Merge branch 'jl/zlib-restore-nul-termination'
[git] / notes-merge.c
1 #include "cache.h"
2 #include "commit.h"
3 #include "refs.h"
4 #include "diff.h"
5 #include "diffcore.h"
6 #include "xdiff-interface.h"
7 #include "ll-merge.h"
8 #include "dir.h"
9 #include "notes.h"
10 #include "notes-merge.h"
11 #include "strbuf.h"
12 #include "notes-utils.h"
13
14 struct notes_merge_pair {
15         struct object_id obj, base, local, remote;
16 };
17
18 void init_notes_merge_options(struct notes_merge_options *o)
19 {
20         memset(o, 0, sizeof(struct notes_merge_options));
21         strbuf_init(&(o->commit_msg), 0);
22         o->verbosity = NOTES_MERGE_VERBOSITY_DEFAULT;
23 }
24
25 static int path_to_oid(const char *path, struct object_id *oid)
26 {
27         char hex_oid[GIT_SHA1_HEXSZ];
28         int i = 0;
29         while (*path && i < GIT_SHA1_HEXSZ) {
30                 if (*path != '/')
31                         hex_oid[i++] = *path;
32                 path++;
33         }
34         if (*path || i != GIT_SHA1_HEXSZ)
35                 return -1;
36         return get_oid_hex(hex_oid, oid);
37 }
38
39 static int verify_notes_filepair(struct diff_filepair *p, struct object_id *oid)
40 {
41         switch (p->status) {
42         case DIFF_STATUS_MODIFIED:
43                 assert(p->one->mode == p->two->mode);
44                 assert(!is_null_oid(&p->one->oid));
45                 assert(!is_null_oid(&p->two->oid));
46                 break;
47         case DIFF_STATUS_ADDED:
48                 assert(is_null_oid(&p->one->oid));
49                 break;
50         case DIFF_STATUS_DELETED:
51                 assert(is_null_oid(&p->two->oid));
52                 break;
53         default:
54                 return -1;
55         }
56         assert(!strcmp(p->one->path, p->two->path));
57         return path_to_oid(p->one->path, oid);
58 }
59
60 static struct notes_merge_pair *find_notes_merge_pair_pos(
61                 struct notes_merge_pair *list, int len, struct object_id *obj,
62                 int insert_new, int *occupied)
63 {
64         /*
65          * Both diff_tree_remote() and diff_tree_local() tend to process
66          * merge_pairs in ascending order. Therefore, cache last returned
67          * index, and search sequentially from there until the appropriate
68          * position is found.
69          *
70          * Since inserts only happen from diff_tree_remote() (which mainly
71          * _appends_), we don't care that inserting into the middle of the
72          * list is expensive (using memmove()).
73          */
74         static int last_index;
75         int i = last_index < len ? last_index : len - 1;
76         int prev_cmp = 0, cmp = -1;
77         while (i >= 0 && i < len) {
78                 cmp = oidcmp(obj, &list[i].obj);
79                 if (!cmp) /* obj belongs @ i */
80                         break;
81                 else if (cmp < 0 && prev_cmp <= 0) /* obj belongs < i */
82                         i--;
83                 else if (cmp < 0) /* obj belongs between i-1 and i */
84                         break;
85                 else if (cmp > 0 && prev_cmp >= 0) /* obj belongs > i */
86                         i++;
87                 else /* if (cmp > 0) */ { /* obj belongs between i and i+1 */
88                         i++;
89                         break;
90                 }
91                 prev_cmp = cmp;
92         }
93         if (i < 0)
94                 i = 0;
95         /* obj belongs at, or immediately preceding, index i (0 <= i <= len) */
96
97         if (!cmp)
98                 *occupied = 1;
99         else {
100                 *occupied = 0;
101                 if (insert_new && i < len) {
102                         MOVE_ARRAY(list + i + 1, list + i, len - i);
103                         memset(list + i, 0, sizeof(struct notes_merge_pair));
104                 }
105         }
