Cache hits even if `wasm-bindgen` binary is missing

[danwilhelm]

🐛 Bug description

This bug affects some v0.6.0 users who will upgrade to v0.6.1, including #497 and #503.

The wasm-bindgen cache falsely reports a hit when the cache directory exists, but the binary does not.

This causes wasm-pack to fail on all subsequent builds requiring a cargo install (at least until the next wasm-bindgen version is released!).

🤔 Expected Behavior

When the wasm-bindgen binary is missing, a new cache should be created that overwrites the old one.

👟 Steps to reproduce

Occurs when all four are present:

1. wasm-bindgen is not in $PATH.
2. A prebuilt binary is not available (e.g. no Internet, no Windows build).
3. wasm-bindgen has been installed previously to the cache.
4. The wasm-bindgen binary in the cache has been removed.

---

MAC reproduction (Linux is similar)

In any WASM project:

1. cargo uninstall wasm-bindgen (removes wasm-bindgen from $PATH)
2. cargo build (creates the lockfile)
3. rm -rf ~/Library/Caches/.wasm_pack (removes existing cache)
4. mkdir -p ~/Library/Caches/.wasm_pack/wasm-bindgen-cargo-install-0.2.32 (creates a fake cargo install without a binary)
5. Disconnect from the Internet (makes the pre-built binary unavailable)
6. wasm-pack build <-- Use master

Should fail with:

Error: /Users/<username>/Library/Caches/.wasm_pack/wasm-bindgen-cargo-install-0.2.32/wasm-bindgen binary does not exist

---

WINDOWS reproduction (easier!)

In any WASM project:

1. cargo uninstall wasm-bindgen (removes wasm-bindgen from $PATH)
2. rm -rf ~\AppData\Local\.wasm_pack (removes existing cache)
3. wasm-pack build <-- Use v0.6.0 (should fail at end)
4. wasm-pack build <-- Use master

Note: This is shorter because the current version of wasm-bindgen does not have pre-built Windows binaries. So, it always defaults to cargo install. In wasm-pack v0.6.0, the correct cache directory is created, yet the binaries are not copied from /bin.

Should fail with:

Error: C:\Users\<username>\Local\.wasm_pack\wasm-bindgen-cargo-install-0.2.32\wasm-bindgen.exe binary does not exist

🌍 Your environment

Include the relevant details of your environment.
wasm-pack version: master branch
rustc version: rustc 1.33.0-nightly (8e2063d02 2019-01-07)

[danwilhelm]

Fixed in #509

[cmdcolin]

just for some posterity I was running into this somehow and I was getting weird errors trying to use the hello-world example in wasm-bindgen starter guide e.g. I would download the hello-world example, run npm run serve, then open the browser to http://localhost:8080 and there would be nothing except this in the dev console

TypeError: m.greet is not a function

in the npm run serve output it would say

~/Downloads/wasm-bindgen/examples/hello_world on main
% npm run serve

> serve
> webpack serve

🧐  Checking for wasm-pack...

✅  wasm-pack is installed at /run/user/1001/fnm_multishells/2028640_1659075796381/bin/wasm-pack.

ℹ️  Compiling your crate in development mode...

ℹ ｢wds｣: Project is running at http://localhost:8080/
ℹ ｢wds｣: webpack output is served from /
ℹ ｢wds｣: Content not from webpack is served from /home/cdiesh/Downloads/wasm-bindgen/examples/hello_world
[INFO]: Checking for the Wasm target...
[INFO]: Compiling to Wasm...
    Finished dev [unoptimized + debuginfo] target(s) in 0.05s
[INFO]: Installing wasm-bindgen...
Error: /home/cdiesh/.cache/.wasm-pack/wasm-bindgen-5edfed224f62a9f4/wasm-bindgen binary does not exist
ℹ ｢wdm｣: asset index.js 339 KiB [emitted] (name: main)
asset pkg_index_js.index.js 833 bytes [emitted]
asset index.html 232 bytes [emitted]
runtime modules 7.81 KiB 11 modules
modules by path ./node_modules/ 298 KiB
  modules by path ./node_modules/webpack-dev-server/ 21.2 KiB 12 modules
  modules by path ./node_modules/html-entities/lib/*.js 61 KiB 5 modules
  modules by path ./node_modules/webpack/hot/ 1.58 KiB 3 modules
  modules by path ./node_modules/url/ 37.4 KiB
    ./node_modules/url/url.js 22.8 KiB [built] [code generated]
    + 2 modules
  modules by path ./node_modules/querystring/*.js 4.51 KiB
    ./node_modules/querystring/index.js 127 bytes [built] [code generated]
    + 2 modules
  + 4 modules
./index.js 266 bytes [built] [code generated]
./pkg/index.js 1 bytes [built] [code generated]
webpack 5.74.0 compiled successfully in 702 ms
ℹ ｢wdm｣: Compiled successfully.

