reset: add t7112 for submodule updates
[git] / merge-recursive.c
1 /*
2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
3  * Fredrik Kuivinen.
4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
5  */
6 #include "advice.h"
7 #include "cache.h"
8 #include "cache-tree.h"
9 #include "commit.h"
10 #include "blob.h"
11 #include "builtin.h"
12 #include "tree-walk.h"
13 #include "diff.h"
14 #include "diffcore.h"
15 #include "tag.h"
16 #include "unpack-trees.h"
17 #include "string-list.h"
18 #include "xdiff-interface.h"
19 #include "ll-merge.h"
20 #include "attr.h"
21 #include "merge-recursive.h"
22 #include "dir.h"
23 #include "submodule.h"
24
25 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
26                                       const char *subtree_shift)
27 {
28         unsigned char shifted[20];
29
30         if (!*subtree_shift) {
31                 shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
32         } else {
33                 shift_tree_by(one->object.sha1, two->object.sha1, shifted,
34                               subtree_shift);
35         }
36         if (!hashcmp(two->object.sha1, shifted))
37                 return two;
38         return lookup_tree(shifted);
39 }
40
41 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
42 {
43         struct commit *commit = xcalloc(1, sizeof(struct commit));
44         struct merge_remote_desc *desc = xmalloc(sizeof(*desc));
45
46         desc->name = comment;
47         desc->obj = (struct object *)commit;
48         commit->tree = tree;
49         commit->util = desc;
50         commit->object.parsed = 1;
51         return commit;
52 }
53
54 /*
55  * Since we use get_tree_entry(), which does not put the read object into
56  * the object pool, we cannot rely on a == b.
57  */
58 static int sha_eq(const unsigned char *a, const unsigned char *b)
59 {
60         if (!a && !b)
61                 return 2;
62         return a && b && hashcmp(a, b) == 0;
63 }
64
65 enum rename_type {
66         RENAME_NORMAL = 0,
67         RENAME_DELETE,
68         RENAME_ONE_FILE_TO_ONE,
69         RENAME_ONE_FILE_TO_TWO,
70         RENAME_TWO_FILES_TO_ONE
71 };
72
73 struct rename_conflict_info {
74         enum rename_type rename_type;
75         struct diff_filepair *pair1;
76         struct diff_filepair *pair2;
77         const char *branch1;
78         const char *branch2;
79         struct stage_data *dst_entry1;
80         struct stage_data *dst_entry2;
81         struct diff_filespec ren1_other;
82         struct diff_filespec ren2_other;
83 };
84
85 /*
86  * Since we want to write the index eventually, we cannot reuse the index
87  * for these (temporary) data.
88  */
89 struct stage_data {
90         struct {
91                 unsigned mode;
92                 unsigned char sha[20];
93         } stages[4];
94         struct rename_conflict_info *rename_conflict_info;
95         unsigned processed:1;
96 };
97
98 static inline void setup_rename_conflict_info(enum rename_type rename_type,
99                                               struct diff_filepair *pair1,
100                                               struct diff_filepair *pair2,
101                                               const char *branch1,
102                                               const char *branch2,
103                                               struct stage_data *dst_entry1,
104                                               struct stage_data *dst_entry2,
105                                               struct merge_options *o,
106                                               struct stage_data *src_entry1,
107                                               struct stage_data *src_entry2)
108 {
109         struct rename_conflict_info *ci = xcalloc(1, sizeof(struct rename_conflict_info));
110         ci->rename_type = rename_type;
111         ci->pair1 = pair1;
112         ci->branch1 = branch1;
113         ci->branch2 = branch2;
114
115         ci->dst_entry1 = dst_entry1;
116         dst_entry1->rename_conflict_info = ci;
117         dst_entry1->processed = 0;
118
119         assert(!pair2 == !dst_entry2);
120         if (dst_entry2) {
121                 ci->dst_entry2 = dst_entry2;
122                 ci->pair2 = pair2;
123                 dst_entry2->rename_conflict_info = ci;
124         }
125
126         if (rename_type == RENAME_TWO_FILES_TO_ONE) {
127                 /*
128                  * For each rename, there could have been
129                  * modifications on the side of history where that
130                  * file was not renamed.
131                  */
132                 int ostage1 = o->branch1 == branch1 ? 3 : 2;
133                 int ostage2 = ostage1 ^ 1;
134
135                 ci->ren1_other.path = pair1->one->path;
136                 hashcpy(ci->ren1_other.sha1, src_entry1->stages[ostage1].sha);
137                 ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
138
139                 ci->ren2_other.path = pair2->one->path;
140                 hashcpy(ci->ren2_other.sha1, src_entry2->stages[ostage2].sha);
141                 ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
142         }
143 }
144
145 static int show(struct merge_options *o, int v)
146 {
147         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
148 }
149
150 static void flush_output(struct merge_options *o)
151 {
152         if (o->obuf.len) {
153                 fputs(o->obuf.buf, stdout);
154                 strbuf_reset(&o->obuf);
155         }
156 }
157
158 __attribute__((format (printf, 3, 4)))
159 static void output(struct merge_options *o, int v, const char *fmt, ...)
160 {
161         va_list ap;
162
163         if (!show(o, v))
164                 return;
165
166         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
167         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
168         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
169
170         va_start(ap, fmt);
171         strbuf_vaddf(&o->obuf, fmt, ap);
172         va_end(ap);
173
174         strbuf_add(&o->obuf, "\n", 1);
175         if (!o->buffer_output)
176                 flush_output(o);
177 }
178
179 static void output_commit_title(struct merge_options *o, struct commit *commit)
180 {
181         int i;
182         flush_output(o);
183         for (i = o->call_depth; i--;)
184                 fputs("  ", stdout);
185         if (commit->util)
186                 printf("virtual %s\n", merge_remote_util(commit)->name);
187         else {
188                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
189                 if (parse_commit(commit) != 0)
190                         printf(_("(bad commit)\n"));
191                 else {
192                         const char *title;
193                         int len = find_commit_subject(commit->buffer, &title);
194                         if (len)
195                                 printf("%.*s\n", len, title);
196                 }
197         }
198 }
199
200 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
201                 const char *path, int stage, int refresh, int options)
202 {
203         struct cache_entry *ce;
204         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage,
205                               (refresh ? (CE_MATCH_REFRESH |
206                                           CE_MATCH_IGNORE_MISSING) : 0 ));
207         if (!ce)
208                 return error(_("addinfo_cache failed for path '%s'"), path);
209         return add_cache_entry(ce, options);
210 }
211
212 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
213 {
214         parse_tree(tree);
215         init_tree_desc(desc, tree->buffer, tree->size);
216 }
217
218 static int git_merge_trees(int index_only,
219                            struct tree *common,
220                            struct tree *head,
221                            struct tree *merge)
222 {
223         int rc;
224         struct tree_desc t[3];
225         struct unpack_trees_options opts;
226
227         memset(&opts, 0, sizeof(opts));
228         if (index_only)
229                 opts.index_only = 1;
230         else
231                 opts.update = 1;
232         opts.merge = 1;
233         opts.head_idx = 2;
234         opts.fn = threeway_merge;
235         opts.src_index = &the_index;
236         opts.dst_index = &the_index;
237         setup_unpack_trees_porcelain(&opts, "merge");
238
239         init_tree_desc_from_tree(t+0, common);
240         init_tree_desc_from_tree(t+1, head);
241         init_tree_desc_from_tree(t+2, merge);
242
243         rc = unpack_trees(3, t, &opts);
244         cache_tree_free(&active_cache_tree);
245         return rc;
246 }
247
248 struct tree *write_tree_from_memory(struct merge_options *o)
249 {
250         struct tree *result = NULL;
251
252         if (unmerged_cache()) {
253                 int i;
254                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
255                 for (i = 0; i < active_nr; i++) {
256                         const struct cache_entry *ce = active_cache[i];
257                         if (ce_stage(ce))
258                                 fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
259                                         (int)ce_namelen(ce), ce->name);
260                 }
261                 die("Bug in merge-recursive.c");
262         }
263
264         if (!active_cache_tree)
265                 active_cache_tree = cache_tree();
266
267         if (!cache_tree_fully_valid(active_cache_tree) &&
268             cache_tree_update(active_cache_tree,
269                               (const struct cache_entry * const *)active_cache,
270                               active_nr, 0) < 0)
271                 die(_("error building trees"));
272
273         result = lookup_tree(active_cache_tree->sha1);
274
275         return result;
276 }
277
278 static int save_files_dirs(const unsigned char *sha1,
279                 const char *base, int baselen, const char *path,
280                 unsigned int mode, int stage, void *context)
281 {
282         int len = strlen(path);
283         char *newpath = xmalloc(baselen + len + 1);
284         struct merge_options *o = context;
285
286         memcpy(newpath, base, baselen);
287         memcpy(newpath + baselen, path, len);
288         newpath[baselen + len] = '\0';
289
290         if (S_ISDIR(mode))
291                 string_list_insert(&o->current_directory_set, newpath);
292         else
293                 string_list_insert(&o->current_file_set, newpath);
294         free(newpath);
295
296         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
297 }
298
299 static int get_files_dirs(struct merge_options *o, struct tree *tree)
300 {
301         int n;
302         struct pathspec match_all;
303         memset(&match_all, 0, sizeof(match_all));
304         if (read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o))
305                 return 0;
306         n = o->current_file_set.nr + o->current_directory_set.nr;
307         return n;
308 }
309
310 /*
311  * Returns an index_entry instance which doesn't have to correspond to
312  * a real cache entry in Git's index.
