line-log: fix "log -LN" crash when N is last line of file
[git] / merge-recursive.c
1 /*
2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
3  * Fredrik Kuivinen.
4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
5  */
6 #include "advice.h"
7 #include "cache.h"
8 #include "cache-tree.h"
9 #include "commit.h"
10 #include "blob.h"
11 #include "builtin.h"
12 #include "tree-walk.h"
13 #include "diff.h"
14 #include "diffcore.h"
15 #include "tag.h"
16 #include "unpack-trees.h"
17 #include "string-list.h"
18 #include "xdiff-interface.h"
19 #include "ll-merge.h"
20 #include "attr.h"
21 #include "merge-recursive.h"
22 #include "dir.h"
23 #include "submodule.h"
24
25 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
26                                       const char *subtree_shift)
27 {
28         unsigned char shifted[20];
29
30         if (!*subtree_shift) {
31                 shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
32         } else {
33                 shift_tree_by(one->object.sha1, two->object.sha1, shifted,
34                               subtree_shift);
35         }
36         if (!hashcmp(two->object.sha1, shifted))
37                 return two;
38         return lookup_tree(shifted);
39 }
40
41 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
42 {
43         struct commit *commit = xcalloc(1, sizeof(struct commit));
44         struct merge_remote_desc *desc = xmalloc(sizeof(*desc));
45
46         desc->name = comment;
47         desc->obj = (struct object *)commit;
48         commit->tree = tree;
49         commit->util = desc;
50         commit->object.parsed = 1;
51         return commit;
52 }
53
54 /*
55  * Since we use get_tree_entry(), which does not put the read object into
56  * the object pool, we cannot rely on a == b.
57  */
58 static int sha_eq(const unsigned char *a, const unsigned char *b)
59 {
60         if (!a && !b)
61                 return 2;
62         return a && b && hashcmp(a, b) == 0;
63 }
64
65 enum rename_type {
66         RENAME_NORMAL = 0,
67         RENAME_DELETE,
68         RENAME_ONE_FILE_TO_ONE,
69         RENAME_ONE_FILE_TO_TWO,
70         RENAME_TWO_FILES_TO_ONE
71 };
72
73 struct rename_conflict_info {
74         enum rename_type rename_type;
75         struct diff_filepair *pair1;
76         struct diff_filepair *pair2;
77         const char *branch1;
78         const char *branch2;
79         struct stage_data *dst_entry1;
80         struct stage_data *dst_entry2;
81         struct diff_filespec ren1_other;
82         struct diff_filespec ren2_other;
83 };
84
85 /*
86  * Since we want to write the index eventually, we cannot reuse the index
87  * for these (temporary) data.
88  */
89 struct stage_data {
90         struct {
91                 unsigned mode;
92                 unsigned char sha[20];
93         } stages[4];
94         struct rename_conflict_info *rename_conflict_info;
95         unsigned processed:1;
96 };
97
98 static inline void setup_rename_conflict_info(enum rename_type rename_type,
99                                               struct diff_filepair *pair1,
100                                               struct diff_filepair *pair2,
101                                               const char *branch1,
102                                               const char *branch2,
103                                               struct stage_data *dst_entry1,
104                                               struct stage_data *dst_entry2,
105                                               struct merge_options *o,
106                                               struct stage_data *src_entry1,
107                                               struct stage_data *src_entry2)
108 {
109         struct rename_conflict_info *ci = xcalloc(1, sizeof(struct rename_conflict_info));
110         ci->rename_type = rename_type;
111         ci->pair1 = pair1;
112         ci->branch1 = branch1;
113         ci->branch2 = branch2;
114
115         ci->dst_entry1 = dst_entry1;
116         dst_entry1->rename_conflict_info = ci;
117         dst_entry1->processed = 0;
118
119         assert(!pair2 == !dst_entry2);
120         if (dst_entry2) {
121                 ci->dst_entry2 = dst_entry2;
122                 ci->pair2 = pair2;
123                 dst_entry2->rename_conflict_info = ci;
124         }
125
126         if (rename_type == RENAME_TWO_FILES_TO_ONE) {
127                 /*
128                  * For each rename, there could have been
129                  * modifications on the side of history where that
130                  * file was not renamed.
131                  */
132                 int ostage1 = o->branch1 == branch1 ? 3 : 2;
133                 int ostage2 = ostage1 ^ 1;
134
135                 ci->ren1_other.path = pair1->one->path;
136                 hashcpy(ci->ren1_other.sha1, src_entry1->stages[ostage1].sha);
137                 ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
138
139                 ci->ren2_other.path = pair2->one->path;
140                 hashcpy(ci->ren2_other.sha1, src_entry2->stages[ostage2].sha);
141                 ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
142         }
143 }
144
145 static int show(struct merge_options *o, int v)
146 {
147         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
148 }
149
150 static void flush_output(struct merge_options *o)
151 {
152         if (o->obuf.len) {
153                 fputs(o->obuf.buf, stdout);
154                 strbuf_reset(&o->obuf);
155         }
156 }
157
158 __attribute__((format (printf, 3, 4)))
159 static void output(struct merge_options *o, int v, const char *fmt, ...)
