[PATCH] Fix `git rev-list --show-notes HEAD` when there are no notes

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Aug 22, 2015, 15:14 UTC
Message-ID: <0LZlZ2-1Z1Zyn1mzk-00lZ3Z@mail.gmx.com>

The `format_display_notes()` function clearly assumes that the data structure holding the notes has been initialized already, i.e. that the `display_notes_trees` variable is no longer `NULL`.

However, when there are no notes whatsoever, this variable is still `NULL`, even after initialization.

So let's be graceful and just return if that data structure is `NULL`.

Reported in https://github.com/msysgit/git/issues/363.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 notes.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/notes.c b/notes.c
index df08209..24a335a 100644
--- a/notes.c
+++ b/notes.c
@@ -1266,7 +1266,10 @@ void format_display_notes(const unsigned char *object_sha1,
 			  struct strbuf *sb, const char *output_encoding, int raw)
 {
 	int i;
-	assert(display_notes_trees);
+
+	if (!display_notes_trees)
+		return;
+
 	for (i = 0; display_notes_trees[i]; i++)
 		format_note(display_notes_trees[i], object_sha1, sb,
 			    output_encoding, raw);

-- 
2.3.1.windows.1.9.g8c01ab4