Support MODULE.bazel in FindRepoBuildFiles()

[mering]

Currently, it only parses WORKSPACE:

buildtools/wspace/workspace.go

Line 123 in 19c62d9

ws := filepath.Join(root, workspaceFile)

This is used for example by edit.InterpretLabel():

buildtools/edit/edit.go

Lines 41 to 113 in 19c62d9

	// InterpretLabelForWorkspaceLocation returns the name of the BUILD file to
	// edit, the full package name, and the rule. It takes a workspace-rooted
	// directory to use.
	func InterpretLabelForWorkspaceLocation(root, target string) (buildFile, repo, pkg, rule string) {
	label := labels.Parse(target)
	repo = label.Repository
	pkg = label.Package
	rule = label.Target
	rootDir, relativePath := wspace.FindWorkspaceRoot(root)
	if repo != "" {
	files, err := wspace.FindRepoBuildFiles(rootDir)
	if err == nil {
	if buildFile, ok := files[repo]; ok {
	return buildFile, repo, pkg, rule
	}
	}
	// TODO(rodrigoq): report error for other repos
	}
	defaultBuildFileName := "BUILD"
	if strings.HasPrefix(target, "//") {
	pkgPath := filepath.Join(rootDir, filepath.FromSlash(pkg))
	if wspace.IsRegularFile(pkgPath) {
	// allow operation on other files like WORKSPACE
	buildFile = pkgPath
	pkg = path.Dir(pkg)
	return
	}
	for _, buildFileName := range BuildFileNames {
	buildFile = filepath.Join(pkgPath, buildFileName)
	if wspace.IsRegularFile(buildFile) {
	return
	}
	}
	buildFile = filepath.Join(pkgPath, defaultBuildFileName)
	return
	}
	if wspace.IsRegularFile(filepath.FromSlash(pkg)) {
	// allow operation on other files like WORKSPACE
	buildFile = pkg
	pkg = filepath.Join(relativePath, filepath.FromSlash(path.Dir(pkg)))
	return
	}
	found := false
	for _, buildFileName := range BuildFileNames {
	buildFile = filepath.Join(pkg, buildFileName)
	if wspace.IsRegularFile(buildFile) {
	found = true
	break
	}
	}
	if !found {
	buildFile = filepath.Join(pkg, defaultBuildFileName)
	}
	pkg = filepath.Join(relativePath, filepath.FromSlash(pkg))
	return
	}
	// InterpretLabel returns the name of the BUILD file to edit, the full
	// package name, and the rule. It uses the pwd for resolving workspace file paths.
	func InterpretLabel(target string) (buildFile string, pkg string, rule string) {
	buildFile, _, pkg, rule = InterpretLabelForWorkspaceLocation("", target)
	return buildFile, pkg, rule
	}
	// InterpretLabelWithRepo returns the name of the BUILD file to edit, repo name,
	// the full package name, and the rule. It uses the pwd for resolving workspace
	// file paths.
	func InterpretLabelWithRepo(target string) (buildFile string, repo string, pkg string, rule string) {
	return InterpretLabelForWorkspaceLocation("", target)
	}