313  */
314 static struct stage_data *insert_stage_data(const char *path,
315                 struct tree *o, struct tree *a, struct tree *b,
316                 struct string_list *entries)
317 {
318         struct string_list_item *item;
319         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
320         get_tree_entry(o->object.sha1, path,
321                         e->stages[1].sha, &e->stages[1].mode);
322         get_tree_entry(a->object.sha1, path,
323                         e->stages[2].sha, &e->stages[2].mode);
324         get_tree_entry(b->object.sha1, path,
325                         e->stages[3].sha, &e->stages[3].mode);
326         item = string_list_insert(entries, path);
327         item->util = e;
328         return e;
329 }
330
331 /*
332  * Create a dictionary mapping file names to stage_data objects. The
333  * dictionary contains one entry for every path with a non-zero stage entry.
334  */
335 static struct string_list *get_unmerged(void)
336 {
337         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
338         int i;
339
340         unmerged->strdup_strings = 1;
341
342         for (i = 0; i < active_nr; i++) {
343                 struct string_list_item *item;
344                 struct stage_data *e;
345                 const struct cache_entry *ce = active_cache[i];
346                 if (!ce_stage(ce))
347                         continue;
348
349                 item = string_list_lookup(unmerged, ce->name);
350                 if (!item) {
351                         item = string_list_insert(unmerged, ce->name);
352                         item->util = xcalloc(1, sizeof(struct stage_data));
353                 }
354                 e = item->util;
355                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
356                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
357         }
358
359         return unmerged;
360 }
361
362 static int string_list_df_name_compare(const void *a, const void *b)
363 {
364         const struct string_list_item *one = a;
365         const struct string_list_item *two = b;
366         int onelen = strlen(one->string);
367         int twolen = strlen(two->string);
368         /*
369          * Here we only care that entries for D/F conflicts are
370          * adjacent, in particular with the file of the D/F conflict
371          * appearing before files below the corresponding directory.
372          * The order of the rest of the list is irrelevant for us.
373          *
374          * To achieve this, we sort with df_name_compare and provide
375          * the mode S_IFDIR so that D/F conflicts will sort correctly.
376          * We use the mode S_IFDIR for everything else for simplicity,
377          * since in other cases any changes in their order due to
378          * sorting cause no problems for us.
379          */
380         int cmp = df_name_compare(one->string, onelen, S_IFDIR,
381                                   two->string, twolen, S_IFDIR);
382         /*
383          * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
384          * that 'foo' comes before 'foo/bar'.
385          */
386         if (cmp)
387                 return cmp;
388         return onelen - twolen;
389 }
390
391 static void record_df_conflict_files(struct merge_options *o,
392                                      struct string_list *entries)
393 {
394         /* If there is a D/F conflict and the file for such a conflict
395          * currently exist in the working tree, we want to allow it to be
396          * removed to make room for the corresponding directory if needed.
397          * The files underneath the directories of such D/F conflicts will
398          * be processed before the corresponding file involved in the D/F
399          * conflict.  If the D/F directory ends up being removed by the
400          * merge, then we won't have to touch the D/F file.  If the D/F
401          * directory needs to be written to the working copy, then the D/F
402          * file will simply be removed (in make_room_for_path()) to make
403          * room for the necessary paths.  Note that if both the directory
404          * and the file need to be present, then the D/F file will be
405          * reinstated with a new unique name at the time it is processed.
406          */
407         struct string_list df_sorted_entries;
408         const char *last_file = NULL;
409         int last_len = 0;
410         int i;
411
412         /*
413          * If we're merging merge-bases, we don't want to bother with
414          * any working directory changes.
415          */
416         if (o->call_depth)
417                 return;
418
419         /* Ensure D/F conflicts are adjacent in the entries list. */
420         memset(&df_sorted_entries, 0, sizeof(struct string_list));
421         for (i = 0; i < entries->nr; i++) {
422                 struct string_list_item *next = &entries->items[i];
423                 string_list_append(&df_sorted_entries, next->string)->util =
424                                    next->util;
425         }
426         qsort(df_sorted_entries.items, entries->nr, sizeof(*entries->items),
427               string_list_df_name_compare);
428
429         string_list_clear(&o->df_conflict_file_set, 1);
430         for (i = 0; i < df_sorted_entries.nr; i++) {
431                 const char *path = df_sorted_entries.items[i].string;
432                 int len = strlen(path);
433                 struct stage_data *e = df_sorted_entries.items[i].util;
434
435                 /*
436                  * Check if last_file & path correspond to a D/F conflict;
437                  * i.e. whether path is last_file+'/'+<something>.
438                  * If so, record that it's okay to remove last_file to make
439                  * room for path and friends if needed.
440                  */
441                 if (last_file &&
442                     len > last_len &&
443                     memcmp(path, last_file, last_len) == 0 &&
444                     path[last_len] == '/') {
445                         string_list_insert(&o->df_conflict_file_set, last_file);
446                 }
447
448                 /*
449                  * Determine whether path could exist as a file in the
450                  * working directory as a possible D/F conflict.  This
451                  * will only occur when it exists in stage 2 as a
452                  * file.
453                  */
454                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
455                         last_file = path;
456                         last_len = len;
457                 } else {
458                         last_file = NULL;
459                 }
460         }
461         string_list_clear(&df_sorted_entries, 0);
462 }
463
464 struct rename {
465         struct diff_filepair *pair;
466         struct stage_data *src_entry;
467         struct stage_data *dst_entry;
468         unsigned processed:1;
469 };
470
471 /*
472  * Get information of all renames which occurred between 'o_tree' and
473  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
474  * 'b_tree') to be able to associate the correct cache entries with
475  * the rename information. 'tree' is always equal to either a_tree or b_tree.
476  */
477 static struct string_list *get_renames(struct merge_options *o,
478                                        struct tree *tree,
479                                        struct tree *o_tree,
480                                        struct tree *a_tree,
481                                        struct tree *b_tree,
482                                        struct string_list *entries)
483 {
484         int i;
485         struct string_list *renames;
486         struct diff_options opts;
487
488         renames = xcalloc(1, sizeof(struct string_list));
489         diff_setup(&opts);
490         DIFF_OPT_SET(&opts, RECURSIVE);
491         DIFF_OPT_CLR(&opts, RENAME_EMPTY);
492         opts.detect_rename = DIFF_DETECT_RENAME;
493         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
494                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
495                             1000;
496         opts.rename_score = o->rename_score;
497         opts.show_rename_progress = o->show_rename_progress;
498         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
499         diff_setup_done(&opts);
500         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
501         diffcore_std(&opts);
502         if (opts.needed_rename_limit > o->needed_rename_limit)
503                 o->needed_rename_limit = opts.needed_rename_limit;
504         for (i = 0; i < diff_queued_diff.nr; ++i) {
505                 struct string_list_item *item;
506                 struct rename *re;
507                 struct diff_filepair *pair = diff_queued_diff.queue[i];
508                 if (pair->status != 'R') {
509                         diff_free_filepair(pair);
510                         continue;
511                 }
512                 re = xmalloc(sizeof(*re));
513                 re->processed = 0;
514                 re->pair = pair;
515                 item = string_list_lookup(entries, re->pair->one->path);
516                 if (!item)
517                         re->src_entry = insert_stage_data(re->pair->one->path,
518                                         o_tree, a_tree, b_tree, entries);
519                 else
520                         re->src_entry = item->util;
521
522                 item = string_list_lookup(entries, re->pair->two->path);
523                 if (!item)
524                         re->dst_entry = insert_stage_data(re->pair->two->path,
525                                         o_tree, a_tree, b_tree, entries);
526                 else
527                         re->dst_entry = item->util;
528                 item = string_list_insert(renames, pair->one->path);
529                 item->util = re;
530         }
531         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
532         diff_queued_diff.nr = 0;
533         diff_flush(&opts);
534         return renames;
535 }
536
537 static int update_stages(const char *path, const struct diff_filespec *o,
538                          const struct diff_filespec *a,
539                          const struct diff_filespec *b)
540 {
541
542         /*
543          * NOTE: It is usually a bad idea to call update_stages on a path
544          * before calling update_file on that same path, since it can
545          * sometimes lead to spurious "refusing to lose untracked file..."
546          * messages from update_file (via make_room_for path via
547          * would_lose_untracked).  Instead, reverse the order of the calls
548          * (executing update_file first and then update_stages).
