FRB Code Generation

> Note: Check your user-level remote-testing rules before running commands. Codegen may require remote execution.

Overview

flutter_rust_bridge requires code generation when Rust APIs change. This skill maps change types to the minimal generation commands needed.

Core principle: Run only the generation commands needed for your change type.

Validation rule: If regenerated outputs cause previously green non-Generate jobs to fail, treat the generated outputs as suspect until they are validated from a clean environment.

> After codegen: Check your user-level remote-testing rules. If codegen was run remotely, pull changes back to local.

Quick Reference

| Change Type | Command | |-------------|---------| | Example Rust API (frb_example/**/rust/src/api/*.rs) | ./frb_internal precommit-generate | | Flutter integrate examples | ./frb_internal precommit-integrate | | frb_codegen/ generation logic | ./frb_internal precommit-generate + generate-internal-rust | | frb_rust/src/ core API | ./frb_internal generate-internal-rust | | frb_example/pure_dart generator | ./frb_internal generate-internal-frb-example-pure-dart | | CLI help documentation | ./frb_internal generate-internal-book-help | | Non-generated (docs, comments, tests, frb_dart/) | No generation needed |

Important Rules

Integrate Template Drift

If a diff touches Flutter integrate example outputs, platform scaffolds, or copied cargokit files under frb_example/**, check whether the real source of truth should also change under frb_codegen/assets/integration_template/.

Do not submit only downstream integrate output changes when the behavior belongs in the template. Update the template first, then run:

bash
./frb_internal precommit-integrate

Treat frb_codegen/assets/integration_template/**/cargokit as the source of truth for copied cargokit output. If the actual bug belongs inside the external cargokit submodule, read the frb-cargokit skill before deciding whether to patch the submodule and update its pointer.

For CI diagnosis rules about generated-file format/lint failures, repeated package-level Generate drift, or Generate :: FRB Codegen :: Command Integrate failures, you MUST read frb-fix-ci first. This skill is for command selection, not CI failure-propagation diagnosis.

For pure_dart / pure_dart_pde generation issues, treat frb_example/pure_dart as the upstream source and frb_example/pure_dart_pde as the derived copy. See frb-fix-ci for the CI diagnosis workflow.

If CI repair has already entered repeated package-level drift, you MUST stop choosing narrower commands and switch to frb-fix-ci.

Do not manually patch generated files as the final fix. The final accepted result should be produced by the corresponding generation command in a clean matching environment.