internal runs code generator, does auto formatting, etc).
• If this PR adds/changes features, documentations (in the ./website folder) are updated.
• CI is passing. Please refer to this page to see how to solve a failed CI.

Remark for PR creator

• ./frb_internal --help shows utilities for development.
• If @fzyzcjy does not reply for a few days, maybe he just did not see it, so please ping him.

[welcome]

Hi! Thanks for opening this pull request! 😄

[Krysl]

I wrote it too hastily and added redundant parameters. I will clean them up.

[fzyzcjy]

Good job! To make CI pass (and if not want to run the too slow precommit), try cd frb_codegen && UPDATE_GOLDENS=1 cargo test. It would also be great to add a test, but since this is so trivial, I can also put the tests there in the next batch.

[fzyzcjy]

No worries about the failed Web test - looks like flaky

[fzyzcjy]

To make a test, just add premable config in https://github.com/fzyzcjy/flutter_rust_bridge/blob/master/frb_example/pure_dart/flutter_rust_bridge.yaml, and then run

./frb_internal generate-internal-frb-example-pure-dart
./frb_internal precommit-generate

and commit the changed code

[Krysl]

Sorry for late. the frb_internal test alwayse has some strange errors, and makes me a little impatient.

To make a test, just add premable config in https://github.com/fzyzcjy/flutter_rust_bridge/blob/master/frb_example/pure_dart/flutter_rust_bridge.yaml, ...

I've already tried adding a line of configuration there before, but the test didn't report any errors, and obviously there wasn't any verification of the generated code. Maybe I'm wrong?

[Krysl]

Adding one line of preamble affects hundreds of generated files in pure_dart and pure_dart_pde...
Should I commit these changes?
（I'm looking for a cleaner way for testing）

[fzyzcjy]

Anyway, then let me do it (hopefully within a day), no worries!

[Krysl]

Sorry, I'm too slow.
I add some test in frb_codegen\test_fixtures\library\codegen\generator\api_dart\mod\simple
Hope this is the right place for test.

[fzyzcjy]

Well, no need to be in there IMHO - just add premable config in master/frb_example/pure_dart/flutter_rust_bridge.yaml.

Adding one line of preamble affects hundreds of generated files in pure_dart and pure_dart_pde...

I am not sure what happened, but the generated code will only contain a few lines of change (the new header). Maybe it is because of failure of text formatting etc?

[Krysl]

Well, it's your code base. If you think it's acceptable, then I'll do as you say.

Maybe it is because of failure of text formatting etc?

No text formatting issues. (It's just that I don't like that such a simple patch affects so many files.)

[fzyzcjy]

If you think it's acceptable, then I'll do as you say.
affects hundreds of generated files in pure_dart and pure_dart_pde...
No text formatting issues. (It's just that I don't like that such a simple patch affects so many files.)

Oh I see - then your simple test looks totally reasonable and elegant! Sorry for the misundestanding, I originally thought you meant some bugs in scripts to run codegen like formatting issues.

[welcome]

Hi! Congrats on merging your first pull request! 🎉

[fzyzcjy]

@all-contributors please add @Krysl for code

[allcontributors]

@fzyzcjy

I've put up a pull request to add @Krysl! 🎉