objdirSeq int // counter for NewObjdir
	pkgSeq    int

	backgroundSh *Shell // Shell that per-Action Shells are derived from

	exec      sync.Mutex
	readySema chan bool
	ready     actionQueue

	id           sync.Mutex
	toolIDCache  map[string]string // tool name -> tool ID
	buildIDCache map[string]string // file name -> build ID
}

	// return the same package.
	ImportFrom(path, dir string, mode ImportMode) (*Package, error)
}

// A Config specifies the configuration for type checking.
// The zero value for Config is a ready-to-use default configuration.
type Config struct {
	// Context is the context used for resolving global identifiers. If nil, the
	// type checker will initialize this field with a newly created context.
	Context *Context

	return i
}

// string reads the next string.
func (r *reader) string() string {
	return r.d.stringTableAt(r.int())
}

// bool reads the next bool.
func (r *reader) bool() bool {
	return r.int() != 0
}

// tokpos reads the next token.Position.
func (r *reader) tokpos() token.Position {
	return token.Position{
		Filename: r.string(),
		Offset:   r.int(),
		Line:     r.int(),

	// check not at EOF
	b.WriteString("abcdefghijklmnopqrstuvwxyz")

	// after unsuccessful read
	if n, err := b.Read(nil); n != 0 || err != nil {
		t.Fatalf("Read(nil) = %d,%v; want 0,nil", n, err)
	}
	if err := b.UnreadByte(); err == nil {
		t.Fatal("UnreadByte after Read(nil): got no error")
	}

	// after successful read
	if _, err := b.ReadBytes('m'); err != nil {
		t.Fatalf("ReadBytes: %v", err)
	}

		return err
	}
	if err := os.Rename(f.Name(), zipfile); err != nil {
		return err
	}

	// TODO(bcmills): Should we make the .zip and .ziphash files read-only to discourage tampering?

	return nil
}

// hashZip reads the zip file opened in f, then writes the hash to ziphashfile,
// overwriting that file if it exists.
//
// If the hash does not match go.sum (or the sumdb if enabled), hashZip returns

// readFrom populates the content of the current file by reading from r.
// The bytes read must match the number of remaining bytes in the current file.
//
// If the current file is sparse and r is an io.ReadSeeker,
// then readFrom uses Seek to skip past holes defined in Header.SparseHoles,
// assuming that skipped regions are all NULs.
// This always reads the last byte to ensure r is the right size.
//

	// the cache was full when the corruption happened. Attempting a trim on
	// an empty cache is cheap, so there wouldn't be a big performance hit in that case.
	if data, err := lockedfile.Read(filepath.Join(c.dir, "trim.txt")); err == nil {
		if t, err := strconv.ParseInt(strings.TrimSpace(string(data)), 10, 64); err == nil {
			lastTrim := time.Unix(t, 0)

	readZip       func(rev, subdir, remote, target string) []string                                   // cmd to read rev's subdir as zip file
	doReadZip     func(ctx context.Context, dst io.Writer, workDir, rev, subdir, remote string) error // arbitrary function to read rev's subdir as zip file
}

var re = lazyregexp.New

	UsageLine: "go work edit [editing flags] [go.work]",
	Short:     "edit go.work from tools or scripts",
	Long: `Edit provides a command-line interface for editing go.work,
for use primarily by tools or scripts. It only reads go.work;
it does not look up information about the modules involved.
If no file is specified, Edit looks for a go.work file in the current
directory and its parent directories

			// Go language version to use, which requires its go.mod file.
			//
			// If the module graph is pruned and this is a test-only dependency
			// of a package in "all", we didn't necessarily load that file
			// when we read the module graph, so do it now to be sure.
			if !skipModFile && cfg.BuildMod != "vendor" && mods[0].Path != "" && !MainModules.Contains(mods[0].Path) {
				if _, err := goModSummary(mods[0]); err != nil {