FRB Debugging

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

When to Use

• Generated code looks wrong
• Code generation fails
• Need to understand FRB internals
• Runtime errors in generated code

Quick Diagnostics

Dump Intermediate Representations

The in-tree examples by default enable dump_all: true in flutter_rust_bridge.yaml for debugability.

Therefore, you can check rust/target/frb_dump/ for:

• Effective configuration
• IR (intermediate representation)
• Generated spec and code
• ...

Debug Logs

bash
RUST_LOG=debug flutter_rust_bridge_codegen ...

Full Troubleshooting

If above doesn't help, see:

• website/docs/docs/guides/contributing/tip.md
• website/docs/manual/troubleshooting.md

Before going deep into FRB internals, first check whether you are actually seeing failure propagation from unstable generated outputs or integrate templates.

In particular:

• If CI failures may be explained by failure propagation, repeated package-level drift, or unstable generated outputs, you MUST use frb-fix-ci first
• You MUST only stay in frb-debugging after frb-fix-ci has ruled out those simpler explanations

Related Skills

• frb-code-generation - Which generation commands to run
• frb-fix-ci - Diagnose CI failure propagation before deep debugging
• frb-develop-feature - Development workflow