misc/cgo/testcarchive: fix tests in module mode

Updates #30228

Change-Id: I830e3c83416b2e5744f30d1a903a74c50462716b
Reviewed-on: https://go-review.googlesource.com/c/163210
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

misc/cgo/testcarchive/carchive_test.go

@@ -10,6 +10,7 @@ import (
 	"debug/elf"
 	"fmt"
 	"io/ioutil"
+	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -28,16 +29,41 @@ var bin []string
 // C compiler with args (from $(go env CC) $(go env GOGCCFLAGS)).
 var cc []string
 
-// An environment with GOPATH=$(pwd).
-var gopathEnv []string
-
 // ".exe" on Windows.
 var exeSuffix string
 
-var GOOS, GOARCH string
+var GOOS, GOARCH, GOPATH string
 var libgodir string
 
-func init() {
+func TestMain(m *testing.M) {
+	log.SetFlags(log.Lshortfile)
+	os.Exit(testMain(m))
+}
+
+func testMain(m *testing.M) int {
+	// We need a writable GOPATH in which to run the tests.
+	// Construct one in a temporary directory.
+	var err error
+	GOPATH, err = ioutil.TempDir("", "carchive_test")
+	if err != nil {
+		log.Panic(err)
+	}
+	defer os.RemoveAll(GOPATH)
+	os.Setenv("GOPATH", GOPATH)
+
+	// Copy testdata into GOPATH/src/testarchive, along with a go.mod file
+	// declaring the same path.
+	modRoot := filepath.Join(GOPATH, "src", "testcarchive")
+	if err := overlayDir(modRoot, "testdata"); err != nil {
+		log.Panic(err)
+	}
+	if err := os.Chdir(modRoot); err != nil {
+		log.Panic(err)
+	}
+	if err := ioutil.WriteFile("go.mod", []byte("module testcarchive\n"), 0666); err != nil {
+		log.Panic(err)
+	}
+
 	GOOS = goEnv("GOOS")
 	GOARCH = goEnv("GOARCH")
 	bin = cmdToRun("./testp")
@@ -83,50 +109,36 @@ func init() {
 		// TODO(crawshaw): can we do better?
 		cc = append(cc, []string{"-framework", "CoreFoundation", "-framework", "Foundation"}...)
 	}
-	libgodir = GOOS + "_" + GOARCH
+	libbase := GOOS + "_" + GOARCH
 	if runtime.Compiler == "gccgo" {
-		libgodir = "gccgo_" + libgodir + "_fPIC"
+		libbase = "gccgo_" + libgodir + "_fPIC"
 	} else {
 		switch GOOS {
 		case "darwin":
 			if GOARCH == "arm" || GOARCH == "arm64" {
-				libgodir += "_shared"
+				libbase += "_shared"
 			}
 		case "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "solaris":
-			libgodir += "_shared"
+			libbase += "_shared"
 		}
 	}
-	cc = append(cc, "-I", filepath.Join("pkg", libgodir))
-
-	// Build an environment with GOPATH=$(pwd)
-	env := os.Environ()
-	var n []string
-	for _, e := range env {
-		if !strings.HasPrefix(e, "GOPATH=") {
-			n = append(n, e)
-		}
-	}
-	dir, err := os.Getwd()
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(2)
-	}
-	n = append(n, "GOPATH="+dir)
-	gopathEnv = n
+	libgodir = filepath.Join(GOPATH, "pkg", libbase, "testcarchive")
+	cc = append(cc, "-I", libgodir)
 
 	if GOOS == "windows" {
 		exeSuffix = ".exe"
 	}
+
+	return m.Run()
 }
 
 func goEnv(key string) string {
 	out, err := exec.Command("go", "env", key).Output()
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "go env %s failed:\n%s\n", key, err)
 		if ee, ok := err.(*exec.ExitError); ok {
 			fmt.Fprintf(os.Stderr, "%s", ee.Stderr)
 		}
-		os.Exit(2)
+		log.Panicf("go env %s failed:\n%s\n", key, err)
 	}
 	return strings.TrimSpace(string(out))
 }
@@ -143,7 +155,6 @@ func cmdToRun(name string) []string {
 func testInstall(t *testing.T, exe, libgoa, libgoh string, buildcmd ...string) {
 	t.Helper()
 	cmd := exec.Command(buildcmd[0], buildcmd[1:]...)
-	cmd.Env = gopathEnv
 	t.Log(buildcmd)
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)
@@ -204,7 +215,7 @@ func checkLineComments(t *testing.T, hdrname string) {
 }
 
 func TestInstall(t *testing.T) {
-	defer os.RemoveAll("pkg")
+	defer os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 
 	libgoa := "libgo.a"
 	if runtime.Compiler == "gccgo" {
@@ -212,17 +223,17 @@ func TestInstall(t *testing.T) {
 	}
 
 	testInstall(t, "./testp1"+exeSuffix,
-		filepath.Join("pkg", libgodir, libgoa),
-		filepath.Join("pkg", libgodir, "libgo.h"),
-		"go", "install", "-i", "-buildmode=c-archive", "libgo")
+		filepath.Join(libgodir, libgoa),
+		filepath.Join(libgodir, "libgo.h"),
+		"go", "install", "-i", "-buildmode=c-archive", "./libgo")
 
