commit-graph: close under reachability

Teach write_commit_graph() to walk all parents from the commits discovered in packfiles. This prevents gaps given by loose objects or previously-missed packfiles. Also automatically add commits from the existing graph file, if it exists. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Derrick Stolee committed Apr 10, 2018 at 08:56 UTC 4f2542b49e1525ebde595a5254743579a28a7382
1 file changed +45
commit-graph.c
+45
@@ -367,6 +367,50 @@ static int add_packed_commits(const struct object_id *oid,
367 return 0;
368 }
369
370 +static void add_missing_parents(struct packed_oid_list *oids, struct commit *commit)
371 +{
372 + struct commit_list *parent;
373 + for (parent = commit->parents; parent; parent = parent->next) {
374 + if (!(parent->item->object.flags & UNINTERESTING)) {
375 + ALLOC_GROW(oids->list, oids->nr + 1, oids->alloc);
376 + oidcpy(&oids->list[oids->nr], &(parent->item->object.oid));
377 + oids->nr++;
378 + parent->item->object.flags |= UNINTERESTING;
379 + }
380 + }
381 +}
382 +
383 +static void close_reachable(struct packed_oid_list *oids)
384 +{
385 + int i;
386 + struct commit *commit;
387 +
388 + for (i = 0; i < oids->nr; i++) {
389 + commit = lookup_commit(&oids->list[i]);
390 + if (commit)
391 + commit->object.flags |= UNINTERESTING;
392 + }
393 +
394 + /*
395 + * As this loop runs, oids->nr may grow, but not more
396 + * than the number of missing commits in the reachable
397 + * closure.
398 + */
399 + for (i = 0; i < oids->nr; i++) {
400 + commit = lookup_commit(&oids->list[i]);
401 +
402 + if (commit && !parse_commit(commit))
403 + add_missing_parents(oids, commit);
404 + }
405 +
406 + for (i = 0; i < oids->nr; i++) {
407 + commit = lookup_commit(&oids->list[i]);
408 +
409 + if (commit)
410 + commit->object.flags &= ~UNINTERESTING;
411 + }
412 +}
413 +
414 void write_commit_graph(const char *obj_dir)
415 {
416 struct packed_oid_list oids;
@@ -390,6 +434,7 @@ void write_commit_graph(const char *obj_dir)
434 ALLOC_ARRAY(oids.list, oids.alloc);
435
436 for_each_packed_object(add_packed_commits, &oids, 0);
437 + close_reachable(&oids);
438
439 QSORT(oids.list, oids.nr, commit_compare);
440