Git 2.4.8
[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 "cache.h"
7 #include "advice.h"
8 #include "lockfile.h"
9 #include "cache-tree.h"
10 #include "commit.h"
11 #include "blob.h"
12 #include "builtin.h"
13 #include "tree-walk.h"
14 #include "diff.h"
15 #include "diffcore.h"
16 #include "tag.h"
17 #include "unpack-trees.h"
18 #include "string-list.h"
19 #include "xdiff-interface.h"
20 #include "ll-merge.h"
21 #include "attr.h"
22 #include "merge-recursive.h"
23 #include "dir.h"
24 #include "submodule.h"
25
26 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
27                                       const char *subtree_shift)
28 {
29         unsigned char shifted[20];
30
31         if (!*subtree_shift) {
32                 shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
33         } else {
34                 shift_tree_by(one->object.sha1, two->object.sha1, shifted,
35                               subtree_shift);
36         }
37         if (!hashcmp(two->object.sha1, shifted))
38                 return two;
39         return lookup_tree(shifted);
40 }
41
42 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
43 {
44         struct commit *commit = alloc_commit_node();
45         struct merge_remote_desc *desc = xmalloc(sizeof(*desc));
46
47         desc->name = comment;
48         desc->obj = (struct object *)commit;
49         commit->tree = tree;
50         commit->util = desc;
51         commit->object.parsed = 1;
52         return commit;
53 }
54
55 /*
56  * Since we use get_tree_entry(), which does not put the read object into
57  * the object pool, we cannot rely on a == b.
58  */
59 static int sha_eq(const unsigned char *a, const unsigned char *b)
60 {
61         if (!a && !b)
62                 return 2;
63         return a && b && hashcmp(a, b) == 0;
64 }
65
66 enum rename_type {
67         RENAME_NORMAL = 0,
68         RENAME_DELETE,
69         RENAME_ONE_FILE_TO_ONE,
70         RENAME_ONE_FILE_TO_TWO,
71         RENAME_TWO_FILES_TO_ONE
72 };
73
74 struct rename_conflict_info {
75         enum rename_type rename_type;
76         struct diff_filepair *pair1;
77         struct diff_filepair *pair2;
78         const char *branch1;
79         const char *branch2;
80         struct stage_data *dst_entry1;
81         struct stage_data *dst_entry2;
82         struct diff_filespec ren1_other;
83         struct diff_filespec ren2_other;
84 };
85
86 /*
87  * Since we want to write the index eventually, we cannot reuse the index
88  * for these (temporary) data.
89  */
90 struct stage_data {
91         struct {
92                 unsigned mode;
93                 unsigned char sha[20];
94         } stages[4];
95         struct rename_conflict_info *rename_conflict_info;
96         unsigned processed:1;
97 };
98
99 static inline void setup_rename_conflict_info(enum rename_type rename_type,
100                                               struct diff_filepair *pair1,
101                                               struct diff_filepair *pair2,
102                                               const char *branch1,
103                                               const char *branch2,
104                                               struct stage_data *dst_entry1,
105                                               struct stage_data *dst_entry2,
106                                               struct merge_options *o,
107                                               struct stage_data *src_entry1,
108                                               struct stage_data *src_entry2)
109 {
110         struct rename_conflict_info *ci = xcalloc(1, sizeof(struct rename_conflict_info));
111         ci->rename_type = rename_type;
112         ci->pair1 = pair1;
113         ci->branch1 = branch1;
114         ci->branch2 = branch2;
115
116         ci->dst_entry1 = dst_entry1;
117         dst_entry1->rename_conflict_info = ci;
118         dst_entry1->processed = 0;
119
120         assert(!pair2 == !dst_entry2);
121         if (dst_entry2) {
122                 ci->dst_entry2 = dst_entry2;
123                 ci->pair2 = pair2;
124                 dst_entry2->rename_conflict_info = ci;
125         }
126
127         if (rename_type == RENAME_TWO_FILES_TO_ONE) {
128                 /*
129                  * For each rename, there could have been
130                  * modifications on the side of history where that
131                  * file was not renamed.
132                  */
133                 int ostage1 = o->branch1 == branch1 ? 3 : 2;
134                 int ostage2 = ostage1 ^ 1;
135
136                 ci->ren1_other.path = pair1->one->path;
137                 hashcpy(ci->ren1_other.sha1, src_entry1->stages[ostage1].sha);
138                 ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
139
140                 ci->ren2_other.path = pair2->one->path;
141                 hashcpy(ci->ren2_other.sha1, src_entry2->stages[ostage2].sha);
142                 ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
143         }
144 }
145
146 static int show(struct merge_options *o, int v)
147 {
148         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
149 }
150
151 static void flush_output(struct merge_options *o)
152 {
153         if (o->obuf.len) {
154                 fputs(o->obuf.buf, stdout);
155                 strbuf_reset(&o->obuf);
156         }
157 }
158
159 __attribute__((format (printf, 3, 4)))
160 static void output(struct merge_options *o, int v, const char *fmt, ...)
161 {
162         va_list ap;
163
164         if (!show(o, v))
165                 return;
166
167         strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
168
169         va_start(ap, fmt);
170         strbuf_vaddf(&o->obuf, fmt, ap);
171         va_end(ap);
172
173         strbuf_addch(&o->obuf, '\n');
174         if (!o->buffer_output)
175                 flush_output(o);
176 }
177
178 static void output_commit_title(struct merge_options *o, struct commit *commit)
179 {
180         int i;
181         flush_output(o);
182         for (i = o->call_depth; i--;)
183                 fputs("  ", stdout);
184         if (commit->util)
185                 printf("virtual %s\n", merge_remote_util(commit)->name);
186         else {
187                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
188                 if (parse_commit(commit) != 0)
189                         printf(_("(bad commit)\n"));
190                 else {
191                         const char *title;
192                         const char *msg = get_commit_buffer(commit, NULL);
193                         int len = find_commit_subject(msg, &title);
194                         if (len)
195                                 printf("%.*s\n", len, title);
196                         unuse_commit_buffer(commit, msg);
197                 }
198         }
199 }
200
201 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
202                 const char *path, int stage, int refresh, int options)
203 {
204         struct cache_entry *ce;
205         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage,
206                               (refresh ? (CE_MATCH_REFRESH |
207                                           CE_MATCH_IGNORE_MISSING) : 0 ));
208         if (!ce)
209                 return error(_("addinfo_cache failed for path '%s'"), path);
210         return add_cache_entry(ce, options);
211 }
212
213 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
214 {
215         parse_tree(tree);
216         init_tree_desc(desc, tree->buffer, tree->size);
217 }
218
219 static int git_merge_trees(int index_only,
220                            struct tree *common,
221                            struct tree *head,
222                            struct tree *merge)
223 {
224         int rc;
225         struct tree_desc t[3];
226         struct unpack_trees_options opts;
227
228         memset(&opts, 0, sizeof(opts));
229         if (index_only)
230                 opts.index_only = 1;
231         else
232                 opts.update = 1;
233         opts.merge = 1;
234         opts.head_idx = 2;
235         opts.fn = threeway_merge;
236         opts.src_index = &the_index;
237         opts.dst_index = &the_index;
238         setup_unpack_trees_porcelain(&opts, "merge");
239
240         init_tree_desc_from_tree(t+0, common);
241         init_tree_desc_from_tree(t+1, head);
242         init_tree_desc_from_tree(t+2, merge);
243
244         rc = unpack_trees(3, t, &opts);
245         cache_tree_free(&active_cache_tree);
246         return rc;
247 }
248
249 struct tree *write_tree_from_memory(struct merge_options *o)
250 {
251         struct tree *result = NULL;
252
253         if (unmerged_cache()) {
254                 int i;
255                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
256                 for (i = 0; i < active_nr; i++) {
257                         const struct cache_entry *ce = active_cache[i];
258                         if (ce_stage(ce))
259                                 fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
260                                         (int)ce_namelen(ce), ce->name);
261                 }
262                 die("Bug in merge-recursive.c");
263         }
264
265         if (!active_cache_tree)
266                 active_cache_tree = cache_tree();
267
268         if (!cache_tree_fully_valid(active_cache_tree) &&
269             cache_tree_update(&the_index, 0) < 0)
270                 die(_("error building trees"));
271
272         result = lookup_tree(active_cache_tree->sha1);
273
274         return result;
275 }
276
277 static int save_files_dirs(const unsigned char *sha1,
278                 struct strbuf *base, const char *path,
279                 unsigned int mode, int stage, void *context)
280 {
281         int baselen = base->len;
282         struct merge_options *o = context;
283
284         strbuf_addstr(base, path);
285
286         if (S_ISDIR(mode))
287                 string_list_insert(&o->current_directory_set, base->buf);
288         else
289                 string_list_insert(&o->current_file_set, base->buf);
290
291         strbuf_setlen(base, baselen);
292         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
293 }
294
295 static int get_files_dirs(struct merge_options *o, struct tree *tree)
296 {
297         int n;
298         struct pathspec match_all;
299         memset(&match_all, 0, sizeof(match_all));
300         if (read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o))
301                 return 0;
302         n = o->current_file_set.nr + o->current_directory_set.nr;
303         return n;
304 }
305
306 /*
307  * Returns an index_entry instance which doesn't have to correspond to
308  * a real cache entry in Git's index.