549          */
550         int clear = 1;
551         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
552         if (clear)
553                 if (remove_file_from_cache(path))
554                         return -1;
555         if (o)
556                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
557                         return -1;
558         if (a)
559                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
560                         return -1;
561         if (b)
562                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
563                         return -1;
564         return 0;
565 }
566
567 static void update_entry(struct stage_data *entry,
568                          struct diff_filespec *o,
569                          struct diff_filespec *a,
570                          struct diff_filespec *b)
571 {
572         entry->processed = 0;
573         entry->stages[1].mode = o->mode;
574         entry->stages[2].mode = a->mode;
575         entry->stages[3].mode = b->mode;
576         hashcpy(entry->stages[1].sha, o->sha1);
577         hashcpy(entry->stages[2].sha, a->sha1);
578         hashcpy(entry->stages[3].sha, b->sha1);
579 }
580
581 static int remove_file(struct merge_options *o, int clean,
582                        const char *path, int no_wd)
583 {
584         int update_cache = o->call_depth || clean;
585         int update_working_directory = !o->call_depth && !no_wd;
586
587         if (update_cache) {
588                 if (remove_file_from_cache(path))
589                         return -1;
590         }
591         if (update_working_directory) {
592                 if (ignore_case) {
593                         struct cache_entry *ce;
594                         ce = cache_file_exists(path, strlen(path), ignore_case);
595                         if (ce && ce_stage(ce) == 0)
596                                 return 0;
597                 }
598                 if (remove_path(path))
599                         return -1;
600         }
601         return 0;
602 }
603
604 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
605 {
606         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
607         int suffix = 0;
608         struct stat st;
609         char *p = newpath + strlen(path);
610         strcpy(newpath, path);
611         *(p++) = '~';
612         strcpy(p, branch);
613         for (; *p; ++p)
614                 if ('/' == *p)
615                         *p = '_';
616         while (string_list_has_string(&o->current_file_set, newpath) ||
617                string_list_has_string(&o->current_directory_set, newpath) ||
618                lstat(newpath, &st) == 0)
619                 sprintf(p, "_%d", suffix++);
620
621         string_list_insert(&o->current_file_set, newpath);
622         return newpath;
623 }
624
625 static int dir_in_way(const char *path, int check_working_copy)
626 {
627         int pos, pathlen = strlen(path);
628         char *dirpath = xmalloc(pathlen + 2);
629         struct stat st;
630
631         strcpy(dirpath, path);
632         dirpath[pathlen] = '/';
633         dirpath[pathlen+1] = '\0';
634
635         pos = cache_name_pos(dirpath, pathlen+1);
636
637         if (pos < 0)
638                 pos = -1 - pos;
639         if (pos < active_nr &&
640             !strncmp(dirpath, active_cache[pos]->name, pathlen+1)) {
641                 free(dirpath);
642                 return 1;
643         }
644
645         free(dirpath);
646         return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode);
647 }
648
649 static int was_tracked(const char *path)
650 {
651         int pos = cache_name_pos(path, strlen(path));
652
653         if (pos < 0)
654                 pos = -1 - pos;
655         while (pos < active_nr &&
656                !strcmp(path, active_cache[pos]->name)) {
657                 /*
658                  * If stage #0, it is definitely tracked.
659                  * If it has stage #2 then it was tracked
660                  * before this merge started.  All other
661                  * cases the path was not tracked.
662                  */
663                 switch (ce_stage(active_cache[pos])) {
664                 case 0:
665                 case 2:
666                         return 1;
667                 }
668                 pos++;
669         }
670         return 0;
671 }
672
673 static int would_lose_untracked(const char *path)
674 {
675         return !was_tracked(path) && file_exists(path);
676 }
677
678 static int make_room_for_path(struct merge_options *o, const char *path)
679 {
680         int status, i;
681         const char *msg = _("failed to create path '%s'%s");
682
683         /* Unlink any D/F conflict files that are in the way */
684         for (i = 0; i < o->df_conflict_file_set.nr; i++) {
685                 const char *df_path = o->df_conflict_file_set.items[i].string;
686                 size_t pathlen = strlen(path);
687                 size_t df_pathlen = strlen(df_path);
688                 if (df_pathlen < pathlen &&
689                     path[df_pathlen] == '/' &&
690                     strncmp(path, df_path, df_pathlen) == 0) {
691                         output(o, 3,
692                                _("Removing %s to make room for subdirectory\n"),
693                                df_path);
694                         unlink(df_path);
695                         unsorted_string_list_delete_item(&o->df_conflict_file_set,
696                                                          i, 0);
697                         break;
698                 }
699         }
700
701         /* Make sure leading directories are created */
702         status = safe_create_leading_directories_const(path);
703         if (status) {
704                 if (status == SCLD_EXISTS) {
705                         /* something else exists */
706                         error(msg, path, _(": perhaps a D/F conflict?"));
707                         return -1;
708                 }
709                 die(msg, path, "");
710         }
711
712         /*
713          * Do not unlink a file in the work tree if we are not
714          * tracking it.
715          */
716         if (would_lose_untracked(path))
717                 return error(_("refusing to lose untracked file at '%s'"),
718                              path);
719
720         /* Successful unlink is good.. */
721         if (!unlink(path))
722                 return 0;
723         /* .. and so is no existing file */
724         if (errno == ENOENT)
725                 return 0;
726         /* .. but not some other error (who really cares what?) */
727         return error(msg, path, _(": perhaps a D/F conflict?"));
728 }
729
730 static void update_file_flags(struct merge_options *o,
731                               const unsigned char *sha,
732                               unsigned mode,
733                               const char *path,
734                               int update_cache,
735                               int update_wd)
736 {
737         if (o->call_depth)
738                 update_wd = 0;
739
740         if (update_wd) {
741                 enum object_type type;
742                 void *buf;
743                 unsigned long size;
744
745                 if (S_ISGITLINK(mode)) {
746                         /*
747                          * We may later decide to recursively descend into
748                          * the submodule directory and update its index
749                          * and/or work tree, but we do not do that now.
750                          */
751                         update_wd = 0;
752                         goto update_index;
753                 }
754
755                 buf = read_sha1_file(sha, &type, &size);
756                 if (!buf)
757                         die(_("cannot read object %s '%s'"), sha1_to_hex(sha), path);
758                 if (type != OBJ_BLOB)
759                         die(_("blob expected for %s '%s'"), sha1_to_hex(sha), path);
760                 if (S_ISREG(mode)) {
761                         struct strbuf strbuf = STRBUF_INIT;
762                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
763                                 free(buf);
764                                 size = strbuf.len;
765                                 buf = strbuf_detach(&strbuf, NULL);
766                         }
767                 }
768
769                 if (make_room_for_path(o, path) < 0) {
770                         update_wd = 0;
771                         free(buf);
772                         goto update_index;
773                 }
774                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
775                         int fd;
776                         if (mode & 0100)
777                                 mode = 0777;
778                         else
779                                 mode = 0666;
780                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
781                         if (fd < 0)
782                                 die_errno(_("failed to open '%s'"), path);
783                         write_in_full(fd, buf, size);
784                         close(fd);
785                 } else if (S_ISLNK(mode)) {
786                         char *lnk = xmemdupz(buf, size);
787                         safe_create_leading_directories_const(path);
788                         unlink(path);
789                         if (symlink(lnk, path))
790                                 die_errno(_("failed to symlink '%s'"), path);
791                         free(lnk);
792                 } else
793                         die(_("do not know what to do with %06o %s '%s'"),
794                             mode, sha1_to_hex(sha), path);
795                 free(buf);
796         }
797  update_index:
798         if (update_cache)
799                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
800 }
801
802 static void update_file(struct merge_options *o,
803                         int clean,
804                         const unsigned char *sha,
805                         unsigned mode,
806                         const char *path)
807 {
808         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
809 }
810
811 /* Low level file merging, update and removal */
812
813 struct merge_file_info {
814         unsigned char sha[20];
815         unsigned mode;
816         unsigned clean:1,
817                  merge:1;
818 };
819
820 static int merge_3way(struct merge_options *o,
821                       mmbuffer_t *result_buf,
822                       const struct diff_filespec *one,
823                       const struct diff_filespec *a,
824                       const struct diff_filespec *b,
825                       const char *branch1,
826                       const char *branch2)
827 {
828         mmfile_t orig, src1, src2;
829         struct ll_merge_options ll_opts = {0};
830         char *base_name, *name1, *name2;
831         int merge_status;
832
833         ll_opts.renormalize = o->renormalize;
834         ll_opts.xdl_opts = o->xdl_opts;
835
836         if (o->call_depth) {
837                 ll_opts.virtual_ancestor = 1;
838                 ll_opts.variant = 0;
839         } else {
840                 switch (o->recursive_variant) {
841                 case MERGE_RECURSIVE_OURS:
842                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
843                         break;
844                 case MERGE_RECURSIVE_THEIRS:
845                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
846                         break;
847                 default:
848                         ll_opts.variant = 0;
849                         break;
850                 }
851         }
852
853         if (strcmp(a->path, b->path) ||
854             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
855                 base_name = o->ancestor == NULL ? NULL :
856                         mkpathdup("%s:%s", o->ancestor, one->path);
857                 name1 = mkpathdup("%s:%s", branch1, a->path);
858                 name2 = mkpathdup("%s:%s", branch2, b->path);
859         } else {
860                 base_name = o->ancestor == NULL ? NULL :
861                         mkpathdup("%s", o->ancestor);
862                 name1 = mkpathdup("%s", branch1);
863                 name2 = mkpathdup("%s", branch2);
864         }
865
866         read_mmblob(&orig, one->sha1);
867         read_mmblob(&src1, a->sha1);
868         read_mmblob(&src2, b->sha1);
869
870         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
871                                 &src1, name1, &src2, name2, &ll_opts);
872
873         free(base_name);
874         free(name1);
875         free(name2);
876         free(orig.ptr);
877         free(src1.ptr);
878         free(src2.ptr);
879         return merge_status;
880 }
881
882 static struct merge_file_info merge_file_1(struct merge_options *o,
883                                            const struct diff_filespec *one,
884                                            const struct diff_filespec *a,
885                                            const struct diff_filespec *b,
886                                            const char *branch1,
887                                            const char *branch2)
888 {
889         struct merge_file_info result;
890         result.merge = 0;
891         result.clean = 1;
892
893         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
894                 result.clean = 0;
