1 /*
2  * Copyright (c) 2018, 2019, 2020 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <sys/queue.h>
20 
21 #include <limits.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <zlib.h>
26 #include <ctype.h>
27 
28 #include "got_compat.h"
29 
30 #include "got_error.h"
31 #include "got_object.h"
32 #include "got_cancel.h"
33 #include "got_commit_graph.h"
34 #include "got_path.h"
35 
36 #include "got_lib_delta.h"
37 #include "got_lib_inflate.h"
38 #include "got_lib_object.h"
39 #include "got_lib_object_idset.h"
40 
41 struct got_commit_graph_node {
42 	struct got_object_id id;
43 
44 	/* Used only during iteration. */
45 	time_t timestamp;
46 	TAILQ_ENTRY(got_commit_graph_node) entry;
47 };
48 
49 TAILQ_HEAD(got_commit_graph_iter_list, got_commit_graph_node);
50 
51 struct got_commit_graph_branch_tip {
52 	struct got_object_id *commit_id;
53 	struct got_commit_object *commit;
54 	struct got_commit_graph_node *new_node;
55 };
56 
57 struct got_commit_graph {
58 	/* The set of all commits we have traversed. */
59 	struct got_object_idset *node_ids;
60 
61 	int flags;
62 #define GOT_COMMIT_GRAPH_FIRST_PARENT_TRAVERSAL		0x01
63 
64 	/*
65 	 * A set of object IDs of known parent commits which we have not yet
66 	 * traversed. Each commit ID in this set represents a branch in commit
67 	 * history: Either the first-parent branch of the head node, or another
68 	 * branch corresponding to a traversed merge commit for which we have
69 	 * not traversed a branch point commit yet.
70 	 *
71 	 * Whenever we add a commit with a matching ID to the graph, we remove
72 	 * its corresponding element from this set, and add new elements for
73 	 * each of that commit's parent commits which were not traversed yet.
74 	 *
75 	 * When API users ask us to fetch more commits, we fetch commits from
76 	 * all currently open branches. This allows API users to process
77 	 * commits in linear order even though the history contains branches.
78 	 */
79 	struct got_object_idset *open_branches;
80 
81 	/* Array of branch tips for fetch_commits_from_open_branches(). */
82 	struct got_commit_graph_branch_tip *tips;
83 	int ntips;
84 
85 	/* Path of tree entry of interest to the API user. */
86 	char *path;
87 
88 	/*
89 	 * Nodes which will be passed to the API user next, sorted by
90 	 * commit timestmap.
91 	 */
92 	struct got_commit_graph_iter_list iter_list;
93 };
94 
95 static const struct got_error *
96 detect_changed_path(int *changed, struct got_commit_object *commit,
97     struct got_object_id *commit_id, const char *path,
98     struct got_repository *repo)
99 {
100 	const struct got_error *err = NULL;
101 	struct got_commit_object *pcommit = NULL;
102 	struct got_tree_object *tree = NULL, *ptree = NULL;
103 	struct got_object_qid *pid;
104 
105 	if (got_path_is_root_dir(path)) {
106 		*changed = 1;
107 		return NULL;
108 	}
109 
110 	*changed = 0;
111 
112 	pid = STAILQ_FIRST(&commit->parent_ids);
113 	if (pid == NULL) {
114 		struct got_object_id *obj_id;
115 		err = got_object_id_by_path(&obj_id, repo, commit, path);
116 		if (err) {
117 			if (err->code == GOT_ERR_NO_TREE_ENTRY)
118 				err = NULL;
119 		} else
120 			*changed = 1; /* The path was created in this commit. */
121 		free(obj_id);
122 		return err;
123 	}
124 
125 	err = got_object_open_as_tree(&tree, repo, commit->tree_id);
126 	if (err)
127 		return err;
128 
129 	err = got_object_open_as_commit(&pcommit, repo, &pid->id);
130 	if (err)
131 		goto done;
132 
133 	err = got_object_open_as_tree(&ptree, repo, pcommit->tree_id);
134 	if (err)
135 		goto done;
136 
137 	err = got_object_tree_path_changed(changed, tree, ptree, path, repo);
138 done:
139 	if (tree)
140 		got_object_tree_close(tree);
141 	if (ptree)
142 		got_object_tree_close(ptree);
143 	if (pcommit)
144 		got_object_commit_close(pcommit);
145 	return err;
146 }
147 
148 static void
