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