Merge branch 'jk/ansi-color'
[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         struct object_id shifted;
30
31         if (!*subtree_shift) {
32                 shift_tree(&one->object.oid, &two->object.oid, &shifted, 0);
33         } else {
34                 shift_tree_by(&one->object.oid, &two->object.oid, &shifted,
35                               subtree_shift);
36         }
37         if (!oidcmp(&two->object.oid, &shifted))
38                 return two;
39         return lookup_tree(shifted.hash);
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.oid.hash, DEFAULT_ABBREV));
188                 if (parse_commit(commit) != 0)
189                         printf(_("(bad commit)\n"));
190                 else {
191                         const char *title;
192                         const char *msg = get_commit_buffer(commit, NULL);
193                         int len = find_commit_subject(msg, &title);
194                         if (len)
195                                 printf("%.*s\n", len, title);
196                         unuse_commit_buffer(commit, msg);
197                 }
198         }
199 }
200
201 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
202                 const char *path, int stage, int refresh, int options)
203 {
204         struct cache_entry *ce;
205         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage,
206                               (refresh ? (CE_MATCH_REFRESH |
207                                           CE_MATCH_IGNORE_MISSING) : 0 ));
208         if (!ce)
209                 return error(_("addinfo_cache failed for path '%s'"), path);
210         return add_cache_entry(ce, options);
211 }
212
213 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
214 {
215         parse_tree(tree);
216         init_tree_desc(desc, tree->buffer, tree->size);
217 }
218
219 static int git_merge_trees(int index_only,
220                            struct tree *common,
221                            struct tree *head,
222                            struct tree *merge)
223 {
224         int rc;
225         struct tree_desc t[3];
226         struct unpack_trees_options opts;
227
228         memset(&opts, 0, sizeof(opts));
229         if (index_only)
230                 opts.index_only = 1;
231         else
232                 opts.update = 1;
233         opts.merge = 1;
234         opts.head_idx = 2;
235         opts.fn = threeway_merge;
236         opts.src_index = &the_index;
237         opts.dst_index = &the_index;
238         setup_unpack_trees_porcelain(&opts, "merge");
239
240         init_tree_desc_from_tree(t+0, common);
241         init_tree_desc_from_tree(t+1, head);
242         init_tree_desc_from_tree(t+2, merge);
243
244         rc = unpack_trees(3, t, &opts);
245         cache_tree_free(&active_cache_tree);
246         return rc;
247 }
248
249 struct tree *write_tree_from_memory(struct merge_options *o)
250 {
251         struct tree *result = NULL;
252
253         if (unmerged_cache()) {
254                 int i;
255                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
256                 for (i = 0; i < active_nr; i++) {
257                         const struct cache_entry *ce = active_cache[i];
258                         if (ce_stage(ce))
259                                 fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
260                                         (int)ce_namelen(ce), ce->name);
261                 }
262                 die("Bug in merge-recursive.c");
263         }
264
265         if (!active_cache_tree)
266                 active_cache_tree = cache_tree();
267
268         if (!cache_tree_fully_valid(active_cache_tree) &&
269             cache_tree_update(&the_index, 0) < 0)
270                 die(_("error building trees"));
271
272         result = lookup_tree(active_cache_tree->sha1);
273
274         return result;
275 }
276
277 static int save_files_dirs(const unsigned char *sha1,
278                 struct strbuf *base, const char *path,
279                 unsigned int mode, int stage, void *context)
280 {
281         int baselen = base->len;
282         struct merge_options *o = context;
283
284         strbuf_addstr(base, path);
285
286         if (S_ISDIR(mode))
287                 string_list_insert(&o->current_directory_set, base->buf);
288         else
289                 string_list_insert(&o->current_file_set, base->buf);
290
291         strbuf_setlen(base, baselen);
292         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
293 }
294
295 static int get_files_dirs(struct merge_options *o, struct tree *tree)
296 {
297         int n;
298         struct pathspec match_all;
299         memset(&match_all, 0, sizeof(match_all));
300         if (read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o))
301                 return 0;
302         n = o->current_file_set.nr + o->current_directory_set.nr;
303         return n;
304 }
305
306 /*
307  * Returns an index_entry instance which doesn't have to correspond to
308  * a real cache entry in Git's index.
309  */
310 static struct stage_data *insert_stage_data(const char *path,
311                 struct tree *o, struct tree *a, struct tree *b,
312                 struct string_list *entries)
313 {
314         struct string_list_item *item;
315         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
316         get_tree_entry(o->object.oid.hash, path,
317                         e->stages[1].sha, &e->stages[1].mode);
318         get_tree_entry(a->object.oid.hash, path,
319                         e->stages[2].sha, &e->stages[2].mode);
320         get_tree_entry(b->object.oid.hash, path,
321                         e->stages[3].sha, &e->stages[3].mode);
322         item = string_list_insert(entries, path);
323         item->util = e;
324         return e;
325 }
326
327 /*
328  * Create a dictionary mapping file names to stage_data objects. The
329  * dictionary contains one entry for every path with a non-zero stage entry.
330  */
331 static struct string_list *get_unmerged(void)
332 {
333         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
334         int i;
335
336         unmerged->strdup_strings = 1;
337
338         for (i = 0; i < active_nr; i++) {
339                 struct string_list_item *item;
340                 struct stage_data *e;
341                 const struct cache_entry *ce = active_cache[i];
342                 if (!ce_stage(ce))
343                         continue;
344
345                 item = string_list_lookup(unmerged, ce->name);
346                 if (!item) {
347                         item = string_list_insert(unmerged, ce->name);
348                         item->util = xcalloc(1, sizeof(struct stage_data));
349                 }
350                 e = item->util;
351                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
352                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
353         }
354
355         return unmerged;
356 }
357
358 static int string_list_df_name_compare(const void *a, const void *b)
359 {
360         const struct string_list_item *one = a;
361         const struct string_list_item *two = b;
362         int onelen = strlen(one->string);
363         int twolen = strlen(two->string);
364         /*
365          * Here we only care that entries for D/F conflicts are
366          * adjacent, in particular with the file of the D/F conflict
367          * appearing before files below the corresponding directory.
368          * The order of the rest of the list is irrelevant for us.
369          *
370          * To achieve this, we sort with df_name_compare and provide
371          * the mode S_IFDIR so that D/F conflicts will sort correctly.
372          * We use the mode S_IFDIR for everything else for simplicity,
373          * since in other cases any changes in their order due to
374          * sorting cause no problems for us.
375          */
376         int cmp = df_name_compare(one->string, onelen, S_IFDIR,
377                                   two->string, twolen, S_IFDIR);
378         /*
379          * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
380          * that 'foo' comes before 'foo/bar'.
381          */
382         if (cmp)
383                 return cmp;
384         return onelen - twolen;
385 }
386
387 static void record_df_conflict_files(struct merge_options *o,
388                                      struct string_list *entries)
389 {
390         /* If there is a D/F conflict and the file for such a conflict
391          * currently exist in the working tree, we want to allow it to be
392          * removed to make room for the corresponding directory if needed.
393          * The files underneath the directories of such D/F conflicts will
394          * be processed before the corresponding file involved in the D/F
395          * conflict.  If the D/F directory ends up being removed by the
396          * merge, then we won't have to touch the D/F file.  If the D/F
397          * directory needs to be written to the working copy, then the D/F
398          * file will simply be removed (in make_room_for_path()) to make
399          * room for the necessary paths.  Note that if both the directory
400          * and the file need to be present, then the D/F file will be
401          * reinstated with a new unique name at the time it is processed.