309  */
310 static struct stage_data *insert_stage_data(const char *path,
311                 struct tree *o, struct tree *a, struct tree *b,
312                 struct string_list *entries)
313 {
314         struct string_list_item *item;
315         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
316         get_tree_entry(o->object.sha1, path,
317                         e->stages[1].sha, &e->stages[1].mode);
318         get_tree_entry(a->object.sha1, path,
319                         e->stages[2].sha, &e->stages[2].mode);
320         get_tree_entry(b->object.sha1, path,
321                         e->stages[3].sha, &e->stages[3].mode);
322         item = string_list_insert(entries, path);
323         item->util = e;
324         return e;
325 }
326
327 /*
328  * Create a dictionary mapping file names to stage_data objects. The
329  * dictionary contains one entry for every path with a non-zero stage entry.
330  */
331 static struct string_list *get_unmerged(void)
332 {
333         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
334         int i;
335
336         unmerged->strdup_strings = 1;
337
338         for (i = 0; i < active_nr; i++) {
339                 struct string_list_item *item;
340                 struct stage_data *e;
341                 const struct cache_entry *ce = active_cache[i];
342                 if (!ce_stage(ce))
343                         continue;
344
345                 item = string_list_lookup(unmerged, ce->name);
346                 if (!item) {
347                         item = string_list_insert(unmerged, ce->name);
348                         item->util = xcalloc(1, sizeof(struct stage_data));
349                 }
350                 e = item->util;
351                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
352                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
353         }
354
355         return unmerged;
356 }
357
358 static int string_list_df_name_compare(const void *a, const void *b)
359 {
360         const struct string_list_item *one = a;
361         const struct string_list_item *two = b;
362         int onelen = strlen(one->string);
363         int twolen = strlen(two->string);
364         /*
365          * Here we only care that entries for D/F conflicts are
366          * adjacent, in particular with the file of the D/F conflict
367          * appearing before files below the corresponding directory.
368          * The order of the rest of the list is irrelevant for us.
369          *
370          * To achieve this, we sort with df_name_compare and provide
371          * the mode S_IFDIR so that D/F conflicts will sort correctly.
372          * We use the mode S_IFDIR for everything else for simplicity,
373          * since in other cases any changes in their order due to
374          * sorting cause no problems for us.
375          */
376         int cmp = df_name_compare(one->string, onelen, S_IFDIR,
377                                   two->string, twolen, S_IFDIR);
378         /*
379          * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
380          * that 'foo' comes before 'foo/bar'.
381          */
382         if (cmp)
383                 return cmp;
384         return onelen - twolen;
385 }
386
387 static void record_df_conflict_files(struct merge_options *o,
388                                      struct string_list *entries)
389 {
390         /* If there is a D/F conflict and the file for such a conflict
391          * currently exist in the working tree, we want to allow it to be
392          * removed to make room for the corresponding directory if needed.
393          * The files underneath the directories of such D/F conflicts will
394          * be processed before the corresponding file involved in the D/F
395          * conflict.  If the D/F directory ends up being removed by the
396          * merge, then we won't have to touch the D/F file.  If the D/F
397          * directory needs to be written to the working copy, then the D/F
398          * file will simply be removed (in make_room_for_path()) to make
399          * room for the necessary paths.  Note that if both the directory
400          * and the file need to be present, then the D/F file will be
401          * reinstated with a new unique name at the time it is processed.
402          */
403         struct string_list df_sorted_entries;
404         const char *last_file = NULL;
405         int last_len = 0;
406         int i;
407
408         /*
409          * If we're merging merge-bases, we don't want to bother with
410          * any working directory changes.
411          */
412         if (o->call_depth)
413                 return;
414
415         /* Ensure D/F conflicts are adjacent in the entries list. */
416         memset(&df_sorted_entries, 0, sizeof(struct string_list));
417         for (i = 0; i < entries->nr; i++) {
418                 struct string_list_item *next = &entries->items[i];
419                 string_list_append(&df_sorted_entries, next->string)->util =
420                                    next->util;
421         }
422         qsort(df_sorted_entries.items, entries->nr, sizeof(*entries->items),
423               string_list_df_name_compare);
424
425         string_list_clear(&o->df_conflict_file_set, 1);
426         for (i = 0; i < df_sorted_entries.nr; i++) {
427                 const char *path = df_sorted_entries.items[i].string;
428                 int len = strlen(path);
429                 struct stage_data *e = df_sorted_entries.items[i].util;
430
431                 /*
432                  * Check if last_file & path correspond to a D/F conflict;
433                  * i.e. whether path is last_file+'/'+<something>.
434                  * If so, record that it's okay to remove last_file to make
435                  * room for path and friends if needed.
436                  */
437                 if (last_file &&
438                     len > last_len &&
439                     memcmp(path, last_file, last_len) == 0 &&
440                     path[last_len] == '/') {
441                         string_list_insert(&o->df_conflict_file_set, last_file);
442                 }
443
444                 /*
445                  * Determine whether path could exist as a file in the
446                  * working directory as a possible D/F conflict.  This
447                  * will only occur when it exists in stage 2 as a
448                  * file.
449                  */
450                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
451                         last_file = path;
452                         last_len = len;
453                 } else {
454                         last_file = NULL;
455                 }
456         }
457         string_list_clear(&df_sorted_entries, 0);
458 }
459
460 struct rename {
461         struct diff_filepair *pair;
462         struct stage_data *src_entry;
463         struct stage_data *dst_entry;
464         unsigned processed:1;
465 };
466
467 /*
468  * Get information of all renames which occurred between 'o_tree' and
469  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
470  * 'b_tree') to be able to associate the correct cache entries with
471  * the rename information. 'tree' is always equal to either a_tree or b_tree.
472  */
473 static struct string_list *get_renames(struct merge_options *o,
474                                        struct tree *tree,
475                                        struct tree *o_tree,
476                                        struct tree *a_tree,
477                                        struct tree *b_tree,
478                                        struct string_list *entries)
479 {
480         int i;
481         struct string_list *renames;
482         struct diff_options opts;
483
484         renames = xcalloc(1, sizeof(struct string_list));
485         diff_setup(&opts);
486         DIFF_OPT_SET(&opts, RECURSIVE);
487         DIFF_OPT_CLR(&opts, RENAME_EMPTY);
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         diff_setup_done(&opts);
496         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
497         diffcore_std(&opts);
498         if (opts.needed_rename_limit > o->needed_rename_limit)
499                 o->needed_rename_limit = opts.needed_rename_limit;
500         for (i = 0; i < diff_queued_diff.nr; ++i) {
501                 struct string_list_item *item;
502                 struct rename *re;
503                 struct diff_filepair *pair = diff_queued_diff.queue[i];
504                 if (pair->status != 'R') {
505                         diff_free_filepair(pair);
506                         continue;
507                 }
508                 re = xmalloc(sizeof(*re));
509                 re->processed = 0;
510                 re->pair = pair;
511                 item = string_list_lookup(entries, re->pair->one->path);
512                 if (!item)
513                         re->src_entry = insert_stage_data(re->pair->one->path,
514                                         o_tree, a_tree, b_tree, entries);
515                 else
516                         re->src_entry = item->util;
517
518                 item = string_list_lookup(entries, re->pair->two->path);
519                 if (!item)
520                         re->dst_entry = insert_stage_data(re->pair->two->path,
521                                         o_tree, a_tree, b_tree, entries);
522                 else
523                         re->dst_entry = item->util;
524                 item = string_list_insert(renames, pair->one->path);
525                 item->util = re;
526         }
527         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
528         diff_queued_diff.nr = 0;
529         diff_flush(&opts);
530         return renames;
531 }
532
533 static int update_stages(const char *path, const struct diff_filespec *o,
534                          const struct diff_filespec *a,
535                          const struct diff_filespec *b)
536 {
537
538         /*
539          * NOTE: It is usually a bad idea to call update_stages on a path
540          * before calling update_file on that same path, since it can
541          * sometimes lead to spurious "refusing to lose untracked file..."
542          * messages from update_file (via make_room_for path via
543          * would_lose_untracked).  Instead, reverse the order of the calls
544          * (executing update_file first and then update_stages).