160 {
161         va_list ap;
162
163         if (!show(o, v))
164                 return;
165
166         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
167         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
168         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
169
170         va_start(ap, fmt);
171         strbuf_vaddf(&o->obuf, fmt, ap);
172         va_end(ap);
173
174         strbuf_add(&o->obuf, "\n", 1);
175         if (!o->buffer_output)
176                 flush_output(o);
177 }
178
179 static void output_commit_title(struct merge_options *o, struct commit *commit)
180 {
181         int i;
182         flush_output(o);
183         for (i = o->call_depth; i--;)
184                 fputs("  ", stdout);
185         if (commit->util)
186                 printf("virtual %s\n", merge_remote_util(commit)->name);
187         else {
188                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
189                 if (parse_commit(commit) != 0)
190                         printf(_("(bad commit)\n"));
191                 else {
192                         const char *title;
193                         int len = find_commit_subject(commit->buffer, &title);
194                         if (len)
195                                 printf("%.*s\n", len, title);
196                 }
197         }
198 }
199
200 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
201                 const char *path, int stage, int refresh, int options)
202 {
203         struct cache_entry *ce;
204         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
205         if (!ce)
206                 return error(_("addinfo_cache failed for path '%s'"), path);
207         return add_cache_entry(ce, options);
208 }
209
210 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
211 {
212         parse_tree(tree);
213         init_tree_desc(desc, tree->buffer, tree->size);
214 }
215
216 static int git_merge_trees(int index_only,
217                            struct tree *common,
218                            struct tree *head,
219                            struct tree *merge)
220 {
221         int rc;
222         struct tree_desc t[3];
223         struct unpack_trees_options opts;
224
225         memset(&opts, 0, sizeof(opts));
226         if (index_only)
227                 opts.index_only = 1;
228         else
229                 opts.update = 1;
230         opts.merge = 1;
231         opts.head_idx = 2;
232         opts.fn = threeway_merge;
233         opts.src_index = &the_index;
234         opts.dst_index = &the_index;
235         setup_unpack_trees_porcelain(&opts, "merge");
236
237         init_tree_desc_from_tree(t+0, common);
238         init_tree_desc_from_tree(t+1, head);
239         init_tree_desc_from_tree(t+2, merge);
240
241         rc = unpack_trees(3, t, &opts);
242         cache_tree_free(&active_cache_tree);
243         return rc;
244 }
245
246 struct tree *write_tree_from_memory(struct merge_options *o)
247 {
248         struct tree *result = NULL;
249
250         if (unmerged_cache()) {
251                 int i;
252                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
253                 for (i = 0; i < active_nr; i++) {
254                         struct cache_entry *ce = active_cache[i];
255                         if (ce_stage(ce))
256                                 fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
257                                         (int)ce_namelen(ce), ce->name);
258                 }
259                 die("Bug in merge-recursive.c");
260         }
261
262         if (!active_cache_tree)
263                 active_cache_tree = cache_tree();
264
265         if (!cache_tree_fully_valid(active_cache_tree) &&
266             cache_tree_update(active_cache_tree,
267                               active_cache, active_nr, 0) < 0)
268                 die(_("error building trees"));
269
270         result = lookup_tree(active_cache_tree->sha1);
271
272         return result;
273 }
274
275 static int save_files_dirs(const unsigned char *sha1,
276                 const char *base, int baselen, const char *path,
277                 unsigned int mode, int stage, void *context)
278 {
279         int len = strlen(path);
280         char *newpath = xmalloc(baselen + len + 1);
281         struct merge_options *o = context;
282
283         memcpy(newpath, base, baselen);
284         memcpy(newpath + baselen, path, len);
285         newpath[baselen + len] = '\0';
286
287         if (S_ISDIR(mode))
288                 string_list_insert(&o->current_directory_set, newpath);
289         else
290                 string_list_insert(&o->current_file_set, newpath);
291         free(newpath);
292
293         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
294 }
295
296 static int get_files_dirs(struct merge_options *o, struct tree *tree)
297 {
298         int n;
299         struct pathspec match_all;
300         init_pathspec(&match_all, NULL);
301         if (read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o))
302                 return 0;
303         n = o->current_file_set.nr + o->current_directory_set.nr;
304         return n;
305 }
306
307 /*
308  * Returns an index_entry instance which doesn't have to correspond to
309  * a real cache entry in Git's index.
310  */
311 static struct stage_data *insert_stage_data(const char *path,
312                 struct tree *o, struct tree *a, struct tree *b,
313                 struct string_list *entries)
314 {
315         struct string_list_item *item;
316         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
317         get_tree_entry(o->object.sha1, path,
318                         e->stages[1].sha, &e->stages[1].mode);
319         get_tree_entry(a->object.sha1, path,
320                         e->stages[2].sha, &e->stages[2].mode);
321         get_tree_entry(b->object.sha1, path,
322                         e->stages[3].sha, &e->stages[3].mode);
323         item = string_list_insert(entries, path);
324         item->util = e;
325         return e;
326 }
327
328 /*
329  * Create a dictionary mapping file names to stage_data objects. The
330  * dictionary contains one entry for every path with a non-zero stage entry.
331  */
332 static struct string_list *get_unmerged(void)
333 {
334         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
335         int i;
336
337         unmerged->strdup_strings = 1;
338
339         for (i = 0; i < active_nr; i++) {
340                 struct string_list_item *item;
341                 struct stage_data *e;
342                 struct cache_entry *ce = active_cache[i];
343                 if (!ce_stage(ce))
344                         continue;
345
346                 item = string_list_lookup(unmerged, ce->name);
347                 if (!item) {
348                         item = string_list_insert(unmerged, ce->name);
349                         item->util = xcalloc(1, sizeof(struct stage_data));
350                 }
351                 e = item->util;
352                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
353                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
354         }
355
356         return unmerged;
357 }
358
359 static int string_list_df_name_compare(const void *a, const void *b)
360 {
361         const struct string_list_item *one = a;
362         const struct string_list_item *two = b;
363         int onelen = strlen(one->string);
364         int twolen = strlen(two->string);
365         /*
366          * Here we only care that entries for D/F conflicts are
367          * adjacent, in particular with the file of the D/F conflict
368          * appearing before files below the corresponding directory.