895                 if (S_ISREG(a->mode)) {
896                         result.mode = a->mode;
897                         hashcpy(result.sha, a->sha1);
898                 } else {
899                         result.mode = b->mode;
900                         hashcpy(result.sha, b->sha1);
901                 }
902         } else {
903                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
904                         result.merge = 1;
905
906                 /*
907                  * Merge modes
908                  */
909                 if (a->mode == b->mode || a->mode == one->mode)
910                         result.mode = b->mode;
911                 else {
912                         result.mode = a->mode;
913                         if (b->mode != one->mode) {
914                                 result.clean = 0;
915                                 result.merge = 1;
916                         }
917                 }
918
919                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
920                         hashcpy(result.sha, b->sha1);
921                 else if (sha_eq(b->sha1, one->sha1))
922                         hashcpy(result.sha, a->sha1);
923                 else if (S_ISREG(a->mode)) {
924                         mmbuffer_t result_buf;
925                         int merge_status;
926
927                         merge_status = merge_3way(o, &result_buf, one, a, b,
928                                                   branch1, branch2);
929
930                         if ((merge_status < 0) || !result_buf.ptr)
931                                 die(_("Failed to execute internal merge"));
932
933                         if (write_sha1_file(result_buf.ptr, result_buf.size,
934                                             blob_type, result.sha))
935                                 die(_("Unable to add %s to database"),
936                                     a->path);
937
938                         free(result_buf.ptr);
939                         result.clean = (merge_status == 0);
940                 } else if (S_ISGITLINK(a->mode)) {
941                         result.clean = merge_submodule(result.sha,
942                                                        one->path, one->sha1,
943                                                        a->sha1, b->sha1,
944                                                        !o->call_depth);
945                 } else if (S_ISLNK(a->mode)) {
946                         hashcpy(result.sha, a->sha1);
947
948                         if (!sha_eq(a->sha1, b->sha1))
949                                 result.clean = 0;
950                 } else {
951                         die(_("unsupported object type in the tree"));
952                 }
953         }
954
955         return result;
956 }
957
958 static struct merge_file_info
959 merge_file_special_markers(struct merge_options *o,
960                            const struct diff_filespec *one,
961                            const struct diff_filespec *a,
962                            const struct diff_filespec *b,
963                            const char *branch1,
964                            const char *filename1,
965                            const char *branch2,
966                            const char *filename2)
967 {
968         char *side1 = NULL;
969         char *side2 = NULL;
970         struct merge_file_info mfi;
971
972         if (filename1) {
973                 side1 = xmalloc(strlen(branch1) + strlen(filename1) + 2);
974                 sprintf(side1, "%s:%s", branch1, filename1);
975         }
976         if (filename2) {
977                 side2 = xmalloc(strlen(branch2) + strlen(filename2) + 2);
978                 sprintf(side2, "%s:%s", branch2, filename2);
979         }
980
981         mfi = merge_file_1(o, one, a, b,
982                            side1 ? side1 : branch1, side2 ? side2 : branch2);
983         free(side1);
984         free(side2);
985         return mfi;
986 }
987
988 static struct merge_file_info merge_file_one(struct merge_options *o,
989                                          const char *path,
990                                          const unsigned char *o_sha, int o_mode,
991                                          const unsigned char *a_sha, int a_mode,
992                                          const unsigned char *b_sha, int b_mode,
993                                          const char *branch1,
994                                          const char *branch2)
995 {
996         struct diff_filespec one, a, b;
997
998         one.path = a.path = b.path = (char *)path;
999         hashcpy(one.sha1, o_sha);
1000         one.mode = o_mode;
1001         hashcpy(a.sha1, a_sha);
1002         a.mode = a_mode;
1003         hashcpy(b.sha1, b_sha);
1004         b.mode = b_mode;
1005         return merge_file_1(o, &one, &a, &b, branch1, branch2);
1006 }
1007
1008 static void handle_change_delete(struct merge_options *o,
1009                                  const char *path,
1010                                  const unsigned char *o_sha, int o_mode,
1011                                  const unsigned char *a_sha, int a_mode,
1012                                  const unsigned char *b_sha, int b_mode,
1013                                  const char *change, const char *change_past)
1014 {
1015         char *renamed = NULL;
1016         if (dir_in_way(path, !o->call_depth)) {
1017                 renamed = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1018         }
1019
1020         if (o->call_depth) {
1021                 /*
1022                  * We cannot arbitrarily accept either a_sha or b_sha as
1023                  * correct; since there is no true "middle point" between
1024                  * them, simply reuse the base version for virtual merge base.
1025                  */
1026                 remove_file_from_cache(path);
1027                 update_file(o, 0, o_sha, o_mode, renamed ? renamed : path);
1028         } else if (!a_sha) {
1029                 if (!renamed) {
1030                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1031                                "and %s in %s. Version %s of %s left in tree."),
1032                                change, path, o->branch1, change_past,
1033                                o->branch2, o->branch2, path);
1034                         update_file(o, 0, b_sha, b_mode, path);
1035                 } else {
1036                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1037                                "and %s in %s. Version %s of %s left in tree at %s."),
1038                                change, path, o->branch1, change_past,
1039                                o->branch2, o->branch2, path, renamed);
1040                         update_file(o, 0, b_sha, b_mode, renamed);
1041                 }
1042         } else {
1043                 if (!renamed) {
1044                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1045                                "and %s in %s. Version %s of %s left in tree."),
1046                                change, path, o->branch2, change_past,
1047                                o->branch1, o->branch1, path);
1048                 } else {
1049                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1050                                "and %s in %s. Version %s of %s left in tree at %s."),
1051                                change, path, o->branch2, change_past,
1052                                o->branch1, o->branch1, path, renamed);
1053                         update_file(o, 0, a_sha, a_mode, renamed);
1054                 }
1055                 /*
1056                  * No need to call update_file() on path when !renamed, since
1057                  * that would needlessly touch path.  We could call
1058                  * update_file_flags() with update_cache=0 and update_wd=0,
1059                  * but that's a no-op.
1060                  */
1061         }
1062         free(renamed);
1063 }
1064
1065 static void conflict_rename_delete(struct merge_options *o,
1066                                    struct diff_filepair *pair,
1067                                    const char *rename_branch,
1068                                    const char *other_branch)
1069 {
1070         const struct diff_filespec *orig = pair->one;
1071         const struct diff_filespec *dest = pair->two;
1072         const unsigned char *a_sha = NULL;
1073         const unsigned char *b_sha = NULL;
1074         int a_mode = 0;
1075         int b_mode = 0;
1076
1077         if (rename_branch == o->branch1) {
1078                 a_sha = dest->sha1;
1079                 a_mode = dest->mode;
1080         } else {
1081                 b_sha = dest->sha1;
1082                 b_mode = dest->mode;
1083         }
1084
1085         handle_change_delete(o,
1086                              o->call_depth ? orig->path : dest->path,
1087                              orig->sha1, orig->mode,
1088                              a_sha, a_mode,
1089                              b_sha, b_mode,
1090                              _("rename"), _("renamed"));
1091
1092         if (o->call_depth) {
1093                 remove_file_from_cache(dest->path);
1094         } else {
1095                 update_stages(dest->path, NULL,
1096                               rename_branch == o->branch1 ? dest : NULL,
1097                               rename_branch == o->branch1 ? NULL : dest);
1098         }
1099
1100 }
1101
1102 static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
1103                                                  struct stage_data *entry,
1104                                                  int stage)
1105 {
1106         unsigned char *sha = entry->stages[stage].sha;
1107         unsigned mode = entry->stages[stage].mode;
1108         if (mode == 0 || is_null_sha1(sha))
1109                 return NULL;
1110         hashcpy(target->sha1, sha);
1111         target->mode = mode;
1112         return target;
1113 }
1114
1115 static void handle_file(struct merge_options *o,
1116                         struct diff_filespec *rename,
1117                         int stage,
1118                         struct rename_conflict_info *ci)
1119 {
1120         char *dst_name = rename->path;
1121         struct stage_data *dst_entry;
1122         const char *cur_branch, *other_branch;
1123         struct diff_filespec other;
1124         struct diff_filespec *add;
1125
1126         if (stage == 2) {
1127                 dst_entry = ci->dst_entry1;
1128                 cur_branch = ci->branch1;
1129                 other_branch = ci->branch2;
1130         } else {
1131                 dst_entry = ci->dst_entry2;
1132                 cur_branch = ci->branch2;
1133                 other_branch = ci->branch1;
1134         }
1135
1136         add = filespec_from_entry(&other, dst_entry, stage ^ 1);
1137         if (add) {
1138                 char *add_name = unique_path(o, rename->path, other_branch);
1139                 update_file(o, 0, add->sha1, add->mode, add_name);
1140
1141                 remove_file(o, 0, rename->path, 0);
1142                 dst_name = unique_path(o, rename->path, cur_branch);
1143         } else {
1144                 if (dir_in_way(rename->path, !o->call_depth)) {
1145                         dst_name = unique_path(o, rename->path, cur_branch);
1146                         output(o, 1, _("%s is a directory in %s adding as %s instead"),
1147                                rename->path, other_branch, dst_name);
1148                 }
1149         }
1150         update_file(o, 0, rename->sha1, rename->mode, dst_name);
1151         if (stage == 2)
1152                 update_stages(rename->path, NULL, rename, add);
1153         else
1154                 update_stages(rename->path, NULL, add, rename);
1155
1156         if (dst_name != rename->path)
1157                 free(dst_name);
1158 }
1159
1160 static void conflict_rename_rename_1to2(struct merge_options *o,
1161                                         struct rename_conflict_info *ci)
1162 {
1163         /* One file was renamed in both branches, but to different names. */
1164         struct diff_filespec *one = ci->pair1->one;
1165         struct diff_filespec *a = ci->pair1->two;
1166         struct diff_filespec *b = ci->pair2->two;
1167
1168         output(o, 1, _("CONFLICT (rename/rename): "
1169                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1170                "rename \"%s\"->\"%s\" in \"%s\"%s"),
1171                one->path, a->path, ci->branch1,
1172                one->path, b->path, ci->branch2,
1173                o->call_depth ? _(" (left unresolved)") : "");
1174         if (o->call_depth) {
1175                 struct merge_file_info mfi;
1176                 struct diff_filespec other;
1177                 struct diff_filespec *add;
1178                 mfi = merge_file_one(o, one->path,
1179                                  one->sha1, one->mode,
1180                                  a->sha1, a->mode,
1181                                  b->sha1, b->mode,
1182                                  ci->branch1, ci->branch2);
1183                 /*
1184                  * FIXME: For rename/add-source conflicts (if we could detect
1185                  * such), this is wrong.  We should instead find a unique
1186                  * pathname and then either rename the add-source file to that
1187                  * unique path, or use that unique path instead of src here.