545          */
546         int clear = 1;
547         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
548         if (clear)
549                 if (remove_file_from_cache(path))
550                         return -1;
551         if (o)
552                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
553                         return -1;
554         if (a)
555                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
556                         return -1;
557         if (b)
558                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
559                         return -1;
560         return 0;
561 }
562
563 static void update_entry(struct stage_data *entry,
564                          struct diff_filespec *o,
565                          struct diff_filespec *a,
566                          struct diff_filespec *b)
567 {
568         entry->processed = 0;
569         entry->stages[1].mode = o->mode;
570         entry->stages[2].mode = a->mode;
571         entry->stages[3].mode = b->mode;
572         hashcpy(entry->stages[1].sha, o->sha1);
573         hashcpy(entry->stages[2].sha, a->sha1);
574         hashcpy(entry->stages[3].sha, b->sha1);
575 }
576
577 static int remove_file(struct merge_options *o, int clean,
578                        const char *path, int no_wd)
579 {
580         int update_cache = o->call_depth || clean;
581         int update_working_directory = !o->call_depth && !no_wd;
582
583         if (update_cache) {
584                 if (remove_file_from_cache(path))
585                         return -1;
586         }
587         if (update_working_directory) {
588                 if (ignore_case) {
589                         struct cache_entry *ce;
590                         ce = cache_file_exists(path, strlen(path), ignore_case);
591                         if (ce && ce_stage(ce) == 0)
592                                 return 0;
593                 }
594                 if (remove_path(path))
595                         return -1;
596         }
597         return 0;
598 }
599
600 /* add a string to a strbuf, but converting "/" to "_" */
601 static void add_flattened_path(struct strbuf *out, const char *s)
602 {
603         size_t i = out->len;
604         strbuf_addstr(out, s);
605         for (; i < out->len; i++)
606                 if (out->buf[i] == '/')
607                         out->buf[i] = '_';
608 }
609
610 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
611 {
612         struct strbuf newpath = STRBUF_INIT;
613         int suffix = 0;
614         size_t base_len;
615
616         strbuf_addf(&newpath, "%s~", path);
617         add_flattened_path(&newpath, branch);
618
619         base_len = newpath.len;
620         while (string_list_has_string(&o->current_file_set, newpath.buf) ||
621                string_list_has_string(&o->current_directory_set, newpath.buf) ||
622                file_exists(newpath.buf)) {
623                 strbuf_setlen(&newpath, base_len);
624                 strbuf_addf(&newpath, "_%d", suffix++);
625         }
626
627         string_list_insert(&o->current_file_set, newpath.buf);
628         return strbuf_detach(&newpath, NULL);
629 }
630
631 static int dir_in_way(const char *path, int check_working_copy)
632 {
633         int pos, pathlen = strlen(path);
634         char *dirpath = xmalloc(pathlen + 2);
635         struct stat st;
636
637         strcpy(dirpath, path);
638         dirpath[pathlen] = '/';
639         dirpath[pathlen+1] = '\0';
640
641         pos = cache_name_pos(dirpath, pathlen+1);
642
643         if (pos < 0)
644                 pos = -1 - pos;
645         if (pos < active_nr &&
646             !strncmp(dirpath, active_cache[pos]->name, pathlen+1)) {
647                 free(dirpath);
648                 return 1;
649         }
650
651         free(dirpath);
652         return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode);
653 }
654
655 static int was_tracked(const char *path)
656 {
657         int pos = cache_name_pos(path, strlen(path));
658
659         if (pos < 0)
660                 pos = -1 - pos;
661         while (pos < active_nr &&
662                !strcmp(path, active_cache[pos]->name)) {
663                 /*
664                  * If stage #0, it is definitely tracked.
665                  * If it has stage #2 then it was tracked
666                  * before this merge started.  All other
667                  * cases the path was not tracked.
668                  */
669                 switch (ce_stage(active_cache[pos])) {
670                 case 0:
671                 case 2:
672                         return 1;
673                 }
674                 pos++;
675         }
676         return 0;
677 }
678
679 static int would_lose_untracked(const char *path)
680 {
681         return !was_tracked(path) && file_exists(path);
682 }
683
684 static int make_room_for_path(struct merge_options *o, const char *path)
685 {
686         int status, i;
687         const char *msg = _("failed to create path '%s'%s");
688
689         /* Unlink any D/F conflict files that are in the way */
690         for (i = 0; i < o->df_conflict_file_set.nr; i++) {
691                 const char *df_path = o->df_conflict_file_set.items[i].string;
692                 size_t pathlen = strlen(path);
693                 size_t df_pathlen = strlen(df_path);
694                 if (df_pathlen < pathlen &&
695                     path[df_pathlen] == '/' &&
696                     strncmp(path, df_path, df_pathlen) == 0) {
697                         output(o, 3,
698                                _("Removing %s to make room for subdirectory\n"),
699                                df_path);
700                         unlink(df_path);
701                         unsorted_string_list_delete_item(&o->df_conflict_file_set,
702                                                          i, 0);
703                         break;
704                 }
705         }
706
707         /* Make sure leading directories are created */
708         status = safe_create_leading_directories_const(path);
709         if (status) {
710                 if (status == SCLD_EXISTS) {
711                         /* something else exists */
712                         error(msg, path, _(": perhaps a D/F conflict?"));
713                         return -1;
714                 }
715                 die(msg, path, "");
716         }
717
718         /*
719          * Do not unlink a file in the work tree if we are not
720          * tracking it.
721          */
722         if (would_lose_untracked(path))
723                 return error(_("refusing to lose untracked file at '%s'"),
724                              path);
725
726         /* Successful unlink is good.. */
727         if (!unlink(path))
728                 return 0;
729         /* .. and so is no existing file */
730         if (errno == ENOENT)
731                 return 0;
732         /* .. but not some other error (who really cares what?) */
733         return error(msg, path, _(": perhaps a D/F conflict?"));
734 }
735
736 static void update_file_flags(struct merge_options *o,
737                               const unsigned char *sha,
738                               unsigned mode,
739                               const char *path,
740                               int update_cache,
741                               int update_wd)
742 {
743         if (o->call_depth)
744                 update_wd = 0;
745
746         if (update_wd) {
747                 enum object_type type;
748                 void *buf;
749                 unsigned long size;
750
751                 if (S_ISGITLINK(mode)) {
752                         /*
753                          * We may later decide to recursively descend into
754                          * the submodule directory and update its index
755                          * and/or work tree, but we do not do that now.
756                          */
757                         update_wd = 0;
758                         goto update_index;
759                 }
760
761                 buf = read_sha1_file(sha, &type, &size);
762                 if (!buf)
763                         die(_("cannot read object %s '%s'"), sha1_to_hex(sha), path);
764                 if (type != OBJ_BLOB)
765                         die(_("blob expected for %s '%s'"), sha1_to_hex(sha), path);
766                 if (S_ISREG(mode)) {
767                         struct strbuf strbuf = STRBUF_INIT;
768                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
769                                 free(buf);
770                                 size = strbuf.len;
771                                 buf = strbuf_detach(&strbuf, NULL);
772                         }
773                 }
774
775                 if (make_room_for_path(o, path) < 0) {
776                         update_wd = 0;
777                         free(buf);
778                         goto update_index;
779                 }
780                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
781                         int fd;
782                         if (mode & 0100)
783                                 mode = 0777;
784                         else
785                                 mode = 0666;
786                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
787                         if (fd < 0)
788                                 die_errno(_("failed to open '%s'"), path);
789                         write_in_full(fd, buf, size);
790                         close(fd);
791                 } else if (S_ISLNK(mode)) {
792                         char *lnk = xmemdupz(buf, size);
793                         safe_create_leading_directories_const(path);
794                         unlink(path);
795                         if (symlink(lnk, path))
796                                 die_errno(_("failed to symlink '%s'"), path);
797                         free(lnk);
798                 } else
799                         die(_("do not know what to do with %06o %s '%s'"),
800                             mode, sha1_to_hex(sha), path);
801                 free(buf);
802         }
803  update_index:
804         if (update_cache)
805                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
806 }
807
808 static void update_file(struct merge_options *o,
809                         int clean,
810                         const unsigned char *sha,
811                         unsigned mode,
812                         const char *path)
813 {
814         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
815 }
816
817 /* Low level file merging, update and removal */
818
819 struct merge_file_info {
820         unsigned char sha[20];
821         unsigned mode;
822         unsigned clean:1,
823                  merge:1;
824 };
825
