Merge branch 'jk/pack-bitmap'

Instead of dying when asked to (re)pack with the reachability
bitmap when a bitmap cannot be built, just (re)pack without
producing a bitmap in such a case, with a warning.

* jk/pack-bitmap:
  pack-objects: turn off bitmaps when skipping objects

builtin/pack-objects.c

@@ -995,6 +995,10 @@ static void create_object_entry(const unsigned char *sha1,
 	entry->no_try_delta = no_try_delta;
 }
 
+static const char no_closure_warning[] = N_(
+"disabling bitmap writing, as some objects are not being packed"
+);
+
 static int add_object_entry(const unsigned char *sha1, enum object_type type,
 			    const char *name, int exclude)
 {
@@ -1005,8 +1009,14 @@ static int add_object_entry(const unsigned char *sha1, enum object_type type,
 	if (have_duplicate_entry(sha1, exclude, &index_pos))
 		return 0;
 
-	if (!want_object_in_pack(sha1, exclude, &found_pack, &found_offset))
+	if (!want_object_in_pack(sha1, exclude, &found_pack, &found_offset)) {
+		/* The pack is missing an object, so it will not have closure */
+		if (write_bitmap_index) {
+			warning(_(no_closure_warning));
+			write_bitmap_index = 0;
+		}
 		return 0;
+	}
 
 	create_object_entry(sha1, type, pack_name_hash(name),
 			    exclude, name && no_try_delta(name),

t/t5310-pack-bitmaps.sh

@@ -91,7 +91,10 @@ test_expect_success 'fetch (partial bitmap)' '
 
 test_expect_success 'incremental repack cannot create bitmaps' '
 	test_commit more-1 &&
-	test_must_fail git repack -d
+	find .git/objects/pack -name "*.bitmap" >expect &&
+	git repack -d &&
+	find .git/objects/pack -name "*.bitmap" >actual &&
+	test_cmp expect actual
 '
 
 test_expect_success 'incremental repack can disable bitmaps' '