cmd/go: remove GO15VENDOREXPERIMENT variable

The Go 1.6 release notes say that Go 1.7 will remove support
for the GO15VENDOREXPERIMENT environment variable,
making vendoring always on. Do that.

Change-Id: Iba8b79532455828869c1a8076a82edce84259468
Reviewed-on: https://go-review.googlesource.com/19615Reviewed-by: Ian Lance Taylor <iant@golang.org>

doc/go1.7.txt

 Tools:
 
-cmd/link: "-X name value" form gone (CL XXX)
+cmd/go: GO15VENDOREXPERIMENT gone, assumed on (CL 19615)
+cmd/link: "-X name value" form gone (CL 19614)
 
 Ports:
 

src/cmd/go/alldocs.go

@@ -1022,12 +1022,6 @@ Vendor directories do not affect the placement of new repositories
 being checked out for the first time by 'go get': those are always
 placed in the main GOPATH, never in a vendor subtree.
 
-In Go 1.5, as an experiment, setting the environment variable
-GO15VENDOREXPERIMENT=1 enabled these features.
-As of Go 1.6 they are on by default. To turn them off, set
-GO15VENDOREXPERIMENT=0. In Go 1.7, the environment
-variable will stop having any effect.
-
 See https://golang.org/s/go15vendor for details.
 
 
@@ -1094,8 +1088,6 @@ Special-purpose environment variables:
 		installed in a location other than where it is built.
 		File names in stack traces are rewritten from GOROOT to
 		GOROOT_FINAL.
-	GO15VENDOREXPERIMENT
-		Set to 0 to disable vendoring semantics.
 	GO_EXTLINK_ENABLED
 		Whether the linker should use external linking mode
 		when using -linkmode=auto with code that uses cgo.

src/cmd/go/env.go

@@ -33,11 +33,6 @@ func mkEnv() []envVar {
 	var b builder
 	b.init()
 
-	vendorExpValue := "0"
-	if go15VendorExperiment {
-		vendorExpValue = "1"
-	}
-
 	env := []envVar{
 		{"GOARCH", goarch},
 		{"GOBIN", gobin},
@@ -49,7 +44,6 @@ func mkEnv() []envVar {
 		{"GORACE", os.Getenv("GORACE")},
 		{"GOROOT", goroot},
 		{"GOTOOLDIR", toolDir},
-		{"GO15VENDOREXPERIMENT", vendorExpValue},
 
 		// disable escape codes in clang errors
 		{"TERM", "dumb"},

src/cmd/go/help.go

@@ -421,12 +421,6 @@ Vendor directories do not affect the placement of new repositories
 being checked out for the first time by 'go get': those are always
 placed in the main GOPATH, never in a vendor subtree.
 
-In Go 1.5, as an experiment, setting the environment variable
-GO15VENDOREXPERIMENT=1 enabled these features.
-As of Go 1.6 they are on by default. To turn them off, set
-GO15VENDOREXPERIMENT=0. In Go 1.7, the environment
-variable will stop having any effect.
-
 See https://golang.org/s/go15vendor for details.
 	`,
 }
@@ -497,8 +491,6 @@ Special-purpose environment variables:
 		installed in a location other than where it is built.
 		File names in stack traces are rewritten from GOROOT to
 		GOROOT_FINAL.
-	GO15VENDOREXPERIMENT
-		Set to 0 to disable vendoring semantics.
 	GO_EXTLINK_ENABLED
 		Whether the linker should use external linking mode
 		when using -linkmode=auto with code that uses cgo.

src/cmd/go/pkg.go

@@ -263,15 +263,6 @@ func reloadPackage(arg string, stk *importStack) *Package {
 	return loadPackage(arg, stk)
 }
 