106         last_index = i;
107         return list + i;
108 }
109
110 static struct object_id uninitialized = {
111         "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" \
112         "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
113 };
114
115 static struct notes_merge_pair *diff_tree_remote(struct notes_merge_options *o,
116                                                  const struct object_id *base,
117                                                  const struct object_id *remote,
118                                                  int *num_changes)
119 {
120         struct diff_options opt;
121         struct notes_merge_pair *changes;
122         int i, len = 0;
123
124         trace_printf("\tdiff_tree_remote(base = %.7s, remote = %.7s)\n",
125                oid_to_hex(base), oid_to_hex(remote));
126
127         diff_setup(&opt);
128         opt.flags.recursive = 1;
129         opt.output_format = DIFF_FORMAT_NO_OUTPUT;
130         diff_setup_done(&opt);
131         diff_tree_oid(base, remote, "", &opt);
132         diffcore_std(&opt);
133
134         changes = xcalloc(diff_queued_diff.nr, sizeof(struct notes_merge_pair));
135
136         for (i = 0; i < diff_queued_diff.nr; i++) {
137                 struct diff_filepair *p = diff_queued_diff.queue[i];
138                 struct notes_merge_pair *mp;
139                 int occupied;
140                 struct object_id obj;
141
142                 if (verify_notes_filepair(p, &obj)) {
143                         trace_printf("\t\tCannot merge entry '%s' (%c): "
144                                "%.7s -> %.7s. Skipping!\n", p->one->path,
145                                p->status, oid_to_hex(&p->one->oid),
146                                oid_to_hex(&p->two->oid));
147                         continue;
148                 }
149                 mp = find_notes_merge_pair_pos(changes, len, &obj, 1, &occupied);
150                 if (occupied) {
151                         /* We've found an addition/deletion pair */
152                         assert(!oidcmp(&mp->obj, &obj));
153                         if (is_null_oid(&p->one->oid)) { /* addition */
154                                 assert(is_null_oid(&mp->remote));
155                                 oidcpy(&mp->remote, &p->two->oid);
156                         } else if (is_null_oid(&p->two->oid)) { /* deletion */
157                                 assert(is_null_oid(&mp->base));
158                                 oidcpy(&mp->base, &p->one->oid);
159                         } else
160                                 assert(!"Invalid existing change recorded");
161                 } else {
162                         oidcpy(&mp->obj, &obj);
163                         oidcpy(&mp->base, &p->one->oid);
164                         oidcpy(&mp->local, &uninitialized);
165                         oidcpy(&mp->remote, &p->two->oid);
166                         len++;
167                 }
168                 trace_printf("\t\tStored remote change for %s: %.7s -> %.7s\n",
169                        oid_to_hex(&mp->obj), oid_to_hex(&mp->base),
170                        oid_to_hex(&mp->remote));
171         }
172         diff_flush(&opt);
173         clear_pathspec(&opt.pathspec);
174
175         *num_changes = len;
176         return changes;
177 }
178
179 static void diff_tree_local(struct notes_merge_options *o,
180                             struct notes_merge_pair *changes, int len,
181                             const struct object_id *base,
182                             const struct object_id *local)
183 {
184         struct diff_options opt;
185         int i;
186
187         trace_printf("\tdiff_tree_local(len = %i, base = %.7s, local = %.7s)\n",
188                len, oid_to_hex(base), oid_to_hex(local));
189
190         diff_setup(&opt);
191         opt.flags.recursive = 1;
