Error when running "cargo leptos watch"

[kaliban2056]

Describe the Bug

I've just created a leptos project with "cargo leptos new --git https://github.com/leptos-rs/start".
The project has been created without problems but when I ran "cargo leptos watch", after the compilation I got this error:

PS C:\Users\%USERNAME%\Documents\Coding\leptos-project> cargo leptos watch
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.19s
       Cargo finished cargo build --package=rusty-llama --lib --target-dir=C:\Users\%USERNAME%\Documents\Coding\leptos-project\target\front --target=wasm32-unknown-unknown --no-default-features --features=hydrate
       Front compiling WASM
Error: at `D:\a\cargo-leptos\cargo-leptos\src\compile\front.rs:47:30`

Caused by:
    0: at `D:\a\cargo-leptos\cargo-leptos\src\compile\front.rs:120:10`
    1:

       it looks like the Rust project used to create this wasm file was linked against
       version of wasm-bindgen that uses a different bindgen format than this binary:

         rust wasm file schema version: 0.2.92
            this binary schema version: 0.2.89

       Currently the bindgen format is unstable enough that these two schema versions
       must exactly match. You can accomplish this by either updating this binary or
       the wasm-bindgen dependency in the Rust project.

       You should be able to update the wasm-bindgen dependency with:

           cargo update -p wasm-bindgen --precise 0.2.89

       don't forget to recompile your wasm file! Alternatively, you can update the
       binary with:

           cargo install -f wasm-bindgen-cli --version 0.2.92

       if this warning fails to go away though and you're not sure what to do feel free
       to open an issue at https://github.com/rustwasm/wasm-bindgen/issues!

I've executed both the commands to update and install the new version, but when I run again "cargo leptos watch" I get the same output.

Steps to Reproduce

1. "cargo leptos new --git https://github.com/leptos-rs/start"
2. Enter the project directory
3. "cargo leptos watch"
4. See error

Expected Behavior

I should be able to see a website hosted on localhost.

Actual Behavior

Doesn't compile and get always the same error.

[kanielrkirby]

I'm no expert, but it would definitely help anyone wanting to help you to have more information about your environment. What did you use to set up your Rust environment (rustup or something else)? Which wasm targets have you added (rustup target list --installed)? What's your OS / package manager / cargo version?

You might also try removing the target, ~/.cargo, some of the ~/.cache folders that are related, etc., as sometimes caches can conflict. Just things that have helped me with similar issues.

[Liamolucko]

This is an unfortunate consequence of the way Leptos handles wasm-bindgen versions.

The first command doesn't work because Leptos' starter template sets wasm-bindgen = "=0.2.92", and cargo update can't update pinned versions.

The second command doesn't work because cargo leptos doesn't actually use wasm-bindgen-cli: it bakes in a specific version of wasm-bindgen-cli-support.

Installing the latest version of cargo-leptos should fix this, since it uses wasm-bindgen 0.2.92 the same as the template.

See also #3900.