lib/commit_graph.c

   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
 257         err = close_branch(graph, commit_id);
 258         if (err)
 259                 return err;
 260
 261         if (graph->flags & GOT_COMMIT_GRAPH_FIRST_PARENT_TRAVERSAL) {
 262                 qid = STAILQ_FIRST(&commit->parent_ids);
 263                 if (qid == NULL ||
 264                     got_object_idset_contains(graph->open_branches, &qid->id))
 265                         return NULL;
 266                 /*
 267                  * The root directory always changes by definition, and when
 268                  * logging the root we want to traverse consecutive commits
 269                  * even if they point at the same tree.
 270                  * But if we are looking for a specific path then we can avoid
 271                  * fetching packed commits which did not modify the path and
 272                  * only fetch their IDs. This speeds up 'got blame'.
 273                  */
 274                 if (!got_path_is_root_dir(graph->path) &&
 275                     (commit->flags & GOT_COMMIT_FLAG_PACKED)) {
 276                         int ncommits = 0;
 277                         err = packed_first_parent_traversal(&ncommits,
 278                             graph, &qid->id, repo);
 279                         if (err || ncommits > 0)
 280                                 return err;
 281                 }
 282                 return got_object_idset_add(graph->open_branches,
 283                     &qid->id, NULL);
 284         }
 285
 286         /*
 287          * If we are graphing commits for a specific path, skip branches
 288          * which do not contribute any content to this path.
 289          */
 290         if (commit->nparents > 1 && !got_path_is_root_dir(graph->path)) {
 291                 struct got_object_id *merged_id, *prev_id = NULL;
 292                 int branches_differ = 0;
 293
 294                 err = got_object_id_by_path(&merged_id, repo, commit,
 295                     graph->path);
 296                 if (err)
 297                         return err;
 298
 299                 STAILQ_FOREACH(qid, &commit->parent_ids, entry) {
 300                         struct got_object_id *id = NULL;
 301                         struct got_commit_object *pcommit = NULL;
 302
 303                         if (got_object_idset_contains(graph->open_branches,
 304                             &qid->id))
 305                                 continue;
 306
 307                         err = got_object_open_as_commit(&pcommit, repo,
 308                             &qid->id);
 309                         if (err) {
 310                                 free(merged_id);
 311                                 free(prev_id);
 312                                 return err;
 313                         }
 314                         err = got_object_id_by_path(&id, repo, pcommit,
 315                             graph->path);
 316                         got_object_commit_close(pcommit);
 317                         pcommit = NULL;
 318                         if (err) {
 319                                 if (err->code == GOT_ERR_NO_TREE_ENTRY) {
 320                                         branches_differ = 1;
 321                                         continue;
 322                                 }
 323                                 free(merged_id);
 324                                 free(prev_id);
 325                                 return err;
 326                         }
 327
 328                         if (prev_id) {
 329                                 if (!branches_differ &&
 330                                     got_object_id_cmp(id, prev_id) != 0)
 331                                         branches_differ = 1;
 332                                 free(prev_id);
 333                         }
 334                         prev_id = id;
 335
 336                         /*
 337                          * If a branch has created the merged content we can
 338                          * skip any other branches.
 339                          */
 340                         if (got_object_id_cmp(merged_id, id) == 0) {
 341                                 err = got_object_idset_add(graph->open_branches,
 342                                     &qid->id, NULL);
 343                                 free(merged_id);
 344                                 free(id);
 345                                 return err;
 346                         }
 347                 }
 348
 349                 free(prev_id);
 350                 prev_id = NULL;
 351                 free(merged_id);
 352                 merged_id = NULL;
 353
 354                 /*
 355                  * If the path's content is the same on all branches,
 356                  * follow the first parent only.