192         opt.output_format = DIFF_FORMAT_NO_OUTPUT;
193         diff_setup_done(&opt);
194         diff_tree_oid(base, local, "", &opt);
195         diffcore_std(&opt);
196
197         for (i = 0; i < diff_queued_diff.nr; i++) {
198                 struct diff_filepair *p = diff_queued_diff.queue[i];
199                 struct notes_merge_pair *mp;
200                 int match;
201                 struct object_id obj;
202
203                 if (verify_notes_filepair(p, &obj)) {
204                         trace_printf("\t\tCannot merge entry '%s' (%c): "
205                                "%.7s -> %.7s. Skipping!\n", p->one->path,
206                                p->status, oid_to_hex(&p->one->oid),
207                                oid_to_hex(&p->two->oid));
208                         continue;
209                 }
210                 mp = find_notes_merge_pair_pos(changes, len, &obj, 0, &match);
211                 if (!match) {
212                         trace_printf("\t\tIgnoring local-only change for %s: "
213                                "%.7s -> %.7s\n", oid_to_hex(&obj),
214                                oid_to_hex(&p->one->oid),
215                                oid_to_hex(&p->two->oid));
216                         continue;
217                 }
218
219                 assert(!oidcmp(&mp->obj, &obj));
220                 if (is_null_oid(&p->two->oid)) { /* deletion */
221                         /*
222                          * Either this is a true deletion (1), or it is part
223                          * of an A/D pair (2), or D/A pair (3):
224                          *
225                          * (1) mp->local is uninitialized; set it to null_sha1
226                          * (2) mp->local is not uninitialized; don't touch it
227                          * (3) mp->local is uninitialized; set it to null_sha1
228                          *     (will be overwritten by following addition)
229                          */
230                         if (!oidcmp(&mp->local, &uninitialized))
231                                 oidclr(&mp->local);
232                 } else if (is_null_oid(&p->one->oid)) { /* addition */
233                         /*
234                          * Either this is a true addition (1), or it is part
235                          * of an A/D pair (2), or D/A pair (3):
236                          *
237                          * (1) mp->local is uninitialized; set to p->two->sha1
238                          * (2) mp->local is uninitialized; set to p->two->sha1
239                          * (3) mp->local is null_sha1;     set to p->two->sha1
240                          */
241                         assert(is_null_oid(&mp->local) ||
242                                !oidcmp(&mp->local, &uninitialized));
243                         oidcpy(&mp->local, &p->two->oid);
244                 } else { /* modification */
245                         /*
246                          * This is a true modification. p->one->sha1 shall
247                          * match mp->base, and mp->local shall be uninitialized.
248                          * Set mp->local to p->two->sha1.
249                          */
250                         assert(!oidcmp(&p->one->oid, &mp->base));
251                         assert(!oidcmp(&mp->local, &uninitialized));
252                         oidcpy(&mp->local, &p->two->oid);
253                 }
254                 trace_printf("\t\tStored local change for %s: %.7s -> %.7s\n",
255                        oid_to_hex(&mp->obj), oid_to_hex(&mp->base),
256                        oid_to_hex(&mp->local));
257         }
258         diff_flush(&opt);
259         clear_pathspec(&opt.pathspec);
260 }
261
262 static void check_notes_merge_worktree(struct notes_merge_options *o)
263 {
264         if (!o->has_worktree) {
265                 /*
266                  * Must establish NOTES_MERGE_WORKTREE.
