internal/testenv: skip tests that need export data for std if 'go tool compile' does not exist

Now that .a files are no longer being preinstalled for
standard-library packages (#47257), tests that require the export data
from those files must have access to 'go list -export' in order to
generate and load export data from the Go build cache.

`go list -export` does not work without a Go compiler, so assume that
tests that need the 'go' command also need the compiler.

This may cause the tests currently failing on the android-.*-emu
builders to instead be skipped, since the test harness does not copy
the compiler to the execution environment.

For golang/go#47257.

Change-Id: Ie82ab09ac8165a01fc1d3a083b1e86226efc469d
Reviewed-on: https://go-review.googlesource.com/c/tools/+/451597
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>
gopls-CI: kokoro <noreply+kokoro@google.com>

go/gcexportdata/example_test.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build go1.7 && gc
-// +build go1.7,gc
+//go:build go1.7 && gc && !android && !ios && !js
+// +build go1.7,gc,!android,!ios,!js
 
 package gcexportdata_test
 

go/packages/overlay_test.go

@@ -1046,6 +1046,7 @@ func Hi() {
 // This does not use go/packagestest because it needs to write a replace
 // directive with an absolute path in one of the module's go.mod files.
 func TestOverlaysInReplace(t *testing.T) {
+	testenv.NeedsGoPackages(t)
 	t.Parallel()
 
 	// Create module b.com in a temporary directory. Do not add any Go files

go/ssa/builder_test.go

@@ -24,6 +24,7 @@ import (
 	"golang.org/x/tools/go/loader"
 	"golang.org/x/tools/go/ssa"
 	"golang.org/x/tools/go/ssa/ssautil"
+	"golang.org/x/tools/internal/testenv"
 	"golang.org/x/tools/internal/typeparams"
 )
 
@@ -32,6 +33,8 @@ func isEmpty(f *ssa.Function) bool { return f.Blocks == nil }
 // Tests that programs partially loaded from gc object files contain
 // functions with no code for the external portions, but are otherwise ok.
 func TestBuildPackage(t *testing.T) {
+	testenv.NeedsGoBuild(t) // for importer.Default()
+
 	input := `
 package main
 
@@ -164,6 +167,8 @@ func main() {
 
 // TestRuntimeTypes tests that (*Program).RuntimeTypes() includes all necessary types.
 func TestRuntimeTypes(t *testing.T) {
+	testenv.NeedsGoBuild(t) // for importer.Default()
+
 	tests := []struct {
 		input string
 		want  []string

go/ssa/example_test.go

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !android && !ios && !js
+// +build !android,!ios,!js
+
 package ssa_test
 
 import (

go/ssa/ssautil/load_test.go

@@ -33,6 +33,8 @@ func main() {
 `
 
 func TestBuildPackage(t *testing.T) {
+	testenv.NeedsGoBuild(t) // for importer.Default()
+
 	// There is a more substantial test of BuildPackage and the
 	// SSA program it builds in ../ssa/builder_test.go.
 

gopls/internal/lsp/regtest/runner.go

@@ -141,6 +141,7 @@ func (r *Runner) Run(t *testing.T, files string, test TestFunc, opts ...RunOptio
 	// refactoring.
 	t.Helper()
 	checkBuilder(t)
+	testenv.NeedsGoPackages(t)
 
 	tests := []struct {
 		name      string

gopls/internal/lsp/safetoken/safetoken_test.go

@@ -10,6 +10,7 @@ import (
 	"testing"
 
 	"golang.org/x/tools/go/packages"
+	"golang.org/x/tools/internal/testenv"
 )
 
 // This test reports any unexpected uses of (*go/token.File).Offset within
@@ -17,6 +18,8 @@ import (
 // to panicking. All calls to (*go/token.File).Offset should be replaced with
 // calls to safetoken.Offset.
 func TestTokenOffset(t *testing.T) {
+	testenv.NeedsGoPackages(t)
+
 	fset := token.NewFileSet()
 	pkgs, err := packages.Load(&packages.Config{
 		Fset: fset,

gopls/internal/vulncheck/command_test.go

@@ -25,6 +25,7 @@ import (
 	"golang.org/x/tools/gopls/internal/lsp/source"
 	"golang.org/x/tools/gopls/internal/lsp/tests"
 	"golang.org/x/tools/gopls/internal/vulncheck/vulntest"
+	"golang.org/x/tools/internal/testenv"
 )
 