149 add_node_to_iter_list(struct got_commit_graph *graph,
150     struct got_commit_graph_node *node, time_t committer_time)
151 {
152 	struct got_commit_graph_node *n, *next;
153 
154 	node->timestamp = committer_time;
155 
156 	n = TAILQ_FIRST(&graph->iter_list);
157 	while (n) {
158 		next = TAILQ_NEXT(n, entry);
159 		if (next && node->timestamp >= next->timestamp) {
160 			TAILQ_INSERT_BEFORE(next, node, entry);
161 			return;
162 		}
163 		n = next;
164 	}
165 	TAILQ_INSERT_TAIL(&graph->iter_list, node, entry);
166 }
167 
168 static const struct got_error *
169 add_node(struct got_commit_graph_node **new_node,
170     struct got_commit_graph *graph, struct got_object_id *commit_id,
171     struct got_repository *repo)
172 {
173 	const struct got_error *err = NULL;
174 	struct got_commit_graph_node *node;
175 
176 	*new_node = NULL;
177 
178 	node = calloc(1, sizeof(*node));
179 	if (node == NULL)
180 		return got_error_from_errno("calloc");
181 
182 	memcpy(&node->id, commit_id, sizeof(node->id));
183 	err = got_object_idset_add(graph->node_ids, &node->id, NULL);
184 	if (err)
185 		free(node);
186 	else
187 		*new_node = node;
188 	return err;
189 }
190 
191 /*
192  * Ask got-read-pack to traverse first-parent history until a commit is
193  * encountered which modified graph->path, or until the pack file runs
194  * out of relevant commits. This is faster than sending an individual
195  * request for each commit stored in the pack file.
196  */
197 static const struct got_error *
198 packed_first_parent_traversal(int *ncommits_traversed,
199     struct got_commit_graph *graph, struct got_object_id *commit_id,
200     struct got_repository *repo)
201 {
202 	const struct got_error *err = NULL;
203 	struct got_object_id_queue traversed_commits;
204 	struct got_object_qid *qid;
205 
206 	STAILQ_INIT(&traversed_commits);
207 	*ncommits_traversed = 0;
208 
209 	err = got_traverse_packed_commits(&traversed_commits,
210 	    commit_id, graph->path, repo);
211 	if (err)
212 		return err;
213 
214 	/* Add all traversed commits to the graph... */
215 	STAILQ_FOREACH(qid, &traversed_commits, entry) {
216 		if (got_object_idset_contains(graph->open_branches, &qid->id))
217 			continue;
218 		if (got_object_idset_contains(graph->node_ids, &qid->id))
219 			continue;
220 
221 		(*ncommits_traversed)++;
222 
223 		/* ... except the last commit is the new branch tip. */
224 		if (STAILQ_NEXT(qid, entry) == NULL) {
225 			err = got_object_idset_add(graph->open_branches,
226 			    &qid->id, NULL);
227 			break;
228 		}
229 
230 		err = got_object_idset_add(graph->node_ids, &qid->id, NULL);
231 		if (err)
232 			break;
233 	}
234 
235 	got_object_id_queue_free(&traversed_commits);
236 	return err;
237 }
238 
239 static const struct got_error *
240 close_branch(struct got_commit_graph *graph, struct got_object_id *commit_id)
241 {
242 	const struct got_error *err;
243 
244 	err = got_object_idset_remove(NULL, graph->open_branches, commit_id);
245 	if (err && err->code != GOT_ERR_NO_OBJ)
246 		return err;
247 	return NULL;
248 }
249 
250 static const struct got_error *
251 advance_branch(struct got_commit_graph *graph, struct got_object_id *commit_id,
252     struct got_commit_object *commit, struct got_repository *repo)
253 {
254 	const struct got_error *err;
255 	struct got_object_qid *qid;
256 	struct got_object_id *merged_id = NULL;
257 
258 	err = close_branch(graph, commit_id);
259 	if (err)
260 		return err;
261 
262 	if (graph->flags & GOT_COMMIT_GRAPH_FIRST_PARENT_TRAVERSAL) {
263 		qid = STAILQ_FIRST(&commit->parent_ids);
264 		if (qid == NULL ||
265 		    got_object_idset_contains(graph->open_branches, &qid->id))
266 			return NULL;
267 		/*
268 		 * The root directory always changes by definition, and when
269 		 * logging the root we want to traverse consecutive commits
270 		 * even if they point at the same tree.