 	// Test building libgo other than installing it.
 	// Header files are now present.
 	testInstall(t, "./testp2"+exeSuffix, "libgo.a", "libgo.h",
-		"go", "build", "-buildmode=c-archive", filepath.Join("src", "libgo", "libgo.go"))
+		"go", "build", "-buildmode=c-archive", filepath.Join(".", "libgo", "libgo.go"))
 
 	testInstall(t, "./testp3"+exeSuffix, "libgo.a", "libgo.h",
-		"go", "build", "-buildmode=c-archive", "-o", "libgo.a", "libgo")
+		"go", "build", "-buildmode=c-archive", "-o", "libgo.a", "./libgo")
 }
 
 func TestEarlySignalHandler(t *testing.T) {
@@ -240,11 +251,10 @@ func TestEarlySignalHandler(t *testing.T) {
 		os.Remove("libgo2.a")
 		os.Remove("libgo2.h")
 		os.Remove("testp")
-		os.RemoveAll("pkg")
+		os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 	}()
 
-	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo2.a", "libgo2")
-	cmd.Env = gopathEnv
+	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo2.a", "./libgo2")
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)
 		t.Fatal(err)
@@ -273,11 +283,10 @@ func TestSignalForwarding(t *testing.T) {
 		os.Remove("libgo2.a")
 		os.Remove("libgo2.h")
 		os.Remove("testp")
-		os.RemoveAll("pkg")
+		os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 	}()
 
-	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo2.a", "libgo2")
-	cmd.Env = gopathEnv
+	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo2.a", "./libgo2")
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)
 		t.Fatal(err)
@@ -317,11 +326,10 @@ func TestSignalForwardingExternal(t *testing.T) {
 		os.Remove("libgo2.a")
 		os.Remove("libgo2.h")
 		os.Remove("testp")
-		os.RemoveAll("pkg")
+		os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 	}()
 
-	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo2.a", "libgo2")
-	cmd.Env = gopathEnv
+	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo2.a", "./libgo2")
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)
 		t.Fatal(err)
@@ -433,11 +441,10 @@ func TestOsSignal(t *testing.T) {
 		os.Remove("libgo3.a")
 		os.Remove("libgo3.h")
 		os.Remove("testp")
-		os.RemoveAll("pkg")
+		os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 	}()
 
-	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo3.a", "libgo3")
-	cmd.Env = gopathEnv
+	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo3.a", "./libgo3")
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)
 		t.Fatal(err)
@@ -469,11 +476,10 @@ func TestSigaltstack(t *testing.T) {
 		os.Remove("libgo4.a")
 		os.Remove("libgo4.h")
 		os.Remove("testp")
-		os.RemoveAll("pkg")
+		os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 	}()
 
-	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo4.a", "libgo4")
-	cmd.Env = gopathEnv
+	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo4.a", "./libgo4")
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)
 		t.Fatal(err)
@@ -517,7 +523,7 @@ func TestExtar(t *testing.T) {
 		os.Remove("libgo4.h")
 		os.Remove("testar")
 		os.Remove("testar.ran")
-		os.RemoveAll("pkg")
+		os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 	}()
 
 	os.Remove("testar")
@@ -530,8 +536,7 @@ func TestExtar(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-ldflags=-extar="+filepath.Join(dir, "testar"), "-o", "libgo4.a", "libgo4")
-	cmd.Env = gopathEnv
+	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-ldflags=-extar="+filepath.Join(dir, "testar"), "-o", "libgo4.a", "./libgo4")
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)
 		t.Fatal(err)
@@ -555,11 +560,10 @@ func TestPIE(t *testing.T) {
 
 	defer func() {
 		os.Remove("testp" + exeSuffix)
-		os.RemoveAll("pkg")
+		os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 	}()
 
-	cmd := exec.Command("go", "install", "-i", "-buildmode=c-archive", "libgo")
-	cmd.Env = gopathEnv
+	cmd := exec.Command("go", "install", "-i", "-buildmode=c-archive", "./libgo")
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)
 		t.Fatal(err)
@@ -570,7 +574,7 @@ func TestPIE(t *testing.T) {
 		libgoa = "liblibgo.a"
 	}
 
-	ccArgs := append(cc, "-fPIE", "-pie", "-o", "testp"+exeSuffix, "main.c", "main_unix.c", filepath.Join("pkg", libgodir, libgoa))
+	ccArgs := append(cc, "-fPIE", "-pie", "-o", "testp"+exeSuffix, "main.c", "main_unix.c", filepath.Join(libgodir, libgoa))
 	if runtime.Compiler == "gccgo" {
 		ccArgs = append(ccArgs, "-lgo")
 	}
@@ -643,8 +647,7 @@ func TestSIGPROF(t *testing.T) {
 		os.Remove("libgo6.h")
 	}()
 
