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