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