 357                  */
 358                 if (!branches_differ) {
 359                         qid = STAILQ_FIRST(&commit->parent_ids);
 360                         if (qid == NULL)
 361                                 return NULL;
 362                         if (got_object_idset_contains(graph->open_branches,
 363                             &qid->id))
 364                                 return NULL;
 365                         if (got_object_idset_contains(graph->node_ids,
 366                             &qid->id))
 367                                 return NULL; /* parent already traversed */
 368                         return got_object_idset_add(graph->open_branches,
 369                             &qid->id, NULL);
 370                 }
 371         }
 372
 373         STAILQ_FOREACH(qid, &commit->parent_ids, entry) {
 374                 if (got_object_idset_contains(graph->open_branches, &qid->id))
 375                         continue;
 376                 if (got_object_idset_contains(graph->node_ids, &qid->id))
 377                         continue; /* parent already traversed */
 378                 err = got_object_idset_add(graph->open_branches, &qid->id,
 379                     NULL);
 380                 if (err)
 381                         return err;
 382         }
 383
 384         return NULL;
 385 }
 386
 387 const struct got_error *
 388 got_commit_graph_open(struct got_commit_graph **graph,
 389     const char *path, int first_parent_traversal)
 390 {
 391         const struct got_error *err = NULL;
 392
 393         *graph = calloc(1, sizeof(**graph));
 394         if (*graph == NULL)
 395                 return got_error_from_errno("calloc");
 396
 397         TAILQ_INIT(&(*graph)->iter_list);
 398
 399         (*graph)->path = strdup(path);
 400         if ((*graph)->path == NULL) {
 401                 err = got_error_from_errno("strdup");
 402                 goto done;
 403         }
 404
 405         (*graph)->node_ids = got_object_idset_alloc();
 406         if ((*graph)->node_ids == NULL) {
 407                 err = got_error_from_errno("got_object_idset_alloc");
 408                 goto done;
 409         }
 410
 411         (*graph)->open_branches = got_object_idset_alloc();
 412         if ((*graph)->open_branches == NULL) {
 413                 err = got_error_from_errno("got_object_idset_alloc");
 414                 goto done;
 415         }
 416
 417         if (first_parent_traversal)
 418                 (*graph)->flags |= GOT_COMMIT_GRAPH_FIRST_PARENT_TRAVERSAL;
 419 done:
 420         if (err) {
 421                 got_commit_graph_close(*graph);
 422                 *graph = NULL;
 423         }
 424         return err;
 425 }
 426
 427 struct add_branch_tip_arg {
 428         struct got_commit_graph_branch_tip *tips;
 429         int ntips;
 430         struct got_repository *repo;
 431         struct got_commit_graph *graph;
 432 };
 433
 434 static const struct got_error *
 435 add_branch_tip(struct got_object_id *commit_id, void *data, void *arg)
 436 {
 437         const struct got_error *err;
 438         struct add_branch_tip_arg *a = arg;
 439         struct got_commit_graph_node *new_node;
 440         struct got_commit_object *commit;
 441
 442         err = got_object_open_as_commit(&commit, a->repo, commit_id);
 443         if (err)
 444                 return err;
 445
 446         err = add_node(&new_node, a->graph, commit_id, a->repo);
 447         if (err) {
 448                 got_object_commit_close(commit);
 449                 return err;
 450         }
 451
 452         a->tips[a->ntips].commit_id = &new_node->id;
 453         a->tips[a->ntips].commit = commit;
 454         a->tips[a->ntips].new_node = new_node;
 455         a->ntips++;
 456
 457         return NULL;
 458 }
 459
 460 static const struct got_error *
 461 fetch_commits_from_open_branches(struct got_commit_graph *graph,
 462     struct got_repository *repo, got_cancel_cb cancel_cb, void *cancel_arg)
 463 {
 464         const struct got_error *err;
 465         struct add_branch_tip_arg arg;
 466         int i, ntips;
 467
 468         ntips = got_object_idset_num_elements(graph->open_branches);
 469         if (ntips == 0)
 470                 return NULL;
 471
 472         /* (Re-)allocate branch tips array if necessary. */
 473         if (graph->ntips < ntips) {
 474                 struct got_commit_graph_branch_tip *tips;
 475                 tips = recallocarray(graph->tips, graph->ntips, ntips,
 476                     sizeof(*tips));
 477                 if (tips == NULL)
 478                         return got_error_from_errno("recallocarray");
 479                 graph->tips = tips;
 480                 graph->ntips = ntips;
 481         }
 482         arg.tips = graph->tips;
 483         arg.ntips = 0; /* add_branch_tip() will increment */
 484         arg.repo = repo;
 485         arg.graph = graph;
 486         err = got_object_idset_for_each(graph->open_branches, add_branch_tip,
 487             &arg);
 488         if (err)
 489                 goto done;
 490
 491         for (i = 0; i < arg.ntips; i++) {
 492                 struct got_object_id *commit_id;
 493                 struct got_commit_object *commit;
 494                 struct got_commit_graph_node *new_node;
 495                 int changed;
 496
 497                 if (cancel_cb) {
 498                         err = (*cancel_cb)(cancel_arg);
 499                         if (err)
 500                                 break;
 501                 }
 502
 503                 commit_id = arg.tips[i].commit_id;
 504                 commit = arg.tips[i].commit;
 505                 new_node = arg.tips[i].new_node;
 506
 507                 err = detect_changed_path(&changed, commit, commit_id,
 508                     graph->path, repo);
 509                 if (err) {
 510                         if (err->code != GOT_ERR_NO_OBJ)
 511                                 break;
 512                         /*
 513                          * History of the path stops here on the current
 514                          * branch. Keep going on other branches.
