cmd/go: TestCgoPkgConfig fails on Windows with pkg-config installed

[qmuntal]

What version of Go are you using (go version)?

$ go version
go version devel go1.21-908310580a Mon Mar 6 10:25:41 2023 +0100 windows/amd64

Does this issue reproduce with the latest release?

No, only on tip.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
set GO111MODULE=
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\***\AppData\Local\go-build
set GOENV=C:\Users\***\AppData\Roaming\go\env
set GOEXE=.exe
set GOEXPERIMENT=
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GOMODCACHE=C:\Users\***\go\pkg\mod
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\***\go
set GOPRIVATE=
set GOPROXY=https://proxy.golang.org,direct
set GOROOT=C:\Users\***\code\go\go
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=C:\Users\***\code\go\go\pkg\tool\windows_amd64
set GOVCS=
set GOVERSION=devel go1.21-908310580a Mon Mar 6 10:25:41 2023 +0100
set GCCGO=gccgo
set GOAMD64=v1
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=C:\Users\***\code\go\go\src\go.mod
set GOWORK=
set CGO_CFLAGS=-O2 -g
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-O2 -g
set CGO_FFLAGS=-O2 -g
set CGO_LDFLAGS=-O2 -g
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=C:\Users\***\AppData\Local\Temp\go-build2848288378=/tmp/go-build -gno-record-gcc-switches

What did you do?

gotip test -run TestCgoPkgConfig cmd/go

What did you expect to see?

ok cmd/go 7.923s

What did you see instead?

--- FAIL: TestCgoPkgConfig (46.16s)
    go_test.go:1582: running testgo [env PKG_CONFIG]
    go_test.go:1582: standard output:
    go_test.go:1582: pkg-config
        
    go_test.go:1618: running testgo [run C:\Users\***\AppData\Local\Temp\cmd-go-test-2864745407\gotest865774581\foo.go]
    go_test.go:1618: standard error:
    go_test.go:1618: command-line-arguments: invalid flag in pkg-config --libs: 
        
    go_test.go:1618: go [run C:\Users\***\AppData\Local\Temp\cmd-go-test-2864745407\gotest865774581\foo.go] failed unexpectedly in c:\Users\***\code\golang-go\src\cmd\go: exit status 1
FAIL

Additional notes

The test only fails if pkg-config is installed, else the test is skipped. Go builders don't have pkg-config, so this failure passed unnoticed when it was introduced in CL 466875 or CL 466864.

@thanm @dmitshur would it be possible to install pkg-config on the Windows builders?

[qmuntal]

This is not an issue with the test, but a bug in the toolchain when pkg-config returns no linker flags but a blank space character. Blank spaces should be trimmed before calling splitPkgConfigOutput in:

go/src/cmd/go/internal/work/exec.go

Lines 1634 to 1643 in b94dc38

	if len(out) > 0 {
	// We need to handle path with spaces so that C:/Program\ Files can pass
	// checkLinkerFlags. Use splitPkgConfigOutput here just like we treat cflags.
	ldflags, err = splitPkgConfigOutput(out)
	if err != nil {
	return nil, nil, err
	}
	if err := checkLinkerFlags("LDFLAGS", "pkg-config --libs", ldflags); err != nil {
	return nil, nil, err
	}

Will submit a fix soon.

[gopherbot]

Change https://go.dev/cl/473616 mentions this issue: cmd/go: trim spaces in pkg-config ldflags output