267                  * Abort if NOTES_MERGE_WORKTREE already exists
268                  */
269                 if (file_exists(git_path(NOTES_MERGE_WORKTREE)) &&
270                     !is_empty_dir(git_path(NOTES_MERGE_WORKTREE))) {
271                         if (advice_resolve_conflict)
272                                 die(_("You have not concluded your previous "
273                                     "notes merge (%s exists).\nPlease, use "
274                                     "'git notes merge --commit' or 'git notes "
275                                     "merge --abort' to commit/abort the "
276                                     "previous merge before you start a new "
277                                     "notes merge."), git_path("NOTES_MERGE_*"));
278                         else
279                                 die(_("You have not concluded your notes merge "
280                                     "(%s exists)."), git_path("NOTES_MERGE_*"));
281                 }
282
283                 if (safe_create_leading_directories_const(git_path(
284                                 NOTES_MERGE_WORKTREE "/.test")))
285                         die_errno("unable to create directory %s",
286                                   git_path(NOTES_MERGE_WORKTREE));
287                 o->has_worktree = 1;
288         } else if (!file_exists(git_path(NOTES_MERGE_WORKTREE)))
289                 /* NOTES_MERGE_WORKTREE should already be established */
290                 die("missing '%s'. This should not happen",
291                     git_path(NOTES_MERGE_WORKTREE));
292 }
293
294 static void write_buf_to_worktree(const struct object_id *obj,
295                                   const char *buf, unsigned long size)
296 {
297         int fd;
298         char *path = git_pathdup(NOTES_MERGE_WORKTREE "/%s", oid_to_hex(obj));
299         if (safe_create_leading_directories_const(path))
300                 die_errno("unable to create directory for '%s'", path);
301
302         fd = xopen(path, O_WRONLY | O_EXCL | O_CREAT, 0666);
303
304         while (size > 0) {
305                 ssize_t ret = write_in_full(fd, buf, size);
306                 if (ret < 0) {
307                         /* Ignore epipe */
308                         if (errno == EPIPE)
309                                 break;
310                         die_errno("notes-merge");
311                 }
312                 size -= ret;
313                 buf += ret;
314         }
315
316         close(fd);
317         free(path);
318 }
319
320 static void write_note_to_worktree(const struct object_id *obj,
321                                    const struct object_id *note)
322 {
323         enum object_type type;
324         unsigned long size;
325         void *buf = read_object_file(note, &type, &size);
326
327         if (!buf)
328                 die("cannot read note %s for object %s",
329                     oid_to_hex(note), oid_to_hex(obj));
330         if (type != OBJ_BLOB)
331                 die("blob expected in note %s for object %s",
332                     oid_to_hex(note), oid_to_hex(obj));
333         write_buf_to_worktree(obj, buf, size);
334         free(buf);
335 }
336
337 static int ll_merge_in_worktree(struct notes_merge_options *o,
338                                 struct notes_merge_pair *p)
339 {
340         mmbuffer_t result_buf;
341         mmfile_t base, local, remote;
342         int status;
343
344         read_mmblob(&base, &p->base);
345         read_mmblob(&local, &p->local);
346         read_mmblob(&remote, &p->remote);
347
348         status = ll_merge(&result_buf, oid_to_hex(&p->obj), &base, NULL,
349                           &local, o->local_ref, &remote, o->remote_ref, NULL);
350
351         free(base.ptr);
352         free(local.ptr);
353         free(remote.ptr);
354
355         if ((status < 0) || !result_buf.ptr)
356                 die("Failed to execute internal merge");
357
358         write_buf_to_worktree(&p->obj, result_buf.ptr, result_buf.size);
359         free(result_buf.ptr);
360
361         return status;
362 }
363
364 static int merge_one_change_manual(struct notes_merge_options *o,
365                                    struct notes_merge_pair *p,
366                                    struct notes_tree *t)
367 {
368         const char *lref = o->local_ref ? o->local_ref : "local version";
369         const char *rref = o->remote_ref ? o->remote_ref : "remote version";
370
371         trace_printf("\t\t\tmerge_one_change_manual(obj = %.7s, base = %.7s, "
372                "local = %.7s, remote = %.7s)\n",
373                oid_to_hex(&p->obj), oid_to_hex(&p->base),
374                oid_to_hex(&p->local), oid_to_hex(&p->remote));