 func TestCmd_Run(t *testing.T) {
@@ -276,6 +277,9 @@ modules:
 `
 
 func runTest(t *testing.T, workspaceData, proxyData string, test func(context.Context, source.Snapshot)) {
+	testenv.NeedsGoBuild(t)
+	testenv.NeedsGoPackages(t)
+
 	ws, err := fake.NewSandbox(&fake.SandboxConfig{
 		Files:      fake.UnpackTxt(workspaceData),
 		ProxyFiles: fake.UnpackTxt(proxyData),

internal/gcimporter/gcimporter_test.go

@@ -373,6 +373,7 @@ func TestVersionHandling(t *testing.T) {
 func TestImportStdLib(t *testing.T) {
 	// This package only handles gc export data.
 	needsCompiler(t, "gc")
+	testenv.NeedsGoBuild(t) // to find stdlib export data in the build cache
 
 	dt := maxTime
 	if testing.Short() && os.Getenv("GO_BUILDER_NAME") == "" {
@@ -422,6 +423,7 @@ func TestImportedTypes(t *testing.T) {
 	testenv.NeedsGo1Point(t, 11)
 	// This package only handles gc export data.
 	needsCompiler(t, "gc")
+	testenv.NeedsGoBuild(t) // to find stdlib export data in the build cache
 
 	for _, test := range importedObjectTests {
 		obj := importObject(t, test.name)
@@ -447,6 +449,8 @@ func TestImportedTypes(t *testing.T) {
 
 func TestImportedConsts(t *testing.T) {
 	testenv.NeedsGo1Point(t, 11)
+	testenv.NeedsGoBuild(t) // to find stdlib export data in the build cache
+
 	tests := []struct {
 		name string
 		want constant.Kind
@@ -530,6 +534,7 @@ func verifyInterfaceMethodRecvs(t *testing.T, named *types.Named, level int) {
 func TestIssue5815(t *testing.T) {
 	// This package only handles gc export data.
 	needsCompiler(t, "gc")
+	testenv.NeedsGoBuild(t) // to find stdlib export data in the build cache
 
 	pkg := importPkg(t, "strings", ".")
 
@@ -555,6 +560,7 @@ func TestIssue5815(t *testing.T) {
 func TestCorrectMethodPackage(t *testing.T) {
 	// This package only handles gc export data.
 	needsCompiler(t, "gc")
+	testenv.NeedsGoBuild(t) // to find stdlib export data in the build cache
 
 	imports := make(map[string]*types.Package)
 	_, err := Import(imports, "net/http", ".", nil)
@@ -609,6 +615,7 @@ func TestIssue13566(t *testing.T) {
 func TestIssue13898(t *testing.T) {
 	// This package only handles gc export data.
 	needsCompiler(t, "gc")
+	testenv.NeedsGoBuild(t) // to find stdlib export data in the build cache
 
 	// import go/internal/gcimporter which imports go/types partially
 	imports := make(map[string]*types.Package)

internal/gcimporter/iexport_go118_test.go

@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	"golang.org/x/tools/internal/gcimporter"
+	"golang.org/x/tools/internal/testenv"
 )
 
 // TODO(rfindley): migrate this to testdata, as has been done in the standard library.
@@ -96,6 +97,8 @@ func testExportSrc(t *testing.T, src []byte) {
 }
 
 func TestImportTypeparamTests(t *testing.T) {
+	testenv.NeedsGoBuild(t) // to find stdlib export data in the build cache
+
 	// Check go files in test/typeparam.
 	rootDir := filepath.Join(runtime.GOROOT(), "test", "typeparam")
 	list, err := os.ReadDir(rootDir)

internal/testenv/testenv.go

@@ -100,6 +100,23 @@ func hasTool(tool string) error {
 			GOROOT := strings.TrimSpace(string(out))
 			if GOROOT != runtime.GOROOT() {
 				checkGoGoroot.err = fmt.Errorf("'go env GOROOT' does not match runtime.GOROOT:\n\tgo env: %s\n\tGOROOT: %s", GOROOT, runtime.GOROOT())
+				return
+			}
+
+			// Also ensure that that GOROOT includes a compiler: 'go' commands
+			// don't in general work without it, and some builders
+			// (such as android-amd64-emu) seem to lack it in the test environment.
+			cmd := exec.Command(tool, "tool", "-n", "compile")
+			stderr := new(bytes.Buffer)
+			stderr.Write([]byte("\n"))
+			cmd.Stderr = stderr
+			out, err = cmd.Output()
+			if err != nil {
+				checkGoGoroot.err = fmt.Errorf("%v: %v%s", cmd, err, stderr)
+				return
+			}
+			if _, err := os.Stat(string(bytes.TrimSpace(out))); err != nil {
+				checkGoGoroot.err = err
 			}
 		})
 		if checkGoGoroot.err != nil {