Go programs cache the static library and do not automatically use the updated version.

[ideazh]

Go version

go version go1.24.3 linux/amd64

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/user/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/home/user/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build50930955=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/dev/null'
GOMODCACHE='/home/user/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/user/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/home/user/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.3'
GOWORK=''
PKG_CONFIG='pkg-config'

What did you do?

abc.go

package abc
/*
#cgo LDFLAGS: -L/path/to/build -labc
*/
import "C"

func Abc() {
    C.abc()
}

abc_test.go

package abc

func TestAbc(t *testing.T) {
    Abc()
}

What did you see happen?

The above code can successfully call the C function, but when I rebuild the libabc.a library, the unit tests still use the old libabc.a file. Even deleting the libabc.a file doesn't prevent the program from running.
I tried running go clean -cache, but it didn't work. Running go clean -cache -modcache does force the use of the new library, but rebuilding the program after running go clean -cache -modcache takes a very long time. If every modification to the library requires such a lengthy rebuild, it's unacceptable. How can this be resolved?

What did you expect to see?

Linked library changes should apply instantly, no cache clearing needed.

[gabyhelp]

Related Issues

• cmd/compile: a rebuild is needed when cgo static library is changed. #29293 (closed)
• cmd/go: go.mod with replace local folder does not pull latest files present on the disk #38206 (closed)
• cmd/go: invalidate cached binaries when statically-linked external libraries change #29843 (closed)
• cmd/go: GOCACHE=off doesn't work if the compiled binary is already there #25929 (closed)
• cmd/go: 'go build' does not cache linked executables #31629 (closed)
• cmd/go: build caching failed to notice cgo header changes #25419 (closed)
• cmd/go: test reported as cached, but not actually cached #41593
• cmd/go: invoking go run from go test can corrupt build cache #69566
• cmd/go clean -testcache does not clean test cache #29757 (closed)
• cgo: regression: go command does not recompile changed packages #58640 (closed)

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

[seankhliao]

I believe go clean -cache should work, -mod cache doesn't make sense.