I had to look closely to see that it was not a success (everything was green) but a failure because of

Error: /home/cdiesh/.cache/.wasm-pack/wasm-bindgen-5edfed224f62a9f4/wasm-bindgen binary does not exist

The fix

I manually ran rm -rf ~/.cache/.wasm-pack and then re-ran the hello-world example npm run serve and it gave the correct compilation

~/wasm-bindgen/examples/hello_world on main took 6m13s
130 % npm run serve

> serve
> webpack serve

🧐  Checking for wasm-pack...

✅  wasm-pack is installed at /run/user/1001/fnm_multishells/2028640_1659075796381/bin/wasm-pack.

ℹ️  Compiling your crate in development mode...

ℹ ｢wds｣: Project is running at http://localhost:8080/
ℹ ｢wds｣: webpack output is served from /
ℹ ｢wds｣: Content not from webpack is served from /home/cdiesh/Downloads/wasm-bindgen/examples/hello_world
[INFO]: Checking for the Wasm target...
[INFO]: Compiling to Wasm...
    Finished dev [unoptimized + debuginfo] target(s) in 0.06s
[INFO]: Installing wasm-bindgen...
[INFO]: Optional fields missing from Cargo.toml: 'description', 'repository', and 'license'. These are not necessary, but recommended
[INFO]: :-) Done in 0.17s
[INFO]: :-) Your wasm pkg is ready to publish at /home/cdiesh/Downloads/wasm-bindgen/examples/hello_world/pkg.
✅  Your crate has been correctly compiled

ℹ ｢wdm｣: assets by path *.js 973 KiB
  asset vendors-node_modules_text-encoding_index_js.index.js 623 KiB [emitted] (id hint: vendors)
  asset index.js 341 KiB [emitted] (name: main)
  asset pkg_index_js.index.js 8.39 KiB [emitted]
asset 92392d6570df2d5d3d48.module.wasm 66.1 KiB [emitted] [immutable]
asset index.html 232 bytes [emitted]
runtime modules 9.58 KiB 13 modules
modules by path ./node_modules/ 915 KiB
  modules by path ./node_modules/webpack-dev-server/ 21.2 KiB 12 modules
  modules by path ./node_modules/html-entities/lib/*.js 61 KiB 5 modules
  modules by path ./node_modules/webpack/hot/ 1.58 KiB 3 modules
  modules by path ./node_modules/url/ 37.4 KiB 3 modules
  modules by path ./node_modules/querystring/*.js 4.51 KiB 3 modules
  modules by path ./node_modules/text-encoding/ 617 KiB 3 modules
  + 4 modules
modules by path ./pkg/ 3.28 KiB (javascript) 66.1 KiB (webassembly)
  ./pkg/index.js 71 bytes [built] [code generated]
  ./pkg/index_bg.js 3.15 KiB [built] [code generated]
  ./pkg/index_bg.wasm 70 bytes (javascript) 66.1 KiB (webassembly) [built] [code generated]
./index.js 266 bytes [built] [code generated]
webpack 5.74.0 compiled successfully in 1111 ms
ℹ ｢wdm｣: Compiled successfully.
ℹ ｢wdm｣: Compiling...
ℹ ｢wdm｣: assets by status 1.01 MiB [cached] 4 assets
asset index.html 232 bytes [emitted]
cached modules 916 KiB (javascript) 9.58 KiB (runtime) [cached] 47 modules
modules by layer 3.28 KiB (javascript) 66.1 KiB (webassembly)
  ./pkg/index.js 71 bytes [built]
  ./pkg/index_bg.js 3.15 KiB [built]
  ./pkg/index_bg.wasm 70 bytes (javascript) 66.1 KiB (webassembly) [built]
webpack 5.74.0 compiled successfully in 111 ms
ℹ ｢wdm｣: Compiled successfully.

possibly I had an older wasm-pack or something that caused this (I had one from february this year) but I just thought I'd add these notes in case it helps someone

[cmdcolin]

random other note: it was odd that it was not giving a 404 from the .wasm file or some different error in the browser, it was unclear that it was actually not able to compile the wasm at all