369          * The order of the rest of the list is irrelevant for us.
370          *
371          * To achieve this, we sort with df_name_compare and provide
372          * the mode S_IFDIR so that D/F conflicts will sort correctly.
373          * We use the mode S_IFDIR for everything else for simplicity,
374          * since in other cases any changes in their order due to
375          * sorting cause no problems for us.
376          */
377         int cmp = df_name_compare(one->string, onelen, S_IFDIR,
378                                   two->string, twolen, S_IFDIR);
379         /*
380          * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
381          * that 'foo' comes before 'foo/bar'.
382          */
383         if (cmp)
384                 return cmp;
385         return onelen - twolen;
386 }
387
388 static void record_df_conflict_files(struct merge_options *o,
389                                      struct string_list *entries)
390 {
391         /* If there is a D/F conflict and the file for such a conflict
392          * currently exist in the working tree, we want to allow it to be
393          * removed to make room for the corresponding directory if needed.
394          * The files underneath the directories of such D/F conflicts will
395          * be processed before the corresponding file involved in the D/F
396          * conflict.  If the D/F directory ends up being removed by the
397          * merge, then we won't have to touch the D/F file.  If the D/F
398          * directory needs to be written to the working copy, then the D/F
399          * file will simply be removed (in make_room_for_path()) to make
400          * room for the necessary paths.  Note that if both the directory
401          * and the file need to be present, then the D/F file will be
402          * reinstated with a new unique name at the time it is processed.
403          */
404         struct string_list df_sorted_entries;
405         const char *last_file = NULL;
406         int last_len = 0;
407         int i;
408
409         /*
410          * If we're merging merge-bases, we don't want to bother with
411          * any working directory changes.
412          */
413         if (o->call_depth)
414                 return;
415
416         /* Ensure D/F conflicts are adjacent in the entries list. */
417         memset(&df_sorted_entries, 0, sizeof(struct string_list));
418         for (i = 0; i < entries->nr; i++) {
419                 struct string_list_item *next = &entries->items[i];
420                 string_list_append(&df_sorted_entries, next->string)->util =
421                                    next->util;
422         }
423         qsort(df_sorted_entries.items, entries->nr, sizeof(*entries->items),
424               string_list_df_name_compare);
425
426         string_list_clear(&o->df_conflict_file_set, 1);
427         for (i = 0; i < df_sorted_entries.nr; i++) {
428                 const char *path = df_sorted_entries.items[i].string;
429                 int len = strlen(path);
430                 struct stage_data *e = df_sorted_entries.items[i].util;
431
432                 /*
433                  * Check if last_file & path correspond to a D/F conflict;
434                  * i.e. whether path is last_file+'/'+<something>.
435                  * If so, record that it's okay to remove last_file to make
436                  * room for path and friends if needed.
437                  */
438                 if (last_file &&
439                     len > last_len &&
440                     memcmp(path, last_file, last_len) == 0 &&
441                     path[last_len] == '/') {
442                         string_list_insert(&o->df_conflict_file_set, last_file);
443                 }
444
445                 /*
446                  * Determine whether path could exist as a file in the
447                  * working directory as a possible D/F conflict.  This
448                  * will only occur when it exists in stage 2 as a
449                  * file.
450                  */
451                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
452                         last_file = path;
453                         last_len = len;
454                 } else {
455                         last_file = NULL;
456                 }
457         }
458         string_list_clear(&df_sorted_entries, 0);
459 }
460
461 struct rename {
462         struct diff_filepair *pair;
463         struct stage_data *src_entry;
464         struct stage_data *dst_entry;
465         unsigned processed:1;
466 };
467
468 /*
469  * Get information of all renames which occurred between 'o_tree' and
470  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
471  * 'b_tree') to be able to associate the correct cache entries with
472  * the rename information. 'tree' is always equal to either a_tree or b_tree.
473  */
474 static struct string_list *get_renames(struct merge_options *o,
475                                        struct tree *tree,
476                                        struct tree *o_tree,
477                                        struct tree *a_tree,
478                                        struct tree *b_tree,
479                                        struct string_list *entries)
480 {
481         int i;
482         struct string_list *renames;
483         struct diff_options opts;
484
485         renames = xcalloc(1, sizeof(struct string_list));
486         diff_setup(&opts);
487         DIFF_OPT_SET(&opts, RECURSIVE);
488         DIFF_OPT_CLR(&opts, RENAME_EMPTY);
489         opts.detect_rename = DIFF_DETECT_RENAME;
490         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
491                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
492                             1000;
493         opts.rename_score = o->rename_score;
494         opts.show_rename_progress = o->show_rename_progress;
495         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
496         diff_setup_done(&opts);
497         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
498         diffcore_std(&opts);
499         if (opts.needed_rename_limit > o->needed_rename_limit)
500                 o->needed_rename_limit = opts.needed_rename_limit;
501         for (i = 0; i < diff_queued_diff.nr; ++i) {
502                 struct string_list_item *item;
503                 struct rename *re;
504                 struct diff_filepair *pair = diff_queued_diff.queue[i];
505                 if (pair->status != 'R') {
506                         diff_free_filepair(pair);
507                         continue;
508                 }
509                 re = xmalloc(sizeof(*re));
510                 re->processed = 0;
511                 re->pair = pair;
512                 item = string_list_lookup(entries, re->pair->one->path);
513                 if (!item)
514                         re->src_entry = insert_stage_data(re->pair->one->path,
515                                         o_tree, a_tree, b_tree, entries);
516                 else
517                         re->src_entry = item->util;
518
519                 item = string_list_lookup(entries, re->pair->two->path);
520                 if (!item)
521                         re->dst_entry = insert_stage_data(re->pair->two->path,
522                                         o_tree, a_tree, b_tree, entries);
523                 else
524                         re->dst_entry = item->util;
525                 item = string_list_insert(renames, pair->one->path);
526                 item->util = re;
527         }
528         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
529         diff_queued_diff.nr = 0;
530         diff_flush(&opts);
531         return renames;
532 }
533
534 static int update_stages(const char *path, const struct diff_filespec *o,
535                          const struct diff_filespec *a,
536                          const struct diff_filespec *b)
537 {
538
539         /*
540          * NOTE: It is usually a bad idea to call update_stages on a path
541          * before calling update_file on that same path, since it can
542          * sometimes lead to spurious "refusing to lose untracked file..."