271 		 * But if we are looking for a specific path then we can avoid
272 		 * fetching packed commits which did not modify the path and
273 		 * only fetch their IDs. This speeds up 'got blame'.
274 		 */
275 		if (!got_path_is_root_dir(graph->path) &&
276 		    (commit->flags & GOT_COMMIT_FLAG_PACKED)) {
277 			int ncommits = 0;
278 			err = packed_first_parent_traversal(&ncommits,
279 			    graph, &qid->id, repo);
280 			if (err || ncommits > 0)
281 				return err;
282 		}
283 		return got_object_idset_add(graph->open_branches,
284 		    &qid->id, NULL);
285 	}
286 
287 	/*
288 	 * If we are graphing commits for a specific path, skip branches
289 	 * which do not contribute any content to this path.
290 	 */
291 	if (commit->nparents > 1 && !got_path_is_root_dir(graph->path)) {
292 		err = got_object_id_by_path(&merged_id, repo, commit, graph->path);
293 		if (err && err->code != GOT_ERR_NO_TREE_ENTRY)
294 			return err;
295 		/* The requested path does not exist in this merge commit. */
296 	}
297 	if (commit->nparents > 1 && !got_path_is_root_dir(graph->path) &&
298 	    merged_id != NULL) {
299 		struct got_object_id *prev_id = NULL;
300 		int branches_differ = 0;
301 
302 
303 		STAILQ_FOREACH(qid, &commit->parent_ids, entry) {
304 			struct got_object_id *id = NULL;
305 			struct got_commit_object *pcommit = NULL;
306 
307 			if (got_object_idset_contains(graph->open_branches,
308 			    &qid->id))
309 				continue;
310 
311 			err = got_object_open_as_commit(&pcommit, repo,
312 			    &qid->id);
313 			if (err) {
314 				free(merged_id);
315 				free(prev_id);
316 				return err;
317 			}
318 			err = got_object_id_by_path(&id, repo, pcommit,
319 			    graph->path);
320 			got_object_commit_close(pcommit);
321 			pcommit = NULL;
322 			if (err) {
323 				if (err->code == GOT_ERR_NO_TREE_ENTRY) {
324 					branches_differ = 1;
325 					continue;
326 				}
327 				free(merged_id);
328 				free(prev_id);
329 				return err;
330 			}
331 
332 			if (prev_id) {
333 				if (!branches_differ &&
334 				    got_object_id_cmp(id, prev_id) != 0)
335 					branches_differ = 1;
336 				free(prev_id);
337 			}
338 			prev_id = id;
339 
340 			/*
341 			 * If a branch has created the merged content we can
342 			 * skip any other branches.
343 			 */
344 			if (got_object_id_cmp(merged_id, id) == 0) {
345 				err = got_object_idset_add(graph->open_branches,
346 				    &qid->id, NULL);
347 				free(merged_id);
348 				free(id);
349 				return err;
350 			}
351 		}
352 
353 		free(prev_id);
354 		prev_id = NULL;
355 		free(merged_id);
356 		merged_id = NULL;
357 
358 		/*
359 		 * If the path's content is the same on all branches,
360 		 * follow the first parent only.
