Keep data in UTC & preserve public API

This addresses PR feedback.

Author: freeformz

diff/diff.go

@@ -15,19 +15,15 @@ type FileDiff struct {
 	// the original name of the file
 	OrigName string
 	// the original timestamp (nil if not present)
-	OrigTime      *time.Time
-	OrigTimeHasTZ bool
+	OrigTime *time.Time
 	// the new name of the file (often same as OrigName)
 	NewName string
 	// the new timestamp (nil if not present)
-	NewTime      *time.Time
-	NewTimeHasTZ bool
+	NewTime *time.Time
 	// 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
@@ -133,11 +129,6 @@ const diffTimeParseWithoutTZLayout = "2006-01-02 15:04:05"
 // 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

@@ -850,13 +850,14 @@ func TestParseFileDiffAndPrintFileDiff(t *testing.T) {
 
 func TestParseMultiFileDiffAndPrintMultiFileDiff(t *testing.T) {
 	tests := []struct {
-		filename      string
-		wantParseErr  error
-		wantFileDiffs int // How many instances of diff.FileDiff are expected.
+		filename        string
+		wantParseErr    error
+		wantFileDiffs   int    // How many instances of diff.FileDiff are expected.
+		wantOutFileName string // If non-empty, the name of the file containing the expected output.
 	}{
 		{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_single_apple_in.diff", wantFileDiffs: 1, wantOutFileName: "sample_multi_file_single_apple_out.diff"},
 		{filename: "sample_multi_file_new.diff", wantFileDiffs: 3},
 		{filename: "sample_multi_file_deleted.diff", wantFileDiffs: 3},
 		{filename: "sample_multi_file_rename.diff", wantFileDiffs: 3},
@@ -893,6 +894,12 @@ func TestParseMultiFileDiffAndPrintMultiFileDiff(t *testing.T) {
 		if err != nil {
 			t.Errorf("%s: PrintMultiFileDiff: %s", test.filename, err)
 		}
+		if test.wantOutFileName != "" {
+			diffData, err = ioutil.ReadFile(filepath.Join("testdata", test.wantOutFileName))
+			if err != nil {
+				t.Fatal(err)
+			}
+		}
 		if !bytes.Equal(printed, diffData) {
 			t.Errorf("%s: printed multi-file diff != original multi-file diff\n\n# PrintMultiFileDiff output - Original:\n%s", test.filename, cmp.Diff(diffData, printed))
 		}

diff/parse.go

@@ -217,18 +217,15 @@ func (r *FileDiffReader) ReadAllHeaders() (*FileDiff, error) {
 	}
 
 	var origTime, newTime *time.Time
-	var origTZ, newTZ bool
-	fd.OrigName, fd.NewName, origTime, newTime, origTZ, newTZ, err = r.ReadFileHeaders()
+	fd.OrigName, fd.NewName, origTime, newTime, 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
@@ -250,21 +247,21 @@ 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, origTZ, newTZ bool, err error) {
+func (r *FileDiffReader) ReadFileHeaders() (origName, newName string, origTimestamp, newTimestamp *time.Time, err error) {
 	if r.fileHeaderLine != nil {
 		if isOnlyMessage, source, filename := parseOnlyInMessage(r.fileHeaderLine); isOnlyMessage {
 			return filepath.Join(string(source), string(filename)),
-				"", nil, nil, false, false, nil
+				"", nil, nil, nil
 		}
 	}
-	origName, origTimestamp, origTZ, err = r.readOneFileHeader([]byte("--- "))
+	origName, origTimestamp, err = r.readOneFileHeader([]byte("--- "))
 	if err != nil {
-		return "", "", nil, nil, false, false, err
+		return "", "", nil, nil, err
 	}
 
-	newName, newTimestamp, newTZ, err = r.readOneFileHeader([]byte("+++ "))
+	newName, newTimestamp, err = r.readOneFileHeader([]byte("+++ "))
 	if err != nil {
-		return "", "", nil, nil, false, false, err
+		return "", "", nil, nil, err
 	}
 
 	unquotedOrigName, err := strconv.Unquote(origName)
@@ -276,29 +273,29 @@ func (r *FileDiffReader) ReadFileHeaders() (origName, newName string, origTimest
 		newName = unquotedNewName
 	}
 
-	return origName, newName, origTimestamp, newTimestamp, origTZ, newTZ, nil
+	return origName, newName, origTimestamp, newTimestamp, nil
 }
 
 // readOneFileHeader reads one of the file headers (prefix should be
 // either "+++ " or "--- ").
-func (r *FileDiffReader) readOneFileHeader(prefix []byte) (filename string, timestamp *time.Time, hadTZ bool, err error) {
+func (r *FileDiffReader) readOneFileHeader(prefix []byte) (filename string, timestamp *time.Time, err error) {
 	var line []byte
 
 	if r.fileHeaderLine == nil {
 		var err error
 		line, err = r.reader.readLine()
 		if err == io.EOF {
-			return "", nil, false, &ParseError{r.line, r.offset, ErrNoFileHeader}
+			return "", nil, &ParseError{r.line, r.offset, ErrNoFileHeader}
 		} else if err != nil {
-			return "", nil, false, err
+			return "", nil, err
 		}
 	} else {
 		line = r.fileHeaderLine
 		r.fileHeaderLine = nil
 	}
 
 	if !bytes.HasPrefix(line, prefix) {
-		return "", nil, false, &ParseError{r.line, r.offset, ErrBadFileHeader}
+		return "", nil, &ParseError{r.line, r.offset, ErrBadFileHeader}
 	}
 
 	r.offset += int64(len(line))
@@ -308,7 +305,6 @@ 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.
@@ -317,16 +313,14 @@ func (r *FileDiffReader) readOneFileHeader(prefix []byte) (filename string, time
 			var err1 error
 			ts, err1 = time.Parse(diffTimeParseWithoutTZLayout, parts[1])
 			if err1 != nil {
-				return "", nil, hadTZ, err
+				return "", nil, err
 			}
-			hadTZ = false
-			ts = ts.In(time.Now().Location())
 			err = nil
 		}
 		timestamp = &ts
 	}
 
-	return filename, timestamp, hadTZ, err
+	return filename, timestamp, 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, d.OrigTimeHasTZ); err != nil {
+	if err := printFileHeader(&buf, "--- ", d.OrigName, d.OrigTime); err != nil {
 		return nil, err
 	}
-	if err := printFileHeader(&buf, "+++ ", d.NewName, d.NewTime, d.NewTimeHasTZ); err != nil {
+	if err := printFileHeader(&buf, "+++ ", d.NewName, d.NewTime); err != nil {
 		return nil, err
 	}
 
@@ -67,16 +67,12 @@ func PrintFileDiff(d *FileDiff) ([]byte, error) {
 	return buf.Bytes(), nil
 }
 
-func printFileHeader(w io.Writer, prefix string, filename string, timestamp *time.Time, tz bool) error {
+func printFileHeader(w io.Writer, prefix string, filename string, timestamp *time.Time) 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(format)); err != nil {
+		if _, err := fmt.Fprint(w, "\t", timestamp.Format(diffTimeFormatLayout)); err != nil {
 			return err
 		}
 	}

diff/testdata/sample_multi_file_single_apple.diff renamed to diff/testdata/sample_multi_file_single_apple_in.diff

@@ -0,0 +1,29 @@
+diff -u a/oldname1 b/newname1
+--- oldname1	2009-10-11 15:12:20.000000000 +0000
++++ newname1	2009-10-11 15:12:30.000000000 +0000
+@@ -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