402          */
403         struct string_list df_sorted_entries;
404         const char *last_file = NULL;
405         int last_len = 0;
406         int i;
407
408         /*
409          * If we're merging merge-bases, we don't want to bother with
410          * any working directory changes.
411          */
412         if (o->call_depth)
413                 return;
414
415         /* Ensure D/F conflicts are adjacent in the entries list. */
416         memset(&df_sorted_entries, 0, sizeof(struct string_list));
417         for (i = 0; i < entries->nr; i++) {
418                 struct string_list_item *next = &entries->items[i];
419                 string_list_append(&df_sorted_entries, next->string)->util =
420                                    next->util;
421         }
422         qsort(df_sorted_entries.items, entries->nr, sizeof(*entries->items),
423               string_list_df_name_compare);
424
425         string_list_clear(&o->df_conflict_file_set, 1);
426         for (i = 0; i < df_sorted_entries.nr; i++) {
427                 const char *path = df_sorted_entries.items[i].string;
428                 int len = strlen(path);
429                 struct stage_data *e = df_sorted_entries.items[i].util;
430
431                 /*
432                  * Check if last_file & path correspond to a D/F conflict;
433                  * i.e. whether path is last_file+'/'+<something>.
434                  * If so, record that it's okay to remove last_file to make
435                  * room for path and friends if needed.
436                  */
437                 if (last_file &&
438                     len > last_len &&
439                     memcmp(path, last_file, last_len) == 0 &&
440                     path[last_len] == '/') {
441                         string_list_insert(&o->df_conflict_file_set, last_file);
442                 }
443
444                 /*
445                  * Determine whether path could exist as a file in the
446                  * working directory as a possible D/F conflict.  This
447                  * will only occur when it exists in stage 2 as a
448                  * file.
449                  */
450                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
451                         last_file = path;
452                         last_len = len;
453                 } else {
454                         last_file = NULL;
455                 }
456         }
457         string_list_clear(&df_sorted_entries, 0);
458 }
459
460 struct rename {
461         struct diff_filepair *pair;
462         struct stage_data *src_entry;
463         struct stage_data *dst_entry;
464         unsigned processed:1;
465 };
466
467 /*
468  * Get information of all renames which occurred between 'o_tree' and
469  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
470  * 'b_tree') to be able to associate the correct cache entries with
471  * the rename information. 'tree' is always equal to either a_tree or b_tree.
472  */
473 static struct string_list *get_renames(struct merge_options *o,
474                                        struct tree *tree,
475                                        struct tree *o_tree,
476                                        struct tree *a_tree,
477                                        struct tree *b_tree,
478                                        struct string_list *entries)
479 {
480         int i;
481         struct string_list *renames;
482         struct diff_options opts;
483
484         renames = xcalloc(1, sizeof(struct string_list));
485         if (!o->detect_rename)
486                 return renames;
487
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.oid.hash, tree->object.oid.hash, "", &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         size_t base_len;
618
619         strbuf_addf(&newpath, "%s~", path);
620         add_flattened_path(&newpath, branch);
621
622         base_len = newpath.len;
623         while (string_list_has_string(&o->current_file_set, newpath.buf) ||
624                string_list_has_string(&o->current_directory_set, newpath.buf) ||
625                (!o->call_depth && file_exists(newpath.buf))) {
626                 strbuf_setlen(&newpath, base_len);
627                 strbuf_addf(&newpath, "_%d", suffix++);
628         }
629
630         string_list_insert(&o->current_file_set, newpath.buf);
631         return strbuf_detach(&newpath, NULL);
632 }
633
634 static int dir_in_way(const char *path, int check_working_copy)
635 {
636         int pos;
637         struct strbuf dirpath = STRBUF_INIT;
638         struct stat st;
639
640         strbuf_addstr(&dirpath, path);
641         strbuf_addch(&dirpath, '/');
642
643         pos = cache_name_pos(dirpath.buf, dirpath.len);
644
645         if (pos < 0)
646                 pos = -1 - pos;
647         if (pos < active_nr &&
648             !strncmp(dirpath.buf, active_cache[pos]->name, dirpath.len)) {
649                 strbuf_release(&dirpath);
650                 return 1;
651         }
652
653         strbuf_release(&dirpath);
654         return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode);
655 }
656
657 static int was_tracked(const char *path)
658 {
659         int pos = cache_name_pos(path, strlen(path));
660
661         if (pos < 0)
662                 pos = -1 - pos;
663         while (pos < active_nr &&
664                !strcmp(path, active_cache[pos]->name)) {
665                 /*
666                  * If stage #0, it is definitely tracked.
667                  * If it has stage #2 then it was tracked
668                  * before this merge started.  All other
669                  * cases the path was not tracked.
670                  */
671                 switch (ce_stage(active_cache[pos])) {
672                 case 0:
673                 case 2:
674                         return 1;
675                 }
676                 pos++;
677         }
678         return 0;
679 }
680
681 static int would_lose_untracked(const char *path)
682 {
683         return !was_tracked(path) && file_exists(path);
684 }
685
686 static int make_room_for_path(struct merge_options *o, const char *path)
687 {
688         int status, i;
689         const char *msg = _("failed to create path '%s'%s");
690
691         /* Unlink any D/F conflict files that are in the way */
692         for (i = 0; i < o->df_conflict_file_set.nr; i++) {
693                 const char *df_path = o->df_conflict_file_set.items[i].string;
694                 size_t pathlen = strlen(path);
695                 size_t df_pathlen = strlen(df_path);
696                 if (df_pathlen < pathlen &&
697                     path[df_pathlen] == '/' &&
698                     strncmp(path, df_path, df_pathlen) == 0) {
699                         output(o, 3,
700                                _("Removing %s to make room for subdirectory\n"),
701                                df_path);
702                         unlink(df_path);
703                         unsorted_string_list_delete_item(&o->df_conflict_file_set,
704                                                          i, 0);
705                         break;
706                 }
707         }
708
709         /* Make sure leading directories are created */
710         status = safe_create_leading_directories_const(path);
711         if (status) {
712                 if (status == SCLD_EXISTS) {
713                         /* something else exists */
714                         error(msg, path, _(": perhaps a D/F conflict?"));
715                         return -1;
716                 }
717                 die(msg, path, "");
718         }
719
720         /*
721          * Do not unlink a file in the work tree if we are not
722          * tracking it.
723          */
724         if (would_lose_untracked(path))
725                 return error(_("refusing to lose untracked file at '%s'"),
726                              path);
727
728         /* Successful unlink is good.. */
729         if (!unlink(path))
730                 return 0;
731         /* .. and so is no existing file */
732         if (errno == ENOENT)
733                 return 0;
734         /* .. but not some other error (who really cares what?) */
735         return error(msg, path, _(": perhaps a D/F conflict?"));
736 }
737
738 static void update_file_flags(struct merge_options *o,
739                               const unsigned char *sha,
740                               unsigned mode,
741                               const char *path,
742                               int update_cache,
743                               int update_wd)
744 {
745         if (o->call_depth)
746                 update_wd = 0;
747
748         if (update_wd) {
749                 enum object_type type;
750                 void *buf;
751                 unsigned long size;
752
753                 if (S_ISGITLINK(mode)) {
754                         /*
755                          * We may later decide to recursively descend into
756                          * the submodule directory and update its index
757                          * and/or work tree, but we do not do that now.
