notes.c: Use two newlines (instead of one) when concatenating notes

When using combine_notes_concatenate() to concatenate notes, it currently
ensures exactly one newline character between the given notes. However,
when using builtin/notes.c:create_note() to concatenate notes (e.g. by
'git notes append'), it adds a newline character to the trailing newline
of the preceding notes object, thus resulting in _two_ newlines (aka. a
blank line) separating contents of the two notes.

This patch brings combine_notes_concatenate() into consistency with
builtin/notes.c:create_note(), by ensuring exactly _two_ newline characters
between concatenated notes.

The patch also changes a few notes-related selftests accordingly.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

notes.c

@@ -812,16 +812,17 @@ int combine_notes_concatenate(unsigned char *cur_sha1,
 		return 0;
 	}
 
-	/* we will separate the notes by a newline anyway */
+	/* we will separate the notes by two newlines anyway */
 	if (cur_msg[cur_len - 1] == '\n')
 		cur_len--;
 
 	/* concatenate cur_msg and new_msg into buf */
-	buf_len = cur_len + 1 + new_len;
+	buf_len = cur_len + 2 + new_len;
 	buf = (char *) xmalloc(buf_len);
 	memcpy(buf, cur_msg, cur_len);
 	buf[cur_len] = '\n';
-	memcpy(buf + cur_len + 1, new_msg, new_len);
+	buf[cur_len + 1] = '\n';
+	memcpy(buf + cur_len + 2, new_msg, new_len);
 	free(cur_msg);
 	free(new_msg);
 

t/t3301-notes.sh

@@ -955,6 +955,7 @@ Date:   Thu Apr 7 15:27:13 2005 -0700
 
 Notes (other):
     a fresh note
+$whitespace
     another fresh note
 EOF
 
@@ -976,8 +977,11 @@ Date:   Thu Apr 7 15:27:13 2005 -0700
 
 Notes (other):
     a fresh note
+$whitespace
     another fresh note
+$whitespace
     append 1
+$whitespace
     append 2
 EOF
 

t/t3303-notes-subtrees.sh

@@ -173,6 +173,7 @@ verify_concatenated_notes () {
 	while [ $i -gt 0 ]; do
 		echo "    commit #$i" &&
 		echo "    first note for commit #$i" &&
+		echo "    " &&
 		echo "    second note for commit #$i" &&
 		i=$(($i-1));
 	done > expect &&

t/t3404-rebase-interactive.sh

@@ -593,6 +593,7 @@ test_expect_success 'rebase -i can copy notes' '
 
 cat >expect <<EOF
 an earlier note
+
 a note
 EOF
 

t/t9301-fast-import-notes.sh

@@ -255,13 +255,18 @@ EOF
 
 INPUT_END
 
+whitespace="    "
+
 cat >expect <<EXPECT_END
     fourth commit
     pre-prefix of note for fourth commit
+$whitespace
     prefix of note for fourth commit
+$whitespace
     third note for fourth commit
     third commit
     prefix of note for third commit
+$whitespace
     third note for third commit
     second commit
     third note for second commit