1188                  */
1189                 update_file(o, 0, mfi.sha, mfi.mode, one->path);
1190
1191                 /*
1192                  * Above, we put the merged content at the merge-base's
1193                  * path.  Now we usually need to delete both a->path and
1194                  * b->path.  However, the rename on each side of the merge
1195                  * could also be involved in a rename/add conflict.  In
1196                  * such cases, we should keep the added file around,
1197                  * resolving the conflict at that path in its favor.
1198                  */
1199                 add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
1200                 if (add)
1201                         update_file(o, 0, add->sha1, add->mode, a->path);
1202                 else
1203                         remove_file_from_cache(a->path);
1204                 add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
1205                 if (add)
1206                         update_file(o, 0, add->sha1, add->mode, b->path);
1207                 else
1208                         remove_file_from_cache(b->path);
1209         } else {
1210                 handle_file(o, a, 2, ci);
1211                 handle_file(o, b, 3, ci);
1212         }
1213 }
1214
1215 static void conflict_rename_rename_2to1(struct merge_options *o,
1216                                         struct rename_conflict_info *ci)
1217 {
1218         /* Two files, a & b, were renamed to the same thing, c. */
1219         struct diff_filespec *a = ci->pair1->one;
1220         struct diff_filespec *b = ci->pair2->one;
1221         struct diff_filespec *c1 = ci->pair1->two;
1222         struct diff_filespec *c2 = ci->pair2->two;
1223         char *path = c1->path; /* == c2->path */
1224         struct merge_file_info mfi_c1;
1225         struct merge_file_info mfi_c2;
1226
1227         output(o, 1, _("CONFLICT (rename/rename): "
1228                "Rename %s->%s in %s. "
1229                "Rename %s->%s in %s"),
1230                a->path, c1->path, ci->branch1,
1231                b->path, c2->path, ci->branch2);
1232
1233         remove_file(o, 1, a->path, would_lose_untracked(a->path));
1234         remove_file(o, 1, b->path, would_lose_untracked(b->path));
1235
1236         mfi_c1 = merge_file_special_markers(o, a, c1, &ci->ren1_other,
1237                                             o->branch1, c1->path,
1238                                             o->branch2, ci->ren1_other.path);
1239         mfi_c2 = merge_file_special_markers(o, b, &ci->ren2_other, c2,
1240                                             o->branch1, ci->ren2_other.path,
1241                                             o->branch2, c2->path);
1242
1243         if (o->call_depth) {
1244                 /*
1245                  * If mfi_c1.clean && mfi_c2.clean, then it might make
1246                  * sense to do a two-way merge of those results.  But, I
1247                  * think in all cases, it makes sense to have the virtual
1248                  * merge base just undo the renames; they can be detected
1249                  * again later for the non-recursive merge.
1250                  */
1251                 remove_file(o, 0, path, 0);
1252                 update_file(o, 0, mfi_c1.sha, mfi_c1.mode, a->path);
1253                 update_file(o, 0, mfi_c2.sha, mfi_c2.mode, b->path);
1254         } else {
1255                 char *new_path1 = unique_path(o, path, ci->branch1);
1256                 char *new_path2 = unique_path(o, path, ci->branch2);
1257                 output(o, 1, _("Renaming %s to %s and %s to %s instead"),
1258                        a->path, new_path1, b->path, new_path2);
1259                 remove_file(o, 0, path, 0);
1260                 update_file(o, 0, mfi_c1.sha, mfi_c1.mode, new_path1);
1261                 update_file(o, 0, mfi_c2.sha, mfi_c2.mode, new_path2);
1262                 free(new_path2);
1263                 free(new_path1);
1264         }
1265 }
1266
1267 static int process_renames(struct merge_options *o,
1268                            struct string_list *a_renames,
1269                            struct string_list *b_renames)
1270 {
1271         int clean_merge = 1, i, j;
1272         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
1273         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
1274         const struct rename *sre;
1275
1276         for (i = 0; i < a_renames->nr; i++) {
1277                 sre = a_renames->items[i].util;
1278                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
1279                         = (void *)sre;
1280         }
1281         for (i = 0; i < b_renames->nr; i++) {
1282                 sre = b_renames->items[i].util;
1283                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
1284                         = (void *)sre;
1285         }
1286
1287         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1288                 struct string_list *renames1, *renames2Dst;
1289                 struct rename *ren1 = NULL, *ren2 = NULL;
1290                 const char *branch1, *branch2;
1291                 const char *ren1_src, *ren1_dst;
1292                 struct string_list_item *lookup;
1293
1294                 if (i >= a_renames->nr) {
1295                         ren2 = b_renames->items[j++].util;
1296                 } else if (j >= b_renames->nr) {
1297                         ren1 = a_renames->items[i++].util;
1298                 } else {
1299                         int compare = strcmp(a_renames->items[i].string,
1300                                              b_renames->items[j].string);
1301                         if (compare <= 0)
1302                                 ren1 = a_renames->items[i++].util;
1303                         if (compare >= 0)
1304                                 ren2 = b_renames->items[j++].util;
1305                 }
1306
1307                 /* TODO: refactor, so that 1/2 are not needed */
1308                 if (ren1) {
1309                         renames1 = a_renames;
1310                         renames2Dst = &b_by_dst;
1311                         branch1 = o->branch1;
1312                         branch2 = o->branch2;
1313                 } else {
1314                         struct rename *tmp;
1315                         renames1 = b_renames;
1316                         renames2Dst = &a_by_dst;
1317                         branch1 = o->branch2;
1318                         branch2 = o->branch1;
1319                         tmp = ren2;
1320                         ren2 = ren1;
1321                         ren1 = tmp;
1322                 }
1323
1324                 if (ren1->processed)
1325                         continue;
1326                 ren1->processed = 1;
1327                 ren1->dst_entry->processed = 1;
1328                 /* BUG: We should only mark src_entry as processed if we
1329                  * are not dealing with a rename + add-source case.
1330                  */
1331                 ren1->src_entry->processed = 1;
1332
1333                 ren1_src = ren1->pair->one->path;
1334                 ren1_dst = ren1->pair->two->path;
1335
1336                 if (ren2) {
1337                         /* One file renamed on both sides */
1338                         const char *ren2_src = ren2->pair->one->path;
1339                         const char *ren2_dst = ren2->pair->two->path;
1340                         enum rename_type rename_type;
1341                         if (strcmp(ren1_src, ren2_src) != 0)
1342                                 die("ren1_src != ren2_src");
1343                         ren2->dst_entry->processed = 1;
1344                         ren2->processed = 1;
1345                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1346                                 rename_type = RENAME_ONE_FILE_TO_TWO;
1347                                 clean_merge = 0;
1348                         } else {
1349                                 rename_type = RENAME_ONE_FILE_TO_ONE;
1350                                 /* BUG: We should only remove ren1_src in
1351                                  * the base stage (think of rename +
1352                                  * add-source cases).