826 static int merge_3way(struct merge_options *o,
827                       mmbuffer_t *result_buf,
828                       const struct diff_filespec *one,
829                       const struct diff_filespec *a,
830                       const struct diff_filespec *b,
831                       const char *branch1,
832                       const char *branch2)
833 {
834         mmfile_t orig, src1, src2;
835         struct ll_merge_options ll_opts = {0};
836         char *base_name, *name1, *name2;
837         int merge_status;
838
839         ll_opts.renormalize = o->renormalize;
840         ll_opts.xdl_opts = o->xdl_opts;
841
842         if (o->call_depth) {
843                 ll_opts.virtual_ancestor = 1;
844                 ll_opts.variant = 0;
845         } else {
846                 switch (o->recursive_variant) {
847                 case MERGE_RECURSIVE_OURS:
848                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
849                         break;
850                 case MERGE_RECURSIVE_THEIRS:
851                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
852                         break;
853                 default:
854                         ll_opts.variant = 0;
855                         break;
856                 }
857         }
858
859         if (strcmp(a->path, b->path) ||
860             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
861                 base_name = o->ancestor == NULL ? NULL :
862                         mkpathdup("%s:%s", o->ancestor, one->path);
863                 name1 = mkpathdup("%s:%s", branch1, a->path);
864                 name2 = mkpathdup("%s:%s", branch2, b->path);
865         } else {
866                 base_name = o->ancestor == NULL ? NULL :
867                         mkpathdup("%s", o->ancestor);
868                 name1 = mkpathdup("%s", branch1);
869                 name2 = mkpathdup("%s", branch2);
870         }
871
872         read_mmblob(&orig, one->sha1);
873         read_mmblob(&src1, a->sha1);
874         read_mmblob(&src2, b->sha1);
875
876         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
877                                 &src1, name1, &src2, name2, &ll_opts);
878
879         free(base_name);
880         free(name1);
881         free(name2);
882         free(orig.ptr);
883         free(src1.ptr);
884         free(src2.ptr);
885         return merge_status;
886 }
887
888 static struct merge_file_info merge_file_1(struct merge_options *o,
889                                            const struct diff_filespec *one,
890                                            const struct diff_filespec *a,
891                                            const struct diff_filespec *b,
892                                            const char *branch1,
893                                            const char *branch2)
894 {
895         struct merge_file_info result;
896         result.merge = 0;
897         result.clean = 1;
898
899         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
900                 result.clean = 0;
901                 if (S_ISREG(a->mode)) {
902                         result.mode = a->mode;
903                         hashcpy(result.sha, a->sha1);
904                 } else {
905                         result.mode = b->mode;
906                         hashcpy(result.sha, b->sha1);
907                 }
908         } else {
909                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
910                         result.merge = 1;
911
912                 /*
913                  * Merge modes
914                  */
915                 if (a->mode == b->mode || a->mode == one->mode)
916                         result.mode = b->mode;
917                 else {
918                         result.mode = a->mode;
919                         if (b->mode != one->mode) {
920                                 result.clean = 0;
921                                 result.merge = 1;
922                         }
923                 }
924
925                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
926                         hashcpy(result.sha, b->sha1);
927                 else if (sha_eq(b->sha1, one->sha1))
928                         hashcpy(result.sha, a->sha1);
929                 else if (S_ISREG(a->mode)) {
930                         mmbuffer_t result_buf;
931                         int merge_status;
932
933                         merge_status = merge_3way(o, &result_buf, one, a, b,
934                                                   branch1, branch2);
935
936                         if ((merge_status < 0) || !result_buf.ptr)
937                                 die(_("Failed to execute internal merge"));
938
939                         if (write_sha1_file(result_buf.ptr, result_buf.size,
940                                             blob_type, result.sha))
941                                 die(_("Unable to add %s to database"),
942                                     a->path);
943
944                         free(result_buf.ptr);
945                         result.clean = (merge_status == 0);
946                 } else if (S_ISGITLINK(a->mode)) {
947                         result.clean = merge_submodule(result.sha,
948                                                        one->path, one->sha1,
949                                                        a->sha1, b->sha1,
950                                                        !o->call_depth);
951                 } else if (S_ISLNK(a->mode)) {
952                         hashcpy(result.sha, a->sha1);
953
954                         if (!sha_eq(a->sha1, b->sha1))
955                                 result.clean = 0;
956                 } else {
957                         die(_("unsupported object type in the tree"));
958                 }
959         }
960
961         return result;
962 }
963
964 static struct merge_file_info
965 merge_file_special_markers(struct merge_options *o,
966                            const struct diff_filespec *one,
967                            const struct diff_filespec *a,
968                            const struct diff_filespec *b,
969                            const char *branch1,
970                            const char *filename1,
971                            const char *branch2,
972                            const char *filename2)
973 {
974         char *side1 = NULL;
975         char *side2 = NULL;
976         struct merge_file_info mfi;
977
978         if (filename1)
979                 side1 = xstrfmt("%s:%s", branch1, filename1);
980         if (filename2)
981                 side2 = xstrfmt("%s:%s", branch2, filename2);
982
983         mfi = merge_file_1(o, one, a, b,
984                            side1 ? side1 : branch1, side2 ? side2 : branch2);
985         free(side1);
986         free(side2);
987         return mfi;
988 }
989
990 static struct merge_file_info merge_file_one(struct merge_options *o,
991                                          const char *path,
992                                          const unsigned char *o_sha, int o_mode,
993                                          const unsigned char *a_sha, int a_mode,
994                                          const unsigned char *b_sha, int b_mode,
995                                          const char *branch1,
996                                          const char *branch2)
997 {
998         struct diff_filespec one, a, b;
999
1000         one.path = a.path = b.path = (char *)path;
1001         hashcpy(one.sha1, o_sha);
1002         one.mode = o_mode;
1003         hashcpy(a.sha1, a_sha);
1004         a.mode = a_mode;
1005         hashcpy(b.sha1, b_sha);
1006         b.mode = b_mode;
1007         return merge_file_1(o, &one, &a, &b, branch1, branch2);
1008 }
1009
1010 static void handle_change_delete(struct merge_options *o,
1011                                  const char *path,
1012                                  const unsigned char *o_sha, int o_mode,
1013                                  const unsigned char *a_sha, int a_mode,
1014                                  const unsigned char *b_sha, int b_mode,
1015                                  const char *change, const char *change_past)
1016 {
1017         char *renamed = NULL;
1018         if (dir_in_way(path, !o->call_depth)) {
1019                 renamed = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1020         }
1021
1022         if (o->call_depth) {
1023                 /*
1024                  * We cannot arbitrarily accept either a_sha or b_sha as
1025                  * correct; since there is no true "middle point" between
1026                  * them, simply reuse the base version for virtual merge base.
1027                  */
1028                 remove_file_from_cache(path);
1029                 update_file(o, 0, o_sha, o_mode, renamed ? renamed : path);
1030         } else if (!a_sha) {
1031                 if (!renamed) {
1032                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1033                                "and %s in %s. Version %s of %s left in tree."),
1034                                change, path, o->branch1, change_past,
1035                                o->branch2, o->branch2, path);
1036                         update_file(o, 0, b_sha, b_mode, path);
1037                 } else {
1038                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1039                                "and %s in %s. Version %s of %s left in tree at %s."),
1040                                change, path, o->branch1, change_past,
1041                                o->branch2, o->branch2, path, renamed);
1042                         update_file(o, 0, b_sha, b_mode, renamed);
1043                 }
1044         } else {
1045                 if (!renamed) {
1046                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1047                                "and %s in %s. Version %s of %s left in tree."),
1048                                change, path, o->branch2, change_past,
1049                                o->branch1, o->branch1, path);
1050                 } else {
1051                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1052                                "and %s in %s. Version %s of %s left in tree at %s."),
1053                                change, path, o->branch2, change_past,
1054                                o->branch1, o->branch1, path, renamed);
1055                         update_file(o, 0, a_sha, a_mode, renamed);
1056                 }
1057                 /*
1058                  * No need to call update_file() on path when !renamed, since
1059                  * that would needlessly touch path.  We could call
1060                  * update_file_flags() with update_cache=0 and update_wd=0,
1061                  * but that's a no-op.
