Stream: cargo-component

Topic: Error compiling a component to `wasm32-unknown-unknown`

Matt Andrews (Jun 26 2024 at 04:49):

Hey everyone,
I'm trying to compile a component without any WASI imports as they're not necessary in this case. I'm using target wasm32-unknown-unknown and I'm getting this error,

error: failed to decode world from module

Caused by:
    0: module was not valid
    1: module requires an import interface named `__wbindgen_placeholder__`

Here is the WIT file,

package graph:api@0.0.1;

interface data-store {
    resource db {
        constructor();
        scan: func(path: tuple<string, string>) -> list<u8>;
        schema: func(path: tuple<string, string>) -> list<u8>;
    }
}

world function {
    enum error {
        none,
        deserialize,
    }

    export run-query: func() -> result<tuple<list<u8>, list<u8>>, error>;

    import data-store;
}

I've been going around in circles with this for a few hours. Any help would be greatly appreciated.

Thanks

Matt Andrews (Jun 26 2024 at 05:36):

I'd also add that the component does actually compile and a wasm file is created, but the error appears after compilation is finished and the component cant be compiled in the runtime.

Ramon Klass (Jun 26 2024 at 11:36):

the mention of wbindgen means that you are using some rust crate that detects "wasm32-unknown-unknown" and assumes that means wasm-bindgen wasm targeting browsers

Ramon Klass (Jun 26 2024 at 11:37):

ask cargo tree what depends on wasm-bindgen

Ramon Klass (Jun 26 2024 at 11:39):

(I hope my information is still up to date, wbindgen_placeholder seems unfamiliar but so far all wbindgen errors meant something depends on wasm-bindgen)

Matt Andrews (Jun 26 2024 at 20:06):

There's no dependency on wasm-bindgen. If I compile with the default wasm32-wasi i get this error when trying to run the component,

component imports instance `wasi:cli/environment@0.2.0`, but a matching implementation was not found in the linker

Ryan Levick (rylev) (Jun 27 2024 at 12:39):

As Roman points out, the most likely cause is that one of your dependencies interprets the wasm32-unknown-unknown target to mean "I'm running in a browser" which is not what you want. Without seeing more about your project (e.g., Cargo.toml file), it's hard to say for sure where the issue is coming from.

Last updated: Nov 25 2024 at 19:03 UTC