1353                                  */
1354                                 remove_file(o, 1, ren1_src, 1);
1355                                 update_entry(ren1->dst_entry,
1356                                              ren1->pair->one,
1357                                              ren1->pair->two,
1358                                              ren2->pair->two);
1359                         }
1360                         setup_rename_conflict_info(rename_type,
1361                                                    ren1->pair,
1362                                                    ren2->pair,
1363                                                    branch1,
1364                                                    branch2,
1365                                                    ren1->dst_entry,
1366                                                    ren2->dst_entry,
1367                                                    o,
1368                                                    NULL,
1369                                                    NULL);
1370                 } else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
1371                         /* Two different files renamed to the same thing */
1372                         char *ren2_dst;
1373                         ren2 = lookup->util;
1374                         ren2_dst = ren2->pair->two->path;
1375                         if (strcmp(ren1_dst, ren2_dst) != 0)
1376                                 die("ren1_dst != ren2_dst");
1377
1378                         clean_merge = 0;
1379                         ren2->processed = 1;
1380                         /*
1381                          * BUG: We should only mark src_entry as processed
1382                          * if we are not dealing with a rename + add-source
1383                          * case.
1384                          */
1385                         ren2->src_entry->processed = 1;
1386
1387                         setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
1388                                                    ren1->pair,
1389                                                    ren2->pair,
1390                                                    branch1,
1391                                                    branch2,
1392                                                    ren1->dst_entry,
1393                                                    ren2->dst_entry,
1394                                                    o,
1395                                                    ren1->src_entry,
1396                                                    ren2->src_entry);
1397
1398                 } else {
1399                         /* Renamed in 1, maybe changed in 2 */
1400                         /* we only use sha1 and mode of these */
1401                         struct diff_filespec src_other, dst_other;
1402                         int try_merge;
1403
1404                         /*
1405                          * unpack_trees loads entries from common-commit
1406                          * into stage 1, from head-commit into stage 2, and
1407                          * from merge-commit into stage 3.  We keep track
1408                          * of which side corresponds to the rename.
1409                          */
1410                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1411                         int other_stage =   a_renames == renames1 ? 3 : 2;
1412
1413                         /* BUG: We should only remove ren1_src in the base
1414                          * stage and in other_stage (think of rename +
1415                          * add-source case).
1416                          */
1417                         remove_file(o, 1, ren1_src,
1418                                     renamed_stage == 2 || !was_tracked(ren1_src));
1419
1420                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1421                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1422                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1423                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1424                         try_merge = 0;
1425
1426                         if (sha_eq(src_other.sha1, null_sha1)) {
1427                                 setup_rename_conflict_info(RENAME_DELETE,
1428                                                            ren1->pair,
1429                                                            NULL,
1430                                                            branch1,
1431                                                            branch2,
1432                                                            ren1->dst_entry,
1433                                                            NULL,
1434                                                            o,
1435                                                            NULL,
1436                                                            NULL);
1437                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1438                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1439                                 /*
1440                                  * Added file on the other side identical to
1441                                  * the file being renamed: clean merge.
1442                                  * Also, there is no need to overwrite the
1443                                  * file already in the working copy, so call
1444                                  * update_file_flags() instead of
1445                                  * update_file().
1446                                  */
1447                                 update_file_flags(o,
1448                                                   ren1->pair->two->sha1,
1449                                                   ren1->pair->two->mode,
1450                                                   ren1_dst,
1451                                                   1, /* update_cache */
1452                                                   0  /* update_wd    */);
1453                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1454                                 clean_merge = 0;
1455                                 try_merge = 1;
1456                                 output(o, 1, _("CONFLICT (rename/add): Rename %s->%s in %s. "
1457                                        "%s added in %s"),
1458                                        ren1_src, ren1_dst, branch1,
1459                                        ren1_dst, branch2);
1460                                 if (o->call_depth) {
1461                                         struct merge_file_info mfi;
1462                                         mfi = merge_file_one(o, ren1_dst, null_sha1, 0,
1463                                                          ren1->pair->two->sha1, ren1->pair->two->mode,
1464                                                          dst_other.sha1, dst_other.mode,
1465                                                          branch1, branch2);
1466                                         output(o, 1, _("Adding merged %s"), ren1_dst);
1467                                         update_file(o, 0, mfi.sha, mfi.mode, ren1_dst);
1468                                         try_merge = 0;
1469                                 } else {
1470                                         char *new_path = unique_path(o, ren1_dst, branch2);
1471                                         output(o, 1, _("Adding as %s instead"), new_path);
1472                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1473                                         free(new_path);
1474                                 }
1475                         } else
1476                                 try_merge = 1;
1477
1478                         if (try_merge) {
1479                                 struct diff_filespec *one, *a, *b;
1480                                 src_other.path = (char *)ren1_src;
1481
1482                                 one = ren1->pair->one;
1483                                 if (a_renames == renames1) {
1484                                         a = ren1->pair->two;
1485                                         b = &src_other;
1486                                 } else {
1487                                         b = ren1->pair->two;
1488                                         a = &src_other;
1489                                 }
1490                                 update_entry(ren1->dst_entry, one, a, b);
1491                                 setup_rename_conflict_info(RENAME_NORMAL,
1492                                                            ren1->pair,
1493                                                            NULL,
1494                                                            branch1,
1495                                                            NULL,
1496                                                            ren1->dst_entry,
1497                                                            NULL,
1498                                                            o,
1499                                                            NULL,
1500                                                            NULL);
1501                         }
1502                 }
1503         }
1504         string_list_clear(&a_by_dst, 0);
1505         string_list_clear(&b_by_dst, 0);
1506
1507         return clean_merge;
1508 }
1509
1510 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1511 {
1512         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1513 }
1514
1515 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1516 {
1517         void *buf;
1518         enum object_type type;
1519         unsigned long size;
1520         buf = read_sha1_file(sha1, &type, &size);
1521         if (!buf)
1522                 return error(_("cannot read object %s"), sha1_to_hex(sha1));
1523         if (type != OBJ_BLOB) {
1524                 free(buf);
1525                 return error(_("object %s is not a blob"), sha1_to_hex(sha1));
1526         }
1527         strbuf_attach(dst, buf, size, size + 1);
1528         return 0;
1529 }
1530
1531 static int blob_unchanged(const unsigned char *o_sha,
1532                           const unsigned char *a_sha,
1533                           int renormalize, const char *path)
1534 {
1535         struct strbuf o = STRBUF_INIT;
1536         struct strbuf a = STRBUF_INIT;
1537         int ret = 0; /* assume changed for safety */
1538
1539         if (sha_eq(o_sha, a_sha))
1540                 return 1;
1541         if (!renormalize)
1542                 return 0;
1543
1544         assert(o_sha && a_sha);
1545         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1546                 goto error_return;
1547         /*
1548          * Note: binary | is used so that both renormalizations are
1549          * performed.  Comparison can be skipped if both files are
1550          * unchanged since their sha1s have already been compared.
1551          */
1552         if (renormalize_buffer(path, o.buf, o.len, &o) |
1553             renormalize_buffer(path, a.buf, o.len, &a))
1554                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1555
1556 error_return:
1557         strbuf_release(&o);
1558         strbuf_release(&a);
1559         return ret;
1560 }
1561
1562 static void handle_modify_delete(struct merge_options *o,
1563                                  const char *path,
1564                                  unsigned char *o_sha, int o_mode,
1565                                  unsigned char *a_sha, int a_mode,
1566                                  unsigned char *b_sha, int b_mode)
1567 {
1568         handle_change_delete(o,
1569                              path,
1570                              o_sha, o_mode,
1571                              a_sha, a_mode,
1572                              b_sha, b_mode,
1573                              _("modify"), _("modified"));
1574 }
1575
1576 static int merge_content(struct merge_options *o,
1577                          const char *path,
1578                          unsigned char *o_sha, int o_mode,
1579                          unsigned char *a_sha, int a_mode,
1580                          unsigned char *b_sha, int b_mode,
1581                          struct rename_conflict_info *rename_conflict_info)
1582 {
1583         const char *reason = _("content");
1584         const char *path1 = NULL, *path2 = NULL;
1585         struct merge_file_info mfi;
1586         struct diff_filespec one, a, b;
1587         unsigned df_conflict_remains = 0;
1588
1589         if (!o_sha) {
1590                 reason = _("add/add");
1591                 o_sha = (unsigned char *)null_sha1;
1592         }
1593         one.path = a.path = b.path = (char *)path;
1594         hashcpy(one.sha1, o_sha);
1595         one.mode = o_mode;
1596         hashcpy(a.sha1, a_sha);
1597         a.mode = a_mode;
1598         hashcpy(b.sha1, b_sha);
1599         b.mode = b_mode;
1600
1601         if (rename_conflict_info) {
1602                 struct diff_filepair *pair1 = rename_conflict_info->pair1;
1603
1604                 path1 = (o->branch1 == rename_conflict_info->branch1) ?
1605                         pair1->two->path : pair1->one->path;
1606                 /* If rename_conflict_info->pair2 != NULL, we are in
1607                  * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
1608                  * normal rename.