375
376         /* add "Conflicts:" section to commit message first time through */
377         if (!o->has_worktree)
378                 strbuf_addstr(&(o->commit_msg), "\n\nConflicts:\n");
379
380         strbuf_addf(&(o->commit_msg), "\t%s\n", oid_to_hex(&p->obj));
381
382         if (o->verbosity >= 2)
383                 printf("Auto-merging notes for %s\n", oid_to_hex(&p->obj));
384         check_notes_merge_worktree(o);
385         if (is_null_oid(&p->local)) {
386                 /* D/F conflict, checkout p->remote */
387                 assert(!is_null_oid(&p->remote));
388                 if (o->verbosity >= 1)
389                         printf("CONFLICT (delete/modify): Notes for object %s "
390                                 "deleted in %s and modified in %s. Version from %s "
391                                 "left in tree.\n",
392                                 oid_to_hex(&p->obj), lref, rref, rref);
393                 write_note_to_worktree(&p->obj, &p->remote);
394         } else if (is_null_oid(&p->remote)) {
395                 /* D/F conflict, checkout p->local */
396                 assert(!is_null_oid(&p->local));
397                 if (o->verbosity >= 1)
398                         printf("CONFLICT (delete/modify): Notes for object %s "
399                                 "deleted in %s and modified in %s. Version from %s "
400                                 "left in tree.\n",
401                                 oid_to_hex(&p->obj), rref, lref, lref);
402                 write_note_to_worktree(&p->obj, &p->local);
403         } else {
404                 /* "regular" conflict, checkout result of ll_merge() */
405                 const char *reason = "content";
406                 if (is_null_oid(&p->base))
407                         reason = "add/add";
408                 assert(!is_null_oid(&p->local));
409                 assert(!is_null_oid(&p->remote));
410                 if (o->verbosity >= 1)
411                         printf("CONFLICT (%s): Merge conflict in notes for "
412                                 "object %s\n", reason,
413                                 oid_to_hex(&p->obj));
414                 ll_merge_in_worktree(o, p);
415         }
416
417         trace_printf("\t\t\tremoving from partial merge result\n");
418         remove_note(t, p->obj.hash);
419
420         return 1;
421 }
422
423 static int merge_one_change(struct notes_merge_options *o,
424                             struct notes_merge_pair *p, struct notes_tree *t)
425 {
426         /*
427          * Return 0 if change is successfully resolved (stored in notes_tree).
428          * Return 1 is change results in a conflict (NOT stored in notes_tree,
429          * but instead written to NOTES_MERGE_WORKTREE with conflict markers).
430          */
431         switch (o->strategy) {
432         case NOTES_MERGE_RESOLVE_MANUAL:
433                 return merge_one_change_manual(o, p, t);
434         case NOTES_MERGE_RESOLVE_OURS:
435                 if (o->verbosity >= 2)
436                         printf("Using local notes for %s\n",
437                                                 oid_to_hex(&p->obj));
438                 /* nothing to do */
439                 return 0;
440         case NOTES_MERGE_RESOLVE_THEIRS:
441                 if (o->verbosity >= 2)
442                         printf("Using remote notes for %s\n",
443                                                 oid_to_hex(&p->obj));
444                 if (add_note(t, &p->obj, &p->remote, combine_notes_overwrite))
445                         BUG("combine_notes_overwrite failed");
446                 return 0;
447         case NOTES_MERGE_RESOLVE_UNION:
448                 if (o->verbosity >= 2)
449                         printf("Concatenating local and remote notes for %s\n",
450                                                         oid_to_hex(&p->obj));
451                 if (add_note(t, &p->obj, &p->remote, combine_notes_concatenate))
452                         die("failed to concatenate notes "
453                             "(combine_notes_concatenate)");
454                 return 0;
455         case NOTES_MERGE_RESOLVE_CAT_SORT_UNIQ:
456                 if (o->verbosity >= 2)
457                         printf("Concatenating unique lines in local and remote "
458                                 "notes for %s\n", oid_to_hex(&p->obj));
459                 if (add_note(t, &p->obj, &p->remote, combine_notes_cat_sort_uniq))
460                         die("failed to concatenate notes "
461                             "(combine_notes_cat_sort_uniq)");
462                 return 0;
463         }
464         die("Unknown strategy (%i).", o->strategy);
465 }
466