-	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo6.a", "libgo6")
-	cmd.Env = gopathEnv
+	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-o", "libgo6.a", "./libgo6")
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)
 		t.Fatal(err)
@@ -683,8 +686,7 @@ func TestCompileWithoutShared(t *testing.T) {
 		os.Remove("libgo2.h")
 	}()
 
-	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-gcflags=-shared=false", "-o", "libgo2.a", "libgo2")
-	cmd.Env = gopathEnv
+	cmd := exec.Command("go", "build", "-buildmode=c-archive", "-gcflags=-shared=false", "-o", "libgo2.a", "./libgo2")
 	t.Log(cmd.Args)
 	out, err := cmd.CombinedOutput()
 	t.Logf("%s", out)
@@ -732,15 +734,14 @@ func TestCompileWithoutShared(t *testing.T) {
 
 // Test that installing a second time recreates the header files.
 func TestCachedInstall(t *testing.T) {
-	defer os.RemoveAll("pkg")
+	defer os.RemoveAll(filepath.Join(GOPATH, "pkg"))
 
-	h1 := filepath.Join("pkg", libgodir, "libgo.h")
-	h2 := filepath.Join("pkg", libgodir, "p.h")
+	h1 := filepath.Join(libgodir, "libgo.h")
+	h2 := filepath.Join(libgodir, "p.h")
 
-	buildcmd := []string{"go", "install", "-i", "-buildmode=c-archive", "libgo"}
+	buildcmd := []string{"go", "install", "-i", "-buildmode=c-archive", "./libgo"}
 
 	cmd := exec.Command(buildcmd[0], buildcmd[1:]...)
-	cmd.Env = gopathEnv
 	t.Log(buildcmd)
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)
@@ -762,7 +763,6 @@ func TestCachedInstall(t *testing.T) {
 	}
 
 	cmd = exec.Command(buildcmd[0], buildcmd[1:]...)
-	cmd.Env = gopathEnv
 	t.Log(buildcmd)
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Logf("%s", out)

misc/cgo/testcarchive/overlaydir_test.go

@@ -0,0 +1,81 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package carchive_test
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// overlayDir makes a minimal-overhead copy of srcRoot in which new files may be added.
+//
+// TODO: Once we no longer need to support the misc module in GOPATH mode,
+// factor this function out into a package to reduce duplication.
+func overlayDir(dstRoot, srcRoot string) error {
+	dstRoot = filepath.Clean(dstRoot)
+	if err := os.MkdirAll(dstRoot, 0777); err != nil {
+		return err
+	}
+
+	symBase, err := filepath.Rel(srcRoot, dstRoot)
+	if err != nil {
+		symBase, err = filepath.Abs(srcRoot)
+		if err != nil {
+			return err
+		}
+	}
+
+	return filepath.Walk(srcRoot, func(srcPath string, info os.FileInfo, err error) error {
+		if err != nil || srcPath == srcRoot {
+			return err
+		}
+
+		suffix := strings.TrimPrefix(srcPath, srcRoot)
+		for len(suffix) > 0 && suffix[0] == filepath.Separator {
+			suffix = suffix[1:]
+		}
+		dstPath := filepath.Join(dstRoot, suffix)
+
+		perm := info.Mode() & os.ModePerm
+		if info.Mode()&os.ModeSymlink != 0 {
+			info, err = os.Stat(srcPath)
+			if err != nil {
+				return err
+			}
+			perm = info.Mode() & os.ModePerm
+		}
+
+		// Always copy directories (don't symlink them).
+		// If we add a file in the overlay, we don't want to add it in the original.
+		if info.IsDir() {
+			return os.Mkdir(dstPath, perm)
+		}
+
+		// If the OS supports symlinks, use them instead of copying bytes.
+		if err := os.Symlink(filepath.Join(symBase, suffix), dstPath); err == nil {
+			return nil
+		}
+
+		// Otherwise, copy the bytes.
+		src, err := os.Open(srcPath)
+		if err != nil {
+			return err
+		}
+		defer src.Close()
+
+		dst, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE|os.O_EXCL, perm)
+		if err != nil {
+			return err
+		}
+
+		_, err = io.Copy(dst, src)
+		if closeErr := dst.Close(); err == nil {
+			err = closeErr
+		}
+		return err
+	})
+}

misc/cgo/testcarchive/testdata/libgo/libgo.go

@@ -10,7 +10,7 @@ import (
 	"syscall"
 	"time"
 
-	_ "p"
+	_ "testcarchive/p"
 )
 
 import "C"

src/cmd/dist/test.go

@@ -692,7 +692,7 @@ func (t *tester) registerTests() {
 			})
 		}
 		if t.supportedBuildmode("c-archive") {
-			t.registerHostTest("testcarchive", "../misc/cgo/testcarchive", "misc/cgo/testcarchive", "carchive_test.go")
+			t.registerHostTest("testcarchive", "../misc/cgo/testcarchive", "misc/cgo/testcarchive", ".")
 		}
 		if t.supportedBuildmode("c-shared") {
 			t.registerHostTest("testcshared", "../misc/cgo/testcshared", "misc/cgo/testcshared", "cshared_test.go")