1062                  */
1063         }
1064         free(renamed);
1065 }
1066
1067 static void conflict_rename_delete(struct merge_options *o,
1068                                    struct diff_filepair *pair,
1069                                    const char *rename_branch,
1070                                    const char *other_branch)
1071 {
1072         const struct diff_filespec *orig = pair->one;
1073         const struct diff_filespec *dest = pair->two;
1074         const unsigned char *a_sha = NULL;
1075         const unsigned char *b_sha = NULL;
1076         int a_mode = 0;
1077         int b_mode = 0;
1078
1079         if (rename_branch == o->branch1) {
1080                 a_sha = dest->sha1;
1081                 a_mode = dest->mode;
1082         } else {
1083                 b_sha = dest->sha1;
1084                 b_mode = dest->mode;
1085         }
1086
1087         handle_change_delete(o,
1088                              o->call_depth ? orig->path : dest->path,
1089                              orig->sha1, orig->mode,
1090                              a_sha, a_mode,
1091                              b_sha, b_mode,
1092                              _("rename"), _("renamed"));
1093
1094         if (o->call_depth) {
1095                 remove_file_from_cache(dest->path);
1096         } else {
1097                 update_stages(dest->path, NULL,
1098                               rename_branch == o->branch1 ? dest : NULL,
1099                               rename_branch == o->branch1 ? NULL : dest);
1100         }
1101
1102 }
1103
1104 static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
1105                                                  struct stage_data *entry,
1106                                                  int stage)
1107 {
1108         unsigned char *sha = entry->stages[stage].sha;
1109         unsigned mode = entry->stages[stage].mode;
1110         if (mode == 0 || is_null_sha1(sha))
1111                 return NULL;
1112         hashcpy(target->sha1, sha);
1113         target->mode = mode;
1114         return target;
1115 }
1116
1117 static void handle_file(struct merge_options *o,
1118                         struct diff_filespec *rename,
1119                         int stage,
1120                         struct rename_conflict_info *ci)
1121 {
1122         char *dst_name = rename->path;
1123         struct stage_data *dst_entry;
1124         const char *cur_branch, *other_branch;
1125         struct diff_filespec other;
1126         struct diff_filespec *add;
1127
1128         if (stage == 2) {
1129                 dst_entry = ci->dst_entry1;
1130                 cur_branch = ci->branch1;
1131                 other_branch = ci->branch2;
1132         } else {
1133                 dst_entry = ci->dst_entry2;
1134                 cur_branch = ci->branch2;
1135                 other_branch = ci->branch1;
1136         }
1137
1138         add = filespec_from_entry(&other, dst_entry, stage ^ 1);
1139         if (add) {
1140                 char *add_name = unique_path(o, rename->path, other_branch);
1141                 update_file(o, 0, add->sha1, add->mode, add_name);
1142
1143                 remove_file(o, 0, rename->path, 0);
1144                 dst_name = unique_path(o, rename->path, cur_branch);
1145         } else {
1146                 if (dir_in_way(rename->path, !o->call_depth)) {
1147                         dst_name = unique_path(o, rename->path, cur_branch);
1148                         output(o, 1, _("%s is a directory in %s adding as %s instead"),
1149                                rename->path, other_branch, dst_name);
1150                 }
1151         }
1152         update_file(o, 0, rename->sha1, rename->mode, dst_name);
1153         if (stage == 2)
1154                 update_stages(rename->path, NULL, rename, add);
1155         else
1156                 update_stages(rename->path, NULL, add, rename);
1157
1158         if (dst_name != rename->path)
1159                 free(dst_name);
1160 }
1161
1162 static void conflict_rename_rename_1to2(struct merge_options *o,
1163                                         struct rename_conflict_info *ci)
1164 {
1165         /* One file was renamed in both branches, but to different names. */
1166         struct diff_filespec *one = ci->pair1->one;
1167         struct diff_filespec *a = ci->pair1->two;
1168         struct diff_filespec *b = ci->pair2->two;
1169
1170         output(o, 1, _("CONFLICT (rename/rename): "
1171                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1172                "rename \"%s\"->\"%s\" in \"%s\"%s"),
1173                one->path, a->path, ci->branch1,
1174                one->path, b->path, ci->branch2,
1175                o->call_depth ? _(" (left unresolved)") : "");
1176         if (o->call_depth) {
1177                 struct merge_file_info mfi;
1178                 struct diff_filespec other;
1179                 struct diff_filespec *add;
1180                 mfi = merge_file_one(o, one->path,
1181                                  one->sha1, one->mode,
1182                                  a->sha1, a->mode,
1183                                  b->sha1, b->mode,
1184                                  ci->branch1, ci->branch2);
1185                 /*
1186                  * FIXME: For rename/add-source conflicts (if we could detect
1187                  * such), this is wrong.  We should instead find a unique
1188                  * pathname and then either rename the add-source file to that
1189                  * unique path, or use that unique path instead of src here.
1190                  */
1191                 update_file(o, 0, mfi.sha, mfi.mode, one->path);
1192
1193                 /*
1194                  * Above, we put the merged content at the merge-base's
1195                  * path.  Now we usually need to delete both a->path and
1196                  * b->path.  However, the rename on each side of the merge
1197                  * could also be involved in a rename/add conflict.  In
1198                  * such cases, we should keep the added file around,
1199                  * resolving the conflict at that path in its favor.
1200                  */
1201                 add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
1202                 if (add)
1203                         update_file(o, 0, add->sha1, add->mode, a->path);
1204                 else
1205                         remove_file_from_cache(a->path);
1206                 add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
1207                 if (add)
1208                         update_file(o, 0, add->sha1, add->mode, b->path);
1209                 else
1210                         remove_file_from_cache(b->path);
1211         } else {
1212                 handle_file(o, a, 2, ci);
1213                 handle_file(o, b, 3, ci);
1214         }
1215 }
1216
1217 static void conflict_rename_rename_2to1(struct merge_options *o,
1218                                         struct rename_conflict_info *ci)
1219 {
1220         /* Two files, a & b, were renamed to the same thing, c. */
1221         struct diff_filespec *a = ci->pair1->one;
1222         struct diff_filespec *b = ci->pair2->one;
1223         struct diff_filespec *c1 = ci->pair1->two;
1224         struct diff_filespec *c2 = ci->pair2->two;
1225         char *path = c1->path; /* == c2->path */
1226         struct merge_file_info mfi_c1;
1227         struct merge_file_info mfi_c2;
1228
1229         output(o, 1, _("CONFLICT (rename/rename): "
1230                "Rename %s->%s in %s. "
1231                "Rename %s->%s in %s"),
1232                a->path, c1->path, ci->branch1,
1233                b->path, c2->path, ci->branch2);
1234
1235         remove_file(o, 1, a->path, would_lose_untracked(a->path));
1236         remove_file(o, 1, b->path, would_lose_untracked(b->path));
1237
1238         mfi_c1 = merge_file_special_markers(o, a, c1, &ci->ren1_other,
1239                                             o->branch1, c1->path,
1240                                             o->branch2, ci->ren1_other.path);
1241         mfi_c2 = merge_file_special_markers(o, b, &ci->ren2_other, c2,
1242                                             o->branch1, ci->ren2_other.path,
1243                                             o->branch2, c2->path);
1244
1245         if (o->call_depth) {
1246                 /*
1247                  * If mfi_c1.clean && mfi_c2.clean, then it might make
1248                  * sense to do a two-way merge of those results.  But, I
1249                  * think in all cases, it makes sense to have the virtual
1250                  * merge base just undo the renames; they can be detected
1251                  * again later for the non-recursive merge.
1252                  */
1253                 remove_file(o, 0, path, 0);
1254                 update_file(o, 0, mfi_c1.sha, mfi_c1.mode, a->path);
1255                 update_file(o, 0, mfi_c2.sha, mfi_c2.mode, b->path);
1256         } else {
1257                 char *new_path1 = unique_path(o, path, ci->branch1);
1258                 char *new_path2 = unique_path(o, path, ci->branch2);
1259                 output(o, 1, _("Renaming %s to %s and %s to %s instead"),
1260                        a->path, new_path1, b->path, new_path2);
1261                 remove_file(o, 0, path, 0);
1262                 update_file(o, 0, mfi_c1.sha, mfi_c1.mode, new_path1);
1263                 update_file(o, 0, mfi_c2.sha, mfi_c2.mode, new_path2);
1264                 free(new_path2);
1265                 free(new_path1);
1266         }
1267 }
1268
1269 static int process_renames(struct merge_options *o,
1270                            struct string_list *a_renames,
1271                            struct string_list *b_renames)
1272 {
1273         int clean_merge = 1, i, j;
1274         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
1275         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
1276         const struct rename *sre;
1277
1278         for (i = 0; i < a_renames->nr; i++) {
1279                 sre = a_renames->items[i].util;
1280                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
1281                         = (void *)sre;
1282         }
1283         for (i = 0; i < b_renames->nr; i++) {
1284                 sre = b_renames->items[i].util;
1285                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
1286                         = (void *)sre;
1287         }
1288
1289         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1290                 struct string_list *renames1, *renames2Dst;
1291                 struct rename *ren1 = NULL, *ren2 = NULL;
1292                 const char *branch1, *branch2;
1293                 const char *ren1_src, *ren1_dst;
1294                 struct string_list_item *lookup;
1295
1296                 if (i >= a_renames->nr) {
1297                         ren2 = b_renames->items[j++].util;
1298                 } else if (j >= b_renames->nr) {
1299                         ren1 = a_renames->items[i++].util;
1300                 } else {
1301                         int compare = strcmp(a_renames->items[i].string,
1302                                              b_renames->items[j].string);
1303                         if (compare <= 0)
1304                                 ren1 = a_renames->items[i++].util;
1305                         if (compare >= 0)
1306                                 ren2 = b_renames->items[j++].util;
1307                 }
1308
1309                 /* TODO: refactor, so that 1/2 are not needed */
1310                 if (ren1) {
1311                         renames1 = a_renames;
1312                         renames2Dst = &b_by_dst;
1313                         branch1 = o->branch1;
1314                         branch2 = o->branch2;
1315                 } else {
1316                         struct rename *tmp;
1317                         renames1 = b_renames;
1318                         renames2Dst = &a_by_dst;
1319                         branch1 = o->branch2;
1320                         branch2 = o->branch1;
1321                         tmp = ren2;
1322                         ren2 = ren1;
1323                         ren1 = tmp;
1324                 }
1325
1326                 if (ren1->processed)
1327                         continue;
1328                 ren1->processed = 1;
1329                 ren1->dst_entry->processed = 1;
1330                 /* BUG: We should only mark src_entry as processed if we
1331                  * are not dealing with a rename + add-source case.