1609                  */
1610                 path2 = (rename_conflict_info->pair2 ||
1611                          o->branch2 == rename_conflict_info->branch1) ?
1612                         pair1->two->path : pair1->one->path;
1613
1614                 if (dir_in_way(path, !o->call_depth))
1615                         df_conflict_remains = 1;
1616         }
1617         mfi = merge_file_special_markers(o, &one, &a, &b,
1618                                          o->branch1, path1,
1619                                          o->branch2, path2);
1620
1621         if (mfi.clean && !df_conflict_remains &&
1622             sha_eq(mfi.sha, a_sha) && mfi.mode == a_mode) {
1623                 int path_renamed_outside_HEAD;
1624                 output(o, 3, _("Skipped %s (merged same as existing)"), path);
1625                 /*
1626                  * The content merge resulted in the same file contents we
1627                  * already had.  We can return early if those file contents
1628                  * are recorded at the correct path (which may not be true
1629                  * if the merge involves a rename).
1630                  */
1631                 path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
1632                 if (!path_renamed_outside_HEAD) {
1633                         add_cacheinfo(mfi.mode, mfi.sha, path,
1634                                       0, (!o->call_depth), 0);
1635                         return mfi.clean;
1636                 }
1637         } else
1638                 output(o, 2, _("Auto-merging %s"), path);
1639
1640         if (!mfi.clean) {
1641                 if (S_ISGITLINK(mfi.mode))
1642                         reason = _("submodule");
1643                 output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
1644                                 reason, path);
1645                 if (rename_conflict_info && !df_conflict_remains)
1646                         update_stages(path, &one, &a, &b);
1647         }
1648
1649         if (df_conflict_remains) {
1650                 char *new_path;
1651                 if (o->call_depth) {
1652                         remove_file_from_cache(path);
1653                 } else {
1654                         if (!mfi.clean)
1655                                 update_stages(path, &one, &a, &b);
1656                         else {
1657                                 int file_from_stage2 = was_tracked(path);
1658                                 struct diff_filespec merged;
1659                                 hashcpy(merged.sha1, mfi.sha);
1660                                 merged.mode = mfi.mode;
1661
1662                                 update_stages(path, NULL,
1663                                               file_from_stage2 ? &merged : NULL,
1664                                               file_from_stage2 ? NULL : &merged);
1665                         }
1666
1667                 }
1668                 new_path = unique_path(o, path, rename_conflict_info->branch1);
1669                 output(o, 1, _("Adding as %s instead"), new_path);
1670                 update_file(o, 0, mfi.sha, mfi.mode, new_path);
1671                 free(new_path);
1672                 mfi.clean = 0;
1673         } else {
1674                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1675         }
1676         return mfi.clean;
1677
1678 }
1679
1680 /* Per entry merge function */
1681 static int process_entry(struct merge_options *o,
1682                          const char *path, struct stage_data *entry)
1683 {
1684         /*
1685         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1686         print_index_entry("\tpath: ", entry);
1687         */
1688         int clean_merge = 1;
1689         int normalize = o->renormalize;
1690         unsigned o_mode = entry->stages[1].mode;
1691         unsigned a_mode = entry->stages[2].mode;
1692         unsigned b_mode = entry->stages[3].mode;
1693         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1694         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1695         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1696
1697         entry->processed = 1;
1698         if (entry->rename_conflict_info) {
1699                 struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
1700                 switch (conflict_info->rename_type) {
1701                 case RENAME_NORMAL:
1702                 case RENAME_ONE_FILE_TO_ONE:
1703                         clean_merge = merge_content(o, path,
1704                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1705                                                     conflict_info);
1706                         break;
1707                 case RENAME_DELETE:
1708                         clean_merge = 0;
1709                         conflict_rename_delete(o, conflict_info->pair1,
1710                                                conflict_info->branch1,
1711                                                conflict_info->branch2);
1712                         break;
1713                 case RENAME_ONE_FILE_TO_TWO:
1714                         clean_merge = 0;
1715                         conflict_rename_rename_1to2(o, conflict_info);
1716                         break;
1717                 case RENAME_TWO_FILES_TO_ONE:
1718                         clean_merge = 0;
1719                         conflict_rename_rename_2to1(o, conflict_info);
1720                         break;
1721                 default:
1722                         entry->processed = 0;
1723                         break;
1724                 }
1725         } else if (o_sha && (!a_sha || !b_sha)) {
1726                 /* Case A: Deleted in one */
1727                 if ((!a_sha && !b_sha) ||
1728                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1729                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1730                         /* Deleted in both or deleted in one and
1731                          * unchanged in the other */
1732                         if (a_sha)
1733                                 output(o, 2, _("Removing %s"), path);
1734                         /* do not touch working file if it did not exist */
1735                         remove_file(o, 1, path, !a_sha);
1736                 } else {
1737                         /* Modify/delete; deleted side may have put a directory in the way */
1738                         clean_merge = 0;
1739                         handle_modify_delete(o, path, o_sha, o_mode,
1740                                              a_sha, a_mode, b_sha, b_mode);
1741                 }
1742         } else if ((!o_sha && a_sha && !b_sha) ||
1743                    (!o_sha && !a_sha && b_sha)) {
1744                 /* Case B: Added in one. */
1745                 /* [nothing|directory] -> ([nothing|directory], file) */
1746
1747                 const char *add_branch;
1748                 const char *other_branch;
1749                 unsigned mode;
1750                 const unsigned char *sha;
1751                 const char *conf;
1752
1753                 if (a_sha) {
1754                         add_branch = o->branch1;
1755                         other_branch = o->branch2;
1756                         mode = a_mode;
1757                         sha = a_sha;
1758                         conf = _("file/directory");
1759                 } else {
1760                         add_branch = o->branch2;
1761                         other_branch = o->branch1;
1762                         mode = b_mode;
1763                         sha = b_sha;
1764                         conf = _("directory/file");
1765                 }
1766                 if (dir_in_way(path, !o->call_depth)) {
1767                         char *new_path = unique_path(o, path, add_branch);
1768                         clean_merge = 0;
1769                         output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
1770                                "Adding %s as %s"),
1771                                conf, path, other_branch, path, new_path);
1772                         if (o->call_depth)
1773                                 remove_file_from_cache(path);
1774                         update_file(o, 0, sha, mode, new_path);
1775                         if (o->call_depth)
1776                                 remove_file_from_cache(path);
1777                         free(new_path);
1778                 } else {
1779                         output(o, 2, _("Adding %s"), path);
1780                         /* do not overwrite file if already present */
1781                         update_file_flags(o, sha, mode, path, 1, !a_sha);
1782                 }
1783         } else if (a_sha && b_sha) {
1784                 /* Case C: Added in both (check for same permissions) and */
1785                 /* case D: Modified in both, but differently. */
1786                 clean_merge = merge_content(o, path,
1787                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1788                                             NULL);
1789         } else if (!o_sha && !a_sha && !b_sha) {
1790                 /*
1791                  * this entry was deleted altogether. a_mode == 0 means
1792                  * we had that path and want to actively remove it.
1793                  */
1794                 remove_file(o, 1, path, !a_mode);
1795         } else
1796                 die(_("Fatal merge failure, shouldn't happen."));
1797
1798         return clean_merge;
1799 }
1800
1801 int merge_trees(struct merge_options *o,
1802                 struct tree *head,
1803                 struct tree *merge,
1804                 struct tree *common,
1805                 struct tree **result)
1806 {
1807         int code, clean;
1808
1809         if (o->subtree_shift) {
1810                 merge = shift_tree_object(head, merge, o->subtree_shift);
1811                 common = shift_tree_object(head, common, o->subtree_shift);
1812         }
1813
1814         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1815                 output(o, 0, _("Already up-to-date!"));
1816                 *result = head;
1817                 return 1;
1818         }
1819
1820         code = git_merge_trees(o->call_depth, common, head, merge);
1821
1822         if (code != 0) {
1823                 if (show(o, 4) || o->call_depth)
1824                         die(_("merging of trees %s and %s failed"),
1825                             sha1_to_hex(head->object.sha1),
1826                             sha1_to_hex(merge->object.sha1));
1827                 else
1828                         exit(128);
1829         }
1830
1831         if (unmerged_cache()) {
1832                 struct string_list *entries, *re_head, *re_merge;
1833                 int i;
1834                 string_list_clear(&o->current_file_set, 1);
1835                 string_list_clear(&o->current_directory_set, 1);
1836                 get_files_dirs(o, head);
1837                 get_files_dirs(o, merge);
1838
1839                 entries = get_unmerged();
1840                 record_df_conflict_files(o, entries);
1841                 re_head  = get_renames(o, head, common, head, merge, entries);
1842                 re_merge = get_renames(o, merge, common, head, merge, entries);
1843                 clean = process_renames(o, re_head, re_merge);
1844                 for (i = entries->nr-1; 0 <= i; i--) {
1845                         const char *path = entries->items[i].string;
1846                         struct stage_data *e = entries->items[i].util;
1847                         if (!e->processed
1848                                 && !process_entry(o, path, e))
1849                                 clean = 0;
1850                 }
1851                 for (i = 0; i < entries->nr; i++) {
1852                         struct stage_data *e = entries->items[i].util;
1853                         if (!e->processed)
1854                                 die(_("Unprocessed path??? %s"),
1855                                     entries->items[i].string);
1856                 }
1857
1858                 string_list_clear(re_merge, 0);
1859                 string_list_clear(re_head, 0);
1860                 string_list_clear(entries, 1);
1861
1862         }
1863         else
1864                 clean = 1;
1865
1866         if (o->call_depth)
1867                 *result = write_tree_from_memory(o);
1868
1869         return clean;
1870 }
1871
1872 static struct commit_list *reverse_commit_list(struct commit_list *list)
1873 {
1874         struct commit_list *next = NULL, *current, *backup;
1875         for (current = list; current; current = backup) {
1876                 backup = current->next;
1877                 current->next = next;
1878                 next = current;
1879         }
1880         return next;
1881 }
1882
1883 /*
1884  * Merge the commits h1 and h2, return the resulting virtual
1885  * commit object and a flag indicating the cleanness of the merge.
