cmd/go: GOFIPS140=v1.0.0 makes tests flaky #71491
Description
Go version
HEAD
Output of go env in your module/workspace:
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE=''
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/home/iant/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/home/iant/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1440155093=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/dev/null'
GOMODCACHE='/home/iant/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/iant/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org'
GOROOT='/home/iant/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='on'
GOTELEMETRYDIR='/home/iant/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/home/iant/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='devel go1.24-e81f715515 Wed Jan 29 07:10:35 2025 -0800'
GOWORK=''
PKG_CONFIG='pkg-config'What did you do?
GOFIPS140=v1.0.0 go test -test.count=10 crypto/x509 crypto/internal/fips140/...
What did you see happen?
--- FAIL: TestInverse (0.00s)
nat_test.go:701: open testdata/mod_inv_tests.txt: no such file or directory
--- FAIL: TestInverse (0.00s)
nat_test.go:701: open testdata/mod_inv_tests.txt: no such file or directory
FAIL
What did you expect to see?
A series of lines starting with ok, indicating that all the tests passed.
The problem is that setting GOFIPS140 to a specific version causes the zip file in $GOROOT/lib/fips140 to be unpacked into the module cache each time that the go command is run. The crypto/x509 package has a test that runs the go command (TestImports). Running that test in parallel with tests of other packages means that the contents of the module cache are being removed and recreated as tests are running. That causes failures like the one above, in which a file is missing just as a test is looking for it.
Fixing this is a release blocker for 1.24.