1332                  */
1333                 ren1->src_entry->processed = 1;
1334
1335                 ren1_src = ren1->pair->one->path;
1336                 ren1_dst = ren1->pair->two->path;
1337
1338                 if (ren2) {
1339                         /* One file renamed on both sides */
1340                         const char *ren2_src = ren2->pair->one->path;
1341                         const char *ren2_dst = ren2->pair->two->path;
1342                         enum rename_type rename_type;
1343                         if (strcmp(ren1_src, ren2_src) != 0)
1344                                 die("ren1_src != ren2_src");
1345                         ren2->dst_entry->processed = 1;
1346                         ren2->processed = 1;
1347                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1348                                 rename_type = RENAME_ONE_FILE_TO_TWO;
1349                                 clean_merge = 0;
1350                         } else {
1351                                 rename_type = RENAME_ONE_FILE_TO_ONE;
1352                                 /* BUG: We should only remove ren1_src in
1353                                  * the base stage (think of rename +
1354                                  * add-source cases).
1355                                  */
1356                                 remove_file(o, 1, ren1_src, 1);
1357                                 update_entry(ren1->dst_entry,
1358                                              ren1->pair->one,
1359                                              ren1->pair->two,
1360                                              ren2->pair->two);
1361                         }
1362                         setup_rename_conflict_info(rename_type,
1363                                                    ren1->pair,
1364                                                    ren2->pair,
1365                                                    branch1,
1366                                                    branch2,
1367                                                    ren1->dst_entry,
1368                                                    ren2->dst_entry,
1369                                                    o,
1370                                                    NULL,
1371                                                    NULL);
1372                 } else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
1373                         /* Two different files renamed to the same thing */
1374                         char *ren2_dst;
1375                         ren2 = lookup->util;
1376                         ren2_dst = ren2->pair->two->path;
1377                         if (strcmp(ren1_dst, ren2_dst) != 0)
1378                                 die("ren1_dst != ren2_dst");
1379
1380                         clean_merge = 0;
1381                         ren2->processed = 1;
1382                         /*
1383                          * BUG: We should only mark src_entry as processed
1384                          * if we are not dealing with a rename + add-source
1385                          * case.
1386                          */
1387                         ren2->src_entry->processed = 1;
1388
1389                         setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
1390                                                    ren1->pair,
1391                                                    ren2->pair,
1392                                                    branch1,
1393                                                    branch2,
1394                                                    ren1->dst_entry,
1395                                                    ren2->dst_entry,
1396                                                    o,
1397                                                    ren1->src_entry,
1398                                                    ren2->src_entry);
1399
1400                 } else {
1401                         /* Renamed in 1, maybe changed in 2 */
1402                         /* we only use sha1 and mode of these */
1403                         struct diff_filespec src_other, dst_other;
1404                         int try_merge;
1405
1406                         /*
1407                          * unpack_trees loads entries from common-commit
1408                          * into stage 1, from head-commit into stage 2, and
1409                          * from merge-commit into stage 3.  We keep track
1410                          * of which side corresponds to the rename.
1411                          */
1412                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1413                         int other_stage =   a_renames == renames1 ? 3 : 2;
1414
1415                         /* BUG: We should only remove ren1_src in the base
1416                          * stage and in other_stage (think of rename +
1417                          * add-source case).
1418                          */
1419                         remove_file(o, 1, ren1_src,
1420                                     renamed_stage == 2 || !was_tracked(ren1_src));
1421
1422                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1423                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1424                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1425                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1426                         try_merge = 0;
1427
1428                         if (sha_eq(src_other.sha1, null_sha1)) {
1429                                 setup_rename_conflict_info(RENAME_DELETE,
1430                                                            ren1->pair,
1431                                                            NULL,
1432                                                            branch1,
1433                                                            branch2,
1434                                                            ren1->dst_entry,
1435                                                            NULL,
1436                                                            o,
1437                                                            NULL,
1438                                                            NULL);
1439                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1440                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1441                                 /*
1442                                  * Added file on the other side identical to
1443                                  * the file being renamed: clean merge.
1444                                  * Also, there is no need to overwrite the
1445                                  * file already in the working copy, so call
1446                                  * update_file_flags() instead of
1447                                  * update_file().
1448                                  */
1449                                 update_file_flags(o,
1450                                                   ren1->pair->two->sha1,
1451                                                   ren1->pair->two->mode,
1452                                                   ren1_dst,
1453                                                   1, /* update_cache */
1454                                                   0  /* update_wd    */);
1455                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1456                                 clean_merge = 0;
1457                                 try_merge = 1;
1458                                 output(o, 1, _("CONFLICT (rename/add): Rename %s->%s in %s. "
1459                                        "%s added in %s"),
1460                                        ren1_src, ren1_dst, branch1,
1461                                        ren1_dst, branch2);
1462                                 if (o->call_depth) {
1463                                         struct merge_file_info mfi;
1464                                         mfi = merge_file_one(o, ren1_dst, null_sha1, 0,
1465                                                          ren1->pair->two->sha1, ren1->pair->two->mode,
1466                                                          dst_other.sha1, dst_other.mode,
1467                                                          branch1, branch2);
1468                                         output(o, 1, _("Adding merged %s"), ren1_dst);
1469                                         update_file(o, 0, mfi.sha, mfi.mode, ren1_dst);
1470                                         try_merge = 0;
1471                                 } else {
1472                                         char *new_path = unique_path(o, ren1_dst, branch2);
1473                                         output(o, 1, _("Adding as %s instead"), new_path);
1474                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1475                                         free(new_path);
1476                                 }
1477                         } else
1478                                 try_merge = 1;
1479
1480                         if (try_merge) {
1481                                 struct diff_filespec *one, *a, *b;
1482                                 src_other.path = (char *)ren1_src;
1483
1484                                 one = ren1->pair->one;
1485                                 if (a_renames == renames1) {
1486                                         a = ren1->pair->two;
1487                                         b = &src_other;
1488                                 } else {
1489                                         b = ren1->pair->two;
1490                                         a = &src_other;
1491                                 }
1492                                 update_entry(ren1->dst_entry, one, a, b);
1493                                 setup_rename_conflict_info(RENAME_NORMAL,
1494                                                            ren1->pair,
1495                                                            NULL,
1496                                                            branch1,
1497                                                            NULL,
1498                                                            ren1->dst_entry,
1499                                                            NULL,
1500                                                            o,
1501                                                            NULL,
1502                                                            NULL);
1503                         }
1504                 }
1505         }
1506         string_list_clear(&a_by_dst, 0);
1507         string_list_clear(&b_by_dst, 0);
1508
1509         return clean_merge;
1510 }
1511
1512 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1513 {
1514         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1515 }
1516
1517 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1518 {
1519         void *buf;
1520         enum object_type type;
1521         unsigned long size;
1522         buf = read_sha1_file(sha1, &type, &size);
1523         if (!buf)
1524                 return error(_("cannot read object %s"), sha1_to_hex(sha1));
1525         if (type != OBJ_BLOB) {
1526                 free(buf);
1527                 return error(_("object %s is not a blob"), sha1_to_hex(sha1));
1528         }
1529         strbuf_attach(dst, buf, size, size + 1);
1530         return 0;
1531 }
1532
1533 static int blob_unchanged(const unsigned char *o_sha,
1534                           const unsigned char *a_sha,
1535                           int renormalize, const char *path)
1536 {
1537         struct strbuf o = STRBUF_INIT;
1538         struct strbuf a = STRBUF_INIT;
1539         int ret = 0; /* assume changed for safety */
1540
1541         if (sha_eq(o_sha, a_sha))
1542                 return 1;
1543         if (!renormalize)
1544                 return 0;
1545
1546         assert(o_sha && a_sha);
1547         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1548                 goto error_return;
1549         /*
1550          * Note: binary | is used so that both renormalizations are
1551          * performed.  Comparison can be skipped if both files are
1552          * unchanged since their sha1s have already been compared.
1553          */
1554         if (renormalize_buffer(path, o.buf, o.len, &o) |
1555             renormalize_buffer(path, a.buf, a.len, &a))
1556                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1557
1558 error_return:
1559         strbuf_release(&o);
1560         strbuf_release(&a);
1561         return ret;
1562 }
1563
1564 static void handle_modify_delete(struct merge_options *o,
1565                                  const char *path,
1566                                  unsigned char *o_sha, int o_mode,
1567                                  unsigned char *a_sha, int a_mode,
1568                                  unsigned char *b_sha, int b_mode)
1569 {
1570         handle_change_delete(o,
1571                              path,
1572                              o_sha, o_mode,
1573                              a_sha, a_mode,
1574                              b_sha, b_mode,
1575                              _("modify"), _("modified"));
1576 }
1577
1578 static int merge_content(struct merge_options *o,
1579                          const char *path,
1580                          unsigned char *o_sha, int o_mode,
1581                          unsigned char *a_sha, int a_mode,
1582                          unsigned char *b_sha, int b_mode,
1583                          struct rename_conflict_info *rename_conflict_info)
1584 {
1585         const char *reason = _("content");
1586         const char *path1 = NULL, *path2 = NULL;
1587         struct merge_file_info mfi;
1588         struct diff_filespec one, a, b;
1589         unsigned df_conflict_remains = 0;
1590
1591         if (!o_sha) {
1592                 reason = _("add/add");
1593                 o_sha = (unsigned char *)null_sha1;
1594         }
1595         one.path = a.path = b.path = (char *)path;
1596         hashcpy(one.sha1, o_sha);
1597         one.mode = o_mode;
1598         hashcpy(a.sha1, a_sha);
1599         a.mode = a_mode;
1600         hashcpy(b.sha1, b_sha);
1601         b.mode = b_mode;
1602
1603         if (rename_conflict_info) {
1604                 struct diff_filepair *pair1 = rename_conflict_info->pair1;
1605
1606                 path1 = (o->branch1 == rename_conflict_info->branch1) ?