758                          */
759                         update_wd = 0;
760                         goto update_index;
761                 }
762
763                 buf = read_sha1_file(sha, &type, &size);
764                 if (!buf)
765                         die(_("cannot read object %s '%s'"), sha1_to_hex(sha), path);
766                 if (type != OBJ_BLOB)
767                         die(_("blob expected for %s '%s'"), sha1_to_hex(sha), path);
768                 if (S_ISREG(mode)) {
769                         struct strbuf strbuf = STRBUF_INIT;
770                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
771                                 free(buf);
772                                 size = strbuf.len;
773                                 buf = strbuf_detach(&strbuf, NULL);
774                         }
775                 }
776
777                 if (make_room_for_path(o, path) < 0) {
778                         update_wd = 0;
779                         free(buf);
780                         goto update_index;
781                 }
782                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
783                         int fd;
784                         if (mode & 0100)
785                                 mode = 0777;
786                         else
787                                 mode = 0666;
788                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
789                         if (fd < 0)
790                                 die_errno(_("failed to open '%s'"), path);
791                         write_in_full(fd, buf, size);
792                         close(fd);
793                 } else if (S_ISLNK(mode)) {
794                         char *lnk = xmemdupz(buf, size);
795                         safe_create_leading_directories_const(path);
796                         unlink(path);
797                         if (symlink(lnk, path))
798                                 die_errno(_("failed to symlink '%s'"), path);
799                         free(lnk);
800                 } else
801                         die(_("do not know what to do with %06o %s '%s'"),
802                             mode, sha1_to_hex(sha), path);
803                 free(buf);
804         }
805  update_index:
806         if (update_cache)
807                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
808 }
809
810 static void update_file(struct merge_options *o,
811                         int clean,
812                         const unsigned char *sha,
813                         unsigned mode,
814                         const char *path)
815 {
816         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
817 }
818
819 /* Low level file merging, update and removal */
820
821 struct merge_file_info {
822         unsigned char sha[20];
823         unsigned mode;
824         unsigned clean:1,
825                  merge:1;
826 };
827
828 static int merge_3way(struct merge_options *o,
829                       mmbuffer_t *result_buf,
830                       const struct diff_filespec *one,
831                       const struct diff_filespec *a,
832                       const struct diff_filespec *b,
833                       const char *branch1,
834                       const char *branch2)
835 {
836         mmfile_t orig, src1, src2;
837         struct ll_merge_options ll_opts = {0};
838         char *base_name, *name1, *name2;
839         int merge_status;
840
841         ll_opts.renormalize = o->renormalize;
842         ll_opts.xdl_opts = o->xdl_opts;
843
844         if (o->call_depth) {
845                 ll_opts.virtual_ancestor = 1;
846                 ll_opts.variant = 0;
847         } else {
848                 switch (o->recursive_variant) {
849                 case MERGE_RECURSIVE_OURS:
850                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
851                         break;
852                 case MERGE_RECURSIVE_THEIRS:
853                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
854                         break;
855                 default:
856                         ll_opts.variant = 0;
857                         break;
858                 }
859         }
860
861         if (strcmp(a->path, b->path) ||
862             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
863                 base_name = o->ancestor == NULL ? NULL :
864                         mkpathdup("%s:%s", o->ancestor, one->path);
865                 name1 = mkpathdup("%s:%s", branch1, a->path);
866                 name2 = mkpathdup("%s:%s", branch2, b->path);
867         } else {
868                 base_name = o->ancestor == NULL ? NULL :
869                         mkpathdup("%s", o->ancestor);
870                 name1 = mkpathdup("%s", branch1);
871                 name2 = mkpathdup("%s", branch2);
872         }
873
874         read_mmblob(&orig, one->sha1);
875         read_mmblob(&src1, a->sha1);
876         read_mmblob(&src2, b->sha1);
877
878         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
879                                 &src1, name1, &src2, name2, &ll_opts);
880
881         free(base_name);
882         free(name1);
883         free(name2);
884         free(orig.ptr);
885         free(src1.ptr);
886         free(src2.ptr);
887         return merge_status;
888 }
889
890 static struct merge_file_info merge_file_1(struct merge_options *o,
891                                            const struct diff_filespec *one,
892                                            const struct diff_filespec *a,
893                                            const struct diff_filespec *b,
894                                            const char *branch1,
895                                            const char *branch2)
896 {
897         struct merge_file_info result;
898         result.merge = 0;
899         result.clean = 1;
900
901         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
902                 result.clean = 0;
903                 if (S_ISREG(a->mode)) {
904                         result.mode = a->mode;
905                         hashcpy(result.sha, a->sha1);
906                 } else {
907                         result.mode = b->mode;
908                         hashcpy(result.sha, b->sha1);
909                 }
910         } else {
911                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
912                         result.merge = 1;
913
914                 /*
915                  * Merge modes
916                  */
917                 if (a->mode == b->mode || a->mode == one->mode)
918                         result.mode = b->mode;
919                 else {
920                         result.mode = a->mode;
921                         if (b->mode != one->mode) {
922                                 result.clean = 0;
923                                 result.merge = 1;
924                         }
925                 }
926
927                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
928                         hashcpy(result.sha, b->sha1);
929                 else if (sha_eq(b->sha1, one->sha1))
930                         hashcpy(result.sha, a->sha1);
931                 else if (S_ISREG(a->mode)) {
932                         mmbuffer_t result_buf;
933                         int merge_status;
934
935                         merge_status = merge_3way(o, &result_buf, one, a, b,
936                                                   branch1, branch2);
937
938                         if ((merge_status < 0) || !result_buf.ptr)
939                                 die(_("Failed to execute internal merge"));
940
941                         if (write_sha1_file(result_buf.ptr, result_buf.size,
942                                             blob_type, result.sha))
943                                 die(_("Unable to add %s to database"),
944                                     a->path);
945
946                         free(result_buf.ptr);
947                         result.clean = (merge_status == 0);
948                 } else if (S_ISGITLINK(a->mode)) {
949                         result.clean = merge_submodule(result.sha,
950                                                        one->path, one->sha1,
951                                                        a->sha1, b->sha1,
952                                                        !o->call_depth);
953                 } else if (S_ISLNK(a->mode)) {
954                         hashcpy(result.sha, a->sha1);
955
956                         if (!sha_eq(a->sha1, b->sha1))
957                                 result.clean = 0;
958                 } else {
959                         die(_("unsupported object type in the tree"));
960                 }
961         }
962
963         return result;
964 }
965
966 static struct merge_file_info
967 merge_file_special_markers(struct merge_options *o,
968                            const struct diff_filespec *one,
969                            const struct diff_filespec *a,
970                            const struct diff_filespec *b,
971                            const char *branch1,
972                            const char *filename1,
973                            const char *branch2,
974                            const char *filename2)
975 {
976         char *side1 = NULL;
977         char *side2 = NULL;
978         struct merge_file_info mfi;
979
980         if (filename1)
981                 side1 = xstrfmt("%s:%s", branch1, filename1);
982         if (filename2)
983                 side2 = xstrfmt("%s:%s", branch2, filename2);
984
985         mfi = merge_file_1(o, one, a, b,
986                            side1 ? side1 : branch1, side2 ? side2 : branch2);
987         free(side1);
988         free(side2);
989         return mfi;
990 }
991
992 static struct merge_file_info merge_file_one(struct merge_options *o,
993                                          const char *path,
994                                          const unsigned char *o_sha, int o_mode,
995                                          const unsigned char *a_sha, int a_mode,
996                                          const unsigned char *b_sha, int b_mode,
997                                          const char *branch1,
998                                          const char *branch2)
999 {
1000         struct diff_filespec one, a, b;
1001
1002         one.path = a.path = b.path = (char *)path;
1003         hashcpy(one.sha1, o_sha);
1004         one.mode = o_mode;
1005         hashcpy(a.sha1, a_sha);
1006         a.mode = a_mode;
1007         hashcpy(b.sha1, b_sha);
1008         b.mode = b_mode;
1009         return merge_file_1(o, &one, &a, &b, branch1, branch2);
1010 }
1011
1012 static void handle_change_delete(struct merge_options *o,
1013                                  const char *path,
1014                                  const unsigned char *o_sha, int o_mode,
1015                                  const unsigned char *a_sha, int a_mode,
1016                                  const unsigned char *b_sha, int b_mode,
1017                                  const char *change, const char *change_past)
1018 {
1019         char *renamed = NULL;
1020         if (dir_in_way(path, !o->call_depth)) {
1021                 renamed = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1022         }
1023
1024         if (o->call_depth) {
1025                 /*
1026                  * We cannot arbitrarily accept either a_sha or b_sha as
1027                  * correct; since there is no true "middle point" between
1028                  * them, simply reuse the base version for virtual merge base.
