pack-bitmap.c: trace bitmap ignore logs when midx-bitmap is found

When we find a midx bitmap, we do not bother checking for pack
bitmaps, since we can use only one. But since we will warn of unused
bitmaps via trace2, let's continue looking for pack bitmaps when
tracing is enabled.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Teng Long <dyroneteng@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pack-bitmap.c

@@ -524,8 +524,6 @@ static int open_pack_bitmap(struct repository *r,
 	struct packed_git *p;
 	int ret = -1;
 
-	assert(!bitmap_git->map);
-
 	for (p = get_all_packs(r); p; p = p->next) {
 		if (open_pack_bitmap_1(bitmap_git, p) == 0) {
 			ret = 0;
@@ -559,11 +557,20 @@ static int open_midx_bitmap(struct repository *r,
 static int open_bitmap(struct repository *r,
 		       struct bitmap_index *bitmap_git)
 {
+	int found;
+
 	assert(!bitmap_git->map);
 
-	if (!open_midx_bitmap(r, bitmap_git))
-		return 0;
-	return open_pack_bitmap(r, bitmap_git);
+	found = !open_midx_bitmap(r, bitmap_git);
+
+	/*
+	 * these will all be skipped if we opened a midx bitmap; but run it
+	 * anyway if tracing is enabled to report the duplicates
+	 */
+	if (!found || trace2_is_enabled())
+		found |= !open_pack_bitmap(r, bitmap_git);
+
+	return found ? 0 : -1;
 }
 
 struct bitmap_index *prepare_bitmap_git(struct repository *r)