}
			base.SetExitStatus(1)
		}
	}()
	g.dir, g.file = filepath.Split(g.path)
	g.dir = filepath.Clean(g.dir) // No final separator please.
	if cfg.BuildV {
		fmt.Fprintf(os.Stderr, "%s\n", base.ShortPath(g.path))
	}

	// Scan for lines that start "//go:generate".
	// Can't use bufio.Scanner because it can't handle long lines,
	// which are likely to appear when using generate.
	input := bufio.NewReader(g.r)

// overlay, locks the file while reading, and applies fix, if applicable.
func ReadModFile(gomod string, fix modfile.VersionFixer) (data []byte, f *modfile.File, err error) {
	gomod = base.ShortPath(gomod) // use short path in any errors
	if gomodActual, ok := fsys.OverlayPath(gomod); ok {
		// Don't lock go.mod if it's part of the overlay.
		// On Plan 9, locking requires chmod, and we don't want to modify any file

	if !anyFlags {
		base.Fatalf("go: no flags specified (see 'go help work edit').")
	}

	workFile, err := modload.ReadWorkFile(gowork)
	if err != nil {
		base.Fatalf("go: errors parsing %s:\n%s", base.ShortPath(gowork), err)
	}

	if *editGo == "none" {
		workFile.DropGoStmt()
	} else if *editGo != "" {
		if err := workFile.AddGoStmt(*editGo); err != nil {
			base.Fatalf("go: internal error: %v", err)
		}
	}

	}

	data, err := lockedfile.Read(gomod)
	if err != nil {
		base.Fatal(err)
	}

	modFile, err := modfile.Parse(gomod, data, nil)
	if err != nil {
		base.Fatalf("go: errors parsing %s:\n%s", base.ShortPath(gomod), err)
	}

	if *editModule != "" {
		modFile.AddModuleStmt(*editModule)
	}

	if *editGo == "none" {
		modFile.DropGoStmt()
	} else if *editGo != "" {

		// prefixes, the only way to find them is to look.
		// This doesn't always produce a relative path --
		// /foo is shorter than ../../.., for example.
		if reldir := base.ShortPath(dir); reldir != dir {
			out = replacePrefix(out, dir, reldir)
			if filepath.Separator == '\\' {
				// Don't know why, sometimes this comes out with slashes, not backslashes.
				wdir := strings.ReplaceAll(dir, "\\", "/")

				if toolVers == "" || (!strings.HasPrefix(toolchain, "go") && !strings.Contains(toolchain, "-go")) {
					counterErrorsInvalidToolchainInFile.Inc()
					base.Fatalf("invalid toolchain %q in %s", toolchain, base.ShortPath(file))
				}
				if gover.Compare(toolVers, minVers) > 0 {
					gotoolchain = toolchain
					minVers = toolVers
					gover.Startup.AutoToolchain = toolchain
				}
			}