-// The Go 1.5 vendoring experiment was enabled by setting GO15VENDOREXPERIMENT=1.
-// In Go 1.6 this is on by default and is disabled by setting GO15VENDOREXPERIMENT=0.
-// In Go 1.7 the variable will stop having any effect.
-// The variable is obnoxiously long so that years from now when people find it in
-// their profiles and wonder what it does, there is some chance that a web search
-// might answer the question.
-// There is a copy of this variable in src/go/build/build.go. Delete that one when this one goes away.
-var go15VendorExperiment = os.Getenv("GO15VENDOREXPERIMENT") != "0"
-
 // dirToImportPath returns the pseudo-import path we use for a package
 // outside the Go path.  It begins with _/ and then contains the full path
 // to the directory.  If the package lives in c:\home\gopher\my\pkg then
@@ -361,7 +352,7 @@ func loadImport(path, srcDir string, parent *Package, stk *importStack, importPo
 	// TODO: After Go 1, decide when to pass build.AllowBinary here.
 	// See issue 3268 for mistakes to avoid.
 	buildMode := build.ImportComment
-	if !go15VendorExperiment || mode&useVendor == 0 || path != origPath {
+	if mode&useVendor == 0 || path != origPath {
 		// Not vendoring, or we already found the vendored path.
 		buildMode |= build.IgnoreVendor
 	}
@@ -371,7 +362,7 @@ func loadImport(path, srcDir string, parent *Package, stk *importStack, importPo
 		bp.BinDir = gobin
 	}
 	if err == nil && !isLocal && bp.ImportComment != "" && bp.ImportComment != path &&
-		(!go15VendorExperiment || (!strings.Contains(path, "/vendor/") && !strings.HasPrefix(path, "vendor/"))) {
+		!strings.Contains(path, "/vendor/") && !strings.HasPrefix(path, "vendor/") {
 		err = fmt.Errorf("code in directory %s expects import %q", bp.Dir, bp.ImportComment)
 	}
 	p.load(stk, bp, err)
@@ -412,7 +403,7 @@ func isDir(path string) bool {
 // x/vendor/path, vendor/path, or else stay path if none of those exist.
 // vendoredImportPath returns the expanded path or, if no expansion is found, the original.
 func vendoredImportPath(parent *Package, path string) (found string) {
-	if parent == nil || parent.Root == "" || !go15VendorExperiment {
+	if parent == nil || parent.Root == "" {
 		return path
 	}
 
@@ -580,10 +571,6 @@ func findInternal(path string) (index int, ok bool) {
 // If the import is allowed, disallowVendor returns the original package p.
 // If not, it returns a new package containing just an appropriate error.
 func disallowVendor(srcDir, path string, p *Package, stk *importStack) *Package {
-	if !go15VendorExperiment {
-		return p
-	}
-
 	// The stack includes p.ImportPath.
 	// If that's the only thing on the stack, we started
 	// with a name given on the command line, not an

src/cmd/go/vcs.go

@@ -383,7 +383,7 @@ func (v *vcsCmd) ping(scheme, repo string) error {
 // The parent of dir must exist; dir must not.
 func (v *vcsCmd) create(dir, repo string) error {
 	for _, cmd := range v.createCmd {
-		if !go15VendorExperiment && strings.Contains(cmd, "submodule") {
+		if strings.Contains(cmd, "submodule") {
 			continue
 		}
 		if err := v.run(".", cmd, "dir", dir, "repo", repo); err != nil {
@@ -396,7 +396,7 @@ func (v *vcsCmd) create(dir, repo string) error {
 // download downloads any new changes for the repo in dir.
 func (v *vcsCmd) download(dir string) error {
 	for _, cmd := range v.downloadCmd {
-		if !go15VendorExperiment && strings.Contains(cmd, "submodule") {
+		if strings.Contains(cmd, "submodule") {
 			continue
 		}
 		if err := v.run(dir, cmd); err != nil {
@@ -445,7 +445,7 @@ func (v *vcsCmd) tagSync(dir, tag string) error {
 
 	if tag == "" && v.tagSyncDefault != nil {
 		for _, cmd := range v.tagSyncDefault {
-			if !go15VendorExperiment && strings.Contains(cmd, "submodule") {
+			if strings.Contains(cmd, "submodule") {
 				continue
 			}
 			if err := v.run(dir, cmd); err != nil {
@@ -456,7 +456,7 @@ func (v *vcsCmd) tagSync(dir, tag string) error {
 	}
 
 	for _, cmd := range v.tagSyncCmd {
-		if !go15VendorExperiment && strings.Contains(cmd, "submodule") {
+		if strings.Contains(cmd, "submodule") {
 			continue
 		}
 		if err := v.run(dir, cmd, "tag", tag); err != nil {

src/cmd/go/vendor_test.go

@@ -20,7 +20,6 @@ func TestVendorImports(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.run("list", "-f", "{{.ImportPath}} {{.Imports}}", "vend/...")
 	want := `
 		vend [vend/vendor/p r]
@@ -51,7 +50,6 @@ func TestVendorBuild(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.run("build", "vend/x")
 }
 
