path/filepath: replace os.MkdirTemp with T.TempDir

Add the tempDirCanonical function, for tests that need a temporary
directory that does not contain symlinks.

Updates #45402

Change-Id: I3d08ef32ef911331544acce3d7d013b4c3382960
Reviewed-on: https://go-review.googlesource.com/c/go/+/308011
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>

src/path/filepath/match_test.go

@@ -181,12 +181,7 @@ var globSymlinkTests = []struct {
 func TestGlobSymlink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpDir, err := os.MkdirTemp("", "globsymlink")
+	tmpDir := t.TempDir()
-	if err != nil {
-		t.Fatal("creating temp dir:", err)
-	}
-	defer os.RemoveAll(tmpDir)
-
 	for _, tt := range globSymlinkTests {
 		path := Join(tmpDir, tt.path)
 		dest := Join(tmpDir, tt.dest)
@@ -267,18 +262,7 @@ func TestWindowsGlob(t *testing.T) {
 		t.Skipf("skipping windows specific test")
 	}
 
-	tmpDir, err := os.MkdirTemp("", "TestWindowsGlob")
+	tmpDir := tempDirCanonical(t)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.RemoveAll(tmpDir)
-
-	// /tmp may itself be a symlink
-	tmpDir, err = EvalSymlinks(tmpDir)
-	if err != nil {
-		t.Fatal("eval symlink for tmp dir:", err)
-	}
-
 	if len(tmpDir) < 3 {
 		t.Fatalf("tmpDir path %q is too short", tmpDir)
 	}
@@ -323,15 +307,13 @@ func TestWindowsGlob(t *testing.T) {
 	// test absolute paths
 	for _, test := range tests {
 		var p string
-		err = test.globAbs(tmpDir, tmpDir)
+		if err := test.globAbs(tmpDir, tmpDir); err != nil {
-		if err != nil {
 			t.Error(err)
 		}
 		// test C:\*Documents and Settings\...
 		p = tmpDir
 		p = strings.Replace(p, `:\`, `:\*`, 1)
-		err = test.globAbs(tmpDir, p)
+		if err := test.globAbs(tmpDir, p); err != nil {
-		if err != nil {
 			t.Error(err)
 		}
 		// test C:\Documents and Settings*\...
@@ -339,8 +321,7 @@ func TestWindowsGlob(t *testing.T) {
 		p = strings.Replace(p, `:\`, `:`, 1)
 		p = strings.Replace(p, `\`, `*\`, 1)
 		p = strings.Replace(p, `:`, `:\`, 1)
-		err = test.globAbs(tmpDir, p)
+		if err := test.globAbs(tmpDir, p); err != nil {
-		if err != nil {
 			t.Error(err)
 		}
 	}

src/path/filepath/path_test.go

@@ -449,6 +449,19 @@ func chtmpdir(t *testing.T) (restore func()) {
 	}
 }
 
+// tempDirCanonical returns a temporary directory for the test to use, ensuring
+// that the returned path does not contain symlinks.
+func tempDirCanonical(t *testing.T) string {
+	dir := t.TempDir()
+
+	cdir, err := filepath.EvalSymlinks(dir)
+	if err != nil {
+		t.Errorf("tempDirCanonical: %v", err)
+	}
+
+	return cdir
+}
+
 func TestWalk(t *testing.T) {
 	walk := func(root string, fn fs.WalkDirFunc) error {
 		return filepath.Walk(root, func(path string, info fs.FileInfo, err error) error {

src/path/filepath/path_windows_test.go

@@ -37,12 +37,7 @@ func testWinSplitListTestIsValid(t *testing.T, ti int, tt SplitListTest,
 		perm    fs.FileMode = 0700
 	)
 
