How to debug CLI

[RunDevelopment]

Summary

How I can attach a debugger to the CLI for tests. I want to debug the JS code gen part but couldn't find any docs for debugging.

I'm using VSCode btw and I cannot figure it out.

Additional Details

I would also like to add how to do it to the docs once I know.

[daxpedda]

Is there anything special about wasm-bindgen that prevents regular debugging from working?

A quick google just gave me this: https://code.visualstudio.com/docs/languages/rust#_debugging, which is pretty much what I use as well.

[RunDevelopment]

No. #4242 just made debug work with the code in reference.rs. I still haven't been able to debug the actual JS code gen.

[daxpedda]

Probably the easiest way I know of to do what you want here is to just start the CLI binary through the debugger directly.
Ergo, just click "Debug" on fn main() in crates/cli/wasm-bindgen.rs and setup the right arguments in launch.json.

Alternatively you could just call the wasm-bindgen-cli-support library directly, then the debugger should work.

AFAIK VSCode doesn't possess any auto attach capability for debugging, but I found this guide for LLDB extension, this way you should be able to tell VSCode to attach the debugger directly from your code!

[daxpedda]

I simply added the lines of code as suggested in the guide into fn main() in crates/cli/wasm-bindgen.rs and it actually worked like a charm.

So this might be the easiest way to do it.

[RunDevelopment]

Thanks for the guides! I'll try them tomorrow.

On a different note: I just had a thought. Why is reference.rs calling the CLI via Command::cargo_bin? Sure, E2E is nice, but couldn't we use the Bindgen API directly to bypass the CLI being separate binary? This would make debugging directly with reference.rs possible.

[daxpedda]

Because of that E2E you mentioned!