@@ -59,7 +57,6 @@ func TestVendorRun(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.cd(filepath.Join(tg.pwd(), "testdata/src/vend/hello"))
 	tg.run("run", "hello.go")
 	tg.grepStdout("hello, world", "missing hello world output")
@@ -74,7 +71,6 @@ func TestVendorGOPATH(t *testing.T) {
 	}
 	gopath := changeVolume(filepath.Join(tg.pwd(), "testdata"), strings.ToLower)
 	tg.setenv("GOPATH", gopath)
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	cd := changeVolume(filepath.Join(tg.pwd(), "testdata/src/vend/hello"), strings.ToUpper)
 	tg.cd(cd)
 	tg.run("run", "hello.go")
@@ -85,7 +81,6 @@ func TestVendorTest(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.cd(filepath.Join(tg.pwd(), "testdata/src/vend/hello"))
 	tg.run("test", "-v")
 	tg.grepStdout("TestMsgInternal", "missing use in internal test")
@@ -96,7 +91,6 @@ func TestVendorInvalid(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 
 	tg.runFail("build", "vend/x/invalid")
 	tg.grepStderr("must be imported as foo", "missing vendor import error")
@@ -106,7 +100,6 @@ func TestVendorImportError(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 
 	tg.runFail("build", "vend/x/vendor/p/p")
 
@@ -173,7 +166,6 @@ func TestVendorGet(t *testing.T) {
 		package p
 		const C = 1`)
 	tg.setenv("GOPATH", tg.path("."))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.cd(tg.path("src/v"))
 	tg.run("run", "m.go")
 	tg.run("test")
@@ -192,7 +184,6 @@ func TestVendorGetUpdate(t *testing.T) {
 	defer tg.cleanup()
 	tg.makeTempdir()
 	tg.setenv("GOPATH", tg.path("."))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.run("get", "github.com/rsc/go-get-issue-11864")
 	tg.run("get", "-u", "github.com/rsc/go-get-issue-11864")
 }
@@ -204,7 +195,6 @@ func TestGetSubmodules(t *testing.T) {
 	defer tg.cleanup()
 	tg.makeTempdir()
 	tg.setenv("GOPATH", tg.path("."))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.run("get", "-d", "github.com/rsc/go-get-issue-12612")
 	tg.run("get", "-u", "-d", "github.com/rsc/go-get-issue-12612")
 }
@@ -213,7 +203,6 @@ func TestVendorCache(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata/testvendor"))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.runFail("build", "p")
 	tg.grepStderr("must be imported as x", "did not fail to build p")
 }
@@ -225,7 +214,6 @@ func TestVendorTest2(t *testing.T) {
 	defer tg.cleanup()
 	tg.makeTempdir()
 	tg.setenv("GOPATH", tg.path("."))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.run("get", "github.com/rsc/go-get-issue-11864")
 
 	// build -i should work
@@ -251,7 +239,6 @@ func TestVendorList(t *testing.T) {
 	defer tg.cleanup()
 	tg.makeTempdir()
 	tg.setenv("GOPATH", tg.path("."))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.run("get", "github.com/rsc/go-get-issue-11864")
 
 	tg.run("list", "-f", `{{join .TestImports "\n"}}`, "github.com/rsc/go-get-issue-11864/t")
@@ -272,7 +259,6 @@ func TestVendor12156(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata/testvendor2"))
-	tg.setenv("GO15VENDOREXPERIMENT", "1")
 	tg.cd(filepath.Join(tg.pwd(), "testdata/testvendor2/src/p"))
 	tg.runFail("build", "p.go")
 	tg.grepStderrNot("panic", "panicked")