-	tmp, err := os.MkdirTemp("", "testWinSplitListTestIsValid")
+	tmp := t.TempDir()
-	if err != nil {
-		t.Fatalf("TempDir failed: %v", err)
-	}
-	defer os.RemoveAll(tmp)
-
 	for i, d := range tt.result {
 		if d == "" {
 			continue
@@ -57,12 +52,12 @@ func testWinSplitListTestIsValid(t *testing.T, ti int, tt SplitListTest,
 			t.Errorf("%d,%d: %#q already exists", ti, i, d)
 			return
 		}
-		if err = os.MkdirAll(dd, perm); err != nil {
+		if err := os.MkdirAll(dd, perm); err != nil {
 			t.Errorf("%d,%d: MkdirAll(%#q) failed: %v", ti, i, dd, err)
 			return
 		}
 		fn, data := filepath.Join(dd, cmdfile), []byte("@echo "+d+"\r\n")
-		if err = os.WriteFile(fn, data, perm); err != nil {
+		if err := os.WriteFile(fn, data, perm); err != nil {
 			t.Errorf("%d,%d: WriteFile(%#q) failed: %v", ti, i, fn, err)
 			return
 		}
@@ -103,18 +98,7 @@ func testWinSplitListTestIsValid(t *testing.T, ti int, tt SplitListTest,
 func TestWindowsEvalSymlinks(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpDir, err := os.MkdirTemp("", "TestWindowsEvalSymlinks")
+	tmpDir := tempDirCanonical(t)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.RemoveAll(tmpDir)
-
-	// /tmp may itself be a symlink! Avoid the confusion, although
-	// it means trusting the thing we're testing.
-	tmpDir, err = filepath.EvalSymlinks(tmpDir)
-	if err != nil {
-		t.Fatal(err)
-	}
 
 	if len(tmpDir) < 3 {
 		t.Fatalf("tmpDir path %q is too short", tmpDir)
@@ -161,18 +145,7 @@ func TestWindowsEvalSymlinks(t *testing.T) {
 // TestEvalSymlinksCanonicalNames verify that EvalSymlinks
 // returns "canonical" path names on windows.
 func TestEvalSymlinksCanonicalNames(t *testing.T) {
-	tmp, err := os.MkdirTemp("", "evalsymlinkcanonical")
+	ctmp := tempDirCanonical(t)
-	if err != nil {
-		t.Fatal("creating temp dir:", err)
-	}
-	defer os.RemoveAll(tmp)
-
-	// os.MkdirTemp might return "non-canonical" name.
-	cTmpName, err := filepath.EvalSymlinks(tmp)
-	if err != nil {
-		t.Errorf("EvalSymlinks(%q) error: %v", tmp, err)
-	}
-
 	dirs := []string{
 		"test",
 		"test/dir",
@@ -181,7 +154,7 @@ func TestEvalSymlinksCanonicalNames(t *testing.T) {
 	}
 
 	for _, d := range dirs {
-		dir := filepath.Join(cTmpName, d)
+		dir := filepath.Join(ctmp, d)
 		err := os.Mkdir(dir, 0755)
 		if err != nil {
 			t.Fatal(err)
@@ -417,25 +390,8 @@ func TestToNorm(t *testing.T) {
 		{".", `\\localhost\c$`, `\\localhost\c$`},
 	}
 
-	tmp, err := os.MkdirTemp("", "testToNorm")
+	ctmp := tempDirCanonical(t)
-	if err != nil {
+	if err := os.MkdirAll(strings.ReplaceAll(testPath, "{{tmp}}", ctmp), 0777); err != nil {
-		t.Fatal(err)
-	}
-	defer func() {
-		err := os.RemoveAll(tmp)
-		if err != nil {
-			t.Fatal(err)
-		}
-	}()
-
-	// os.MkdirTemp might return "non-canonical" name.
-	ctmp, err := filepath.EvalSymlinks(tmp)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	err = os.MkdirAll(strings.ReplaceAll(testPath, "{{tmp}}", ctmp), 0777)
-	if err != nil {
 		t.Fatal(err)
 	}
 
@@ -526,20 +482,10 @@ func TestNTNamespaceSymlink(t *testing.T) {
 		t.Skip("skipping test because mklink command does not support junctions")
 	}
 
-	tmpdir, err := os.MkdirTemp("", "TestNTNamespaceSymlink")
+	tmpdir := tempDirCanonical(t)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.RemoveAll(tmpdir)
-
-	// Make sure tmpdir is not a symlink, otherwise tests will fail.
-	tmpdir, err = filepath.EvalSymlinks(tmpdir)
-	if err != nil {
-		t.Fatal(err)
-	}
 
 	vol := filepath.VolumeName(tmpdir)
-	output, err = exec.Command("cmd", "/c", "mountvol", vol, "/L").CombinedOutput()
+	output, err := exec.Command("cmd", "/c", "mountvol", vol, "/L").CombinedOutput()
 	if err != nil {
 		t.Fatalf("failed to run mountvol %v /L: %v %q", vol, err, output)
 	}