1607                         pair1->two->path : pair1->one->path;
1608                 /* If rename_conflict_info->pair2 != NULL, we are in
1609                  * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
1610                  * normal rename.
1611                  */
1612                 path2 = (rename_conflict_info->pair2 ||
1613                          o->branch2 == rename_conflict_info->branch1) ?
1614                         pair1->two->path : pair1->one->path;
1615
1616                 if (dir_in_way(path, !o->call_depth))
1617                         df_conflict_remains = 1;
1618         }
1619         mfi = merge_file_special_markers(o, &one, &a, &b,
1620                                          o->branch1, path1,
1621                                          o->branch2, path2);
1622
1623         if (mfi.clean && !df_conflict_remains &&
1624             sha_eq(mfi.sha, a_sha) && mfi.mode == a_mode) {
1625                 int path_renamed_outside_HEAD;
1626                 output(o, 3, _("Skipped %s (merged same as existing)"), path);
1627                 /*
1628                  * The content merge resulted in the same file contents we
1629                  * already had.  We can return early if those file contents
1630                  * are recorded at the correct path (which may not be true
1631                  * if the merge involves a rename).
1632                  */
1633                 path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
1634                 if (!path_renamed_outside_HEAD) {
1635                         add_cacheinfo(mfi.mode, mfi.sha, path,
1636                                       0, (!o->call_depth), 0);
1637                         return mfi.clean;
1638                 }
1639         } else
1640                 output(o, 2, _("Auto-merging %s"), path);
1641
1642         if (!mfi.clean) {
1643                 if (S_ISGITLINK(mfi.mode))
1644                         reason = _("submodule");
1645                 output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
1646                                 reason, path);
1647                 if (rename_conflict_info && !df_conflict_remains)
1648                         update_stages(path, &one, &a, &b);
1649         }
1650
1651         if (df_conflict_remains) {
1652                 char *new_path;
1653                 if (o->call_depth) {
1654                         remove_file_from_cache(path);
1655                 } else {
1656                         if (!mfi.clean)
1657                                 update_stages(path, &one, &a, &b);
1658                         else {
1659                                 int file_from_stage2 = was_tracked(path);
1660                                 struct diff_filespec merged;
1661                                 hashcpy(merged.sha1, mfi.sha);
1662                                 merged.mode = mfi.mode;
1663
1664                                 update_stages(path, NULL,
1665                                               file_from_stage2 ? &merged : NULL,
1666                                               file_from_stage2 ? NULL : &merged);
1667                         }
1668
1669                 }
1670                 new_path = unique_path(o, path, rename_conflict_info->branch1);
1671                 output(o, 1, _("Adding as %s instead"), new_path);
1672                 update_file(o, 0, mfi.sha, mfi.mode, new_path);
1673                 free(new_path);
1674                 mfi.clean = 0;
1675         } else {
1676                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1677         }
1678         return mfi.clean;
1679
1680 }
1681
1682 /* Per entry merge function */
1683 static int process_entry(struct merge_options *o,
1684                          const char *path, struct stage_data *entry)
1685 {
1686         int clean_merge = 1;
1687         int normalize = o->renormalize;
1688         unsigned o_mode = entry->stages[1].mode;
1689         unsigned a_mode = entry->stages[2].mode;
1690         unsigned b_mode = entry->stages[3].mode;
1691         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1692         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1693         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1694
1695         entry->processed = 1;
1696         if (entry->rename_conflict_info) {
1697                 struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
1698                 switch (conflict_info->rename_type) {
1699                 case RENAME_NORMAL:
1700                 case RENAME_ONE_FILE_TO_ONE:
1701                         clean_merge = merge_content(o, path,
1702                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1703                                                     conflict_info);
1704                         break;
1705                 case RENAME_DELETE:
1706                         clean_merge = 0;
1707                         conflict_rename_delete(o, conflict_info->pair1,
1708                                                conflict_info->branch1,
1709                                                conflict_info->branch2);
1710                         break;
1711                 case RENAME_ONE_FILE_TO_TWO:
1712                         clean_merge = 0;
1713                         conflict_rename_rename_1to2(o, conflict_info);
1714                         break;
1715                 case RENAME_TWO_FILES_TO_ONE:
1716                         clean_merge = 0;
1717                         conflict_rename_rename_2to1(o, conflict_info);
1718                         break;
1719                 default:
1720                         entry->processed = 0;
1721                         break;
1722                 }
1723         } else if (o_sha && (!a_sha || !b_sha)) {
1724                 /* Case A: Deleted in one */
1725                 if ((!a_sha && !b_sha) ||
1726                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1727                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1728                         /* Deleted in both or deleted in one and
1729                          * unchanged in the other */
1730                         if (a_sha)
1731                                 output(o, 2, _("Removing %s"), path);
1732                         /* do not touch working file if it did not exist */
1733                         remove_file(o, 1, path, !a_sha);
1734                 } else {
1735                         /* Modify/delete; deleted side may have put a directory in the way */
1736                         clean_merge = 0;
1737                         handle_modify_delete(o, path, o_sha, o_mode,
1738                                              a_sha, a_mode, b_sha, b_mode);
1739                 }
1740         } else if ((!o_sha && a_sha && !b_sha) ||
1741                    (!o_sha && !a_sha && b_sha)) {
1742                 /* Case B: Added in one. */
1743                 /* [nothing|directory] -> ([nothing|directory], file) */
1744
1745                 const char *add_branch;
1746                 const char *other_branch;
1747                 unsigned mode;
1748                 const unsigned char *sha;
1749                 const char *conf;
1750
1751                 if (a_sha) {
1752                         add_branch = o->branch1;
1753                         other_branch = o->branch2;
1754                         mode = a_mode;
1755                         sha = a_sha;
1756                         conf = _("file/directory");
1757                 } else {
1758                         add_branch = o->branch2;
1759                         other_branch = o->branch1;
1760                         mode = b_mode;
1761                         sha = b_sha;
1762                         conf = _("directory/file");
1763                 }
1764                 if (dir_in_way(path, !o->call_depth)) {
1765                         char *new_path = unique_path(o, path, add_branch);
1766                         clean_merge = 0;
1767                         output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
1768                                "Adding %s as %s"),
1769                                conf, path, other_branch, path, new_path);
1770                         if (o->call_depth)
1771                                 remove_file_from_cache(path);
1772                         update_file(o, 0, sha, mode, new_path);
1773                         if (o->call_depth)
1774                                 remove_file_from_cache(path);
1775                         free(new_path);
1776                 } else {
1777                         output(o, 2, _("Adding %s"), path);
1778                         /* do not overwrite file if already present */
1779                         update_file_flags(o, sha, mode, path, 1, !a_sha);
1780                 }
1781         } else if (a_sha && b_sha) {
1782                 /* Case C: Added in both (check for same permissions) and */
1783                 /* case D: Modified in both, but differently. */
1784                 clean_merge = merge_content(o, path,
1785                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1786                                             NULL);
1787         } else if (!o_sha && !a_sha && !b_sha) {
1788                 /*
1789                  * this entry was deleted altogether. a_mode == 0 means
1790                  * we had that path and want to actively remove it.