361 		 */
362 		if (!branches_differ) {
363 			qid = STAILQ_FIRST(&commit->parent_ids);
364 			if (qid == NULL)
365 				return NULL;
366 			if (got_object_idset_contains(graph->open_branches,
367 			    &qid->id))
368 				return NULL;
369 			if (got_object_idset_contains(graph->node_ids,
370 			    &qid->id))
371 				return NULL; /* parent already traversed */
372 			return got_object_idset_add(graph->open_branches,
373 			    &qid->id, NULL);
374 		}
375 	}
376 
377 	STAILQ_FOREACH(qid, &commit->parent_ids, entry) {
378 		if (got_object_idset_contains(graph->open_branches, &qid->id))
379 			continue;
380 		if (got_object_idset_contains(graph->node_ids, &qid->id))
381 			continue; /* parent already traversed */
382 		err = got_object_idset_add(graph->open_branches, &qid->id,
383 		    NULL);
384 		if (err)
385 			return err;
386 	}
387 
388 	return NULL;
389 }
390 
391 const struct got_error *
392 got_commit_graph_open(struct got_commit_graph **graph,
393     const char *path, int first_parent_traversal)
394 {
395 	const struct got_error *err = NULL;
396 
397 	*graph = calloc(1, sizeof(**graph));
398 	if (*graph == NULL)
399 		return got_error_from_errno("calloc");
400 
401 	TAILQ_INIT(&(*graph)->iter_list);
402 
403 	(*graph)->path = strdup(path);
404 	if ((*graph)->path == NULL) {
405 		err = got_error_from_errno("strdup");
406 		goto done;
407 	}
408 
409 	(*graph)->node_ids = got_object_idset_alloc();
410 	if ((*graph)->node_ids == NULL) {
411 		err = got_error_from_errno("got_object_idset_alloc");
412 		goto done;
413 	}
414 
415 	(*graph)->open_branches = got_object_idset_alloc();
416 	if ((*graph)->open_branches == NULL) {
417 		err = got_error_from_errno("got_object_idset_alloc");
418 		goto done;
419 	}
420 
421 	if (first_parent_traversal)
422 		(*graph)->flags |= GOT_COMMIT_GRAPH_FIRST_PARENT_TRAVERSAL;
423 done:
424 	if (err) {
425 		got_commit_graph_close(*graph);
426 		*graph = NULL;
427 	}
428 	return err;
429 }
430 
431 struct add_branch_tip_arg {
432 	struct got_commit_graph_branch_tip *tips;
433 	int ntips;
434 	struct got_repository *repo;
435 	struct got_commit_graph *graph;
436 };
437 
438 static const struct got_error *
439 add_branch_tip(struct got_object_id *commit_id, void *data, void *arg)
440 {
441 	const struct got_error *err;
442 	struct add_branch_tip_arg *a = arg;
443 	struct got_commit_graph_node *new_node;
444 	struct got_commit_object *commit;
445 
446 	err = got_object_open_as_commit(&commit, a->repo, commit_id);
447 	if (err)
448 		return err;
449 
450 	err = add_node(&new_node, a->graph, commit_id, a->repo);
451 	if (err) {
452 		got_object_commit_close(commit);
453 		return err;
454 	}
455 
456 	a->tips[a->ntips].commit_id = &new_node->id;
457 	a->tips[a->ntips].commit = commit;
458 	a->tips[a->ntips].new_node = new_node;
459 	a->ntips++;
460 
461 	return NULL;
462 }
463 
464 static const struct got_error *
465 fetch_commits_from_open_branches(struct got_commit_graph *graph,
466     struct got_repository *repo, got_cancel_cb cancel_cb, void *cancel_arg)
467 {
468 	const struct got_error *err;
469 	struct add_branch_tip_arg arg;
470 	int i, ntips;
471 
472 	ntips = got_object_idset_num_elements(graph->open_branches);
473 	if (ntips == 0)
474 		return NULL;
475 
476 	/* (Re-)allocate branch tips array if necessary. */
477 	if (graph->ntips < ntips) {
478 		struct got_commit_graph_branch_tip *tips;
479 		tips = recallocarray(graph->tips, graph->ntips, ntips,
480 		    sizeof(*tips));
481 		if (tips == NULL)
482 			return got_error_from_errno("recallocarray");
483 		graph->tips = tips;
484 		graph->ntips = ntips;
485 	}
486 	arg.tips = graph->tips;
487 	arg.ntips = 0; /* add_branch_tip() will increment */
488 	arg.repo = repo;
489 	arg.graph = graph;
490 	err = got_object_idset_for_each(graph->open_branches, add_branch_tip,
491 	    &arg);
492 	if (err)
493 		goto done;
494 
495 	for (i = 0; i < arg.ntips; i++) {
496 		struct got_object_id *commit_id;
497 		struct got_commit_object *commit;
498 		struct got_commit_graph_node *new_node;
499 		int changed;
500 
501 		if (cancel_cb) {
502 			err = (*cancel_cb)(cancel_arg);
503 			if (err)
504 				break;
505 		}
506 
507 		commit_id = arg.tips[i].commit_id;
508 		commit = arg.tips[i].commit;
509 		new_node = arg.tips[i].new_node;
510 
511 		err = detect_changed_path(&changed, commit, commit_id,
512 		    graph->path, repo);
513 		if (err) {
514 			if (err->code != GOT_ERR_NO_OBJ)
515 				break;
516 			/*
517 			 * History of the path stops here on the current
518 			 * branch. Keep going on other branches.