1886  */
1887 int merge_recursive(struct merge_options *o,
1888                     struct commit *h1,
1889                     struct commit *h2,
1890                     struct commit_list *ca,
1891                     struct commit **result)
1892 {
1893         struct commit_list *iter;
1894         struct commit *merged_common_ancestors;
1895         struct tree *mrtree = mrtree;
1896         int clean;
1897
1898         if (show(o, 4)) {
1899                 output(o, 4, _("Merging:"));
1900                 output_commit_title(o, h1);
1901                 output_commit_title(o, h2);
1902         }
1903
1904         if (!ca) {
1905                 ca = get_merge_bases(h1, h2, 1);
1906                 ca = reverse_commit_list(ca);
1907         }
1908
1909         if (show(o, 5)) {
1910                 unsigned cnt = commit_list_count(ca);
1911
1912                 output(o, 5, Q_("found %u common ancestor:",
1913                                 "found %u common ancestors:", cnt), cnt);
1914                 for (iter = ca; iter; iter = iter->next)
1915                         output_commit_title(o, iter->item);
1916         }
1917
1918         merged_common_ancestors = pop_commit(&ca);
1919         if (merged_common_ancestors == NULL) {
1920                 /* if there is no common ancestor, use an empty tree */
1921                 struct tree *tree;
1922
1923                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1924                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1925         }
1926
1927         for (iter = ca; iter; iter = iter->next) {
1928                 const char *saved_b1, *saved_b2;
1929                 o->call_depth++;
1930                 /*
1931                  * When the merge fails, the result contains files
1932                  * with conflict markers. The cleanness flag is
1933                  * ignored, it was never actually used, as result of
1934                  * merge_trees has always overwritten it: the committed
1935                  * "conflicts" were already resolved.
1936                  */
1937                 discard_cache();
1938                 saved_b1 = o->branch1;
1939                 saved_b2 = o->branch2;
1940                 o->branch1 = "Temporary merge branch 1";
1941                 o->branch2 = "Temporary merge branch 2";
1942                 merge_recursive(o, merged_common_ancestors, iter->item,
1943                                 NULL, &merged_common_ancestors);
1944                 o->branch1 = saved_b1;
1945                 o->branch2 = saved_b2;
1946                 o->call_depth--;
1947
1948                 if (!merged_common_ancestors)
1949                         die(_("merge returned no commit"));
1950         }
1951
1952         discard_cache();
1953         if (!o->call_depth)
1954                 read_cache();
1955
1956         o->ancestor = "merged common ancestors";
1957         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1958                             &mrtree);
1959
1960         if (o->call_depth) {
1961                 *result = make_virtual_commit(mrtree, "merged tree");
1962                 commit_list_insert(h1, &(*result)->parents);
1963                 commit_list_insert(h2, &(*result)->parents->next);
1964         }
1965         flush_output(o);
1966         if (show(o, 2))
1967                 diff_warn_rename_limit("merge.renamelimit",
1968                                        o->needed_rename_limit, 0);
1969         return clean;
1970 }
1971
1972 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1973 {
1974         struct object *object;
1975
1976         object = deref_tag(parse_object(sha1), name, strlen(name));
1977         if (!object)
1978                 return NULL;
1979         if (object->type == OBJ_TREE)
1980                 return make_virtual_commit((struct tree*)object, name);
1981         if (object->type != OBJ_COMMIT)
1982                 return NULL;
1983         if (parse_commit((struct commit *)object))
1984                 return NULL;
1985         return (struct commit *)object;
1986 }
1987
1988 int merge_recursive_generic(struct merge_options *o,
1989                             const unsigned char *head,
1990                             const unsigned char *merge,
1991                             int num_base_list,
1992                             const unsigned char **base_list,
1993                             struct commit **result)
1994 {
1995         int clean, index_fd;
1996         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1997         struct commit *head_commit = get_ref(head, o->branch1);
1998         struct commit *next_commit = get_ref(merge, o->branch2);
1999         struct commit_list *ca = NULL;
2000
2001         if (base_list) {
2002                 int i;
2003                 for (i = 0; i < num_base_list; ++i) {
2004                         struct commit *base;
2005                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
2006                                 return error(_("Could not parse object '%s'"),
2007                                         sha1_to_hex(base_list[i]));
2008                         commit_list_insert(base, &ca);
2009                 }
2010         }
2011
2012         index_fd = hold_locked_index(lock, 1);
2013         clean = merge_recursive(o, head_commit, next_commit, ca,
2014                         result);
2015         if (active_cache_changed &&
2016                         (write_cache(index_fd, active_cache, active_nr) ||
2017                          commit_locked_index(lock)))
2018                 return error(_("Unable to write index."));
2019
2020         return clean ? 0 : 1;
2021 }
2022
2023 static int merge_recursive_config(const char *var, const char *value, void *cb)
2024 {
2025         struct merge_options *o = cb;
2026         if (!strcmp(var, "merge.verbosity")) {
2027                 o->verbosity = git_config_int(var, value);
2028                 return 0;
2029         }
2030         if (!strcmp(var, "diff.renamelimit")) {
2031                 o->diff_rename_limit = git_config_int(var, value);
2032                 return 0;
2033         }
2034         if (!strcmp(var, "merge.renamelimit")) {
2035                 o->merge_rename_limit = git_config_int(var, value);
2036                 return 0;
2037         }
2038         return git_xmerge_config(var, value, cb);
2039 }
2040
2041 void init_merge_options(struct merge_options *o)
2042 {
2043         memset(o, 0, sizeof(struct merge_options));
2044         o->verbosity = 2;
2045         o->buffer_output = 1;
2046         o->diff_rename_limit = -1;
2047         o->merge_rename_limit = -1;
2048         o->renormalize = 0;
2049         git_config(merge_recursive_config, o);
2050         if (getenv("GIT_MERGE_VERBOSITY"))
2051                 o->verbosity =
2052                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
2053         if (o->verbosity >= 5)
2054                 o->buffer_output = 0;
2055         strbuf_init(&o->obuf, 0);
2056         memset(&o->current_file_set, 0, sizeof(struct string_list));
2057         o->current_file_set.strdup_strings = 1;
2058         memset(&o->current_directory_set, 0, sizeof(struct string_list));
2059         o->current_directory_set.strdup_strings = 1;
2060         memset(&o->df_conflict_file_set, 0, sizeof(struct string_list));
2061         o->df_conflict_file_set.strdup_strings = 1;
2062 }
2063
2064 int parse_merge_opt(struct merge_options *o, const char *s)
2065 {
2066         if (!s || !*s)
2067                 return -1;
2068         if (!strcmp(s, "ours"))
2069                 o->recursive_variant = MERGE_RECURSIVE_OURS;
2070         else if (!strcmp(s, "theirs"))
2071                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
2072         else if (!strcmp(s, "subtree"))
2073                 o->subtree_shift = "";
2074         else if (starts_with(s, "subtree="))
2075                 o->subtree_shift = s + strlen("subtree=");
2076         else if (!strcmp(s, "patience"))
2077                 o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
2078         else if (!strcmp(s, "histogram"))
2079                 o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
2080         else if (starts_with(s, "diff-algorithm=")) {
2081                 long value = parse_algorithm_value(s + strlen("diff-algorithm="));
2082                 if (value < 0)
2083                         return -1;
2084                 /* clear out previous settings */
2085                 DIFF_XDL_CLR(o, NEED_MINIMAL);
2086                 o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
2087                 o->xdl_opts |= value;
2088         }
2089         else if (!strcmp(s, "ignore-space-change"))
2090                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2091         else if (!strcmp(s, "ignore-all-space"))
2092                 o->xdl_opts |= XDF_IGNORE_WHITESPACE;
2093         else if (!strcmp(s, "ignore-space-at-eol"))
2094                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2095         else if (!strcmp(s, "renormalize"))
2096                 o->renormalize = 1;
2097         else if (!strcmp(s, "no-renormalize"))
2098                 o->renormalize = 0;
2099         else if (starts_with(s, "rename-threshold=")) {
2100                 const char *score = s + strlen("rename-threshold=");
2101                 if ((o->rename_score = parse_rename_score(&score)) == -1 || *score != 0)
2102                         return -1;
2103         }
2104         else
2105                 return -1;
2106         return 0;
2107 }