n

Change-Id: Iabbb564b16abf1be55280d39152155f6748ec5fb

Author: qiulaidongfeng

src/cmd/go/internal/cfg/cfg.go

@@ -103,6 +103,7 @@ var (
 	// explanation why GOPATH is unset.
 	GoPathError   string
 	GOPATHChanged bool
+	CGOChanged    bool
 )
 
 func defaultContext() build.Context {
@@ -131,7 +132,7 @@ func defaultContext() build.Context {
 	//	3. Otherwise, use built-in default for GOOS/GOARCH.
 	// Recreate that logic here with the new GOOS/GOARCH setting.
 	if v := Getenv("CGO_ENABLED"); v == "0" || v == "1" {
-		ctxt.CgoEnabled = v[0] == '1'
+		ctxt.CgoEnabled, CGOChanged = v[0] == '1', v[0] != '0'
 	} else if ctxt.GOOS != runtime.GOOS || ctxt.GOARCH != runtime.GOARCH {
 		ctxt.CgoEnabled = false
 	} else {
@@ -411,7 +412,7 @@ var (
 	GOMIPS, goMIPSChanged       = EnvOrAndChanged("GOMIPS", buildcfg.GOMIPS)
 	GOMIPS64, goMIPS64Changed   = EnvOrAndChanged("GOMIPS64", buildcfg.GOMIPS64)
 	GOPPC64, goPPC64Changed     = EnvOrAndChanged("GOPPC64", fmt.Sprintf("%s%d", "power", buildcfg.GOPPC64))
-	GORISCV64, gORISCV64Changed = EnvOrAndChanged("GORISCV64", fmt.Sprintf("rva%du64", buildcfg.GORISCV64))
+	GORISCV64, goRISCV64Changed = EnvOrAndChanged("GORISCV64", fmt.Sprintf("rva%du64", buildcfg.GORISCV64))
 	GOWASM, goWASMChanged       = EnvOrAndChanged("GOWASM", fmt.Sprint(buildcfg.GOWASM))
 
 	GOPROXY, GOPROXYChanged     = EnvOrAndChanged("GOPROXY", "")
@@ -456,7 +457,7 @@ func GetArchEnv() (key, val string, changed bool) {
 	case "ppc64", "ppc64le":
 		return "GOPPC64", GOPPC64, goPPC64Changed
 	case "riscv64":
-		return "GORISCV64", GORISCV64, gORISCV64Changed
+		return "GORISCV64", GORISCV64, goRISCV64Changed
 	case "wasm":
 		return "GOWASM", GOWASM, goWASMChanged
 	}

src/cmd/go/internal/envcmd/env.go

@@ -162,9 +162,9 @@ func MkEnv() []cfg.EnvVar {
 	env = append(env, cfg.EnvVar{Name: "CXX", Value: cxx, Changed: cxxChanged})
 
 	if cfg.BuildContext.CgoEnabled {
-		env = append(env, cfg.EnvVar{Name: "CGO_ENABLED", Value: "1", Changed: true})
+		env = append(env, cfg.EnvVar{Name: "CGO_ENABLED", Value: "1", Changed: cfg.CGOChanged})
 	} else {
-		env = append(env, cfg.EnvVar{Name: "CGO_ENABLED", Value: "0"})
+		env = append(env, cfg.EnvVar{Name: "CGO_ENABLED", Value: "0", Changed: cfg.CGOChanged})
 	}
 
 	return env

src/cmd/go/testdata/script/env_changed.txt

@@ -10,12 +10,12 @@ env CGO_CPPFLAGS=nodefault
 go env -changed
 # linux output like GOTOOLCHAIN='local'
 # windows output like GOTOOLCHAIN=local
-stdout 'GOTOOLCHAIN=local|GOTOOLCHAIN=''local'''
-stdout 'GOSUMDB=nodefault|GOSUMDB=''nodefault'''
-stdout 'GOPROXY=nodefault|GOPROXY=''nodefault'''
-stdout 'GO111MODULE=auto|GO111MODULE=''auto'''
-stdout 'CGO_CFLAGS=nodefault|CGO_CFLAGS=''nodefault'''
-stdout 'CGO_CPPFLAGS=nodefault|CGO_CPPFLAGS=''nodefault'''
+stdout 'GOTOOLCHAIN=''?local''?'
+stdout 'GOSUMDB=''?nodefault''?'
+stdout 'GOPROXY=''?nodefault''?'
+stdout 'GO111MODULE=''?auto''?'
+stdout 'CGO_CFLAGS=''?nodefault''?'
+stdout 'CGO_CPPFLAGS=''?nodefault''?'
 
 go env -changed -json
 stdout '"GOTOOLCHAIN": "local"'

src/go/build/build.go

@@ -286,7 +286,7 @@ func (ctxt *Context) SrcDirs() []string {
 // if set, or else the compiled code's GOARCH, GOOS, and GOROOT.
 var Default Context = defaultContext()
 
-// defaultGOPATH now semantics are actually the same in cmd/go/internal/cfg.gopath.
+// Keep consistent with cmd/go/internal/cfg.defaultGOPATH.
 func defaultGOPATH() string {
 	env := "HOME"
 	if runtime.GOOS == "windows" {

src/go/build/deps_test.go

@@ -40,7 +40,7 @@ var depsRules = `
 	# No dependencies allowed for any of these packages.
 	NONE
 	< cmp, container/list, container/ring,
-	  internal/coverage, internal/coverage/rtcov,
+	  internal/cfg, internal/coverage, internal/coverage/rtcov,
 	  internal/coverage/uleb128, internal/coverage/calloc,
 	  internal/cpu, internal/goarch, internal/godebugs,
 	  internal/goexperiment, internal/goos,
@@ -323,9 +323,7 @@ var depsRules = `
 	go/doc/comment, go/parser, internal/lazyregexp, text/template
 	< go/doc;
 
-	os, path/filepath, runtime < internal/cfg;
-
-	go/build/constraint, go/doc, go/parser, internal/buildcfg, internal/goroot, internal/goversion, internal/platform, internal/cfg
+	go/build/constraint, go/doc, go/parser, internal/buildcfg, internal/goroot, internal/goversion, internal/platform
 	< go/build;
 
 	# databases