519 			 */
520 			err = close_branch(graph, commit_id);
521 			if (err)
522 				break;
523 			continue;
524 		}
525 		if (changed) {
526 			add_node_to_iter_list(graph, new_node,
527 			    got_object_commit_get_committer_time(commit));
528 			arg.tips[i].new_node = NULL;
529 		}
530 		err = advance_branch(graph, commit_id, commit, repo);
531 		if (err)
532 			break;
533 	}
534 done:
535 	for (i = 0; i < arg.ntips; i++) {
536 		got_object_commit_close(arg.tips[i].commit);
537 		free(arg.tips[i].new_node);
538 	}
539 	return err;
540 }
541 
542 void
543 got_commit_graph_close(struct got_commit_graph *graph)
544 {
545 	struct got_commit_graph_node *node;
546 
547 	while ((node = TAILQ_FIRST(&graph->iter_list))) {
548 		TAILQ_REMOVE(&graph->iter_list, node, entry);
549 		free(node);
550 	}
551 
552 	if (graph->open_branches)
553 		got_object_idset_free(graph->open_branches);
554 	if (graph->node_ids)
555 		got_object_idset_free(graph->node_ids);
556 	free(graph->tips);
557 	free(graph->path);
558 	free(graph);
559 }
560 
561 static const struct got_error *
562 remove_branch_tip(struct got_object_id *commit_id, void *data, void *arg)
563 {
564 	struct got_object_idset *open_branches = arg;
565 
566 	return got_object_idset_remove(NULL, open_branches, commit_id);
567 }
568 
569 const struct got_error *
570 got_commit_graph_iter_start(struct got_commit_graph *graph,
571     struct got_object_id *id, struct got_repository *repo,
572     got_cancel_cb cancel_cb, void *cancel_arg)
573 {
574 	const struct got_error *err = NULL;
575 	struct got_commit_graph_node *node;
576 
577 	/* Clear left-over state from previous iteration attempts. */
578 	while ((node = TAILQ_FIRST(&graph->iter_list)))
579 		TAILQ_REMOVE(&graph->iter_list, node, entry);
580 	err = got_object_idset_for_each(graph->open_branches,
581 	    remove_branch_tip, graph->open_branches);
582 	if (err)
583 		return err;
584 
585 	err = got_object_idset_add(graph->open_branches, id, NULL);
586 	if (err)
587 		return err;
588 
589 	/* Locate first commit which changed graph->path. */
590 	while (TAILQ_EMPTY(&graph->iter_list) &&
591 	    got_object_idset_num_elements(graph->open_branches) > 0) {
592 		err = fetch_commits_from_open_branches(graph, repo,
593 		    cancel_cb, cancel_arg);
594 		if (err)
595 			return err;
596 	}
597 
598 	if (TAILQ_EMPTY(&graph->iter_list)) {
599 		const char *path;
600 		if (got_path_is_root_dir(graph->path))
601 			return got_error_no_obj(id);
602 		path = graph->path;
603 		while (path[0] == '/')
604 			path++;
605 		return got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
606 	}
607 
608 	return NULL;
609 }
610 
611 const struct got_error *
612 got_commit_graph_iter_next(struct got_object_id *id,
613     struct got_commit_graph *graph, struct got_repository *repo,
614     got_cancel_cb cancel_cb, void *cancel_arg)
615 {
616 	const struct got_error *err = NULL;
617 	struct got_commit_graph_node *node;
618 
619 	node = TAILQ_FIRST(&graph->iter_list);
620 	if (node == NULL) {
621 		/* We are done iterating, or iteration was not started. */
622 		return got_error(GOT_ERR_ITER_COMPLETED);
623 	}
624 
625 	while (TAILQ_NEXT(node, entry) == NULL &&
626 	    got_object_idset_num_elements(graph->open_branches) > 0) {
627 		err = fetch_commits_from_open_branches(graph, repo,
628 		    cancel_cb, cancel_arg);