543          * messages from update_file (via make_room_for path via
544          * would_lose_untracked).  Instead, reverse the order of the calls
545          * (executing update_file first and then update_stages).
546          */
547         int clear = 1;
548         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
549         if (clear)
550                 if (remove_file_from_cache(path))
551                         return -1;
552         if (o)
553                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
554                         return -1;
555         if (a)
556                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
557                         return -1;
558         if (b)
559                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
560                         return -1;
561         return 0;
562 }
563
564 static void update_entry(struct stage_data *entry,
565                          struct diff_filespec *o,
566                          struct diff_filespec *a,
567                          struct diff_filespec *b)
568 {
569         entry->processed = 0;
570         entry->stages[1].mode = o->mode;
571         entry->stages[2].mode = a->mode;
572         entry->stages[3].mode = b->mode;
573         hashcpy(entry->stages[1].sha, o->sha1);
574         hashcpy(entry->stages[2].sha, a->sha1);
575         hashcpy(entry->stages[3].sha, b->sha1);
576 }
577
578 static int remove_file(struct merge_options *o, int clean,
579                        const char *path, int no_wd)
580 {
581         int update_cache = o->call_depth || clean;
582         int update_working_directory = !o->call_depth && !no_wd;
583
584         if (update_cache) {
585                 if (remove_file_from_cache(path))
586                         return -1;
587         }
588         if (update_working_directory) {
589                 if (remove_path(path))
590                         return -1;
591         }
592         return 0;
593 }
594
595 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
596 {
597         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
598         int suffix = 0;
599         struct stat st;
600         char *p = newpath + strlen(path);
601         strcpy(newpath, path);
602         *(p++) = '~';
603         strcpy(p, branch);
604         for (; *p; ++p)
605                 if ('/' == *p)
606                         *p = '_';
607         while (string_list_has_string(&o->current_file_set, newpath) ||
608                string_list_has_string(&o->current_directory_set, newpath) ||
609                lstat(newpath, &st) == 0)
610                 sprintf(p, "_%d", suffix++);
611
612         string_list_insert(&o->current_file_set, newpath);
613         return newpath;
614 }
615
616 static int dir_in_way(const char *path, int check_working_copy)
617 {
618         int pos, pathlen = strlen(path);
619         char *dirpath = xmalloc(pathlen + 2);
620         struct stat st;
621
622         strcpy(dirpath, path);
623         dirpath[pathlen] = '/';
624         dirpath[pathlen+1] = '\0';
625
626         pos = cache_name_pos(dirpath, pathlen+1);
627
628         if (pos < 0)
629                 pos = -1 - pos;
630         if (pos < active_nr &&
631             !strncmp(dirpath, active_cache[pos]->name, pathlen+1)) {
632                 free(dirpath);
633                 return 1;
634         }
635
636         free(dirpath);
637         return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode);
638 }
639
640 static int was_tracked(const char *path)
641 {
642         int pos = cache_name_pos(path, strlen(path));
643
644         if (pos < 0)
645                 pos = -1 - pos;
646         while (pos < active_nr &&
647                !strcmp(path, active_cache[pos]->name)) {
648                 /*
649                  * If stage #0, it is definitely tracked.
650                  * If it has stage #2 then it was tracked
651                  * before this merge started.  All other
652                  * cases the path was not tracked.
653                  */
654                 switch (ce_stage(active_cache[pos])) {
655                 case 0:
656                 case 2:
657                         return 1;
658                 }
659                 pos++;
660         }
661         return 0;
662 }
663
664 static int would_lose_untracked(const char *path)
665 {
666         return !was_tracked(path) && file_exists(path);
667 }
668
669 static int make_room_for_path(struct merge_options *o, const char *path)
670 {
671         int status, i;
672         const char *msg = _("failed to create path '%s'%s");
673
674         /* Unlink any D/F conflict files that are in the way */
675         for (i = 0; i < o->df_conflict_file_set.nr; i++) {
676                 const char *df_path = o->df_conflict_file_set.items[i].string;
677                 size_t pathlen = strlen(path);
678                 size_t df_pathlen = strlen(df_path);
679                 if (df_pathlen < pathlen &&
680                     path[df_pathlen] == '/' &&
681                     strncmp(path, df_path, df_pathlen) == 0) {
682                         output(o, 3,
683                                _("Removing %s to make room for subdirectory\n"),
684                                df_path);
685                         unlink(df_path);
686                         unsorted_string_list_delete_item(&o->df_conflict_file_set,
687                                                          i, 0);
688                         break;
689                 }
690         }
691
692         /* Make sure leading directories are created */
693         status = safe_create_leading_directories_const(path);
694         if (status) {
695                 if (status == -3) {
696                         /* something else exists */
697                         error(msg, path, _(": perhaps a D/F conflict?"));
698                         return -1;
699                 }
700                 die(msg, path, "");
701         }
702
703         /*
704          * Do not unlink a file in the work tree if we are not
705          * tracking it.
