1 files changed, 101 insertions, 0 deletions
diff --git a/misc/reboot/experiment_toolid_test.go b/misc/reboot/experiment_toolid_test.go
new file mode 100644
index 0000000..87a828e
--- /dev/null
+++ b/misc/reboot/experiment_toolid_test.go
@@ -0,0 +1,101 @@
+// 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.
+
+//go:build explicit
+// +build explicit
+
+// Package experiment_toolid_test verifies that GOEXPERIMENT settings built
+// into the toolchain influence tool ids in the Go command.
+// This test requires bootstrapping the toolchain twice, so it's very expensive.
+// It must be run explicitly with -tags=explicit.
+// Verifies golang.org/issue/33091.
+package reboot_test
+
+import (
+	"bytes"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"testing"
+)
+
+func TestExperimentToolID(t *testing.T) {
+	// Set up GOROOT
+	goroot, err := os.MkdirTemp("", "experiment-goroot")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(goroot)
+
+	gorootSrc := filepath.Join(goroot, "src")
+	if err := overlayDir(gorootSrc, filepath.Join(runtime.GOROOT(), "src")); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := os.WriteFile(filepath.Join(goroot, "VERSION"), []byte("go1.999"), 0666); err != nil {
+		t.Fatal(err)
+	}
+	env := append(os.Environ(), "GOROOT=", "GOROOT_BOOTSTRAP="+runtime.GOROOT())
+
+	// Use a clean cache.
+	gocache, err := os.MkdirTemp("", "experiment-gocache")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(gocache)
+	env = append(env, "GOCACHE="+gocache)
+
+	// Build the toolchain without GOEXPERIMENT.
+	var makeScript string
+	switch runtime.GOOS {
+	case "windows":
+		makeScript = "make.bat"
+	case "plan9":
+		makeScript = "make.rc"
+	default:
+		makeScript = "make.bash"
+	}
+	makeScriptPath := filepath.Join(runtime.GOROOT(), "src", makeScript)
+	runCmd(t, gorootSrc, env, makeScriptPath)
+
+	// Verify compiler version string.
+	goCmdPath := filepath.Join(goroot, "bin", "go")
+	if runtime.GOOS == "windows" {
+		goCmdPath += ".exe"
+	}
+	gotVersion := bytes.TrimSpace(runCmd(t, gorootSrc, env, goCmdPath, "tool", "compile", "-V=full"))
+	wantVersion := []byte(`compile version go1.999`)
+	if !bytes.Equal(gotVersion, wantVersion) {
+		t.Errorf("compile version without experiment: got %q, want %q", gotVersion, wantVersion)
+	}
+
+	// Build a package in a mode not handled by the make script.
+	runCmd(t, gorootSrc, env, goCmdPath, "build", "-race", "archive/tar")
+
+	// Rebuild the toolchain with GOEXPERIMENT.
+	env = append(env, "GOEXPERIMENT=fieldtrack")
+	runCmd(t, gorootSrc, env, makeScriptPath)
+
+	// Verify compiler version string.
+	gotVersion = bytes.TrimSpace(runCmd(t, gorootSrc, env, goCmdPath, "tool", "compile", "-V=full"))
+	wantVersion = []byte(`compile version go1.999 X:fieldtrack,framepointer`)
+	if !bytes.Equal(gotVersion, wantVersion) {
+		t.Errorf("compile version with experiment: got %q, want %q", gotVersion, wantVersion)
+	}
+
+	// Build the same package. We should not get a cache conflict.
+	runCmd(t, gorootSrc, env, goCmdPath, "build", "-race", "archive/tar")
+}
+
+func runCmd(t *testing.T, dir string, env []string, path string, args ...string) []byte {
+	cmd := exec.Command(path, args...)
+	cmd.Dir = dir
+	cmd.Env = env
+	out, err := cmd.Output()
+	if err != nil {
+		t.Fatal(err)
+	}
+	return out
+}