467 static int merge_changes(struct notes_merge_options *o,
468                          struct notes_merge_pair *changes, int *num_changes,
469                          struct notes_tree *t)
470 {
471         int i, conflicts = 0;
472
473         trace_printf("\tmerge_changes(num_changes = %i)\n", *num_changes);
474         for (i = 0; i < *num_changes; i++) {
475                 struct notes_merge_pair *p = changes + i;
476                 trace_printf("\t\t%.7s: %.7s -> %.7s/%.7s\n",
477                        oid_to_hex(&p->obj), oid_to_hex(&p->base),
478                        oid_to_hex(&p->local),
479                        oid_to_hex(&p->remote));
480
481                 if (!oidcmp(&p->base, &p->remote)) {
482                         /* no remote change; nothing to do */
483                         trace_printf("\t\t\tskipping (no remote change)\n");
484                 } else if (!oidcmp(&p->local, &p->remote)) {
485                         /* same change in local and remote; nothing to do */
486                         trace_printf("\t\t\tskipping (local == remote)\n");
487                 } else if (!oidcmp(&p->local, &uninitialized) ||
488                            !oidcmp(&p->local, &p->base)) {
489                         /* no local change; adopt remote change */
490                         trace_printf("\t\t\tno local change, adopted remote\n");
491                         if (add_note(t, &p->obj, &p->remote,
492                                      combine_notes_overwrite))
493                                 BUG("combine_notes_overwrite failed");
494                 } else {
495                         /* need file-level merge between local and remote */
496                         trace_printf("\t\t\tneed content-level merge\n");
497                         conflicts += merge_one_change(o, p, t);
498                 }
499         }
500
501         return conflicts;
502 }
503
504 static int merge_from_diffs(struct notes_merge_options *o,
505                             const struct object_id *base,
506                             const struct object_id *local,
507                             const struct object_id *remote,
508                             struct notes_tree *t)
509 {
510         struct notes_merge_pair *changes;
511         int num_changes, conflicts;
512
513         trace_printf("\tmerge_from_diffs(base = %.7s, local = %.7s, "
514                "remote = %.7s)\n", oid_to_hex(base), oid_to_hex(local),
515                oid_to_hex(remote));
516
517         changes = diff_tree_remote(o, base, remote, &num_changes);
518         diff_tree_local(o, changes, num_changes, base, local);
519
520         conflicts = merge_changes(o, changes, &num_changes, t);
521         free(changes);
522
523         if (o->verbosity >= 4)
524                 printf(t->dirty ?
525                        "Merge result: %i unmerged notes and a dirty notes tree\n" :
526                        "Merge result: %i unmerged notes and a clean notes tree\n",
527                        conflicts);
528
529         return conflicts ? -1 : 1;
530 }
531
532 int notes_merge(struct notes_merge_options *o,
533                 struct notes_tree *local_tree,
534                 struct object_id *result_oid)
535 {
536         struct object_id local_oid, remote_oid;
537         struct commit *local, *remote;
538         struct commit_list *bases = NULL;
539         const struct object_id *base_oid, *base_tree_oid;
540         int result = 0;
541
542         assert(o->local_ref && o->remote_ref);
543         assert(!strcmp(o->local_ref, local_tree->ref));
544         oidclr(result_oid);
545
546         trace_printf("notes_merge(o->local_ref = %s, o->remote_ref = %s)\n",
547                o->local_ref, o->remote_ref);
548
549         /* Dereference o->local_ref into local_sha1 */
550         if (read_ref_full(o->local_ref, 0, &local_oid, NULL))
551                 die("Failed to resolve local notes ref '%s'", o->local_ref);
552         else if (!check_refname_format(o->local_ref, 0) &&
553                 is_null_oid(&local_oid))
554                 local = NULL; /* local_oid == null_oid indicates unborn ref */
555         else if (!(local = lookup_commit_reference(&local_oid)))
556                 die("Could not parse local commit %s (%s)",
557                     oid_to_hex(&local_oid), o->local_ref);
558         trace_printf("\tlocal commit: %.7s\n", oid_to_hex(&local_oid));
559
560         /* Dereference o->remote_ref into remote_oid */
561         if (get_oid(o->remote_ref, &remote_oid)) {
562                 /*
563                  * Failed to get remote_oid. If o->remote_ref looks like an
564                  * unborn ref, perform the merge using an empty notes tree.