706          */
707         if (would_lose_untracked(path))
708                 return error(_("refusing to lose untracked file at '%s'"),
709                              path);
710
711         /* Successful unlink is good.. */
712         if (!unlink(path))
713                 return 0;
714         /* .. and so is no existing file */
715         if (errno == ENOENT)
716                 return 0;
717         /* .. but not some other error (who really cares what?) */
718         return error(msg, path, _(": perhaps a D/F conflict?"));
719 }
720
721 static void update_file_flags(struct merge_options *o,
722                               const unsigned char *sha,
723                               unsigned mode,
724                               const char *path,
725                               int update_cache,
726                               int update_wd)
727 {
728         if (o->call_depth)
729                 update_wd = 0;
730
731         if (update_wd) {
732                 enum object_type type;
733                 void *buf;
734                 unsigned long size;
735
736                 if (S_ISGITLINK(mode)) {
737                         /*
738                          * We may later decide to recursively descend into
739                          * the submodule directory and update its index
740                          * and/or work tree, but we do not do that now.
741                          */
742                         update_wd = 0;
743                         goto update_index;
744                 }
745
746                 buf = read_sha1_file(sha, &type, &size);
747                 if (!buf)
748                         die(_("cannot read object %s '%s'"), sha1_to_hex(sha), path);
749                 if (type != OBJ_BLOB)
750                         die(_("blob expected for %s '%s'"), sha1_to_hex(sha), path);
751                 if (S_ISREG(mode)) {
752                         struct strbuf strbuf = STRBUF_INIT;
753                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
754                                 free(buf);
755                                 size = strbuf.len;
756                                 buf = strbuf_detach(&strbuf, NULL);
757                         }
758                 }
759
760                 if (make_room_for_path(o, path) < 0) {
761                         update_wd = 0;
762                         free(buf);
763                         goto update_index;
764                 }
765                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
766                         int fd;
767                         if (mode & 0100)
768                                 mode = 0777;
769                         else
770                                 mode = 0666;
771                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
772                         if (fd < 0)
773                                 die_errno(_("failed to open '%s'"), path);
774                         write_in_full(fd, buf, size);
775                         close(fd);
776                 } else if (S_ISLNK(mode)) {
777                         char *lnk = xmemdupz(buf, size);
778                         safe_create_leading_directories_const(path);
779                         unlink(path);
780                         if (symlink(lnk, path))
781                                 die_errno(_("failed to symlink '%s'"), path);
782                         free(lnk);
783                 } else
784                         die(_("do not know what to do with %06o %s '%s'"),
785                             mode, sha1_to_hex(sha), path);
786                 free(buf);
787         }
788  update_index:
789         if (update_cache)
790                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
791 }
792
793 static void update_file(struct merge_options *o,
794                         int clean,
795                         const unsigned char *sha,
796                         unsigned mode,
797                         const char *path)
798 {
799         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
800 }
801
802 /* Low level file merging, update and removal */
803
804 struct merge_file_info {
805         unsigned char sha[20];
806         unsigned mode;
807         unsigned clean:1,
808                  merge:1;
809 };
810
811 static int merge_3way(struct merge_options *o,
812                       mmbuffer_t *result_buf,
813                       const struct diff_filespec *one,
814                       const struct diff_filespec *a,
815                       const struct diff_filespec *b,
816                       const char *branch1,
817                       const char *branch2)
818 {
819         mmfile_t orig, src1, src2;
820         struct ll_merge_options ll_opts = {0};
821         char *base_name, *name1, *name2;
822         int merge_status;
823
824         ll_opts.renormalize = o->renormalize;
825         ll_opts.xdl_opts = o->xdl_opts;
826
827         if (o->call_depth) {
828                 ll_opts.virtual_ancestor = 1;
829                 ll_opts.variant = 0;
830         } else {
831                 switch (o->recursive_variant) {
832                 case MERGE_RECURSIVE_OURS:
833                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
834                         break;
835                 case MERGE_RECURSIVE_THEIRS:
836                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
837                         break;
838                 default:
839                         ll_opts.variant = 0;
840                         break;
841                 }
842         }
843
844         if (strcmp(a->path, b->path) ||
845             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
846                 base_name = o->ancestor == NULL ? NULL :
847                         mkpathdup("%s:%s", o->ancestor, one->path);
848                 name1 = mkpathdup("%s:%s", branch1, a->path);
849                 name2 = mkpathdup("%s:%s", branch2, b->path);
850         } else {
851                 base_name = o->ancestor == NULL ? NULL :
852                         mkpathdup("%s", o->ancestor);
853                 name1 = mkpathdup("%s", branch1);
854                 name2 = mkpathdup("%s", branch2);
855         }
856
857         read_mmblob(&orig, one->sha1);
858         read_mmblob(&src1, a->sha1);
859         read_mmblob(&src2, b->sha1);
860
861         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
862                                 &src1, name1, &src2, name2, &ll_opts);
863
864         free(base_name);
865         free(name1);
866         free(name2);
867         free(orig.ptr);
868         free(src1.ptr);
869         free(src2.ptr);
870         return merge_status;
871 }
872
873 static struct merge_file_info merge_file_1(struct merge_options *o,
874                                            const struct diff_filespec *one,
875                                            const struct diff_filespec *a,
876                                            const struct diff_filespec *b,
877                                            const char *branch1,
878                                            const char *branch2)
879 {
880         struct merge_file_info result;
881         result.merge = 0;
882         result.clean = 1;
883
884         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
885                 result.clean = 0;
886                 if (S_ISREG(a->mode)) {
887                         result.mode = a->mode;
888                         hashcpy(result.sha, a->sha1);
889                 } else {
