cmd/go: add go command known variables to test cache hash

The go test result must not be cached when each of known variables to go
command change.

To do this, add all known variables to test metadata.

Fixes #32285

Change-Id: I90be6a72f46c42d965aec4fed534c0623244cd3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/179040
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>

5 files changed, 88 insertions, 54 deletions

diff --git a/src/cmd/go/internal/cfg/cfg.go b/src/cmd/go/internal/cfg/cfg.go
index a0b51a72c3..a3277a6c3f 100644
--- a/src/cmd/go/internal/cfg/cfg.go
+++ b/src/cmd/go/internal/cfg/cfg.go
@@ -10,6 +10,7 @@ import (
 	"bytes"
 	"fmt"
 	"go/build"
+	"internal/cfg"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -221,61 +222,9 @@ func Getenv(key string) string {
 
 // CanGetenv reports whether key is a valid go/env configuration key.
 func CanGetenv(key string) bool {
-	return strings.Contains(knownEnv, "\t"+key+"\n")
+	return strings.Contains(cfg.KnownEnv, "\t"+key+"\n")
 }
 
-var knownEnv = `
-	AR
-	CC
-	CGO_CFLAGS
-	CGO_CFLAGS_ALLOW
-	CGO_CFLAGS_DISALLOW
-	CGO_CPPFLAGS
-	CGO_CPPFLAGS_ALLOW
-	CGO_CPPFLAGS_DISALLOW
-	CGO_CXXFLAGS
-	CGO_CXXFLAGS_ALLOW
-	CGO_CXXFLAGS_DISALLOW
-	CGO_ENABLED
-	CGO_FFLAGS
-	CGO_FFLAGS_ALLOW
-	CGO_FFLAGS_DISALLOW
-	CGO_LDFLAGS
-	CGO_LDFLAGS_ALLOW
-	CGO_LDFLAGS_DISALLOW
-	CXX
-	FC
-	GCCGO
-	GO111MODULE
-	GO386
-	GOARCH
-	GOARM
-	GOBIN
-	GOCACHE
-	GOENV
-	GOEXE
-	GOFLAGS
-	GOGCCFLAGS
-	GOHOSTARCH
-	GOHOSTOS
-	GOMIPS
-	GOMIPS64
-	GONOPROXY
-	GONOSUMDB
-	GOOS
-	GOPATH
-	GOPPC64
-	GOPRIVATE
-	GOPROXY
-	GOROOT
-	GOSUMDB
-	GOTMPDIR
-	GOTOOLDIR
-	GOWASM
-	GO_EXTLINK_ENABLED
-	PKG_CONFIG
-`
-
 var (
 	GOROOT       = BuildContext.GOROOT
 	GOBIN        = Getenv("GOBIN")
diff --git a/src/cmd/go/testdata/script/test_go111module_cache.txt b/src/cmd/go/testdata/script/test_go111module_cache.txt
new file mode 100644
index 0000000000..ca1de43a2b
--- /dev/null
+++ b/src/cmd/go/testdata/script/test_go111module_cache.txt
@@ -0,0 +1,15 @@
+env GO111MODULE=on
+go mod init foo
+go test
+stdout ^ok\s+foo
+env GO111MODULE=off
+go test
+stdout ^ok\s+
+! stdout ^ok\s+(cache)$
+
+-- main_test.go --
+package main
+
+import "testing"
+
+func TestF(t *testing.T) {}
diff --git a/src/go/build/deps_test.go b/src/go/build/deps_test.go
index 709c43a52a..bd866ee738 100644
--- a/src/go/build/deps_test.go
+++ b/src/go/build/deps_test.go
@@ -166,6 +166,7 @@ var pkgDeps = map[string][]string{
 		"syscall/js",
 	},
 