1791                  */
1792                 remove_file(o, 1, path, !a_mode);
1793         } else
1794                 die(_("Fatal merge failure, shouldn't happen."));
1795
1796         return clean_merge;
1797 }
1798
1799 int merge_trees(struct merge_options *o,
1800                 struct tree *head,
1801                 struct tree *merge,
1802                 struct tree *common,
1803                 struct tree **result)
1804 {
1805         int code, clean;
1806
1807         if (o->subtree_shift) {
1808                 merge = shift_tree_object(head, merge, o->subtree_shift);
1809                 common = shift_tree_object(head, common, o->subtree_shift);
1810         }
1811
1812         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1813                 output(o, 0, _("Already up-to-date!"));
1814                 *result = head;
1815                 return 1;
1816         }
1817
1818         code = git_merge_trees(o->call_depth, common, head, merge);
1819
1820         if (code != 0) {
1821                 if (show(o, 4) || o->call_depth)
1822                         die(_("merging of trees %s and %s failed"),
1823                             sha1_to_hex(head->object.sha1),
1824                             sha1_to_hex(merge->object.sha1));
1825                 else
1826                         exit(128);
1827         }
1828
1829         if (unmerged_cache()) {
1830                 struct string_list *entries, *re_head, *re_merge;
1831                 int i;
1832                 string_list_clear(&o->current_file_set, 1);
1833                 string_list_clear(&o->current_directory_set, 1);
1834                 get_files_dirs(o, head);
1835                 get_files_dirs(o, merge);
1836
1837                 entries = get_unmerged();
1838                 record_df_conflict_files(o, entries);
1839                 re_head  = get_renames(o, head, common, head, merge, entries);
1840                 re_merge = get_renames(o, merge, common, head, merge, entries);
1841                 clean = process_renames(o, re_head, re_merge);
1842                 for (i = entries->nr-1; 0 <= i; i--) {
1843                         const char *path = entries->items[i].string;
1844                         struct stage_data *e = entries->items[i].util;
1845                         if (!e->processed
1846                                 && !process_entry(o, path, e))
1847                                 clean = 0;
1848                 }
1849                 for (i = 0; i < entries->nr; i++) {
1850                         struct stage_data *e = entries->items[i].util;
1851                         if (!e->processed)
1852                                 die(_("Unprocessed path??? %s"),
1853                                     entries->items[i].string);
1854                 }
1855
1856                 string_list_clear(re_merge, 0);
1857                 string_list_clear(re_head, 0);
1858                 string_list_clear(entries, 1);
1859
1860                 free(re_merge);
1861                 free(re_head);
1862                 free(entries);
1863         }
1864         else
1865                 clean = 1;
1866
1867         if (o->call_depth)
1868                 *result = write_tree_from_memory(o);
1869
1870         return clean;
1871 }
1872
1873 static struct commit_list *reverse_commit_list(struct commit_list *list)
1874 {
1875         struct commit_list *next = NULL, *current, *backup;
1876         for (current = list; current; current = backup) {
1877                 backup = current->next;
1878                 current->next = next;
1879                 next = current;
1880         }
1881         return next;
1882 }
1883
1884 /*
1885  * Merge the commits h1 and h2, return the resulting virtual
1886  * commit object and a flag indicating the cleanness of the merge.
1887  */
1888 int merge_recursive(struct merge_options *o,
1889                     struct commit *h1,
1890                     struct commit *h2,
1891                     struct commit_list *ca,
1892                     struct commit **result)
1893 {
1894         struct commit_list *iter;
1895         struct commit *merged_common_ancestors;
1896         struct tree *mrtree = mrtree;
1897         int clean;
1898
1899         if (show(o, 4)) {
1900                 output(o, 4, _("Merging:"));
1901                 output_commit_title(o, h1);
1902                 output_commit_title(o, h2);
1903         }
1904
1905         if (!ca) {
1906                 ca = get_merge_bases(h1, h2);
1907                 ca = reverse_commit_list(ca);
1908         }
1909
1910         if (show(o, 5)) {
1911                 unsigned cnt = commit_list_count(ca);
1912
1913                 output(o, 5, Q_("found %u common ancestor:",
1914                                 "found %u common ancestors:", cnt), cnt);
1915                 for (iter = ca; iter; iter = iter->next)
1916                         output_commit_title(o, iter->item);
1917         }
1918
1919         merged_common_ancestors = pop_commit(&ca);
1920         if (merged_common_ancestors == NULL) {
1921                 /* if there is no common ancestor, use an empty tree */
1922                 struct tree *tree;
1923
1924                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1925                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1926         }
1927
1928         for (iter = ca; iter; iter = iter->next) {
1929                 const char *saved_b1, *saved_b2;
1930                 o->call_depth++;
1931                 /*
1932                  * When the merge fails, the result contains files
1933                  * with conflict markers. The cleanness flag is
1934                  * ignored, it was never actually used, as result of
1935                  * merge_trees has always overwritten it: the committed
1936                  * "conflicts" were already resolved.
1937                  */
1938                 discard_cache();
1939                 saved_b1 = o->branch1;
1940                 saved_b2 = o->branch2;
1941                 o->branch1 = "Temporary merge branch 1";
1942                 o->branch2 = "Temporary merge branch 2";
1943                 merge_recursive(o, merged_common_ancestors, iter->item,
1944                                 NULL, &merged_common_ancestors);
1945                 o->branch1 = saved_b1;
1946                 o->branch2 = saved_b2;
1947                 o->call_depth--;
1948
1949                 if (!merged_common_ancestors)
1950                         die(_("merge returned no commit"));
1951         }
1952
1953         discard_cache();
1954         if (!o->call_depth)
1955                 read_cache();
1956
1957         o->ancestor = "merged common ancestors";
1958         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1959                             &mrtree);
1960
1961         if (o->call_depth) {
1962                 *result = make_virtual_commit(mrtree, "merged tree");
1963                 commit_list_insert(h1, &(*result)->parents);
1964                 commit_list_insert(h2, &(*result)->parents->next);
1965         }
1966         flush_output(o);
1967         if (show(o, 2))
1968                 diff_warn_rename_limit("merge.renamelimit",
1969                                        o->needed_rename_limit, 0);
1970         return clean;
1971 }
1972
1973 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1974 {
1975         struct object *object;
1976
1977         object = deref_tag(parse_object(sha1), name, strlen(name));
1978         if (!object)
1979                 return NULL;
1980         if (object->type == OBJ_TREE)
1981                 return make_virtual_commit((struct tree*)object, name);
1982         if (object->type != OBJ_COMMIT)
1983                 return NULL;
1984         if (parse_commit((struct commit *)object))
1985                 return NULL;
1986         return (struct commit *)object;
1987 }
1988
1989 int merge_recursive_generic(struct merge_options *o,
1990                             const unsigned char *head,
1991                             const unsigned char *merge,
1992                             int num_base_list,
1993                             const unsigned char **base_list,
1994                             struct commit **result)
1995 {
1996         int clean;
1997         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1998         struct commit *head_commit = get_ref(head, o->branch1);
1999         struct commit *next_commit = get_ref(merge, o->branch2);
2000         struct commit_list *ca = NULL;
2001
2002         if (base_list) {
2003                 int i;
2004                 for (i = 0; i < num_base_list; ++i) {
2005                         struct commit *base;
2006                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
2007                                 return error(_("Could not parse object '%s'"),
2008                                         sha1_to_hex(base_list[i]));
2009                         commit_list_insert(base, &ca);
2010                 }
2011         }
2012
2013         hold_locked_index(lock, 1);
2014         clean = merge_recursive(o, head_commit, next_commit, ca,
2015                         result);
2016         if (active_cache_changed &&
2017             write_locked_index(&the_index, lock, COMMIT_LOCK))
2018                 return error(_("Unable to write index."));
2019
2020         return clean ? 0 : 1;
2021 }
2022
2023 static void merge_recursive_config(struct merge_options *o)
2024 {
2025         git_config_get_int("merge.verbosity", &o->verbosity);
2026         git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
2027         git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
2028         git_config(git_xmerge_config, NULL);
2029 }
2030
2031 void init_merge_options(struct merge_options *o)
2032 {
2033         memset(o, 0, sizeof(struct merge_options));
2034         o->verbosity = 2;
2035         o->buffer_output = 1;
2036         o->diff_rename_limit = -1;
2037         o->merge_rename_limit = -1;
2038         o->renormalize = 0;
2039         merge_recursive_config(o);
2040         if (getenv("GIT_MERGE_VERBOSITY"))
2041                 o->verbosity =
2042                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
2043         if (o->verbosity >= 5)
2044                 o->buffer_output = 0;
2045         strbuf_init(&o->obuf, 0);
2046         string_list_init(&o->current_file_set, 1);
2047         string_list_init(&o->current_directory_set, 1);
2048         string_list_init(&o->df_conflict_file_set, 1);
2049 }
2050
2051 int parse_merge_opt(struct merge_options *o, const char *s)
2052 {
2053         const char *arg;
2054
2055         if (!s || !*s)
2056                 return -1;
2057         if (!strcmp(s, "ours"))
2058                 o->recursive_variant = MERGE_RECURSIVE_OURS;
2059         else if (!strcmp(s, "theirs"))
2060                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
2061         else if (!strcmp(s, "subtree"))
2062                 o->subtree_shift = "";
2063         else if (skip_prefix(s, "subtree=", &arg))
2064                 o->subtree_shift = arg;
2065         else if (!strcmp(s, "patience"))
2066                 o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
2067         else if (!strcmp(s, "histogram"))
2068                 o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
2069         else if (skip_prefix(s, "diff-algorithm=", &arg)) {
2070                 long value = parse_algorithm_value(arg);
2071                 if (value < 0)
2072                         return -1;
2073                 /* clear out previous settings */
2074                 DIFF_XDL_CLR(o, NEED_MINIMAL);
2075                 o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
2076                 o->xdl_opts |= value;
2077         }
2078         else if (!strcmp(s, "ignore-space-change"))
2079                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2080         else if (!strcmp(s, "ignore-all-space"))
2081                 o->xdl_opts |= XDF_IGNORE_WHITESPACE;
2082         else if (!strcmp(s, "ignore-space-at-eol"))
2083                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2084         else if (!strcmp(s, "renormalize"))
2085                 o->renormalize = 1;
2086         else if (!strcmp(s, "no-renormalize"))
2087                 o->renormalize = 0;
2088         else if (skip_prefix(s, "rename-threshold=", &arg)) {
2089                 if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
2090                         return -1;
2091         }
2092         else
2093                 return -1;
2094         return 0;
2095 }