Remove --root, require the cwd to be the root

This allows us to use relative paths everywhere.
It also produces more accurate emulation of TOPDIR,
which should be an empty string.

Bug: 213508006
Test: go test
Change-Id: Ie4e357687486e84e9f4aad0f6776d8feb2b9fc63

mk2rbc/cmd/mk2rbc.go

@@ -40,7 +40,6 @@ import (
 )
 
 var (
-	rootDir = flag.String("root", ".", "the value of // for load paths")
 	// TODO(asmundak): remove this option once there is a consensus on suffix
 	suffix   = flag.String("suffix", ".rbc", "generated files' suffix")
 	dryRun   = flag.Bool("dry_run", false, "dry run")
@@ -71,7 +70,6 @@ func init() {
 		quit("cannot alias unknown flag " + target)
 	}
 	flagAlias("suffix", "s")
-	flagAlias("root", "d")
 	flagAlias("dry_run", "n")
 	flagAlias("convert_dependents", "r")
 	flagAlias("error_stat", "e")
@@ -91,6 +89,10 @@ func main() {
 	}
 	flag.Parse()
 
+	if _, err := os.Stat("build/soong/mk2rbc"); err != nil {
+		quit("Must be run from the root of the android tree. (build/soong/mk2rbc does not exist)")
+	}
+
 	// Delouse
 	if *suffix == ".mk" {
 		quit("cannot use .mk as generated file suffix")
@@ -228,17 +230,16 @@ func buildProductConfigMap() map[string]string {
 	const androidProductsMk = "AndroidProducts.mk"
 	// Build the list of AndroidProducts.mk files: it's
 	// build/make/target/product/AndroidProducts.mk + device/**/AndroidProducts.mk plus + vendor/**/AndroidProducts.mk
-	targetAndroidProductsFile := filepath.Join(*rootDir, "build", "make", "target", "product", androidProductsMk)
+	targetAndroidProductsFile := filepath.Join("build", "make", "target", "product", androidProductsMk)
 	if _, err := os.Stat(targetAndroidProductsFile); err != nil {
-		fmt.Fprintf(os.Stderr, "%s: %s\n(hint: %s is not a source tree root)\n",
-			targetAndroidProductsFile, err, *rootDir)
+		fmt.Fprintf(os.Stderr, "%s: %s\n", targetAndroidProductsFile, err)
 	}
 	productConfigMap := make(map[string]string)
 	if err := mk2rbc.UpdateProductConfigMap(productConfigMap, targetAndroidProductsFile); err != nil {
 		fmt.Fprintf(os.Stderr, "%s: %s\n", targetAndroidProductsFile, err)
 	}
 	for _, t := range []string{"device", "vendor"} {
-		_ = filepath.WalkDir(filepath.Join(*rootDir, t),
+		_ = filepath.WalkDir(t,
 			func(path string, d os.DirEntry, err error) error {
 				if err != nil || d.IsDir() || filepath.Base(path) != androidProductsMk {
 					return nil
@@ -254,10 +255,9 @@ func buildProductConfigMap() map[string]string {
 }
 
 func getConfigVariables() {
-	path := filepath.Join(*rootDir, "build", "make", "core", "product.mk")
+	path := filepath.Join("build", "make", "core", "product.mk")
 	if err := mk2rbc.FindConfigVariables(path, mk2rbc.KnownVariables); err != nil {
-		quit(fmt.Errorf("%s\n(check --root[=%s], it should point to the source root)",
-			err, *rootDir))
+		quit(err)
 	}
 }
 
