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# Regression test for https://go.dev/issue/64423:
#
# When we parse the version for a Clang binary, we should accept
# an arbitrary vendor prefix, which (as of 2023) may be injected
# by defining CLANG_VENDOR when building clang itself.
#
# Since we don't want to actually rebuild the Clang toolchain in
# this test, we instead simulate it by injecting a fake "clang"
# binary that runs the real one as a subprocess.
[!cgo] skip
[short] skip 'builds and links a fake clang binary'
[!cc:clang] skip 'test is specific to clang version parsing'
# Save the location of the real clang command for our fake one to use.
go run ./which clang
cp stdout $WORK/.realclang
# Build a fake clang and ensure that it is the one in $PATH.
mkdir $WORK/bin
go build -o $WORK/bin/clang$GOEXE ./fakeclang
[!GOOS:plan9] env PATH=$WORK${/}bin
[GOOS:plan9] env path=$WORK${/}bin
# Force CGO_ENABLED=1 so that the following commands should error
# out if the fake clang doesn't work.
env CGO_ENABLED=1
# The bug in https://go.dev/issue/64423 resulted in cache keys that
# didn't contain any information about the C compiler.
# Since the bug was in cache key computation, isolate the cache:
# if we change the way caching works, we want the test to fail
# instead of accidentally reusing the cached information from a
# previous test run.
env GOCACHE=$WORK${/}.cache
mkdir $GOCACHE
go build -x runtime/cgo
# Tell our fake clang to stop working.
# Previously, 'go build -x runtime/cgo' would continue to
# succeed because both the broken clang and the non-broken one
# resulted in a cache key with no clang version information.
env GO_BREAK_CLANG=1
! go build -x runtime/cgo
stderr '# runtime/cgo\nGO_BREAK_CLANG is set'
-- go.mod --
module example/issue64423
go 1.20
-- which/main.go --
package main
import (
"os"
"os/exec"
)
func main() {
path, err := exec.LookPath(os.Args[1])
if err != nil {
panic(err)
}
os.Stdout.WriteString(path)
}
-- fakeclang/main.go --
package main
import (
"bufio"
"bytes"
"log"
"os"
"os/exec"
"path/filepath"
"strings"
)
func main() {
if os.Getenv("GO_BREAK_CLANG") != "" {
os.Stderr.WriteString("GO_BREAK_CLANG is set\n")
os.Exit(1)
}
b, err := os.ReadFile(filepath.Join(os.Getenv("WORK"), ".realclang"))
if err != nil {
log.Fatal(err)
}
clang := string(bytes.TrimSpace(b))
cmd := exec.Command(clang, os.Args[1:]...)
cmd.Stdout = os.Stdout
stderr, err := cmd.StderrPipe()
if err != nil {
log.Fatal(err)
}
if err := cmd.Start(); err != nil {
log.Fatal(err)
}
r := bufio.NewReader(stderr)
for {
line, err := r.ReadString('\n')
if line != "" {
if strings.Contains(line, "clang version") {
// Simulate a clang version string with an arbitrary vendor prefix.
const vendorString = "Gopher Solutions Unlimited "
os.Stderr.WriteString(vendorString)
}
os.Stderr.WriteString(line)
}
if err != nil {
break
}
}
os.Stderr.Close()
if err := cmd.Wait(); err != nil {
os.Exit(1)
}
}
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