890                         result.mode = b->mode;
891                         hashcpy(result.sha, b->sha1);
892                 }
893         } else {
894                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
895                         result.merge = 1;
896
897                 /*
898                  * Merge modes
899                  */
900                 if (a->mode == b->mode || a->mode == one->mode)
901                         result.mode = b->mode;
902                 else {
903                         result.mode = a->mode;
904                         if (b->mode != one->mode) {
905                                 result.clean = 0;
906                                 result.merge = 1;
907                         }
908                 }
909
910                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
911                         hashcpy(result.sha, b->sha1);
912                 else if (sha_eq(b->sha1, one->sha1))
913                         hashcpy(result.sha, a->sha1);
914                 else if (S_ISREG(a->mode)) {
915                         mmbuffer_t result_buf;
916                         int merge_status;
917
918                         merge_status = merge_3way(o, &result_buf, one, a, b,
919                                                   branch1, branch2);
920
921                         if ((merge_status < 0) || !result_buf.ptr)
922                                 die(_("Failed to execute internal merge"));
923
924                         if (write_sha1_file(result_buf.ptr, result_buf.size,
925                                             blob_type, result.sha))
926                                 die(_("Unable to add %s to database"),
927                                     a->path);
928
929                         free(result_buf.ptr);
930                         result.clean = (merge_status == 0);
931                 } else if (S_ISGITLINK(a->mode)) {
932                         result.clean = merge_submodule(result.sha,
933                                                        one->path, one->sha1,
934                                                        a->sha1, b->sha1,
935                                                        !o->call_depth);
936                 } else if (S_ISLNK(a->mode)) {
937                         hashcpy(result.sha, a->sha1);
938
939                         if (!sha_eq(a->sha1, b->sha1))
940                                 result.clean = 0;
941                 } else {
942                         die(_("unsupported object type in the tree"));
943                 }
944         }
945
946         return result;
947 }
948
949 static struct merge_file_info
950 merge_file_special_markers(struct merge_options *o,
951                            const struct diff_filespec *one,
952                            const struct diff_filespec *a,
953                            const struct diff_filespec *b,
954                            const char *branch1,
955                            const char *filename1,
956                            const char *branch2,
957                            const char *filename2)
958 {
959         char *side1 = NULL;
960         char *side2 = NULL;
961         struct merge_file_info mfi;
962
963         if (filename1) {
964                 side1 = xmalloc(strlen(branch1) + strlen(filename1) + 2);
965                 sprintf(side1, "%s:%s", branch1, filename1);
966         }
967         if (filename2) {
968                 side2 = xmalloc(strlen(branch2) + strlen(filename2) + 2);
969                 sprintf(side2, "%s:%s", branch2, filename2);
970         }
971
972         mfi = merge_file_1(o, one, a, b,
973                            side1 ? side1 : branch1, side2 ? side2 : branch2);
974         free(side1);
975         free(side2);
976         return mfi;
977 }
978
979 static struct merge_file_info merge_file_one(struct merge_options *o,
980                                          const char *path,
981                                          const unsigned char *o_sha, int o_mode,
982                                          const unsigned char *a_sha, int a_mode,
983                                          const unsigned char *b_sha, int b_mode,
984                                          const char *branch1,
985                                          const char *branch2)
986 {
987         struct diff_filespec one, a, b;
988
989         one.path = a.path = b.path = (char *)path;
990         hashcpy(one.sha1, o_sha);
991         one.mode = o_mode;
992         hashcpy(a.sha1, a_sha);
993         a.mode = a_mode;
994         hashcpy(b.sha1, b_sha);
995         b.mode = b_mode;
996         return merge_file_1(o, &one, &a, &b, branch1, branch2);
997 }
998
999 static void handle_change_delete(struct merge_options *o,
1000                                  const char *path,
1001                                  const unsigned char *o_sha, int o_mode,
1002                                  const unsigned char *a_sha, int a_mode,
1003                                  const unsigned char *b_sha, int b_mode,
1004                                  const char *change, const char *change_past)
1005 {
1006         char *renamed = NULL;
1007         if (dir_in_way(path, !o->call_depth)) {
1008                 renamed = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1009         }
1010
1011         if (o->call_depth) {
1012                 /*
1013                  * We cannot arbitrarily accept either a_sha or b_sha as
1014                  * correct; since there is no true "middle point" between
1015                  * them, simply reuse the base version for virtual merge base.
1016                  */
1017                 remove_file_from_cache(path);
1018                 update_file(o, 0, o_sha, o_mode, renamed ? renamed : path);
1019         } else if (!a_sha) {
1020                 if (!renamed) {
1021                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1022                                "and %s in %s. Version %s of %s left in tree."),
1023                                change, path, o->branch1, change_past,
1024                                o->branch2, o->branch2, path);
1025                         update_file(o, 0, b_sha, b_mode, path);
1026                 } else {
1027                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1028                                "and %s in %s. Version %s of %s left in tree at %s."),
1029                                change, path, o->branch1, change_past,
1030                                o->branch2, o->branch2, path, renamed);
1031                         update_file(o, 0, b_sha, b_mode, renamed);
1032                 }
1033         } else {
1034                 if (!renamed) {
1035                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1036                                "and %s in %s. Version %s of %s left in tree."),
1037                                change, path, o->branch2, change_past,
1038                                o->branch1, o->branch1, 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->branch2, change_past,
1043                                o->branch1, o->branch1, path, renamed);
1044                         update_file(o, 0, a_sha, a_mode, renamed);
1045                 }
1046                 /*
1047                  * No need to call update_file() on path when !renamed, since
1048                  * that would needlessly touch path.  We could call
1049                  * update_file_flags() with update_cache=0 and update_wd=0,
1050                  * but that's a no-op.