565                  */
566                 if (!check_refname_format(o->remote_ref, 0)) {
567                         oidclr(&remote_oid);
568                         remote = NULL;
569                 } else {
570                         die("Failed to resolve remote notes ref '%s'",
571                             o->remote_ref);
572                 }
573         } else if (!(remote = lookup_commit_reference(&remote_oid))) {
574                 die("Could not parse remote commit %s (%s)",
575                     oid_to_hex(&remote_oid), o->remote_ref);
576         }
577         trace_printf("\tremote commit: %.7s\n", oid_to_hex(&remote_oid));
578
579         if (!local && !remote)
580                 die("Cannot merge empty notes ref (%s) into empty notes ref "
581                     "(%s)", o->remote_ref, o->local_ref);
582         if (!local) {
583                 /* result == remote commit */
584                 oidcpy(result_oid, &remote_oid);
585                 goto found_result;
586         }
587         if (!remote) {
588                 /* result == local commit */
589                 oidcpy(result_oid, &local_oid);
590                 goto found_result;
591         }
592         assert(local && remote);
593
594         /* Find merge bases */
595         bases = get_merge_bases(local, remote);
596         if (!bases) {
597                 base_oid = &null_oid;
598                 base_tree_oid = the_hash_algo->empty_tree;
599                 if (o->verbosity >= 4)
600                         printf("No merge base found; doing history-less merge\n");
601         } else if (!bases->next) {
602                 base_oid = &bases->item->object.oid;
603                 base_tree_oid = get_commit_tree_oid(bases->item);
604                 if (o->verbosity >= 4)
605                         printf("One merge base found (%.7s)\n",
606                                oid_to_hex(base_oid));
607         } else {
608                 /* TODO: How to handle multiple merge-bases? */
609                 base_oid = &bases->item->object.oid;
610                 base_tree_oid = get_commit_tree_oid(bases->item);
611                 if (o->verbosity >= 3)
612                         printf("Multiple merge bases found. Using the first "
613                                 "(%.7s)\n", oid_to_hex(base_oid));
614         }
615
616         if (o->verbosity >= 4)
617                 printf("Merging remote commit %.7s into local commit %.7s with "
618                         "merge-base %.7s\n", oid_to_hex(&remote->object.oid),
619                         oid_to_hex(&local->object.oid),
620                         oid_to_hex(base_oid));
621
622         if (!oidcmp(&remote->object.oid, base_oid)) {
623                 /* Already merged; result == local commit */
624                 if (o->verbosity >= 2)
625                         printf("Already up to date!\n");
626                 oidcpy(result_oid, &local->object.oid);
627                 goto found_result;
628         }
629         if (!oidcmp(&local->object.oid, base_oid)) {
630                 /* Fast-forward; result == remote commit */
631                 if (o->verbosity >= 2)
632                         printf("Fast-forward\n");
633                 oidcpy(result_oid, &remote->object.oid);
634                 goto found_result;
635         }
636
637         result = merge_from_diffs(o, base_tree_oid,
638                                   get_commit_tree_oid(local),
639                                   get_commit_tree_oid(remote), local_tree);
640
641         if (result != 0) { /* non-trivial merge (with or without conflicts) */
642                 /* Commit (partial) result */
643                 struct commit_list *parents = NULL;
644                 commit_list_insert(remote, &parents); /* LIFO order */
645                 commit_list_insert(local, &parents);
646                 create_notes_commit(local_tree, parents, o->commit_msg.buf,
647                                     o->commit_msg.len, result_oid);
648         }
649
650 found_result:
651         free_commit_list(bases);
652         strbuf_release(&(o->commit_msg));
653         trace_printf("notes_merge(): result = %i, result_oid = %.7s\n",
654                result, oid_to_hex(result_oid));
655         return result;
656 }
657
658 int notes_merge_commit(struct notes_merge_options *o,
659                        struct notes_tree *partial_tree,
660                        struct commit *partial_commit,
661                        struct object_id *result_oid)
662 {
663         /*
664          * Iterate through files in .git/NOTES_MERGE_WORKTREE and add all
665          * found notes to 'partial_tree'. Write the updated notes tree to
666          * the DB, and commit the resulting tree object while reusing the
667          * commit message and parents from 'partial_commit'.
