path/filepath: Rel returns non-Clean'ed path.

[ukai]

Go version

go version go1.24.7 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='/usr/local/google/home/ukai/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/usr/local/google/home/ukai/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build937578986=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/usr/local/google/home/ukai/src/crbuild/build/siso/go.mod'
GOMODCACHE='/usr/local/google/home/ukai/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/usr/local/google/home/ukai/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/google/home/ukai/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.24.7.linux-amd64'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/usr/local/google/home/ukai/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/google/home/ukai/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.24.7.linux-amd64/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.7'
GOWORK='off'
PKG_CONFIG='pkg-config'

What did you do?

https://go.dev/play/p/L5wdhU8S2T7

What did you see happen?

Rel("foo/bar", ".")="../../.", <nil>
Clean("../../.")="../.."  cleaned=false
Rel("foo/bar", "")="../../.", <nil>
Clean("../../.")="../.."  cleaned=false

What did you expect to see?

rel should be the same as cleanedRel ?

https://pkg.go.dev/path/filepath#Rel says

Rel calls Clean on the result.

[gabyhelp]

Related Issues

• path/filepath: Rel is not returning an error for symlinks #66622 (closed)
• path/filepath: Rel() fails for UNC volumes when trailing slash is omitted #41230 (closed)

Related Code Changes

• path/filepath: include the original paths in error messages

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

[Jorropo]

I agree do you want submit a fix ?

[gopherbot]

Change https://go.dev/cl/708816 mentions this issue: [release-branch.go1.25] path/filepath: return cleaned path from Rel.

[gopherbot]

Change https://go.dev/cl/709675 mentions this issue: path/filepath: return cleaned path from Rel.