add support for trailing spaces

Author: maerlyn5

.github/workflows/scip.yml

@@ -7,7 +7,7 @@ import (
 	"log"
 	"os"
 
-	"github.com/sourcegraph/go-diff/diff"
+	"github.com/prassoai/go-diff/diff"
 )
 
 // A diagnostic program to aid in debugging diff parsing or printing

cmd/go-diff/go-diff.go

@@ -723,6 +723,15 @@ func TestParseMultiFileDiffHeaders(t *testing.T) {
 		{
 			filename: "complicated_filenames.diff",
 			wantDiffs: []*FileDiff{
+				{
+					OrigName: "/dev/null",
+					NewName:  "b/trailing_space ",
+					Extended: []string{
+						"diff --git a/trailing_space  b/trailing_space ",
+						"new file mode 100644",
+						"index 0000000..c3ed4be",
+					},
+				},
 				{
 					OrigName: "/dev/null",
 					NewName:  "b/new empty file with spaces",

diff/diff_test.go

@@ -302,10 +302,13 @@ func (r *FileDiffReader) readOneFileHeader(prefix []byte) (filename string, time
 	r.line++
 	line = line[len(prefix):]
 
-	trimmedLine := strings.TrimSpace(string(line)) // filenames that contain spaces may be terminated by a tab
-	parts := strings.SplitN(trimmedLine, "\t", 2)
+	// Trim only newline characters so that trailing spaces (and a tab delimiter) are preserved.
+	cleanedLine := strings.TrimRight(string(line), "\r\n")
+	parts := strings.SplitN(cleanedLine, "\t", 2)
 	filename = parts[0]
-	if len(parts) == 2 {
+
+	// Only try to parse the timestamp if a non-empty value is present.
+	if len(parts) == 2 && parts[1] != "" {
 		var ts time.Time
 		// Timestamp is optional, but this header has it.
 		ts, err = time.Parse(diffTimeParseLayout, parts[1])

diff/parse.go

@@ -1,3 +1,8 @@
+diff --git a/trailing_space  b/trailing_space 
+new file mode 100644
+index 0000000..c3ed4be
+--- /dev/null
++++ b/trailing_space 	
 diff --git a/new empty file with spaces b/new empty file with spaces
 new file mode 100644
 index 0000000..e69de29

diff/testdata/complicated_filenames.diff

@@ -1,4 +1,4 @@
-module github.com/sourcegraph/go-diff
+module github.com/prassoai/go-diff
 
 go 1.14