668          * Finally store the new commit object OID into 'result_oid'.
669          */
670         DIR *dir;
671         struct dirent *e;
672         struct strbuf path = STRBUF_INIT;
673         const char *buffer = get_commit_buffer(partial_commit, NULL);
674         const char *msg = strstr(buffer, "\n\n");
675         int baselen;
676
677         git_path_buf(&path, NOTES_MERGE_WORKTREE);
678         if (o->verbosity >= 3)
679                 printf("Committing notes in notes merge worktree at %s\n",
680                         path.buf);
681
682         if (!msg || msg[2] == '\0')
683                 die("partial notes commit has empty message");
684         msg += 2;
685
686         dir = opendir(path.buf);
687         if (!dir)
688                 die_errno("could not open %s", path.buf);
689
690         strbuf_addch(&path, '/');
691         baselen = path.len;
692         while ((e = readdir(dir)) != NULL) {
693                 struct stat st;
694                 struct object_id obj_oid, blob_oid;
695
696                 if (is_dot_or_dotdot(e->d_name))
697                         continue;
698
699                 if (get_oid_hex(e->d_name, &obj_oid)) {
700                         if (o->verbosity >= 3)
701                                 printf("Skipping non-SHA1 entry '%s%s'\n",
702                                         path.buf, e->d_name);
703                         continue;
704                 }
705
706                 strbuf_addstr(&path, e->d_name);
707                 /* write file as blob, and add to partial_tree */
708                 if (stat(path.buf, &st))
709                         die_errno("Failed to stat '%s'", path.buf);
710                 if (index_path(&blob_oid, path.buf, &st, HASH_WRITE_OBJECT))
711                         die("Failed to write blob object from '%s'", path.buf);
712                 if (add_note(partial_tree, &obj_oid, &blob_oid, NULL))
713                         die("Failed to add resolved note '%s' to notes tree",
714                             path.buf);
715                 if (o->verbosity >= 4)
716                         printf("Added resolved note for object %s: %s\n",
717                                 oid_to_hex(&obj_oid), oid_to_hex(&blob_oid));
718                 strbuf_setlen(&path, baselen);
719         }
720
721         create_notes_commit(partial_tree, partial_commit->parents, msg,
722                             strlen(msg), result_oid);
723         unuse_commit_buffer(partial_commit, buffer);
724         if (o->verbosity >= 4)
725                 printf("Finalized notes merge commit: %s\n",
726                         oid_to_hex(result_oid));
727         strbuf_release(&path);
728         closedir(dir);
729         return 0;
730 }
731
732 int notes_merge_abort(struct notes_merge_options *o)
733 {
734         /*
735          * Remove all files within .git/NOTES_MERGE_WORKTREE. We do not remove
736          * the .git/NOTES_MERGE_WORKTREE directory itself, since it might be
737          * the current working directory of the user.
738          */
739         struct strbuf buf = STRBUF_INIT;
740         int ret;
741
742         git_path_buf(&buf, NOTES_MERGE_WORKTREE);
743         if (o->verbosity >= 3)
744                 printf("Removing notes merge worktree at %s/*\n", buf.buf);
745         ret = remove_dir_recursively(&buf, REMOVE_DIR_KEEP_TOPLEVEL);
746         strbuf_release(&buf);
747         return ret;
748 }