wasm-shrink doesn't work as described?

[osa1]

I'm trying to run wasm-shrink on a 17M .wasm file.

Issues:

• The interestingness script path works if I pass ./script.sh or absolute path to the script, but script.sh fails with error: Failed to run predicate script 'test.sh'.

• It seems to ignore -o, it always dumps the shrunk program to stdout, with or without -o.

• The output is as .wat instead of .wasm, and contains a header like blah.shrunken.wasm :: 17840554 bytes (0.00% smaller).

• It doesn't seem to shrink: see 0.00% above. I haven't compared the actual output because it's in wat format and my input is .wasm, but it seems like it's generating .wasm as well as .wat, as 0.00% smaller would be the shown amount in .wasm, not in .wat.

  When I enable trace logs I see lines like:

  [2025-02-13T11:23:45Z TRACE] Attempt #423: mutation failed (Error { kind: Parse(BinaryReaderError { inner: BinaryReaderErrorInner { message: "gc proposal not supported", kind: Custom, offset: 15, needed_hint: None } }) })
  

  So that should be the reason why it doesn't shrink.

  But it would be helpful to the user if it failed with this error in a visible way.

I tried with the latest released version of wasm-tools.

[alexcrichton]

For ./script.sh, did you do chmod +x ./script.sh? For -o looking at the implementation it looks like the directory is mostly used rather than the exact -o so that's something we should fix! Right now the output should include both *.wasm and *.wat so they can be seen side-by-side.

For the actual reduction there's not a lot of gc support just yet. There's some graceful error handling for unsupported proposals as there's varying degrees of support amongst the supported mutations. In that sense it's sort of like how the GC proposal is 1% supported and 99% unsupported and reasonable reduction here probably requires the 99%.