WebAssembly with Reference Types cannot be parsed

[CryZe]

Reopened #13559

Bug report

WebAssembly modules with enabled Reference Types cannot be loaded. The webpack version I tested this with is 5.38.1

For a minimal reproduction I created this repository: https://github.com/Tarnadas/webpack-5-wasm-reftypes

The error message is the following:

ERROR in ./pkg/webpack_5_wasm_reftypes_bg.wasm
Module parse failed: Internal failure: parseVec could not cast the value
You may need an appropriate loader to handle this file type, currently no loaders are configured to process this file. See https://webpack.js.org/concepts#loaders
Error: Internal failure: parseVec could not cast the value
    at new CompileError (/home/marior/projects/webpack-5-wasm-reftypes/node_modules/@webassemblyjs/helper-api-error/lib/index.js:40:109)
    at parseVec (/home/marior/projects/webpack-5-wasm-reftypes/node_modules/@webassemblyjs/wasm-parser/lib/decoder.js:328:15)
    at parseTypeSection (/home/marior/projects/webpack-5-wasm-reftypes/node_modules/@webassemblyjs/wasm-parser/lib/decoder.js:360:22)
    at parseSection (/home/marior/projects/webpack-5-wasm-reftypes/node_modules/@webassemblyjs/wasm-parser/lib/decoder.js:1363:24)
    at Object.decode (/home/marior/projects/webpack-5-wasm-reftypes/node_modules/@webassemblyjs/wasm-parser/lib/decoder.js:1712:25)
    at decode (/home/marior/projects/webpack-5-wasm-reftypes/node_modules/@webassemblyjs/wasm-parser/lib/index.js:248:21)
    at WebAssemblyParser.parse (/home/marior/projects/webpack-5-wasm-reftypes/node_modules/webpack/lib/wasm-async/AsyncWebAssemblyParser.js:48:19)
    at /home/marior/projects/webpack-5-wasm-reftypes/node_modules/webpack/lib/NormalModule.js:1018:26
    at processResult (/home/marior/projects/webpack-5-wasm-reftypes/node_modules/webpack/lib/NormalModule.js:745:11)
    at /home/marior/projects/webpack-5-wasm-reftypes/node_modules/webpack/lib/NormalModule.js:809:5
 @ ./pkg/webpack_5_wasm_reftypes.js 1:0-58 4:0-21
 @ ./src/index.js 1:0-16

webpack 5.38.1 compiled with 1 error in 572 ms
error Command failed with exit code 1.

I used Rust with wasm-bindgen, which provides a cli option to enable reference types. Instead of directly using wasm-bindgen, I’ve been using wasm-pack, but since it’s unmaintained, you will need my fork to pass the cli option down to wasm-bindgen. You can see my PR for wasm-pack here: rustwasm/wasm-pack#888

By looking at the error message, it seems to be a problem with the wasm parser library. I checked its repository and couldn’t find any mentions about reference types unfortunately, so I’m not sure how to proceed with this.

[vankop]

I think parser does not support them.. (@webassemblyjs/wasm-parser) . Right now there is no workaround for this.

[enomado]

Why webpack try to parse it? can we just use file-loader?

[vankop]

Why webpack try to parse it?

There are some exports optimization.. so webpack parsing wasm.

can we just use file-loader?

yes, sure. also in webpack@5 there is asset type.

[sokra]

@xtuc

[webpack-bot]

This issue had no activity for at least three months.

It's subject to automatic issue closing if there is no activity in the next 15 days.

[CryZe]

ping

[webpack-bot]

Issue was closed because of inactivity.

If you think this is still a valid issue, please file a new issue with additional information.

[CryZe]

Last time you at least gave a warning, and it's marked as completed?? This has to be the worst bot ever.

[CryZe]

Ok dude

[alexander-akait]

@xtuc Friendly ping

[bes]

Stripping solves the problem:

[profile.release]
strip = true

This isn't great for debug builds however, as you usually want the debug symbols. I believe the reason why stripping works isn't because it does any stripping, but because it likely optimizes the overlong immediates encoding back to how it was before LLVM 19. Running wasm-opt probably behaves the same way.