1029                  */
1030                 remove_file_from_cache(path);
1031                 update_file(o, 0, o_sha, o_mode, renamed ? renamed : path);
1032         } else if (!a_sha) {
1033                 if (!renamed) {
1034                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1035                                "and %s in %s. Version %s of %s left in tree."),
1036                                change, path, o->branch1, change_past,
1037                                o->branch2, o->branch2, path);
1038                         update_file(o, 0, b_sha, b_mode, path);
1039                 } else {
1040                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1041                                "and %s in %s. Version %s of %s left in tree at %s."),
1042                                change, path, o->branch1, change_past,
1043                                o->branch2, o->branch2, path, renamed);
1044                         update_file(o, 0, b_sha, b_mode, renamed);
1045                 }
1046         } else {
1047                 if (!renamed) {
1048                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1049                                "and %s in %s. Version %s of %s left in tree."),
1050                                change, path, o->branch2, change_past,
1051                                o->branch1, o->branch1, path);
1052                 } else {
1053                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1054                                "and %s in %s. Version %s of %s left in tree at %s."),
1055                                change, path, o->branch2, change_past,
1056                                o->branch1, o->branch1, path, renamed);
1057                         update_file(o, 0, a_sha, a_mode, renamed);
1058                 }
1059                 /*
1060                  * No need to call update_file() on path when !renamed, since
1061                  * that would needlessly touch path.  We could call
1062                  * update_file_flags() with update_cache=0 and update_wd=0,
1063                  * but that's a no-op.
1064                  */
1065         }
1066         free(renamed);
1067 }
1068
1069 static void conflict_rename_delete(struct merge_options *o,
1070                                    struct diff_filepair *pair,
1071                                    const char *rename_branch,
1072                                    const char *other_branch)
1073 {
1074         const struct diff_filespec *orig = pair->one;
1075         const struct diff_filespec *dest = pair->two;
1076         const unsigned char *a_sha = NULL;
1077         const unsigned char *b_sha = NULL;
1078         int a_mode = 0;
1079         int b_mode = 0;
1080
1081         if (rename_branch == o->branch1) {
1082                 a_sha = dest->sha1;
1083                 a_mode = dest->mode;
1084         } else {
1085                 b_sha = dest->sha1;
1086                 b_mode = dest->mode;
1087         }
1088
1089         handle_change_delete(o,
1090                              o->call_depth ? orig->path : dest->path,
1091                              orig->sha1, orig->mode,
1092                              a_sha, a_mode,
1093                              b_sha, b_mode,
1094                              _("rename"), _("renamed"));
1095
1096         if (o->call_depth) {
1097                 remove_file_from_cache(dest->path);
1098         } else {
1099                 update_stages(dest->path, NULL,
1100                               rename_branch == o->branch1 ? dest : NULL,
1101                               rename_branch == o->branch1 ? NULL : dest);
1102         }
1103
1104 }
1105
1106 static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
1107                                                  struct stage_data *entry,
1108                                                  int stage)
1109 {
1110         unsigned char *sha = entry->stages[stage].sha;
1111         unsigned mode = entry->stages[stage].mode;
1112         if (mode == 0 || is_null_sha1(sha))
1113                 return NULL;
1114         hashcpy(target->sha1, sha);
1115         target->mode = mode;
1116         return target;
1117 }
1118
1119 static void handle_file(struct merge_options *o,
1120                         struct diff_filespec *rename,
1121                         int stage,
1122                         struct rename_conflict_info *ci)
1123 {
1124         char *dst_name = rename->path;
1125         struct stage_data *dst_entry;
1126         const char *cur_branch, *other_branch;
1127         struct diff_filespec other;
1128         struct diff_filespec *add;
1129
1130         if (stage == 2) {
1131                 dst_entry = ci->dst_entry1;
1132                 cur_branch = ci->branch1;
1133                 other_branch = ci->branch2;
1134         } else {
1135                 dst_entry = ci->dst_entry2;
1136                 cur_branch = ci->branch2;
1137                 other_branch = ci->branch1;
1138         }
1139
1140         add = filespec_from_entry(&other, dst_entry, stage ^ 1);
1141         if (add) {
1142                 char *add_name = unique_path(o, rename->path, other_branch);
1143                 update_file(o, 0, add->sha1, add->mode, add_name);
1144
1145                 remove_file(o, 0, rename->path, 0);
1146                 dst_name = unique_path(o, rename->path, cur_branch);
1147         } else {
1148                 if (dir_in_way(rename->path, !o->call_depth)) {
1149                         dst_name = unique_path(o, rename->path, cur_branch);
1150                         output(o, 1, _("%s is a directory in %s adding as %s instead"),
1151                                rename->path, other_branch, dst_name);
1152                 }
1153         }
1154         update_file(o, 0, rename->sha1, rename->mode, dst_name);
1155         if (stage == 2)
1156                 update_stages(rename->path, NULL, rename, add);
1157         else
1158                 update_stages(rename->path, NULL, add, rename);
1159
1160         if (dst_name != rename->path)
1161                 free(dst_name);
1162 }
1163
1164 static void conflict_rename_rename_1to2(struct merge_options *o,
1165                                         struct rename_conflict_info *ci)
1166 {
1167         /* One file was renamed in both branches, but to different names. */
1168         struct diff_filespec *one = ci->pair1->one;
1169         struct diff_filespec *a = ci->pair1->two;
1170         struct diff_filespec *b = ci->pair2->two;
1171
1172         output(o, 1, _("CONFLICT (rename/rename): "
1173                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1174                "rename \"%s\"->\"%s\" in \"%s\"%s"),
1175                one->path, a->path, ci->branch1,
1176                one->path, b->path, ci->branch2,
1177                o->call_depth ? _(" (left unresolved)") : "");
1178         if (o->call_depth) {
1179                 struct merge_file_info mfi;
1180                 struct diff_filespec other;
1181                 struct diff_filespec *add;
1182                 mfi = merge_file_one(o, one->path,
1183                                  one->sha1, one->mode,
1184                                  a->sha1, a->mode,
1185                                  b->sha1, b->mode,
1186                                  ci->branch1, ci->branch2);
1187                 /*
1188                  * FIXME: For rename/add-source conflicts (if we could detect
1189                  * such), this is wrong.  We should instead find a unique
1190                  * pathname and then either rename the add-source file to that
1191                  * unique path, or use that unique path instead of src here.
1192                  */
1193                 update_file(o, 0, mfi.sha, mfi.mode, one->path);
1194
1195                 /*
1196                  * Above, we put the merged content at the merge-base's
1197                  * path.  Now we usually need to delete both a->path and
1198                  * b->path.  However, the rename on each side of the merge
1199                  * could also be involved in a rename/add conflict.  In
1200                  * such cases, we should keep the added file around,
1201                  * resolving the conflict at that path in its favor.
