cmd/go: go test for GOOS=js GOARCH=wasm looks for wasm_exec.js in the old misc/wasm/ path instead of lib/wasm/

[maxence-charriere]

Go version

go version go1.24.0 darwin/arm64

Output of go env in your module/workspace:

AR='ar'
CC='cc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='c++'
GCCGO='gccgo'
GO111MODULE=''
GOARCH='arm64'
GOARM64='v8.0'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/Users/maxence/Library/Caches/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/Users/maxence/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/g6/n3gnkjq13yl_dcp6qd69fs940000gn/T/go-build787758416=/tmp/go-build -gno-record-gcc-switches -fno-common'
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMOD='/Users/maxence/Dev/src/github.com/maxence-charriere/murlok/go.mod'
GOMODCACHE='/Users/maxence/dev/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='/Users/maxence/dev'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/opt/homebrew/Cellar/go/1.24.0/libexec'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/Users/maxence/Library/Application Support/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/opt/homebrew/Cellar/go/1.24.0/libexec/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.24.0'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

Ran:

GOARCH=wasm GOOS=js go test

What did you see happen?

GOARCH=wasm GOOS=js go test
open /opt/homebrew/Cellar/go/1.24.0/libexec/misc/wasm/wasm_exec.js: no such file or directory
exit status 1

What did you expect to see?

Tests run successfully with wasm_exec.js located in the new path.

[gabyhelp]

Related Issues

• cmd/test2json: 'exec format error' for os/exec when exec is set to go_js_wasm_exec #32442 (closed)
• misc/wasm: `wasm_exec.js` missing after toolchain update #69989 (closed)
• cmd/distpack: wasm runtime js should be kept in the toolchain package #68024 (closed)
• os: invalid tmp dir for GOARCH=wasm, GOOS=js when GOHOSTOS=windows #27306 (closed)
• os: `GOOS=wasip1 GOARCH=wasm` the `ReadFile` function gives `-1` as the `rootFd` to `path_open` causing `Bad file number` error #63466
• os: Windows-style absolute paths are not recognized correctly in wasm environments #68820 (closed)
• cmd/link: regression on building an app with `GOOS=wasip1 GOARCH=wasm` #65786 (closed)
• cmd/go: GOOS=js GOARCH=wasm go build -o [non-empty parent dir] ./... fails on Windows host #37472 (closed)
• x/pkgsite/internal/tests/deps: TestCmdPkgsiteDeps failing on js/wasm due to lack of `exec` support #64942 (closed)
• unknown ptrSize for $GOARCH "wasm" #40543 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[Zxilly]

The go test implicitly looks for go_js_wasm_exec in path to execute the built unit test binary, can you check where go_js_wasm_exec is located in the environment? like which go_js_wasm_exec

[seankhliao]

I don't think cmd/go ever automatically added the wasm execution wrappers to PATH?
this looks more likely to be that you have kept around stale references in your shell environment, see https://go.dev/blog/wasi#running-go-tests-with-wasip1

[maxence-charriere]

@Zxilly

▶ where go_js_wasm_exec
/Users/maxence/dev/bin/go_js_wasm_exec
/opt/homebrew/Cellar/go/1.24.0/libexec/lib/wasm/go_js_wasm_exec

Look like there there is 2 locations for it.

[Zxilly]

You should remove outdated binary