1051                  */
1052         }
1053         free(renamed);
1054 }
1055
1056 static void conflict_rename_delete(struct merge_options *o,
1057                                    struct diff_filepair *pair,
1058                                    const char *rename_branch,
1059                                    const char *other_branch)
1060 {
1061         const struct diff_filespec *orig = pair->one;
1062         const struct diff_filespec *dest = pair->two;
1063         const unsigned char *a_sha = NULL;
1064         const unsigned char *b_sha = NULL;
1065         int a_mode = 0;
1066         int b_mode = 0;
1067
1068         if (rename_branch == o->branch1) {
1069                 a_sha = dest->sha1;
1070                 a_mode = dest->mode;
1071         } else {
1072                 b_sha = dest->sha1;
1073                 b_mode = dest->mode;
1074         }
1075
1076         handle_change_delete(o,
1077                              o->call_depth ? orig->path : dest->path,
1078                              orig->sha1, orig->mode,
1079                              a_sha, a_mode,
1080                              b_sha, b_mode,
1081                              _("rename"), _("renamed"));
1082
1083         if (o->call_depth) {
1084                 remove_file_from_cache(dest->path);
1085         } else {
1086                 update_stages(dest->path, NULL,
1087                               rename_branch == o->branch1 ? dest : NULL,
1088                               rename_branch == o->branch1 ? NULL : dest);
1089         }
1090
1091 }
1092
1093 static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
1094                                                  struct stage_data *entry,
1095                                                  int stage)
1096 {
1097         unsigned char *sha = entry->stages[stage].sha;
1098         unsigned mode = entry->stages[stage].mode;
1099         if (mode == 0 || is_null_sha1(sha))
1100                 return NULL;
1101         hashcpy(target->sha1, sha);
1102         target->mode = mode;
1103         return target;
1104 }
1105
1106 static void handle_file(struct merge_options *o,
1107                         struct diff_filespec *rename,
1108                         int stage,
1109                         struct rename_conflict_info *ci)
1110 {
1111         char *dst_name = rename->path;
1112         struct stage_data *dst_entry;
1113         const char *cur_branch, *other_branch;
1114         struct diff_filespec other;
1115         struct diff_filespec *add;
1116
1117         if (stage == 2) {
1118                 dst_entry = ci->dst_entry1;
1119                 cur_branch = ci->branch1;
1120                 other_branch = ci->branch2;
1121         } else {
1122                 dst_entry = ci->dst_entry2;
1123                 cur_branch = ci->branch2;
1124                 other_branch = ci->branch1;
1125         }
1126
1127         add = filespec_from_entry(&other, dst_entry, stage ^ 1);
1128         if (add) {
1129                 char *add_name = unique_path(o, rename->path, other_branch);
1130                 update_file(o, 0, add->sha1, add->mode, add_name);
1131
1132                 remove_file(o, 0, rename->path, 0);
1133                 dst_name = unique_path(o, rename->path, cur_branch);
1134         } else {
1135                 if (dir_in_way(rename->path, !o->call_depth)) {
1136                         dst_name = unique_path(o, rename->path, cur_branch);
1137                         output(o, 1, _("%s is a directory in %s adding as %s instead"),
1138                                rename->path, other_branch, dst_name);
1139                 }
1140         }
1141         update_file(o, 0, rename->sha1, rename->mode, dst_name);
1142         if (stage == 2)
1143                 update_stages(rename->path, NULL, rename, add);
1144         else
1145                 update_stages(rename->path, NULL, add, rename);
1146
1147         if (dst_name != rename->path)
1148                 free(dst_name);
1149 }
1150
1151 static void conflict_rename_rename_1to2(struct merge_options *o,
1152                                         struct rename_conflict_info *ci)
1153 {
1154         /* One file was renamed in both branches, but to different names. */
1155         struct diff_filespec *one = ci->pair1->one;
1156         struct diff_filespec *a = ci->pair1->two;
1157         struct diff_filespec *b = ci->pair2->two;
1158
1159         output(o, 1, _("CONFLICT (rename/rename): "
1160                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1161                "rename \"%s\"->\"%s\" in \"%s\"%s"),
1162                one->path, a->path, ci->branch1,
1163                one->path, b->path, ci->branch2,
1164                o->call_depth ? _(" (left unresolved)") : "");
1165         if (o->call_depth) {
1166                 struct merge_file_info mfi;
1167                 struct diff_filespec other;
1168                 struct diff_filespec *add;
1169                 mfi = merge_file_one(o, one->path,
1170                                  one->sha1, one->mode,
1171                                  a->sha1, a->mode,
1172                                  b->sha1, b->mode,
1173                                  ci->branch1, ci->branch2);
1174                 /*
1175                  * FIXME: For rename/add-source conflicts (if we could detect
1176                  * such), this is wrong.  We should instead find a unique
1177                  * pathname and then either rename the add-source file to that
1178                  * unique path, or use that unique path instead of src here.
1179                  */
1180                 update_file(o, 0, mfi.sha, mfi.mode, one->path);
1181
1182                 /*
1183                  * Above, we put the merged content at the merge-base's
1184                  * path.  Now we usually need to delete both a->path and
1185                  * b->path.  However, the rename on each side of the merge
1186                  * could also be involved in a rename/add conflict.  In
1187                  * such cases, we should keep the added file around,
1188                  * resolving the conflict at that path in its favor.
