1# Regression test for https://go.dev/issue/64423:
2#
3# When we parse the version for a Clang binary, we should accept
4# an arbitrary vendor prefix, which (as of 2023) may be injected
5# by defining CLANG_VENDOR when building clang itself.
6#
7# Since we don't want to actually rebuild the Clang toolchain in
8# this test, we instead simulate it by injecting a fake "clang"
9# binary that runs the real one as a subprocess.
10
11[!cgo] skip
12[short] skip 'builds and links a fake clang binary'
13[!cc:clang] skip 'test is specific to clang version parsing'
14
15# Save the location of the real clang command for our fake one to use.
16go run ./which clang
17cp stdout $WORK/.realclang
18
19# Build a fake clang and ensure that it is the one in $PATH.
20mkdir $WORK/bin
21go build -o $WORK/bin/clang$GOEXE ./fakeclang
22[!GOOS:plan9] env PATH=$WORK${/}bin
23[GOOS:plan9] env path=$WORK${/}bin
24
25# Force CGO_ENABLED=1 so that the following commands should error
26# out if the fake clang doesn't work.
27env CGO_ENABLED=1
28
29# The bug in https://go.dev/issue/64423 resulted in cache keys that
30# didn't contain any information about the C compiler.
31# Since the bug was in cache key computation, isolate the cache:
32# if we change the way caching works, we want the test to fail
33# instead of accidentally reusing the cached information from a
34# previous test run.
35env GOCACHE=$WORK${/}.cache
36mkdir $GOCACHE
37
38go build -x runtime/cgo
39
40 # Tell our fake clang to stop working.
41 # Previously, 'go build -x runtime/cgo' would continue to
42 # succeed because both the broken clang and the non-broken one
43 # resulted in a cache key with no clang version information.
44env GO_BREAK_CLANG=1
45! go build -x runtime/cgo
46stderr '# runtime/cgo\nGO_BREAK_CLANG is set'
47
48-- go.mod --
49module example/issue64423
50go 1.20
51-- which/main.go --
52package main
53
54import (
55 "os"
56 "os/exec"
57)
58
59func main() {
60 path, err := exec.LookPath(os.Args[1])
61 if err != nil {
62 panic(err)
63 }
64 os.Stdout.WriteString(path)
65}
66-- fakeclang/main.go --
67package main
68
69import (
70 "bufio"
71 "bytes"
72 "log"
73 "os"
74 "os/exec"
75 "path/filepath"
76 "strings"
77)
78
79func main() {
80 if os.Getenv("GO_BREAK_CLANG") != "" {
81 os.Stderr.WriteString("GO_BREAK_CLANG is set\n")
82 os.Exit(1)
83 }
84
85 b, err := os.ReadFile(filepath.Join(os.Getenv("WORK"), ".realclang"))
86 if err != nil {
87 log.Fatal(err)
88 }
89 clang := string(bytes.TrimSpace(b))
90 cmd := exec.Command(clang, os.Args[1:]...)
91 cmd.Stdout = os.Stdout
92 stderr, err := cmd.StderrPipe()
93 if err != nil {
94 log.Fatal(err)
95 }
96
97 if err := cmd.Start(); err != nil {
98 log.Fatal(err)
99 }
100
101 r := bufio.NewReader(stderr)
102 for {
103 line, err := r.ReadString('\n')
104 if line != "" {
105 if strings.Contains(line, "clang version") {
106 // Simulate a clang version string with an arbitrary vendor prefix.
107 const vendorString = "Gopher Solutions Unlimited "
108 os.Stderr.WriteString(vendorString)
109 }
110 os.Stderr.WriteString(line)
111 }
112 if err != nil {
113 break
114 }
115 }
116 os.Stderr.Close()
117
118 if err := cmd.Wait(); err != nil {
119 os.Exit(1)
120 }
121}
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