cmd/go: improvements

Do not treat $GOROOT/src/pkg, $GOROOT/src/cmd,
$GOPATH/src as package directories (only subdirectories
of those can be package directories).  Fixes issue 2602.

Accept additional compiler and linker arguments during
cgo from $CGO_CFLAGS and $CGO_LDFLAGS, as the
Makefiles used to do.

Show failed pkg-config output.  Fixes issue 2785.

Use different (perhaps better) git commands.  Fixes issue 2109.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5605045

src/cmd/go/build.go

@@ -1131,6 +1131,10 @@ func (b *builder) gccCmd(objdir string) []string {
 	return a
 }
 
+func envList(key string) []string {
+	return strings.Fields(os.Getenv(key))
+}
+
 var cgoRe = regexp.MustCompile(`[/\\:]`)
 
 func (b *builder) cgo(p *Package, cgoExe, obj string, gccfiles []string) (outGo, outObj []string, err error) {
@@ -1140,19 +1144,24 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, gccfiles []string) (outGo,
 
 	outObj = append(outObj, "") // for importObj, at end of function
 
-	cgoCFLAGS := stringList(p.info.CgoCFLAGS)
+	cgoCFLAGS := stringList(envList("CGO_CFLAGS"), p.info.CgoCFLAGS)
-	cgoLDFLAGS := stringList(p.info.CgoLDFLAGS)
+	cgoLDFLAGS := stringList(envList("CGO_LDFLAGS"), p.info.CgoLDFLAGS)
+
 	if pkgs := p.info.CgoPkgConfig; len(pkgs) > 0 {
 		out, err := b.runOut(p.Dir, p.ImportPath, "pkg-config", "--cflags", pkgs)
 		if err != nil {
-			return nil, nil, err
+			b.showOutput(p.Dir, "pkg-config --cflags "+strings.Join(pkgs, " "), string(out))
+			b.print(err.Error() + "\n")
+			return nil, nil, errPrintedOutput
 		}
 		if len(out) > 0 {
 			cgoCFLAGS = append(cgoCFLAGS, strings.Fields(string(out))...)
 		}
 		out, err = b.runOut(p.Dir, p.ImportPath, "pkg-config", "--libs", pkgs)
 		if err != nil {
-			return nil, nil, err
+			b.showOutput(p.Dir, "pkg-config --libs "+strings.Join(pkgs, " "), string(out))
+			b.print(err.Error() + "\n")
+			return nil, nil, errPrintedOutput
 		}
 		if len(out) > 0 {
 			cgoLDFLAGS = append(cgoLDFLAGS, strings.Fields(string(out))...)

src/cmd/go/get.go

@@ -215,11 +215,7 @@ func downloadPackage(p *Package) error {
 	if i := strings.Index(vers, " "); i >= 0 {
 		vers = vers[:i]
 	}
-	tag := selectTag(vers, tags)
+	if err := vcs.tagSync(root, selectTag(vers, tags)); err != nil {
-	if tag == "" {
-		tag = vcs.tagDefault
-	}
-	if err := vcs.tagSync(root, tag); err != nil {
 		return err
 	}
 

src/cmd/go/main.go

@@ -347,7 +347,7 @@ func allPackages(pattern string) []string {
 	goroot := build.Path[0].Path
 	cmd := filepath.Join(goroot, "src/cmd") + string(filepath.Separator)
 	filepath.Walk(cmd, func(path string, fi os.FileInfo, err error) error {
-		if err != nil || !fi.IsDir() {
+		if err != nil || !fi.IsDir() || path == cmd {
 			return nil
 		}
 		name := path[len(cmd):]
@@ -378,7 +378,7 @@ func allPackages(pattern string) []string {
 		}
 		src := t.SrcDir() + string(filepath.Separator)
 		filepath.Walk(src, func(path string, fi os.FileInfo, err error) error {
-			if err != nil || !fi.IsDir() {
+			if err != nil || !fi.IsDir() || path == src {
 				return nil
 			}
 
@@ -445,7 +445,7 @@ func allPackagesInFS(pattern string) []string {
 
 	var pkgs []string
 	filepath.Walk(dir, func(path string, fi os.FileInfo, err error) error {
-		if err != nil || !fi.IsDir() {
+		if err != nil || !fi.IsDir() || path == dir {
 			return nil
 		}
 

src/cmd/go/vcs.go

@@ -24,8 +24,8 @@ type vcsCmd struct {
 	downloadCmd string // command to download updates into an existing repository
 
 	tagCmd         []tagCmd // commands to list tags
-	tagDefault string   // default tag to use
 	tagSyncCmd     string   // command to sync to specific tag
+	tagSyncDefault string   // command to sync to default tag
 }
 
 // A tagCmd describes a command to list available tags
@@ -71,8 +71,8 @@ var vcsHg = &vcsCmd{
 		{"tags", `^(\S+)`},
 		{"branches", `^(\S+)`},
 	},
-	tagDefault: "default",
 	tagSyncCmd:     "update -r {tag}",
+	tagSyncDefault: "update default",
 }
 
 // vcsGit describes how to use Git.
@@ -84,8 +84,8 @@ var vcsGit = &vcsCmd{
 	downloadCmd: "fetch",
 
 	tagCmd:         []tagCmd{{"tag", `^(\S+)$`}},
-	tagDefault: "master",
 	tagSyncCmd:     "checkout {tag}",
+	tagSyncDefault: "checkout origin/master",
 }
 
 // vcsBzr describes how to use Bazaar.
@@ -100,8 +100,8 @@ var vcsBzr = &vcsCmd{
 	downloadCmd: "pull --overwrite",
 
 	tagCmd:         []tagCmd{{"tags", `^(\S+)`}},
-	tagDefault: "revno:-1",
 	tagSyncCmd:     "update -r {tag}",
+	tagSyncDefault: "update -r revno:-1",
 }
 
 // vcsSvn describes how to use Subversion.
@@ -198,6 +198,9 @@ func (v *vcsCmd) tagSync(dir, tag string) error {
 	if v.tagSyncCmd == "" {
 		return nil
 	}
+	if tag == "" && v.tagSyncDefault != "" {
+		return v.run(dir, v.tagSyncDefault)
+	}
 	return v.run(dir, v.tagSyncCmd, "tag", tag)
 }