@CryZe What problem did you solve by stripping? I tried stripping but I still get the same error:

Can't import the named export '__wbindgen_start' (imported as 'wasm') from default-exporting module (only default export is available)

EDIT; stripping seems to work, but not in combination with the suggested module/rules fix by @alexander-akait above. Stripping has some other issues, but it's better than nothing!

[CryZe]

Without the babel-loader workaround that you tried.

[bes]

Sorry, yeah, I just tried that and it worked (edited my reply)

[bes]

Just as a FYI, it's still not possible to actually use reference types (as far as I can tell). Stripping, gets me as far as "my old binary without reference types works".

To get reference types to even pass compile/wasm-pack/wasm-opt I needed to:

//.cargo/config.toml
[target.wasm32-unknown-unknown]
rustflags = [
    "-C", "target-feature=+bulk-memory,+mutable-globals"
]

// Cargo.toml
[package.metadata.wasm-pack.profile.release]
wasm-opt = ['-Oz', '--enable-bulk-memory']

// Shell / Building
  wasm-pack build \
    --release \
    --weak-refs \
    --reference-types \
    --target bundler \
    --scope "myscope" .

But then webpack says

Module parse failed: Internal failure: parseVec could not cast the value
You may need an appropriate loader to handle this file type, currently no loaders are configured to process this file. See https://webpack.js.org/concepts#loaders
Error: Internal failure: parseVec could not cast the value

I don't need reference types, I just wanted to see how far I would get.

[stephanemagnenat]

I believe the reason why stripping works isn't because it does any stripping, but because it likely optimizes the overlong immediates encoding back to how it was before LLVM 19.

I can confirm this, as switching back to WebAssembly MVP features with:

[package.metadata.wasm-pack.profile.release]
wasm-opt = ['-Os', '-mvp', '--strip-target-features']

does not solve the problem. I did not find a way to use wasm-opt to change the immediate encoding back to something supported by webpack.

[stephanemagnenat]

Note that in big projects with a workspace having multiple crates, the current webpack limitation is really annoying, because due to a cargo limitation, the strip option must be specified at the workspace level, so that would affect all crates including the ones not compiled for WASM targets. As @CryZe mentioned, that is really a problem for debugging.

[CryZe]

On the weekend I tracked down the issue back into wasm-bindgen which apparently uses the target_features section to detect if it should automatically enable its full reference types support. I opened a PR that ensures that you still have to opt into that manually, so that should fix all issues that were caused by Rust 1.82: rustwasm/wasm-bindgen#4213

[alexander-akait]

@bes can you make a reproducible example so that I can examine it?

@stephanemagnenat

Note that in big projects with a workspace having multiple crates, the current webpack limitation is really annoying, because due to a cargo limitation

This is not our limitation because we simply cannot run the parser, it crashes with an error, this should be fixed in @webassemblyjs/wasm-parser, that's why I ping @xtuc

[bes]

@alexander-akait here you go https://github.com/bes/webpack-wasm-reference-types-1.82-poc

[alexander-akait]

@bes Yeah, I see the problem, need wait - rustwasm/wasm-bindgen#4211, but anyway, it will not solve - xtuc/webassemblyjs#1146, we need someone to send a pr and solve this issue, unfortunately my knowledge in you is not deep enough to complete this task.

I would say more that this problem is more a question of the node ecosystem, not just webpack

[xtuc]

Version 1.13.1 has been published with reference types support. We need to update in webpack.

[alexander-akait]

@xtuc I tried 1.13.1 update and still get - Error: Internal failure: parseVec could not cast the value, repro - https://github.com/bes/webpack-wasm-reference-types-1.82-poc

[alexander-akait]

The same - #18940

[xtuc]

Thanks for checking @alexander-akait . I'm having a look.

[xtuc]

I published 1.14.1. Could you please try again @alexander-akait ?

Sorry I had some issues with my publish setup.

[mateuszJS]

@xtuc Works for me!

    "@webassemblyjs/ast": "^1.14.1",
    "@webassemblyjs/wasm-edit": "^1.14.1",
    "@webassemblyjs/wasm-parser": "^1.14.1",

https://github.com/mateuszJS/rust-webpack-v5-template/tree/webpack-v5-migration
Thank you for great work 👍

[stephanemagnenat]

@xtuc works for me as well! Thank you very much!