1202                  */
1203                 add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
1204                 if (add)
1205                         update_file(o, 0, add->sha1, add->mode, a->path);
1206                 else
1207                         remove_file_from_cache(a->path);
1208                 add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
1209                 if (add)
1210                         update_file(o, 0, add->sha1, add->mode, b->path);
1211                 else
1212                         remove_file_from_cache(b->path);
1213         } else {
1214                 handle_file(o, a, 2, ci);
1215                 handle_file(o, b, 3, ci);
1216         }
1217 }
1218
1219 static void conflict_rename_rename_2to1(struct merge_options *o,
1220                                         struct rename_conflict_info *ci)
1221 {
1222         /* Two files, a & b, were renamed to the same thing, c. */
1223         struct diff_filespec *a = ci->pair1->one;
1224         struct diff_filespec *b = ci->pair2->one;
1225         struct diff_filespec *c1 = ci->pair1->two;
1226         struct diff_filespec *c2 = ci->pair2->two;
1227         char *path = c1->path; /* == c2->path */
1228         struct merge_file_info mfi_c1;
1229         struct merge_file_info mfi_c2;
1230
1231         output(o, 1, _("CONFLICT (rename/rename): "
1232                "Rename %s->%s in %s. "
1233                "Rename %s->%s in %s"),
1234                a->path, c1->path, ci->branch1,
1235                b->path, c2->path, ci->branch2);
1236
1237         remove_file(o, 1, a->path, o->call_depth || would_lose_untracked(a->path));
1238         remove_file(o, 1, b->path, o->call_depth || would_lose_untracked(b->path));
1239
1240         mfi_c1 = merge_file_special_markers(o, a, c1, &ci->ren1_other,
1241                                             o->branch1, c1->path,
1242                                             o->branch2, ci->ren1_other.path);
1243         mfi_c2 = merge_file_special_markers(o, b, &ci->ren2_other, c2,
1244                                             o->branch1, ci->ren2_other.path,
1245                                             o->branch2, c2->path);
1246
1247         if (o->call_depth) {
1248                 /*
1249                  * If mfi_c1.clean && mfi_c2.clean, then it might make
1250                  * sense to do a two-way merge of those results.  But, I
1251                  * think in all cases, it makes sense to have the virtual
1252                  * merge base just undo the renames; they can be detected
1253                  * again later for the non-recursive merge.
1254                  */
1255                 remove_file(o, 0, path, 0);
1256                 update_file(o, 0, mfi_c1.sha, mfi_c1.mode, a->path);
1257                 update_file(o, 0, mfi_c2.sha, mfi_c2.mode, b->path);
1258         } else {
1259                 char *new_path1 = unique_path(o, path, ci->branch1);
1260                 char *new_path2 = unique_path(o, path, ci->branch2);
1261                 output(o, 1, _("Renaming %s to %s and %s to %s instead"),
1262                        a->path, new_path1, b->path, new_path2);
1263                 remove_file(o, 0, path, 0);
1264                 update_file(o, 0, mfi_c1.sha, mfi_c1.mode, new_path1);
1265                 update_file(o, 0, mfi_c2.sha, mfi_c2.mode, new_path2);
1266                 free(new_path2);
1267                 free(new_path1);
1268         }
1269 }
1270
1271 static int process_renames(struct merge_options *o,
1272                            struct string_list *a_renames,
1273                            struct string_list *b_renames)
1274 {
1275         int clean_merge = 1, i, j;
1276         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
1277         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
1278         const struct rename *sre;
1279
1280         for (i = 0; i < a_renames->nr; i++) {
1281                 sre = a_renames->items[i].util;
1282                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
1283                         = (void *)sre;
1284         }
1285         for (i = 0; i < b_renames->nr; i++) {
1286                 sre = b_renames->items[i].util;
1287                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
1288                         = (void *)sre;
1289         }
1290
1291         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1292                 struct string_list *renames1, *renames2Dst;
1293                 struct rename *ren1 = NULL, *ren2 = NULL;
1294                 const char *branch1, *branch2;
1295                 const char *ren1_src, *ren1_dst;
1296                 struct string_list_item *lookup;
1297
1298                 if (i >= a_renames->nr) {
1299                         ren2 = b_renames->items[j++].util;
1300                 } else if (j >= b_renames->nr) {
1301                         ren1 = a_renames->items[i++].util;
1302                 } else {
1303                         int compare = strcmp(a_renames->items[i].string,
1304                                              b_renames->items[j].string);
1305                         if (compare <= 0)
1306                                 ren1 = a_renames->items[i++].util;
1307                         if (compare >= 0)
1308                                 ren2 = b_renames->items[j++].util;
1309                 }
1310
1311                 /* TODO: refactor, so that 1/2 are not needed */
1312                 if (ren1) {
1313                         renames1 = a_renames;
1314                         renames2Dst = &b_by_dst;
1315                         branch1 = o->branch1;
1316                         branch2 = o->branch2;
1317                 } else {
1318                         struct rename *tmp;
1319                         renames1 = b_renames;
1320                         renames2Dst = &a_by_dst;
1321                         branch1 = o->branch2;
1322                         branch2 = o->branch1;
1323                         tmp = ren2;
1324                         ren2 = ren1;
1325                         ren1 = tmp;
1326                 }
1327
1328                 if (ren1->processed)
1329                         continue;
1330                 ren1->processed = 1;
1331                 ren1->dst_entry->processed = 1;
1332                 /* BUG: We should only mark src_entry as processed if we
1333                  * are not dealing with a rename + add-source case.
1334                  */
1335                 ren1->src_entry->processed = 1;
1336
1337                 ren1_src = ren1->pair->one->path;
1338                 ren1_dst = ren1->pair->two->path;
1339
1340                 if (ren2) {
1341                         /* One file renamed on both sides */
1342                         const char *ren2_src = ren2->pair->one->path;
1343                         const char *ren2_dst = ren2->pair->two->path;
1344                         enum rename_type rename_type;
1345                         if (strcmp(ren1_src, ren2_src) != 0)
1346                                 die("ren1_src != ren2_src");
1347                         ren2->dst_entry->processed = 1;
1348                         ren2->processed = 1;
1349                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1350                                 rename_type = RENAME_ONE_FILE_TO_TWO;
1351                                 clean_merge = 0;
1352                         } else {
1353                                 rename_type = RENAME_ONE_FILE_TO_ONE;
1354                                 /* BUG: We should only remove ren1_src in
1355                                  * the base stage (think of rename +
1356                                  * add-source cases).
1357                                  */
1358                                 remove_file(o, 1, ren1_src, 1);
1359                                 update_entry(ren1->dst_entry,
1360                                              ren1->pair->one,
1361                                              ren1->pair->two,
1362                                              ren2->pair->two);
1363                         }
1364                         setup_rename_conflict_info(rename_type,
1365                                                    ren1->pair,
1366                                                    ren2->pair,
1367                                                    branch1,
1368                                                    branch2,
1369                                                    ren1->dst_entry,
1370                                                    ren2->dst_entry,
1371                                                    o,
1372                                                    NULL,
1373                                                    NULL);
1374                 } else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
1375                         /* Two different files renamed to the same thing */
1376                         char *ren2_dst;
1377                         ren2 = lookup->util;
1378                         ren2_dst = ren2->pair->two->path;
1379                         if (strcmp(ren1_dst, ren2_dst) != 0)
1380                                 die("ren1_dst != ren2_dst");
1381
1382                         clean_merge = 0;
1383                         ren2->processed = 1;
1384                         /*
1385                          * BUG: We should only mark src_entry as processed
1386                          * if we are not dealing with a rename + add-source
1387                          * case.
