cmd/go: GO111MODULE does not invalidate test cache #69203
Description
Go version
go version go1.22.6 darwin/amd64
Output of go env in your module/workspace:
GO111MODULE='auto'
GOARCH='amd64'
GOBIN=''
GOCACHE='/tmp/.gocache'
GOENV='/Users/rittneje/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/rittneje/go/pkg/mod'
GONOPROXY='[REDACTED]'
GONOSUMDB='[REDACTED]'
GOOS='darwin'
GOPATH='/Users/rittneje/go'
GOPRIVATE='[REDACTED]'
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/Users/rittneje/go1.22.6'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='local'
GOTOOLDIR='/Users/rittneje/go1.22.6/pkg/tool/darwin_amd64'
GOVCS='[REDACTED]'
GOVERSION='go1.22.6'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='clang'
CXX='clang++'
CGO_ENABLED='1'
GOMOD=''
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/kf/kr7_s3xx0l12zbj3jrn082hmzy5gvy/T/go-build1131392119=/tmp/go-build -gno-record-gcc-switches -fno-common'What did you do?
$ GO111MODULE=auto go test net/http -v -run=^TestReadResponseErrors$
=== RUN TestReadResponseErrors
response_test.go:944: status "200 OK" "Content-Length:\r\nContent-Length:\r\n\r\nGophers\r\n": unexpected success; want error with substring "invalid empty Content-Length"
--- FAIL: TestReadResponseErrors (0.00s)
FAIL
FAIL net/http 0.282s
FAIL
$ GO111MODULE=on go test net/http -v -run=^TestReadResponseErrors$
=== RUN TestReadResponseErrors
--- PASS: TestReadResponseErrors (0.00s)
PASS
ok net/http 0.278s
$ GO111MODULE=auto go test net/http -v -run=^TestReadResponseErrors$
=== RUN TestReadResponseErrors
--- PASS: TestReadResponseErrors (0.00s)
PASS
ok net/http (cached)
$ go clean -testcache
$ GO111MODULE=auto go test net/http -v -run=^TestReadResponseErrors$
=== RUN TestReadResponseErrors
response_test.go:944: status "200 OK" "Content-Length:\r\nContent-Length:\r\n\r\nGophers\r\n": unexpected success; want error with substring "invalid empty Content-Length"
--- FAIL: TestReadResponseErrors (0.00s)
FAIL
FAIL net/http 0.366s
FAIL
What did you see happen?
As seen above, changing GO111MODULE did not invalidate the test cache, even though it factors into the compiler's behavior around the default GODEBUG selection and thus by extension the behavior of the code being tested.
What did you expect to see?
Changing GO111MODULE should invalidate the test cache, given that it changes the default GODEBUG. (Or at least, the default GODEBUG itself ought to factor into the cache.)