cmd/go: include GOEXPERIMENT flags in tool id for cache key

The go command invokes each tool with -V=full to discover its version
to compute a tool id. For release versions (that don't include the
word "devel"), the go command only used the third word in
the output (e.g., "go1.13"), ignoring any toolchain experiments that
followed. With this change, the go command will use whole version line
in the tool id for release versions.

Also, when -V=full is set and there are non-default experiments,
experiments are no longer printed twice.

Fixes #33091

Change-Id: I19b96f939c7e2fbc5d8befe3659156ee4b58daef
Reviewed-on: https://go-review.googlesource.com/c/go/+/186200
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

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 0000000000..eabf06b19e
--- /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.
+
+// +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"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"testing"
+)
+
+func TestExperimentToolID(t *testing.T) {
+	// Set up GOROOT
+	goroot, err := ioutil.TempDir("", "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 := ioutil.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 := ioutil.TempDir("", "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
+}