1388                          */
1389                         ren2->src_entry->processed = 1;
1390
1391                         setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
1392                                                    ren1->pair,
1393                                                    ren2->pair,
1394                                                    branch1,
1395                                                    branch2,
1396                                                    ren1->dst_entry,
1397                                                    ren2->dst_entry,
1398                                                    o,
1399                                                    ren1->src_entry,
1400                                                    ren2->src_entry);
1401
1402                 } else {
1403                         /* Renamed in 1, maybe changed in 2 */
1404                         /* we only use sha1 and mode of these */
1405                         struct diff_filespec src_other, dst_other;
1406                         int try_merge;
1407
1408                         /*
1409                          * unpack_trees loads entries from common-commit
1410                          * into stage 1, from head-commit into stage 2, and
1411                          * from merge-commit into stage 3.  We keep track
1412                          * of which side corresponds to the rename.
1413                          */
1414                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1415                         int other_stage =   a_renames == renames1 ? 3 : 2;
1416
1417                         /* BUG: We should only remove ren1_src in the base
1418                          * stage and in other_stage (think of rename +
1419                          * add-source case).
1420                          */
1421                         remove_file(o, 1, ren1_src,
1422                                     renamed_stage == 2 || !was_tracked(ren1_src));
1423
1424                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1425                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1426                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1427                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1428                         try_merge = 0;
1429
1430                         if (sha_eq(src_other.sha1, null_sha1)) {
1431                                 setup_rename_conflict_info(RENAME_DELETE,
1432                                                            ren1->pair,
1433                                                            NULL,
1434                                                            branch1,
1435                                                            branch2,
1436                                                            ren1->dst_entry,
1437                                                            NULL,
1438                                                            o,
1439                                                            NULL,
1440                                                            NULL);
1441                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1442                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1443                                 /*
1444                                  * Added file on the other side identical to
1445                                  * the file being renamed: clean merge.
1446                                  * Also, there is no need to overwrite the
1447                                  * file already in the working copy, so call
1448                                  * update_file_flags() instead of
1449                                  * update_file().
1450                                  */
1451                                 update_file_flags(o,
1452                                                   ren1->pair->two->sha1,
1453                                                   ren1->pair->two->mode,
1454                                                   ren1_dst,
1455                                                   1, /* update_cache */
1456                                                   0  /* update_wd    */);
1457                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1458                                 clean_merge = 0;
1459                                 try_merge = 1;
1460                                 output(o, 1, _("CONFLICT (rename/add): Rename %s->%s in %s. "
1461                                        "%s added in %s"),
1462                                        ren1_src, ren1_dst, branch1,
1463                                        ren1_dst, branch2);
1464                                 if (o->call_depth) {
1465                                         struct merge_file_info mfi;
1466                                         mfi = merge_file_one(o, ren1_dst, null_sha1, 0,
1467                                                          ren1->pair->two->sha1, ren1->pair->two->mode,
1468                                                          dst_other.sha1, dst_other.mode,
1469                                                          branch1, branch2);
1470                                         output(o, 1, _("Adding merged %s"), ren1_dst);
1471                                         update_file(o, 0, mfi.sha, mfi.mode, ren1_dst);
1472                                         try_merge = 0;
1473                                 } else {
1474                                         char *new_path = unique_path(o, ren1_dst, branch2);
1475                                         output(o, 1, _("Adding as %s instead"), new_path);
1476                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1477                                         free(new_path);
1478                                 }
1479                         } else
1480                                 try_merge = 1;
1481
1482                         if (try_merge) {
1483                                 struct diff_filespec *one, *a, *b;
1484                                 src_other.path = (char *)ren1_src;
1485
1486                                 one = ren1->pair->one;
1487                                 if (a_renames == renames1) {
1488                                         a = ren1->pair->two;
1489                                         b = &src_other;
1490                                 } else {
1491                                         b = ren1->pair->two;
1492                                         a = &src_other;
1493                                 }
1494                                 update_entry(ren1->dst_entry, one, a, b);
1495                                 setup_rename_conflict_info(RENAME_NORMAL,
1496                                                            ren1->pair,
1497                                                            NULL,
1498                                                            branch1,
1499                                                            NULL,
1500                                                            ren1->dst_entry,
1501                                                            NULL,
1502                                                            o,
1503                                                            NULL,
1504                                                            NULL);
1505                         }
1506                 }
1507         }
1508         string_list_clear(&a_by_dst, 0);
1509         string_list_clear(&b_by_dst, 0);
1510
1511         return clean_merge;
1512 }
1513
1514 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1515 {
1516         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1517 }
1518
1519 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1520 {
1521         void *buf;
1522         enum object_type type;
1523         unsigned long size;
1524         buf = read_sha1_file(sha1, &type, &size);
1525         if (!buf)
1526                 return error(_("cannot read object %s"), sha1_to_hex(sha1));
1527         if (type != OBJ_BLOB) {
1528                 free(buf);
1529                 return error(_("object %s is not a blob"), sha1_to_hex(sha1));
1530         }
1531         strbuf_attach(dst, buf, size, size + 1);
1532         return 0;
1533 }
1534
1535 static int blob_unchanged(const unsigned char *o_sha,
1536                           unsigned o_mode,
1537                           const unsigned char *a_sha,
1538                           unsigned a_mode,
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 (a_mode != o_mode)
1546                 return 0;
1547         if (sha_eq(o_sha, a_sha))
1548                 return 1;
1549         if (!renormalize)
1550                 return 0;
1551
1552         assert(o_sha && a_sha);
1553         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1554                 goto error_return;
1555         /*
1556          * Note: binary | is used so that both renormalizations are
1557          * performed.  Comparison can be skipped if both files are
1558          * unchanged since their sha1s have already been compared.
1559          */
1560         if (renormalize_buffer(path, o.buf, o.len, &o) |
1561             renormalize_buffer(path, a.buf, a.len, &a))
1562                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1563
1564 error_return:
1565         strbuf_release(&o);
1566         strbuf_release(&a);
1567         return ret;
1568 }
1569
1570 static void handle_modify_delete(struct merge_options *o,
1571                                  const char *path,
1572                                  unsigned char *o_sha, int o_mode,
1573                                  unsigned char *a_sha, int a_mode,
1574                                  unsigned char *b_sha, int b_mode)
1575 {
1576         handle_change_delete(o,
1577                              path,
1578                              o_sha, o_mode,
1579                              a_sha, a_mode,
1580                              b_sha, b_mode,
1581                              _("modify"), _("modified"));
1582 }
1583
1584 static int merge_content(struct merge_options *o,
1585                          const char *path,
1586                          unsigned char *o_sha, int o_mode,
1587                          unsigned char *a_sha, int a_mode,
1588                          unsigned char *b_sha, int b_mode,
1589                          struct rename_conflict_info *rename_conflict_info)
1590 {
1591         const char *reason = _("content");
1592         const char *path1 = NULL, *path2 = NULL;
1593         struct merge_file_info mfi;
1594         struct diff_filespec one, a, b;
1595         unsigned df_conflict_remains = 0;
1596
1597         if (!o_sha) {
1598                 reason = _("add/add");
1599                 o_sha = (unsigned char *)null_sha1;
1600         }
1601         one.path = a.path = b.path = (char *)path;
1602         hashcpy(one.sha1, o_sha);
1603         one.mode = o_mode;
1604         hashcpy(a.sha1, a_sha);
1605         a.mode = a_mode;
1606         hashcpy(b.sha1, b_sha);
1607         b.mode = b_mode;
1608
1609         if (rename_conflict_info) {
1610                 struct diff_filepair *pair1 = rename_conflict_info->pair1;
1611
1612                 path1 = (o->branch1 == rename_conflict_info->branch1) ?