@@ -270,11 +270,11 @@ func (s fileNameScope) Get(name string) string {
 	if name != "BUILD_SYSTEM" {
 		return fmt.Sprintf("$(%s)", name)
 	}
-	return filepath.Join(*rootDir, "build", "make", "core")
+	return filepath.Join("build", "make", "core")
 }
 
 func getSoongVariables() {
-	path := filepath.Join(*rootDir, "build", "make", "core", "soong_config.mk")
+	path := filepath.Join("build", "make", "core", "soong_config.mk")
 	err := mk2rbc.FindSoongVariables(path, fileNameScope{}, mk2rbc.KnownVariables)
 	if err != nil {
 		quit(err)
@@ -325,12 +325,11 @@ func convertOne(mkFile string) (ok bool) {
 	mk2starRequest := mk2rbc.Request{
 		MkFile:          mkFile,
 		Reader:          nil,
-		RootDir:         *rootDir,
 		OutputDir:       *outputTop,
 		OutputSuffix:    *suffix,
 		TracedVariables: tracedVariables,
 		TraceCalls:      *traceCalls,
-		SourceFS:        os.DirFS(*rootDir),
+		SourceFS:        os.DirFS("."),
 		MakefileFinder:  makefileFinder,
 		ErrorLogger:     errorLogger,
 	}
@@ -587,7 +586,7 @@ type FileListMakefileFinder struct {
 
 func (l *FileListMakefileFinder) Find(root string) []string {
 	root, err1 := filepath.Abs(root)
-	wd, err2 := filepath.Abs(*rootDir)
+	wd, err2 := os.Getwd()
 	if root != wd || err1 != nil || err2 != nil {
 		return l.FindCommandMakefileFinder.Find(root)
 	}

mk2rbc/mk2rbc.go

@@ -142,7 +142,6 @@ var identifierFullMatchRegex = regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$")
 type Request struct {
 	MkFile          string    // file to convert
 	Reader          io.Reader // if set, read input from this stream instead
-	RootDir         string    // root directory path used to resolve included files
 	OutputSuffix    string    // generated Starlark files suffix
 	OutputDir       string    // if set, root of the output hierarchy
 	ErrorLogger     ErrorLogger
@@ -378,7 +377,6 @@ type StarlarkScript struct {
 	nodes          []starlarkNode
 	inherited      []*moduleInfo
 	hasErrors      bool
-	topDir         string
 	traceCalls     bool // print enter/exit each init function
 	sourceFS       fs.FS
 	makefileFinder MakefileFinder
@@ -414,11 +412,10 @@ type parseContext struct {
 }
 
 func newParseContext(ss *StarlarkScript, nodes []mkparser.Node) *parseContext {
-	topdir, _ := filepath.Split(filepath.Join(ss.topDir, "foo"))
 	predefined := []struct{ name, value string }{
 		{"SRC_TARGET_DIR", filepath.Join("build", "make", "target")},
 		{"LOCAL_PATH", filepath.Dir(ss.mkFile)},
-		{"TOPDIR", topdir},
+		{"TOPDIR", ""}, // TOPDIR is just set to an empty string in cleanbuild.mk and core.mk
 		// TODO(asmundak): maybe read it from build/make/core/envsetup.mk?
 		{"TARGET_COPY_OUT_SYSTEM", "system"},
 		{"TARGET_COPY_OUT_SYSTEM_OTHER", "system_other"},
@@ -827,7 +824,7 @@ func (ctx *parseContext) handleSubConfig(
 }
 
 func (ctx *parseContext) findMatchingPaths(pattern []string) []string {
-	files := ctx.script.makefileFinder.Find(ctx.script.topDir)
+	files := ctx.script.makefileFinder.Find(".")
 	if len(pattern) == 0 {
 		return files
 	}
@@ -1864,7 +1861,6 @@ func Convert(req Request) (*StarlarkScript, error) {
 	starScript := &StarlarkScript{
 		moduleName:     moduleNameForFile(req.MkFile),
 		mkFile:         req.MkFile,
-		topDir:         req.RootDir,
 		traceCalls:     req.TraceCalls,
 		sourceFS:       req.SourceFS,
 		makefileFinder: req.MakefileFinder,

mk2rbc/mk2rbc_test.go

@@ -1387,7 +1387,6 @@ func TestGood(t *testing.T) {
 				ss, err := Convert(Request{
 					MkFile:         test.mkname,
 					Reader:         bytes.NewBufferString(test.in),
-					RootDir:        ".",
 					OutputSuffix:   ".star",
 					SourceFS:       fs,
 					MakefileFinder: &testMakefileFinder{fs: fs},