Merge 'some-small-patches'

This topic branch brings some small patches from the mailing list to
GVFS.

1. Preempt a `has_object_file()` call during
`mark_parents_uninteresting()` to speed up merge base calculations. I
measured a 7% improvement in `git status` on Linux without the graph and
a 27% improvement with the graph. See [the discussion on the mailing
list](https://public-inbox.org/git/20180226013822.GA9385@sigill.intra.peff.net/T/#t).

2. Fix an uninitialized memory issue in the abbreviation code for
packfiles; carry that over to the MIDX. See  [the discussion on the
mailing
list](https://public-inbox.org/git/0a85ea3b-3f64-f67d-b4d5-a761cbc4c6db@gmail.com/T/#t)

revision.c

@@ -113,7 +113,8 @@ void mark_parents_uninteresting(struct commit *commit)
 			 * it is popped next time around, we won't be trying
 			 * to parse it and get an error.
 			 */
-			if (!has_object_file(&commit->object.oid))
+			if (!commit->object.parsed &&
+			    !has_object_file(&commit->object.oid))
 				commit->object.parsed = 1;
 
 			if (commit->object.flags & UNINTERESTING)

sha1_name.c

@@ -557,17 +557,14 @@ static void find_abbrev_len_for_midx(struct midxed_git *m,
 	 * nearby for the abbreviation length.
 	 */
 	mad->init_len = 0;
-	if (!match) {
-		nth_midxed_object_oid(&oid, m, first);
+	if (!match && nth_midxed_object_oid(&oid, m, first))
 		extend_abbrev_len(&oid, mad);
-	} else if (first < m->num_objects - 1) {
-		nth_midxed_object_oid(&oid, m, first + 1);
+	else if (first < m->num_objects - 1 &&
+		 nth_midxed_object_oid(&oid, m, first + 1))
 		extend_abbrev_len(&oid, mad);
-	}
-	if (first > 0) {
-		nth_midxed_object_oid(&oid, m, first - 1);
+	if (first > 0 && nth_midxed_object_oid(&oid, m, first - 1))
 		extend_abbrev_len(&oid, mad);
-	}
+
 	mad->init_len = mad->cur_len;
 }
 
@@ -609,17 +606,12 @@ static void find_abbrev_len_for_pack(struct packed_git *p,
 	 * nearby for the abbreviation length.
 	 */
 	mad->init_len = 0;
-	if (!match) {
-		nth_packed_object_oid(&oid, p, first);
+	if (!match && nth_packed_object_oid(&oid, p, first))
 		extend_abbrev_len(&oid, mad);
-	} else if (first < num - 1) {
-		nth_packed_object_oid(&oid, p, first + 1);
+	if (first < num - 1 && nth_packed_object_oid(&oid, p, first + 1))
 		extend_abbrev_len(&oid, mad);
-	}
-	if (first > 0) {
-		nth_packed_object_oid(&oid, p, first - 1);
+	if (first > 0 && nth_packed_object_oid(&oid, p, first - 1))
 		extend_abbrev_len(&oid, mad);
-	}
 	mad->init_len = mad->cur_len;
 }