629 		if (err)
630 			return err;
631 	}
632 
633 	memcpy(id, &node->id, sizeof(*id));
634 
635 	TAILQ_REMOVE(&graph->iter_list, node, entry);
636 	free(node);
637 	return NULL;
638 }
639 
640 static const struct got_error *
641 find_yca_add_id(struct got_object_id **yca_id, struct got_commit_graph *graph,
642     struct got_object_idset *commit_ids, struct got_repository *repo,
643     got_cancel_cb cancel_cb, void *cancel_arg)
644 {
645 	const struct got_error *err = NULL;
646 	struct got_object_id id;
647 
648 	err = got_commit_graph_iter_next(&id, graph, repo, cancel_cb,
649 	    cancel_arg);
650 	if (err)
651 		return err;
652 
653 	if (got_object_idset_contains(commit_ids, &id)) {
654 		*yca_id = got_object_id_dup(&id);
655 		if (*yca_id == NULL)
656 			err = got_error_from_errno("got_object_id_dup");
657 		return err;
658 	}
659 
660 	return got_object_idset_add(commit_ids, &id, NULL);
661 }
662 
663 /*
664  * Sets *yca_id to the youngest common ancestor of commit_id and
665  * commit_id2. Returns got_error(GOT_ERR_ANCESTRY) if they have no
666  * common ancestors.
667  *
668  * If first_parent_traversal is nonzero, only linear history is considered.
669  */
670 const struct got_error *
671 got_commit_graph_find_youngest_common_ancestor(struct got_object_id **yca_id,
672     struct got_object_id *commit_id, struct got_object_id *commit_id2,
673     int first_parent_traversal,
674     struct got_repository *repo, got_cancel_cb cancel_cb, void *cancel_arg)
675 {
676 	const struct got_error *err = NULL;
677 	struct got_commit_graph *graph = NULL, *graph2 = NULL;
678 	int completed = 0, completed2 = 0;
679 	struct got_object_idset *commit_ids;
680 
681 	*yca_id = NULL;
682 
683 	commit_ids = got_object_idset_alloc();
684 	if (commit_ids == NULL)
685 		return got_error_from_errno("got_object_idset_alloc");
686 
687 	err = got_commit_graph_open(&graph, "/", first_parent_traversal);
688 	if (err)
689 		goto done;
690 
691 	err = got_commit_graph_open(&graph2, "/", first_parent_traversal);
692 	if (err)
693 		goto done;
694 
695 	err = got_commit_graph_iter_start(graph, commit_id, repo,
696 	    cancel_cb, cancel_arg);
697 	if (err)
698 		goto done;
699 
700 	err = got_commit_graph_iter_start(graph2, commit_id2, repo,
701 	    cancel_cb, cancel_arg);
702 	if (err)
703 		goto done;
704 
705 	for (;;) {
706 		if (cancel_cb) {
707 			err = (*cancel_cb)(cancel_arg);
708 			if (err)
709 				break;
710 		}
711 
712 		if (!completed) {
713 			err = find_yca_add_id(yca_id, graph, commit_ids, repo,
714 			    cancel_cb, cancel_arg);
715 			if (err) {
716 				if (err->code != GOT_ERR_ITER_COMPLETED)
717 					break;
718 				err = NULL;
719 				completed = 1;
720 			}
721 			if (*yca_id)
722 				break;
723 		}
724 
725 		if (!completed2) {
726 			err = find_yca_add_id(yca_id, graph2, commit_ids, repo,
727 			    cancel_cb, cancel_arg);
728 			if (err) {
729 				if (err->code != GOT_ERR_ITER_COMPLETED)
730 					break;
731 				err = NULL;
732 				completed2 = 1;
733 			}
734 			if (*yca_id)
735 				break;
736 		}
737 
738 		if (completed && completed2) {
739 			err = got_error(GOT_ERR_ANCESTRY);
740 			break;
741 		}
742 	}
743 done:
744 	got_object_idset_free(commit_ids);
745 	if (graph)
746 		got_commit_graph_close(graph);
747 	if (graph2)
748 		got_commit_graph_close(graph2);
749 	return err;
750 }