Support Apple Diff timestamps

diff/diff.go

@@ -15,15 +15,19 @@ type FileDiff struct {
 	// the original name of the file
 	OrigName string
 	// the original timestamp (nil if not present)
-	OrigTime *time.Time
+	OrigTime      *time.Time
+	OrigTimeHasTZ bool
 	// the new name of the file (often same as OrigName)
 	NewName string
 	// the new timestamp (nil if not present)
-	NewTime *time.Time
+	NewTime      *time.Time
+	NewTimeHasTZ bool
 	// extended header lines (e.g., git's "new mode <mode>", "rename from <path>", etc.)
 	Extended []string
 	// hunks that were changed from orig to new
 	Hunks []*Hunk
+
+	includeTZ bool
 }
 
 // A Hunk represents a series of changes (additions or deletions) in a file's
@@ -120,11 +124,20 @@ const onlyInMessage = "Only in %s: %s\n"
 // See https://www.gnu.org/software/diffutils/manual/html_node/Detailed-Unified.html.
 const diffTimeParseLayout = "2006-01-02 15:04:05 -0700"
 
+// Apple's diff is based on freebsd diff, which uses a timestamp format that does
+// not include the timezone offset.
+const diffTimeParseWithoutTZLayout = "2006-01-02 15:04:05"
+
 // diffTimeFormatLayout is the layout used to format (i.e., print) the time in unified diff file
 // header timestamps.
 // See https://www.gnu.org/software/diffutils/manual/html_node/Detailed-Unified.html.
 const diffTimeFormatLayout = "2006-01-02 15:04:05.000000000 -0700"
 
+// diffTimeFormatWithoutTZLayout is the layout used to format (i.e., print) the time in unified diff file
+// header timestamps without the timezone offset and the fractional seconds. This is used when the diff
+// does not include the timezone offset and fractional seconds.
+const diffTimeFormatWithoutTZLayout = "2006-01-02 15:04:05"
+
 func (s *Stat) add(o Stat) {
 	s.Added += o.Added
 	s.Changed += o.Changed

diff/diff_test.go

@@ -856,6 +856,7 @@ func TestParseMultiFileDiffAndPrintMultiFileDiff(t *testing.T) {
 	}{
 		{filename: "sample_multi_file.diff", wantFileDiffs: 2},
 		{filename: "sample_multi_file_single.diff", wantFileDiffs: 1},
+		{filename: "sample_multi_file_single_apple.diff", wantFileDiffs: 1},
 		{filename: "sample_multi_file_new.diff", wantFileDiffs: 3},
 		{filename: "sample_multi_file_deleted.diff", wantFileDiffs: 3},
 		{filename: "sample_multi_file_rename.diff", wantFileDiffs: 3},

diff/parse.go

@@ -217,15 +217,18 @@ func (r *FileDiffReader) ReadAllHeaders() (*FileDiff, error) {
 	}
 
 	var origTime, newTime *time.Time
-	fd.OrigName, fd.NewName, origTime, newTime, err = r.ReadFileHeaders()
+	var origTZ, newTZ bool
+	fd.OrigName, fd.NewName, origTime, newTime, origTZ, newTZ, err = r.ReadFileHeaders()
 	if err != nil {
 		return nil, err
 	}
 	if origTime != nil {
 		fd.OrigTime = origTime
+		fd.OrigTimeHasTZ = origTZ
 	}
 	if newTime != nil {
 		fd.NewTime = newTime
+		fd.NewTimeHasTZ = newTZ
 	}
 
 	return fd, nil
@@ -247,22 +250,21 @@ func (r *FileDiffReader) HunksReader() *HunksReader {
 // start with "---" and "+++" with the orig/new file names and
 // timestamps). Or which starts with "Only in " with dir path and filename.
 // "Only in" message is supported in POSIX locale: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/diff.html#tag_20_34_10
-func (r *FileDiffReader) ReadFileHeaders() (origName, newName string, origTimestamp, newTimestamp *time.Time, err error) {
+func (r *FileDiffReader) ReadFileHeaders() (origName, newName string, origTimestamp, newTimestamp *time.Time, origTZ, newTZ bool, err error) {
 	if r.fileHeaderLine != nil {
 		if isOnlyMessage, source, filename := parseOnlyInMessage(r.fileHeaderLine); isOnlyMessage {
 			return filepath.Join(string(source), string(filename)),
-				"", nil, nil, nil
+				"", nil, nil, false, false, nil
 		}
 	}
-
-	origName, origTimestamp, err = r.readOneFileHeader([]byte("--- "))
+	origName, origTimestamp, origTZ, err = r.readOneFileHeader([]byte("--- "))
 	if err != nil {
-		return "", "", nil, nil, err
+		return "", "", nil, nil, false, false, err
 	}
 
-	newName, newTimestamp, err = r.readOneFileHeader([]byte("+++ "))
+	newName, newTimestamp, newTZ, err = r.readOneFileHeader([]byte("+++ "))
 	if err != nil {
-		return "", "", nil, nil, err
+		return "", "", nil, nil, false, false, err
 	}
 
 	unquotedOrigName, err := strconv.Unquote(origName)
@@ -274,29 +276,29 @@ func (r *FileDiffReader) ReadFileHeaders() (origName, newName string, origTimest
 		newName = unquotedNewName
 	}
 