1613                         pair1->two->path : pair1->one->path;
1614                 /* If rename_conflict_info->pair2 != NULL, we are in
1615                  * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
1616                  * normal rename.
1617                  */
1618                 path2 = (rename_conflict_info->pair2 ||
1619                          o->branch2 == rename_conflict_info->branch1) ?
1620                         pair1->two->path : pair1->one->path;
1621
1622                 if (dir_in_way(path, !o->call_depth))
1623                         df_conflict_remains = 1;
1624         }
1625         mfi = merge_file_special_markers(o, &one, &a, &b,
1626                                          o->branch1, path1,
1627                                          o->branch2, path2);
1628
1629         if (mfi.clean && !df_conflict_remains &&
1630             sha_eq(mfi.sha, a_sha) && mfi.mode == a_mode) {
1631                 int path_renamed_outside_HEAD;
1632                 output(o, 3, _("Skipped %s (merged same as existing)"), path);
1633                 /*
1634                  * The content merge resulted in the same file contents we
1635                  * already had.  We can return early if those file contents
1636                  * are recorded at the correct path (which may not be true
1637                  * if the merge involves a rename).
1638                  */
1639                 path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
1640                 if (!path_renamed_outside_HEAD) {
1641                         add_cacheinfo(mfi.mode, mfi.sha, path,
1642                                       0, (!o->call_depth), 0);
1643                         return mfi.clean;
1644                 }
1645         } else
1646                 output(o, 2, _("Auto-merging %s"), path);
1647
1648         if (!mfi.clean) {
1649                 if (S_ISGITLINK(mfi.mode))
1650                         reason = _("submodule");
1651                 output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
1652                                 reason, path);
1653                 if (rename_conflict_info && !df_conflict_remains)
1654                         update_stages(path, &one, &a, &b);
1655         }
1656
1657         if (df_conflict_remains) {
1658                 char *new_path;
1659                 if (o->call_depth) {
1660                         remove_file_from_cache(path);
1661                 } else {
1662                         if (!mfi.clean)
1663                                 update_stages(path, &one, &a, &b);
1664                         else {
1665                                 int file_from_stage2 = was_tracked(path);
1666                                 struct diff_filespec merged;
1667                                 hashcpy(merged.sha1, mfi.sha);
1668                                 merged.mode = mfi.mode;
1669
1670                                 update_stages(path, NULL,
1671                                               file_from_stage2 ? &merged : NULL,
1672                                               file_from_stage2 ? NULL : &merged);
1673                         }
1674
1675                 }
1676                 new_path = unique_path(o, path, rename_conflict_info->branch1);
1677                 output(o, 1, _("Adding as %s instead"), new_path);
1678                 update_file(o, 0, mfi.sha, mfi.mode, new_path);
1679                 free(new_path);
1680                 mfi.clean = 0;
1681         } else {
1682                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1683         }
1684         return mfi.clean;
1685
1686 }
1687
1688 /* Per entry merge function */
1689 static int process_entry(struct merge_options *o,
1690                          const char *path, struct stage_data *entry)
1691 {
1692         int clean_merge = 1;
1693         int normalize = o->renormalize;
1694         unsigned o_mode = entry->stages[1].mode;
1695         unsigned a_mode = entry->stages[2].mode;
1696         unsigned b_mode = entry->stages[3].mode;
1697         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1698         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1699         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1700
1701         entry->processed = 1;
1702         if (entry->rename_conflict_info) {
1703                 struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
1704                 switch (conflict_info->rename_type) {
1705                 case RENAME_NORMAL:
1706                 case RENAME_ONE_FILE_TO_ONE:
1707                         clean_merge = merge_content(o, path,
1708                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1709                                                     conflict_info);
1710                         break;
1711                 case RENAME_DELETE:
1712                         clean_merge = 0;
1713                         conflict_rename_delete(o, conflict_info->pair1,
1714                                                conflict_info->branch1,
1715                                                conflict_info->branch2);
1716                         break;
1717                 case RENAME_ONE_FILE_TO_TWO:
1718                         clean_merge = 0;
1719                         conflict_rename_rename_1to2(o, conflict_info);
1720                         break;
1721                 case RENAME_TWO_FILES_TO_ONE:
1722                         clean_merge = 0;
1723                         conflict_rename_rename_2to1(o, conflict_info);
1724                         break;
1725                 default:
1726                         entry->processed = 0;
1727                         break;
1728                 }
1729         } else if (o_sha && (!a_sha || !b_sha)) {
1730                 /* Case A: Deleted in one */
1731                 if ((!a_sha && !b_sha) ||
1732                     (!b_sha && blob_unchanged(o_sha, o_mode, a_sha, a_mode, normalize, path)) ||
1733                     (!a_sha && blob_unchanged(o_sha, o_mode, b_sha, b_mode, normalize, path))) {
1734                         /* Deleted in both or deleted in one and
1735                          * unchanged in the other */
1736                         if (a_sha)
1737                                 output(o, 2, _("Removing %s"), path);
1738                         /* do not touch working file if it did not exist */
1739                         remove_file(o, 1, path, !a_sha);
1740                 } else {
1741                         /* Modify/delete; deleted side may have put a directory in the way */
1742                         clean_merge = 0;
1743                         handle_modify_delete(o, path, o_sha, o_mode,
1744                                              a_sha, a_mode, b_sha, b_mode);
1745                 }
1746         } else if ((!o_sha && a_sha && !b_sha) ||
1747                    (!o_sha && !a_sha && b_sha)) {
1748                 /* Case B: Added in one. */
1749                 /* [nothing|directory] -> ([nothing|directory], file) */
1750
1751                 const char *add_branch;
1752                 const char *other_branch;
1753                 unsigned mode;
1754                 const unsigned char *sha;
1755                 const char *conf;
1756
1757                 if (a_sha) {
1758                         add_branch = o->branch1;
1759                         other_branch = o->branch2;
1760                         mode = a_mode;
1761                         sha = a_sha;
1762                         conf = _("file/directory");
1763                 } else {
1764                         add_branch = o->branch2;
1765                         other_branch = o->branch1;
1766                         mode = b_mode;
1767                         sha = b_sha;
1768                         conf = _("directory/file");
1769                 }
1770                 if (dir_in_way(path, !o->call_depth)) {
1771                         char *new_path = unique_path(o, path, add_branch);
1772                         clean_merge = 0;
1773                         output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
1774                                "Adding %s as %s"),
1775                                conf, path, other_branch, path, new_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.oid.hash, merge->object.oid.hash)) {
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                             oid_to_hex(&head->object.oid),
1828                             oid_to_hex(&merge->object.oid));
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                 free(re_merge);
1865                 free(re_head);
1866                 free(entries);
1867         }
1868         else
1869                 clean = 1;
1870
1871         if (o->call_depth)
1872                 *result = write_tree_from_memory(o);
1873
1874         return clean;
1875 }
1876
1877 static struct commit_list *reverse_commit_list(struct commit_list *list)
1878 {
1879         struct commit_list *next = NULL, *current, *backup;
1880         for (current = list; current; current = backup) {
1881                 backup = current->next;
1882                 current->next = next;
1883                 next = current;
1884         }
1885         return next;
1886 }
1887
1888 /*
1889  * Merge the commits h1 and h2, return the resulting virtual
1890  * commit object and a flag indicating the cleanness of the merge.
