In wasm-bindgen 0.2.84 version, webpack cannot generate wasm files

[linzhipeng98]

Steps to Reproduce

I created a repo with the problem here

Step1:
npm run i

Step2:
wasm-pack build

Step3:
npm run build

A dist dir contain index.js and wasm file will be generated in the project root; It is expected behavior.

When i change the wasm-bindgen version to 0.2.84 and run
rm -r pkg && wasm-pack build && npm run build

In dist dir, webpack doesn't generate wasm files.

[hschimke]

I've noticed this as well, additionally: setting the version of wasm-bindgen back to 83 isn't respected for some reason, and cargo continues building with 84 regardless.

In my case, the files are being generated but they are invalid, and any use of them results in a javascript undefined.

[AlexTMjugador]

I can reproduce this issue on my project too. Trying to use the WASM module from JS in a development server throws a wasm is undefined exception.

[Liamolucko]

This seems to be a bug in Webpack, triggered by #3152. As a workaround, switching to dynamically importing the wasm-bindgen shim fixes it for some reason.

[Liamolucko]

It turns out this is happening because wasm-pack sets "sideEffects": false for wasm-bindgen generated code, which is a Webpack-specific flag that tells Webpack it can remove any code whose only impact is a side effect. In #3152, I unwittingly made initialisation rely on side effects, causing this problem.

(So, it's not a Webpack bug, I was a bit quick to assume that.)

I've opened rustwasm/wasm-pack#1224 to fix this. @alexcrichton or @drager, could you take a look at that PR?

[alexcrichton]

Ah sorry, I don't manage the wasm-pack repository myself.

[drager]

It turns out this is happening because wasm-pack sets "sideEffects": false for wasm-bindgen generated code, which is a Webpack-specific flag that tells Webpack it can remove any code whose only impact is a side effect. In #3152, I unwittingly made initialisation rely on side effects, causing this problem.

(So, it's not a Webpack bug, I was a bit quick to assume that.)

I've opened rustwasm/wasm-pack#1224 to fix this. @alexcrichton or @drager, could you take a look at that PR?

Yeah, I will take a look soon. Thanks for looking into and fixing it!

[cryptoquick]

I tried setting everything back to 0.2.83, by running these steps in this order (after some trial and error):

cargo update -p wasm-bindgen-test --precise 0.3.33
cargo update -p wasm-bindgen-futures --precise 0.4.33
cargo update -p web-sys --precise 0.3.60
cargo update -p js-sys --precise 0.3.60
cargo update -p wasm-bindgen --precise 0.2.83

And then built it with rustc 1.67.1, making sure that the old versions were indeed the ones that were compiled...

But it still didn't solve the issue I ran into in #3306.

[Liamolucko]

I tried setting everything back to 0.2.83, by running these steps in this order (after some trial and error):

cargo update -p wasm-bindgen-test --precise 0.3.33
cargo update -p wasm-bindgen-futures --precise 0.4.33
cargo update -p web-sys --precise 0.3.60
cargo update -p js-sys --precise 0.3.60
cargo update -p wasm-bindgen --precise 0.2.83

And then built it with rustc 1.67.1, making sure that the old versions were indeed the ones that were compiled...

But it still didn't solve the issue I ran into in #3306.

I can't reproduce this. Could you give more detailed instructions?

[cryptoquick]

I tried setting everything back to 0.2.83, by running these steps in this order (after some trial and error):

cargo update -p wasm-bindgen-test --precise 0.3.33
cargo update -p wasm-bindgen-futures --precise 0.4.33
cargo update -p web-sys --precise 0.3.60
cargo update -p js-sys --precise 0.3.60
cargo update -p wasm-bindgen --precise 0.2.83

And then built it with rustc 1.67.1, making sure that the old versions were indeed the ones that were compiled...
But it still didn't solve the issue I ran into in #3306.

I can't reproduce this. Could you give more detailed instructions?

I've updated and uploaded my MRE:
https://github.com/cryptoquick/wasm-bindgen-mre

I've made a few more changes, up to here: cryptoquick/wasm-bindgen-mre@ee313c0

Still not working, same error as in README, not sure what else I can do...

I'm sure the cache is clearing too, since each time, I test with a different port on my local server.

[Liamolucko]

I've updated and uploaded my MRE:

https://github.com/cryptoquick/wasm-bindgen-mre

I've made a few more changes, up to here: cryptoquick/wasm-bindgen-mre@ee313c0

Still not working, same error as in README, not sure what else I can do...

I'm sure the cache is clearing too, since each time, I test with a different port on my local server.

That repo isn't demonstrating the original issue that you had in #3306, it's a completely separate issue which is occurring because you're not running await init() before using the wasm exports on --target web, as people already pointed out in #3306.

The original problem was with --target bundler, not --target web, and that's the issue that I believe is the same as this one and wasn't present in 0.2.83.

[kleinesfilmroellchen]

I have this exact issue, as soon as I upgrade to web_sys 0.3.61 from 0.3.60 any call to a Rust function from JavaScript results in an undefined error like:

bootstrap.js:2 Error importing `index.js`: TypeError: Cannot read properties of undefined (reading 'on_assembly_change')
    at Module.on_assembly_change (spcasm_web_bg.js:269:10)
    at eval (index.js:36:46)
    at __webpack_require__.a (bootstrap.js:357:13)
    at eval (index.js:1:21)
    at ./index.js (index_js.bootstrap.js:28:1)
    at __webpack_require__ (bootstrap.js:284:33)
    at Function.fn (bootstrap.js:592:21)

(on_assembly_change is the Rust function being called, which sort of has bindings generated, as you can see)

[FlareFlo]

I have this exact issue, as soon as I upgrade to web_sys 0.3.61 from 0.3.60 any call to a Rust function from JavaScript results in an undefined error like:

bootstrap.js:2 Error importing `index.js`: TypeError: Cannot read properties of undefined (reading 'on_assembly_change')
    at Module.on_assembly_change (spcasm_web_bg.js:269:10)
    at eval (index.js:36:46)
    at __webpack_require__.a (bootstrap.js:357:13)
    at eval (index.js:1:21)
    at ./index.js (index_js.bootstrap.js:28:1)
    at __webpack_require__ (bootstrap.js:284:33)
    at Function.fn (bootstrap.js:592:21)

(on_assembly_change is the Rust function being called, which sort of has bindings generated, as you can see)

I get issues with my own functions, or some stack pointer calls, such as Uncaught (in promise) TypeError: Cannot read properties of undefined (reading '__wbindgen_add_to_stack_pointer')

[cryptoquick]

That repo isn't demonstrating the original issue that you had in #3306, it's a completely separate issue which is occurring because you're not running await init() before using the wasm exports on --target web, as people already pointed out in #3306.

The original problem was with --target bundler, not --target web, and that's the issue that I believe is the same as this one and wasn't present in 0.2.83.

I actually updated the comment you responded to only a few minutes after I posted it. Please take another look.

[cryptoquick]

@Liamolucko I just took another look at my code and realized what you were explaining. I've fixed it and the MRE passes, so you are correct in that it is no longer relevant to this discussion.

[Liamolucko]

This is now fixed in wasm-pack v0.11.0.