testing: allow specify temp dir by GOTMPDIR environment variable

Allow change the default temp directory returned by t.TempDir()
by environment variable GOTMPDIR.

Fixes #61585

Change-Id: Iba969bb02744e106cf15d80e0eda0245a55fc290
GitHub-Last-Rev: aeacea00952b11990b49a0fde6a0ce4fe910b777
GitHub-Pull-Request: golang/go#74844
Reviewed-on: https://go-review.googlesource.com/c/go/+/692455
Reviewed-by: Damien Neil <dneil@google.com>
Auto-Submit: Sean Liao <sean@liao.dev>
Reviewed-by: Sean Liao <sean@liao.dev>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>

diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 69102231d2fa278f5503a8d5d61b4a2a4125dc62..fd23d829f531f82a88ad9d7199057b8d97facd2d 100644 (file)
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -2407,8 +2407,10 @@
 //             The name of checksum database to use and optionally its public key and
 //             URL. See https://golang.org/ref/mod#authenticating.
 //     GOTMPDIR
-//             The directory where the go command will write
-//             temporary source files, packages, and binaries.
+//             Temporary directory used by the go command and testing package.
+//             Overrides the platform-specific temporary directory such as "/tmp".
+//             The go command and testing package will write temporary source files,
+//             packages, and binaries here.
 //     GOTOOLCHAIN
 //             Controls which Go toolchain is used. See https://go.dev/doc/toolchain.
 //     GOVCS

diff --git a/src/cmd/go/internal/help/helpdoc.go b/src/cmd/go/internal/help/helpdoc.go
index 9d44b862eec3e543153279848cceb5b4177692d2..ab04ce001c41db3724ee818f5b14188cc9b4f603 100644 (file)
--- a/src/cmd/go/internal/help/helpdoc.go
+++ b/src/cmd/go/internal/help/helpdoc.go
@@ -573,8 +573,10 @@ General-purpose environment variables:
                The name of checksum database to use and optionally its public key and
                URL. See https://golang.org/ref/mod#authenticating.
        GOTMPDIR
-               The directory where the go command will write
-               temporary source files, packages, and binaries.
+               Temporary directory used by the go command and testing package.
+               Overrides the platform-specific temporary directory such as "/tmp".
+               The go command and testing package will write temporary source files,
+               packages, and binaries here.
        GOTOOLCHAIN
                Controls which Go toolchain is used. See https://go.dev/doc/toolchain.
        GOVCS

diff --git a/src/testing/testing.go b/src/testing/testing.go
index 3475bfca4a6976cdd2d2e0a80702583d2585ab13..2f0206b0a4dae107b1c7c614f8b64403e5d26557 100644 (file)
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -1318,6 +1318,8 @@ func (c *common) Cleanup(f func()) {
 // all its subtests complete.
 // Each subsequent call to TempDir returns a unique directory;
 // if the directory creation fails, TempDir terminates the test by calling Fatal.
+// If the environment variable GOTMPDIR is set, the temporary directory will
+// be created somewhere beneath it.
 func (c *common) TempDir() string {
        c.checkFuzzFn("TempDir")
        // Use a single parent directory for all the temporary directories
@@ -1362,7 +1364,7 @@ func (c *common) TempDir() string {
                        return -1
                }
                pattern = strings.Map(mapper, pattern)
-               c.tempDir, c.tempDirErr = os.MkdirTemp("", pattern)
+               c.tempDir, c.tempDirErr = os.MkdirTemp(os.Getenv("GOTMPDIR"), pattern)
                if c.tempDirErr == nil {
                        c.Cleanup(func() {
                                if err := removeAll(c.tempDir); err != nil {

diff --git a/src/testing/testing_test.go b/src/testing/testing_test.go
index f4f5817a37ddb37a69915cfae62100a9ebd49a9c..cc89e4144e6a7801bc1bb89e8381c112d296d097 100644 (file)
--- a/src/testing/testing_test.go
+++ b/src/testing/testing_test.go
@@ -147,6 +147,39 @@ func testTempDir(t *testing.T) {
        }
 }
 
+func TestTempDirGOTMPDIR(t *testing.T) {
+       // The first call to t.TempDir will create a parent temporary directory
+       // that will contain all temporary directories created by TempDir.
+       //
+       // Use os.TempDir (not t.TempDir) to get a temporary directory,
+       // set GOTMPDIR to that directory,
+       // and then verify that t.TempDir creates a directory in GOTMPDIR.
+       customTmpDir := filepath.Join(os.TempDir(), "custom-gotmpdir-test")
+       if err := os.MkdirAll(customTmpDir, 0777); err != nil {
+               t.Fatal(err)
+       }
+       defer os.RemoveAll(customTmpDir)
+
+       t.Setenv("GOTMPDIR", customTmpDir)
+
+       dir := t.TempDir()
+       if dir == "" {
+               t.Fatal("expected dir")
+       }
+
+       if !strings.HasPrefix(dir, customTmpDir) {
+               t.Errorf("TempDir did not use GOTMPDIR: got %q, want prefix %q", dir, customTmpDir)
+       }
+
+       fi, err := os.Stat(dir)
+       if err != nil {
+               t.Fatal(err)
+       }
+       if !fi.IsDir() {
+               t.Errorf("dir %q is not a dir", dir)
+       }
+}
+
 func TestSetenv(t *testing.T) {
        tests := []struct {
                name               string