+	"internal/cfg":     {"L0"},
 	"internal/poll":    {"L0", "internal/oserror", "internal/race", "syscall", "time", "unicode/utf16", "unicode/utf8", "internal/syscall/windows"},
 	"internal/testlog": {"L0"},
 	"os":               {"L1", "os", "syscall", "time", "internal/oserror", "internal/poll", "internal/syscall/windows", "internal/syscall/unix", "internal/testlog"},
@@ -199,7 +200,7 @@ var pkgDeps = map[string][]string{
 	"testing":               {"L2", "flag", "fmt", "internal/race", "os", "runtime/debug", "runtime/pprof", "runtime/trace", "time"},
 	"testing/iotest":        {"L2", "log"},
 	"testing/quick":         {"L2", "flag", "fmt", "reflect", "time"},
-	"internal/testenv":      {"L2", "OS", "flag", "testing", "syscall"},
+	"internal/testenv":      {"L2", "OS", "flag", "testing", "syscall", "internal/cfg"},
 	"internal/lazyregexp":   {"L2", "OS", "regexp"},
 	"internal/lazytemplate": {"L2", "OS", "text/template"},
 
diff --git a/src/internal/cfg/cfg.go b/src/internal/cfg/cfg.go
new file mode 100644
index 0000000000..4c2cf8ee8b
--- /dev/null
+++ b/src/internal/cfg/cfg.go
@@ -0,0 +1,62 @@
+// 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 cfg holds configuration shared by the Go command and internal/testenv.
+// Definitions that don't need to be exposed outside of cmd/go should be in
+// cmd/go/internal/cfg instead of this package.
+package cfg
+
+// KnownEnv is a list of environment variables that affect the operation
+// of the Go command.
+const KnownEnv = `
+	AR
+	CC
+	CGO_CFLAGS
+	CGO_CFLAGS_ALLOW
+	CGO_CFLAGS_DISALLOW
+	CGO_CPPFLAGS
+	CGO_CPPFLAGS_ALLOW
+	CGO_CPPFLAGS_DISALLOW
+	CGO_CXXFLAGS
+	CGO_CXXFLAGS_ALLOW
+	CGO_CXXFLAGS_DISALLOW
+	CGO_ENABLED
+	CGO_FFLAGS
+	CGO_FFLAGS_ALLOW
+	CGO_FFLAGS_DISALLOW
+	CGO_LDFLAGS
+	CGO_LDFLAGS_ALLOW
+	CGO_LDFLAGS_DISALLOW
+	CXX
+	FC
+	GCCGO
+	GO111MODULE
+	GO386
+	GOARCH
+	GOARM
+	GOBIN
+	GOCACHE
+	GOENV
+	GOEXE
+	GOFLAGS
+	GOGCCFLAGS
+	GOHOSTARCH
+	GOHOSTOS
+	GOMIPS
+	GOMIPS64
+	GONOPROXY
+	GONOSUMDB
+	GOOS
+	GOPATH
+	GOPPC64
+	GOPRIVATE
+	GOPROXY
+	GOROOT
+	GOSUMDB
+	GOTMPDIR
+	GOTOOLDIR
+	GOWASM
+	GO_EXTLINK_ENABLED
+	PKG_CONFIG
+`
diff --git a/src/internal/testenv/testenv.go b/src/internal/testenv/testenv.go
index c27fcfa208..f7a9730ca6 100644
--- a/src/internal/testenv/testenv.go
+++ b/src/internal/testenv/testenv.go
@@ -13,6 +13,7 @@ package testenv
 import (
 	"errors"
 	"flag"
+	"internal/cfg"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -88,6 +89,12 @@ func GoToolPath(t testing.TB) string {
 	if err != nil {
 		t.Fatal(err)
 	}
+	// Add all environment variables that affect the Go command to test metadata.
+	// Cached test results will be invalidate when these variables change.
+	// See golang.org/issue/32285.
+	for _, envVar := range strings.Fields(cfg.KnownEnv) {
+		os.Getenv(envVar)
+	}
 	return path
 }