1891  */
1892 int merge_recursive(struct merge_options *o,
1893                     struct commit *h1,
1894                     struct commit *h2,
1895                     struct commit_list *ca,
1896                     struct commit **result)
1897 {
1898         struct commit_list *iter;
1899         struct commit *merged_common_ancestors;
1900         struct tree *mrtree = mrtree;
1901         int clean;
1902
1903         if (show(o, 4)) {
1904                 output(o, 4, _("Merging:"));
1905                 output_commit_title(o, h1);
1906                 output_commit_title(o, h2);
1907         }
1908
1909         if (!ca) {
1910                 ca = get_merge_bases(h1, h2);
1911                 ca = reverse_commit_list(ca);
1912         }
1913
1914         if (show(o, 5)) {
1915                 unsigned cnt = commit_list_count(ca);
1916
1917                 output(o, 5, Q_("found %u common ancestor:",
1918                                 "found %u common ancestors:", cnt), cnt);
1919                 for (iter = ca; iter; iter = iter->next)
1920                         output_commit_title(o, iter->item);
1921         }
1922
1923         merged_common_ancestors = pop_commit(&ca);
1924         if (merged_common_ancestors == NULL) {
1925                 /* if there is no common ancestor, use an empty tree */
1926                 struct tree *tree;
1927
1928                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1929                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1930         }
1931
1932         for (iter = ca; iter; iter = iter->next) {
1933                 const char *saved_b1, *saved_b2;
1934                 o->call_depth++;
1935                 /*
1936                  * When the merge fails, the result contains files
1937                  * with conflict markers. The cleanness flag is
1938                  * ignored, it was never actually used, as result of
1939                  * merge_trees has always overwritten it: the committed
1940                  * "conflicts" were already resolved.
1941                  */
1942                 discard_cache();
1943                 saved_b1 = o->branch1;
1944                 saved_b2 = o->branch2;
1945                 o->branch1 = "Temporary merge branch 1";
1946                 o->branch2 = "Temporary merge branch 2";
1947                 merge_recursive(o, merged_common_ancestors, iter->item,
1948                                 NULL, &merged_common_ancestors);
1949                 o->branch1 = saved_b1;
1950                 o->branch2 = saved_b2;
1951                 o->call_depth--;
1952
1953                 if (!merged_common_ancestors)
1954                         die(_("merge returned no commit"));
1955         }
1956
1957         discard_cache();
1958         if (!o->call_depth)
1959                 read_cache();
1960
1961         o->ancestor = "merged common ancestors";
1962         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1963                             &mrtree);
1964
1965         if (o->call_depth) {
1966                 *result = make_virtual_commit(mrtree, "merged tree");
1967                 commit_list_insert(h1, &(*result)->parents);
1968                 commit_list_insert(h2, &(*result)->parents->next);
1969         }
1970         flush_output(o);
1971         if (show(o, 2))
1972                 diff_warn_rename_limit("merge.renamelimit",
1973                                        o->needed_rename_limit, 0);
1974         return clean;
1975 }
1976
1977 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1978 {
1979         struct object *object;
1980
1981         object = deref_tag(parse_object(sha1), name, strlen(name));
1982         if (!object)
1983                 return NULL;
1984         if (object->type == OBJ_TREE)
1985                 return make_virtual_commit((struct tree*)object, name);
1986         if (object->type != OBJ_COMMIT)
1987                 return NULL;
1988         if (parse_commit((struct commit *)object))
1989                 return NULL;
1990         return (struct commit *)object;
1991 }
1992
1993 int merge_recursive_generic(struct merge_options *o,
1994                             const unsigned char *head,
1995                             const unsigned char *merge,
1996                             int num_base_list,
1997                             const unsigned char **base_list,
1998                             struct commit **result)
1999 {
2000         int clean;
2001         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
2002         struct commit *head_commit = get_ref(head, o->branch1);
2003         struct commit *next_commit = get_ref(merge, o->branch2);
2004         struct commit_list *ca = NULL;
2005
2006         if (base_list) {
2007                 int i;
2008                 for (i = 0; i < num_base_list; ++i) {
2009                         struct commit *base;
2010                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
2011                                 return error(_("Could not parse object '%s'"),
2012                                         sha1_to_hex(base_list[i]));
2013                         commit_list_insert(base, &ca);
2014                 }
2015         }
2016
2017         hold_locked_index(lock, 1);
2018         clean = merge_recursive(o, head_commit, next_commit, ca,
2019                         result);
2020         if (active_cache_changed &&
2021             write_locked_index(&the_index, lock, COMMIT_LOCK))
2022                 return error(_("Unable to write index."));
2023
2024         return clean ? 0 : 1;
2025 }
2026
2027 static void merge_recursive_config(struct merge_options *o)
2028 {
2029         git_config_get_int("merge.verbosity", &o->verbosity);
2030         git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
2031         git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
2032         git_config(git_xmerge_config, NULL);
2033 }
2034
2035 void init_merge_options(struct merge_options *o)
2036 {
2037         memset(o, 0, sizeof(struct merge_options));
2038         o->verbosity = 2;
2039         o->buffer_output = 1;
2040         o->diff_rename_limit = -1;
2041         o->merge_rename_limit = -1;
2042         o->renormalize = 0;
2043         o->detect_rename = 1;
2044         merge_recursive_config(o);
2045         if (getenv("GIT_MERGE_VERBOSITY"))
2046                 o->verbosity =
2047                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
2048         if (o->verbosity >= 5)
2049                 o->buffer_output = 0;
2050         strbuf_init(&o->obuf, 0);
2051         string_list_init(&o->current_file_set, 1);
2052         string_list_init(&o->current_directory_set, 1);
2053         string_list_init(&o->df_conflict_file_set, 1);
2054 }
2055
2056 int parse_merge_opt(struct merge_options *o, const char *s)
2057 {
2058         const char *arg;
2059
2060         if (!s || !*s)
2061                 return -1;
2062         if (!strcmp(s, "ours"))
2063                 o->recursive_variant = MERGE_RECURSIVE_OURS;
2064         else if (!strcmp(s, "theirs"))
2065                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
2066         else if (!strcmp(s, "subtree"))
2067                 o->subtree_shift = "";
2068         else if (skip_prefix(s, "subtree=", &arg))
2069                 o->subtree_shift = arg;
2070         else if (!strcmp(s, "patience"))
2071                 o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
2072         else if (!strcmp(s, "histogram"))
2073                 o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
2074         else if (skip_prefix(s, "diff-algorithm=", &arg)) {
2075                 long value = parse_algorithm_value(arg);
2076                 if (value < 0)
2077                         return -1;
2078                 /* clear out previous settings */
2079                 DIFF_XDL_CLR(o, NEED_MINIMAL);
2080                 o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
2081                 o->xdl_opts |= value;
2082         }
2083         else if (!strcmp(s, "ignore-space-change"))
2084                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2085         else if (!strcmp(s, "ignore-all-space"))
2086                 o->xdl_opts |= XDF_IGNORE_WHITESPACE;
2087         else if (!strcmp(s, "ignore-space-at-eol"))
2088                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2089         else if (!strcmp(s, "renormalize"))
2090                 o->renormalize = 1;
2091         else if (!strcmp(s, "no-renormalize"))
2092                 o->renormalize = 0;
2093         else if (!strcmp(s, "no-renames"))
2094                 o->detect_rename = 0;
2095         else if (!strcmp(s, "find-renames")) {
2096                 o->detect_rename = 1;
2097                 o->rename_score = 0;
2098         }
2099         else if (skip_prefix(s, "find-renames=", &arg) ||
2100                  skip_prefix(s, "rename-threshold=", &arg)) {
2101                 if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
2102                         return -1;
2103                 o->detect_rename = 1;
2104         }
2105         else
2106                 return -1;
2107         return 0;
2108 }