 515                          */
 516                         err = close_branch(graph, commit_id);
 517                         if (err)
 518                                 break;
 519                         continue;
 520                 }
 521                 if (changed) {
 522                         add_node_to_iter_list(graph, new_node,
 523                             got_object_commit_get_committer_time(commit));
 524                         arg.tips[i].new_node = NULL;
 525                 }
 526                 err = advance_branch(graph, commit_id, commit, repo);
 527                 if (err)
 528                         break;
 529         }
 530 done:
 531         for (i = 0; i < arg.ntips; i++) {
 532                 got_object_commit_close(arg.tips[i].commit);
 533                 free(arg.tips[i].new_node);
 534         }
 535         return err;
 536 }
 537
 538 void
 539 got_commit_graph_close(struct got_commit_graph *graph)
 540 {
 541         struct got_commit_graph_node *node;
 542
 543         while ((node = TAILQ_FIRST(&graph->iter_list))) {
 544                 TAILQ_REMOVE(&graph->iter_list, node, entry);
 545                 free(node);
 546         }
 547
 548         if (graph->open_branches)
 549                 got_object_idset_free(graph->open_branches);
 550         if (graph->node_ids)
 551                 got_object_idset_free(graph->node_ids);
 552         free(graph->tips);
 553         free(graph->path);
 554         free(graph);
 555 }
 556
 557 const struct got_error *
 558 got_commit_graph_iter_start(struct got_commit_graph *graph,
 559     struct got_object_id *id, struct got_repository *repo,
 560     got_cancel_cb cancel_cb, void *cancel_arg)
 561 {
 562         const struct got_error *err = NULL;
 563
 564         if (!TAILQ_EMPTY(&graph->iter_list))
 565                 return got_error(GOT_ERR_ITER_BUSY);
 566
 567         err = got_object_idset_add(graph->open_branches, id, NULL);
 568         if (err)
 569                 return err;
 570
 571         /* Locate first commit which changed graph->path. */
 572         while (TAILQ_EMPTY(&graph->iter_list) &&
 573             got_object_idset_num_elements(graph->open_branches) > 0) {
 574                 err = fetch_commits_from_open_branches(graph, repo,
 575                     cancel_cb, cancel_arg);
 576                 if (err)
 577                         return err;
 578         }
 579
 580         if (TAILQ_EMPTY(&graph->iter_list)) {
 581                 const char *path;
 582                 if (got_path_is_root_dir(graph->path))
 583                         return got_error_no_obj(id);
 584                 path = graph->path;
 585                 while (path[0] == '/')
 586                         path++;
 587                 return got_error_path(path, GOT_ERR_NO_TREE_ENTRY);
 588         }
 589
 590         return NULL;
 591 }
 592
 593 const struct got_error *
 594 got_commit_graph_iter_next(struct got_object_id *id,
 595     struct got_commit_graph *graph, struct got_repository *repo,
 596     got_cancel_cb cancel_cb, void *cancel_arg)
 597 {
 598         const struct got_error *err = NULL;
 599         struct got_commit_graph_node *node;
 600
 601         node = TAILQ_FIRST(&graph->iter_list);
 602         if (node == NULL) {
 603                 /* We are done iterating, or iteration was not started. */
 604                 return got_error(GOT_ERR_ITER_COMPLETED);
 605         }
 606
 607         while (TAILQ_NEXT(node, entry) == NULL &&
 608             got_object_idset_num_elements(graph->open_branches) > 0) {
 609                 err = fetch_commits_from_open_branches(graph, repo,
 610                     cancel_cb, cancel_arg);
 611                 if (err)
 612                         return err;
 613         }
 614
 615         memcpy(id, &node->id, sizeof(*id));
 616
 617         TAILQ_REMOVE(&graph->iter_list, node, entry);
 618         free(node);
 619         return NULL;
 620 }
 621
 622 static const struct got_error *
 623 find_yca_add_id(struct got_object_id **yca_id, struct got_commit_graph *graph,
 624     struct got_object_idset *commit_ids, struct got_repository *repo,
