os: remove stuttering return value names

Old style. Make it compliant with our code review comments document.

Also, make WriteString's return parameter named 'n', not 'ret', for
consistency.

Noticed during another documentation review.

Change-Id: Ie88910c5841f8353bc5c0152e2168b497578e15e
Reviewed-on: https://go-review.googlesource.com/12324Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/os/file.go

@@ -192,7 +192,7 @@ func (f *File) Seek(offset int64, whence int) (ret int64, err error) {
 
 // WriteString is like Write, but writes the contents of string s rather than
 // a slice of bytes.
-func (f *File) WriteString(s string) (ret int, err error) {
+func (f *File) WriteString(s string) (n int, err error) {
 	if f == nil {
 		return 0, ErrInvalid
 	}
@@ -242,16 +242,16 @@ func (f *File) Chdir() error {
 // the returned file can be used for reading; the associated file
 // descriptor has mode O_RDONLY.
 // If there is an error, it will be of type *PathError.
-func Open(name string) (file *File, err error) {
+func Open(name string) (*File, error) {
 	return OpenFile(name, O_RDONLY, 0)
 }
 
-// Create creates the named file mode 0666 (before umask), truncating
-// it if it already exists.  If successful, methods on the returned
+// Create creates the named file with mode 0666 (before umask), truncating
+// it if it already exists. If successful, methods on the returned
 // File can be used for I/O; the associated file descriptor has mode
 // O_RDWR.
 // If there is an error, it will be of type *PathError.
-func Create(name string) (file *File, err error) {
+func Create(name string) (*File, error) {
 	return OpenFile(name, O_RDWR|O_CREATE|O_TRUNC, 0666)
 }
 

src/os/file_plan9.go

@@ -79,7 +79,7 @@ func syscallMode(i FileMode) (o uint32) {
 // (O_RDONLY etc.) and perm, (0666 etc.) if applicable.  If successful,
 // methods on the returned File can be used for I/O.
 // If there is an error, it will be of type *PathError.
-func OpenFile(name string, flag int, perm FileMode) (file *File, err error) {
+func OpenFile(name string, flag int, perm FileMode) (*File, error) {
 	var (
 		fd     int
 		e      error
@@ -159,7 +159,7 @@ func (file *file) close() error {
 
 // Stat returns the FileInfo structure describing file.
 // If there is an error, it will be of type *PathError.
-func (f *File) Stat() (fi FileInfo, err error) {
+func (f *File) Stat() (FileInfo, error) {
 	if f == nil {
 		return nil, ErrInvalid
 	}
@@ -224,7 +224,7 @@ func (f *File) Chmod(mode FileMode) error {
 // Sync commits the current contents of the file to stable storage.
 // Typically, this means flushing the file system's in-memory copy
 // of recently written data to disk.
-func (f *File) Sync() (err error) {
+func (f *File) Sync() error {
 	if f == nil {
 		return ErrInvalid
 	}

src/os/file_posix.go

@@ -114,7 +114,7 @@ func (f *File) Truncate(size int64) error {
 // Sync commits the current contents of the file to stable storage.
 // Typically, this means flushing the file system's in-memory copy
 // of recently written data to disk.
-func (f *File) Sync() (err error) {
+func (f *File) Sync() error {
 	if f == nil {
 		return ErrInvalid
 	}

src/os/file_unix.go

@@ -82,7 +82,7 @@ const DevNull = "/dev/null"
 // (O_RDONLY etc.) and perm, (0666 etc.) if applicable.  If successful,
 // methods on the returned File can be used for I/O.
 // If there is an error, it will be of type *PathError.
-func OpenFile(name string, flag int, perm FileMode) (file *File, err error) {
+func OpenFile(name string, flag int, perm FileMode) (*File, error) {
 	chmod := false
 	if !supportsCreateWithStickyBit && flag&O_CREATE != 0 && perm&ModeSticky != 0 {
 		if _, err := Stat(name); IsNotExist(err) {
@@ -135,12 +135,12 @@ func (file *file) close() error {
 
 // Stat returns the FileInfo structure describing file.
 // If there is an error, it will be of type *PathError.
-func (f *File) Stat() (fi FileInfo, err error) {
+func (f *File) Stat() (FileInfo, error) {
 	if f == nil {
 		return nil, ErrInvalid
 	}
 	var stat syscall.Stat_t
-	err = syscall.Fstat(f.fd, &stat)
+	err := syscall.Fstat(f.fd, &stat)
 	if err != nil {
 		return nil, &PathError{"stat", f.name, err}
 	}
@@ -149,9 +149,9 @@ func (f *File) Stat() (fi FileInfo, err error) {
 
