Merge pull request #18 from git-lfs/large-message

Allow parsing very long lines in commit messages

Author: bk2204

commit.go

@@ -96,6 +96,7 @@ func (c *Commit) Decode(from io.Reader, size int64) (n int, err error) {
 	var messageParts []string
 
 	s := bufio.NewScanner(from)
+	s.Buffer(nil, 1024 * 1024)
 	for s.Scan() {
 		text := s.Text()
 		n = n + len(text+"\n")
@@ -169,7 +170,7 @@ func (c *Commit) Decode(from io.Reader, size int64) (n int, err error) {
 	c.Message = strings.Join(messageParts, "\n")
 
 	if err = s.Err(); err != nil {
-		return n, err
+		return n, fmt.Errorf("failed to parse commit buffer: %s", err)
 	}
 	return n, err
 }

commit_test.go

@@ -117,6 +117,37 @@ func TestCommitDecodingWithEmptyName(t *testing.T) {
 	assert.Equal(t, "initial commit", commit.Message)
 }
 
+func TestCommitDecodingWithLargeCommitMessage(t *testing.T) {
+	message := "This message text is, with newline, exactly 64 characters long. ";
+	// This message will be exactly 1 MiB in size when part of the commit.
+	longMessage := strings.Repeat(message, (1024 * 1024 / 64) - 1)
+	longMessage += strings.TrimSpace(message);
+
+	author := &Signature{Name: "", Email: "john@example.com", When: time.Now()}
+	committer := &Signature{Name: "", Email: "jane@example.com", When: time.Now()}
+
+	treeId := []byte("cccccccccccccccccccc")
+
+	from := new(bytes.Buffer)
+
+	fmt.Fprintf(from, "author %s\n", author)
+	fmt.Fprintf(from, "committer %s\n", committer)
+	fmt.Fprintf(from, "tree %s\n", hex.EncodeToString(treeId))
+	fmt.Fprintf(from, "\n%s\n", longMessage)
+
+	flen := from.Len()
+
+	commit := new(Commit)
+	n, err := commit.Decode(from, int64(flen))
+
+	assert.Nil(t, err)
+	assert.Equal(t, flen, n)
+
+	assert.Equal(t, author.String(), commit.Author)
+	assert.Equal(t, committer.String(), commit.Committer)
+	assert.Equal(t, longMessage, commit.Message)
+}
+
 func TestCommitDecodingWithMessageKeywordPrefix(t *testing.T) {
 	author := &Signature{Name: "John Doe", Email: "john@example.com", When: time.Now()}
 	committer := &Signature{Name: "Jane Doe", Email: "jane@example.com", When: time.Now()}