 625     got_cancel_cb cancel_cb, void *cancel_arg)
 626 {
 627         const struct got_error *err = NULL;
 628         struct got_object_id id;
 629
 630         err = got_commit_graph_iter_next(&id, graph, repo, cancel_cb,
 631             cancel_arg);
 632         if (err)
 633                 return err;
 634
 635         if (got_object_idset_contains(commit_ids, &id)) {
 636                 *yca_id = got_object_id_dup(&id);
 637                 if (*yca_id == NULL)
 638                         err = got_error_from_errno("got_object_id_dup");
 639                 return err;
 640         }
 641
 642         return got_object_idset_add(commit_ids, &id, NULL);
 643 }
 644
 645 /*
 646  * Sets *yca_id to the youngest common ancestor of commit_id and
 647  * commit_id2. Returns got_error(GOT_ERR_ANCESTRY) if they have no
 648  * common ancestors.
 649  *
 650  * If first_parent_traversal is nonzero, only linear history is considered.
 651  */
 652 const struct got_error *
 653 got_commit_graph_find_youngest_common_ancestor(struct got_object_id **yca_id,
 654     struct got_object_id *commit_id, struct got_object_id *commit_id2,
 655     int first_parent_traversal,
 656     struct got_repository *repo, got_cancel_cb cancel_cb, void *cancel_arg)
 657 {
 658         const struct got_error *err = NULL;
 659         struct got_commit_graph *graph = NULL, *graph2 = NULL;
 660         int completed = 0, completed2 = 0;
 661         struct got_object_idset *commit_ids;
 662
 663         *yca_id = NULL;
 664
 665         commit_ids = got_object_idset_alloc();
 666         if (commit_ids == NULL)
 667                 return got_error_from_errno("got_object_idset_alloc");
 668
 669         err = got_commit_graph_open(&graph, "/", first_parent_traversal);
 670         if (err)
 671                 goto done;
 672
 673         err = got_commit_graph_open(&graph2, "/", first_parent_traversal);
 674         if (err)
 675                 goto done;
 676
 677         err = got_commit_graph_iter_start(graph, commit_id, repo,
 678             cancel_cb, cancel_arg);
 679         if (err)
 680                 goto done;
 681
 682         err = got_commit_graph_iter_start(graph2, commit_id2, repo,
 683             cancel_cb, cancel_arg);
 684         if (err)
 685                 goto done;
 686
 687         for (;;) {
 688                 if (cancel_cb) {
 689                         err = (*cancel_cb)(cancel_arg);
 690                         if (err)
 691                                 break;
 692                 }
 693
 694                 if (!completed) {
 695                         err = find_yca_add_id(yca_id, graph, commit_ids, repo,
 696                             cancel_cb, cancel_arg);
 697                         if (err) {
 698                                 if (err->code != GOT_ERR_ITER_COMPLETED)
 699                                         break;
 700                                 err = NULL;
 701                                 completed = 1;
 702                         }
 703                         if (*yca_id)
 704                                 break;
 705                 }
 706
 707                 if (!completed2) {
 708                         err = find_yca_add_id(yca_id, graph2, commit_ids, repo,
 709                             cancel_cb, cancel_arg);
 710                         if (err) {
 711                                 if (err->code != GOT_ERR_ITER_COMPLETED)
 712                                         break;
 713                                 err = NULL;
 714                                 completed2 = 1;
 715                         }
 716                         if (*yca_id)
 717                                 break;
 718                 }
 719
 720                 if (completed && completed2) {
 721                         err = got_error(GOT_ERR_ANCESTRY);
 722                         break;
 723                 }
 724         }
 725 done:
 726         got_object_idset_free(commit_ids);
 727         if (graph)
 728                 got_commit_graph_close(graph);
 729         if (graph2)
 730                 got_commit_graph_close(graph2);
 731         return err;
 732 }