 // Stat returns a FileInfo describing the named file.
 // If there is an error, it will be of type *PathError.
-func Stat(name string) (fi FileInfo, err error) {
+func Stat(name string) (FileInfo, error) {
 	var stat syscall.Stat_t
-	err = syscall.Stat(name, &stat)
+	err := syscall.Stat(name, &stat)
 	if err != nil {
 		return nil, &PathError{"stat", name, err}
 	}
@@ -162,9 +162,9 @@ func Stat(name string) (fi FileInfo, err error) {
 // If the file is a symbolic link, the returned FileInfo
 // describes the symbolic link.  Lstat makes no attempt to follow the link.
 // If there is an error, it will be of type *PathError.
-func Lstat(name string) (fi FileInfo, err error) {
+func Lstat(name string) (FileInfo, error) {
 	var stat syscall.Stat_t
-	err = syscall.Lstat(name, &stat)
+	err := syscall.Lstat(name, &stat)
 	if err != nil {
 		return nil, &PathError{"lstat", name, err}
 	}

src/os/file_windows.go

@@ -134,7 +134,7 @@ func openDir(name string) (file *File, err error) {
 // (O_RDONLY etc.) and perm, (0666 etc.) if applicable.  If successful,
 // methods on the returned File can be used for I/O.
 // If there is an error, it will be of type *PathError.
-func OpenFile(name string, flag int, perm FileMode) (file *File, err error) {
+func OpenFile(name string, flag int, perm FileMode) (*File, error) {
 	if name == "" {
 		return nil, &PathError{"open", name, syscall.ENOENT}
 	}

src/os/stat_plan9.go

@@ -90,7 +90,7 @@ func dirstat(arg interface{}) (*syscall.Dir, error) {
 
 // Stat returns a FileInfo describing the named file.
 // If there is an error, it will be of type *PathError.
-func Stat(name string) (fi FileInfo, err error) {
+func Stat(name string) (FileInfo, error) {
 	d, err := dirstat(name)
 	if err != nil {
 		return nil, err
@@ -102,7 +102,7 @@ func Stat(name string) (fi FileInfo, err error) {
 // If the file is a symbolic link, the returned FileInfo
 // describes the symbolic link.  Lstat makes no attempt to follow the link.
 // If there is an error, it will be of type *PathError.
-func Lstat(name string) (fi FileInfo, err error) {
+func Lstat(name string) (FileInfo, error) {
 	return Stat(name)
 }
 

src/os/stat_windows.go

@@ -11,7 +11,7 @@ import (
 
 // Stat returns the FileInfo structure describing file.
 // If there is an error, it will be of type *PathError.
-func (file *File) Stat() (fi FileInfo, err error) {
+func (file *File) Stat() (FileInfo, error) {
 	if file == nil {
 		return nil, ErrInvalid
 	}
@@ -48,28 +48,29 @@ func (file *File) Stat() (fi FileInfo, err error) {
 
 // Stat returns a FileInfo structure describing the named file.
 // If there is an error, it will be of type *PathError.
-func Stat(name string) (fi FileInfo, err error) {
+func Stat(name string) (FileInfo, error) {
+	var fi FileInfo
+	var err error
 	for {
 		fi, err = Lstat(name)
 		if err != nil {
-			return
+			return fi, err
 		}
 		if fi.Mode()&ModeSymlink == 0 {
-			return
+			return fi, nil
 		}
 		name, err = Readlink(name)
 		if err != nil {
-			return
+			return fi, err
 		}
 	}
-	return fi, err
 }
 
 // Lstat returns the FileInfo structure describing the named file.
 // If the file is a symbolic link, the returned FileInfo
 // describes the symbolic link.  Lstat makes no attempt to follow the link.
 // If there is an error, it will be of type *PathError.
-func Lstat(name string) (fi FileInfo, err error) {
+func Lstat(name string) (FileInfo, error) {
 	if len(name) == 0 {
 		return nil, &PathError{"Lstat", name, syscall.Errno(syscall.ERROR_PATH_NOT_FOUND)}
 	}