wasm-pack build --target web panics for hello_world from a checked out repository

[kud1ing]

Describe the Bug

wasm-pack build --target web on the hello_world example in a repository checkout gives a panic:

[INFO]: 🎯  Checking for the Wasm target...
[INFO]: 🌀  Compiling to Wasm...
    Finished release [optimized] target(s) in 0.21s
[INFO]: ⬇️  Installing wasm-bindgen...
thread 'main' panicked at 'index out of bounds: the len is 0 but the index is 0', crates/cli-support/src/descriptor.rs:195:15
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
   1: std::sys_common::backtrace::_print
   2: std::panicking::default_hook::{{closure}}
   3: std::panicking::default_hook
   4: std::panicking::rust_panic_with_hook
   5: std::panicking::continue_panic_fmt
   6: rust_begin_unwind
   7: core::panicking::panic_fmt
   8: core::panicking::panic_bounds_check
   9: wasm_bindgen_cli_support::descriptor::Descriptor::_decode
  10: wasm_bindgen_cli_support::descriptor::Descriptor::_decode
  11: wasm_bindgen_cli_support::descriptor::Descriptor::_decode
  12: wasm_bindgen_cli_support::descriptor::Descriptor::_decode
  13: <alloc::vec::Vec<T> as alloc::vec::SpecExtend<T,I>>::from_iter
  14: wasm_bindgen_cli_support::descriptor::Function::decode
  15: wasm_bindgen_cli_support::descriptor::Descriptor::_decode
  16: wasm_bindgen_cli_support::descriptors::execute
  17: wasm_bindgen_cli_support::Bindgen::_generate
  18: wasm_bindgen::main
  19: std::rt::lang_start::{{closure}}
  20: std::panicking::try::do_call
  21: __rust_maybe_catch_panic
  22: std::rt::lang_start_internal
  23: main
Error: Running the wasm-bindgen CLI
Caused by: failed to execute `wasm-bindgen`: exited with exit code: 101

Steps to Reproduce

• checkout https://github.com/rustwasm/wasm-bindgen
• got to examples/hello_world/
• execute wasm-pack build --target web

Expected Behavior

wasm-pack build --target web should not panic.

Actual Behavior

wasm-pack build --target web panics.

Additional Context

There is no panic, if only the hello_world directory is downloaded, instead of checking out the repository.

[alexcrichton]

Thanks for the report! This is an issue of mismatch between the git crate and the crates.io CLI. The bug here is in wasm-bindgen itself and is tracked at #1227.

To build the examples out of the wasm-bindgen repository the best way to do it is to copy them out and then wasm-pack build should work.

[kud1ing]

Thank you.