-	return origName, newName, origTimestamp, newTimestamp, nil
+	return origName, newName, origTimestamp, newTimestamp, origTZ, newTZ, nil
 }
 
 // readOneFileHeader reads one of the file headers (prefix should be
 // either "+++ " or "--- ").
-func (r *FileDiffReader) readOneFileHeader(prefix []byte) (filename string, timestamp *time.Time, err error) {
+func (r *FileDiffReader) readOneFileHeader(prefix []byte) (filename string, timestamp *time.Time, hadTZ bool, err error) {
 	var line []byte
 
 	if r.fileHeaderLine == nil {
 		var err error
 		line, err = r.reader.readLine()
 		if err == io.EOF {
-			return "", nil, &ParseError{r.line, r.offset, ErrNoFileHeader}
+			return "", nil, false, &ParseError{r.line, r.offset, ErrNoFileHeader}
 		} else if err != nil {
-			return "", nil, err
+			return "", nil, false, err
 		}
 	} else {
 		line = r.fileHeaderLine
 		r.fileHeaderLine = nil
 	}
 
 	if !bytes.HasPrefix(line, prefix) {
-		return "", nil, &ParseError{r.line, r.offset, ErrBadFileHeader}
+		return "", nil, false, &ParseError{r.line, r.offset, ErrBadFileHeader}
 	}
 
 	r.offset += int64(len(line))
@@ -306,16 +308,25 @@ func (r *FileDiffReader) readOneFileHeader(prefix []byte) (filename string, time
 	trimmedLine := strings.TrimSpace(string(line)) // filenames that contain spaces may be terminated by a tab
 	parts := strings.SplitN(trimmedLine, "\t", 2)
 	filename = parts[0]
+	hadTZ = true
 	if len(parts) == 2 {
+		var ts time.Time
 		// Timestamp is optional, but this header has it.
-		ts, err := time.Parse(diffTimeParseLayout, parts[1])
+		ts, err = time.Parse(diffTimeParseLayout, parts[1])
 		if err != nil {
-			return "", nil, err
+			var err1 error
+			ts, err1 = time.Parse(diffTimeParseWithoutTZLayout, parts[1])
+			if err1 != nil {
+				return "", nil, hadTZ, err
+			}
+			hadTZ = false
+			ts = ts.In(time.Now().Location())
+			err = nil
 		}
 		timestamp = &ts
 	}
 
-	return filename, timestamp, err
+	return filename, timestamp, hadTZ, err
 }
 
 // OverflowError is returned when we have overflowed into the start

diff/print.go

@@ -49,10 +49,10 @@ func PrintFileDiff(d *FileDiff) ([]byte, error) {
 		return buf.Bytes(), nil
 	}
 
-	if err := printFileHeader(&buf, "--- ", d.OrigName, d.OrigTime); err != nil {
+	if err := printFileHeader(&buf, "--- ", d.OrigName, d.OrigTime, d.OrigTimeHasTZ); err != nil {
 		return nil, err
 	}
-	if err := printFileHeader(&buf, "+++ ", d.NewName, d.NewTime); err != nil {
+	if err := printFileHeader(&buf, "+++ ", d.NewName, d.NewTime, d.NewTimeHasTZ); err != nil {
 		return nil, err
 	}
 
@@ -67,12 +67,16 @@ func PrintFileDiff(d *FileDiff) ([]byte, error) {
 	return buf.Bytes(), nil
 }
 
-func printFileHeader(w io.Writer, prefix string, filename string, timestamp *time.Time) error {
+func printFileHeader(w io.Writer, prefix string, filename string, timestamp *time.Time, tz bool) error {
 	if _, err := fmt.Fprint(w, prefix, filename); err != nil {
 		return err
 	}
+	format := diffTimeFormatLayout
+	if !tz {
+		format = diffTimeFormatWithoutTZLayout
+	}
 	if timestamp != nil {
-		if _, err := fmt.Fprint(w, "\t", timestamp.Format(diffTimeFormatLayout)); err != nil {
+		if _, err := fmt.Fprint(w, "\t", timestamp.Format(format)); err != nil {
 			return err
 		}
 	}

diff/testdata/sample_multi_file_single_apple.diff

@@ -0,0 +1,29 @@
+diff -u a/oldname1 b/newname1
+--- oldname1	2009-10-11 15:12:20
++++ newname1	2009-10-11 15:12:30
+@@ -1,3 +1,9 @@
++This is an important
++notice! It should
++therefore be located at
++the beginning of this
++document!
++
+ This part of the
+ document has stayed the
+ same from version to
+@@ -5,16 +11,10 @@
+ be shown if it doesn't
+ change.  Otherwise, that
+ would not be helping to
+-compress the size of the
+-changes.
+-
+-This paragraph contains
+-text that is outdated.
+-It will be deleted in the
+-near future.
++compress anything.
+
+ It is important to spell
+-check this dokument. On
++check this document. On