1189                  */
1190                 add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
1191                 if (add)
1192                         update_file(o, 0, add->sha1, add->mode, a->path);
1193                 else
1194                         remove_file_from_cache(a->path);
1195                 add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
1196                 if (add)
1197                         update_file(o, 0, add->sha1, add->mode, b->path);
1198                 else
1199                         remove_file_from_cache(b->path);
1200         } else {
1201                 handle_file(o, a, 2, ci);
1202                 handle_file(o, b, 3, ci);
1203         }
1204 }
1205
1206 static void conflict_rename_rename_2to1(struct merge_options *o,
1207                                         struct rename_conflict_info *ci)
1208 {
1209         /* Two files, a & b, were renamed to the same thing, c. */
1210         struct diff_filespec *a = ci->pair1->one;
1211         struct diff_filespec *b = ci->pair2->one;
1212         struct diff_filespec *c1 = ci->pair1->two;
1213         struct diff_filespec *c2 = ci->pair2->two;
1214         char *path = c1->path; /* == c2->path */
1215         struct merge_file_info mfi_c1;
1216         struct merge_file_info mfi_c2;
1217
1218         output(o, 1, _("CONFLICT (rename/rename): "
1219                "Rename %s->%s in %s. "
1220                "Rename %s->%s in %s"),
1221                a->path, c1->path, ci->branch1,
1222                b->path, c2->path, ci->branch2);
1223
1224         remove_file(o, 1, a->path, would_lose_untracked(a->path));
1225         remove_file(o, 1, b->path, would_lose_untracked(b->path));
1226
1227         mfi_c1 = merge_file_special_markers(o, a, c1, &ci->ren1_other,
1228                                             o->branch1, c1->path,
1229                                             o->branch2, ci->ren1_other.path);
1230         mfi_c2 = merge_file_special_markers(o, b, &ci->ren2_other, c2,
1231                                             o->branch1, ci->ren2_other.path,
1232                                             o->branch2, c2->path);
1233
1234         if (o->call_depth) {
1235                 /*
1236                  * If mfi_c1.clean && mfi_c2.clean, then it might make
1237                  * sense to do a two-way merge of those results.  But, I
1238                  * think in all cases, it makes sense to have the virtual
1239                  * merge base just undo the renames; they can be detected
1240                  * again later for the non-recursive merge.
1241                  */
1242                 remove_file(o, 0, path, 0);
1243                 update_file(o, 0, mfi_c1.sha, mfi_c1.mode, a->path);
1244                 update_file(o, 0, mfi_c2.sha, mfi_c2.mode, b->path);
1245         } else {
1246                 char *new_path1 = unique_path(o, path, ci->branch1);
1247                 char *new_path2 = unique_path(o, path, ci->branch2);
1248                 output(o, 1, _("Renaming %s to %s and %s to %s instead"),
1249                        a->path, new_path1, b->path, new_path2);
1250                 remove_file(o, 0, path, 0);
1251                 update_file(o, 0, mfi_c1.sha, mfi_c1.mode, new_path1);
1252                 update_file(o, 0, mfi_c2.sha, mfi_c2.mode, new_path2);
1253                 free(new_path2);
1254                 free(new_path1);
1255         }
1256 }
1257
1258 static int process_renames(struct merge_options *o,
1259                            struct string_list *a_renames,
1260                            struct string_list *b_renames)
1261 {
1262         int clean_merge = 1, i, j;
1263         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
1264         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
1265         const struct rename *sre;
1266
1267         for (i = 0; i < a_renames->nr; i++) {
1268                 sre = a_renames->items[i].util;
1269                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
1270                         = (void *)sre;
1271         }
1272         for (i = 0; i < b_renames->nr; i++) {
1273                 sre = b_renames->items[i].util;
1274                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
1275                         = (void *)sre;
1276         }
1277
1278         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1279                 struct string_list *renames1, *renames2Dst;
1280                 struct rename *ren1 = NULL, *ren2 = NULL;
1281                 const char *branch1, *branch2;
1282                 const char *ren1_src, *ren1_dst;
1283                 struct string_list_item *lookup;
1284
1285                 if (i >= a_renames->nr) {
1286                         ren2 = b_renames->items[j++].util;
1287                 } else if (j >= b_renames->nr) {
1288                         ren1 = a_renames->items[i++].util;
1289                 } else {
1290                         int compare = strcmp(a_renames->items[i].string,
1291                                              b_renames->items[j].string);
1292                         if (compare <= 0)
1293                                 ren1 = a_renames->items[i++].util;
1294                         if (compare >= 0)
1295                                 ren2 = b_renames->items[j++].util;
1296                 }
1297
1298                 /* TODO: refactor, so that 1/2 are not needed */
1299                 if (ren1) {
1300                         renames1 = a_renames;
1301                         renames2Dst = &b_by_dst;
1302                         branch1 = o->branch1;
1303                         branch2 = o->branch2;
1304                 } else {
1305                         struct rename *tmp;
1306                         renames1 = b_renames;
1307                         renames2Dst = &a_by_dst;
1308                         branch1 = o->branch2;
1309                         branch2 = o->branch1;
1310                         tmp = ren2;
1311                         ren2 = ren1;
1312                         ren1 = tmp;
1313                 }
1314
1315                 if (ren1->processed)
1316                         continue;
1317                 ren1->processed = 1;
1318                 ren1->dst_entry->processed = 1;
1319                 /* BUG: We should only mark src_entry as processed if we
1320                  * are not dealing with a rename + add-source case.
1321                  */
1322                 ren1->src_entry->processed = 1;
1323
1324                 ren1_src = ren1->pair->one->path;
1325                 ren1_dst = ren1->pair->two->path;
1326
1327                 if (ren2) {
1328                         /* One file renamed on both sides */
1329                         const char *ren2_src = ren2->pair->one->path;
1330                         const char *ren2_dst = ren2->pair->two->path;
1331                         enum rename_type rename_type;
1332                         if (strcmp(ren1_src, ren2_src) != 0)
1333                                 die("ren1_src != ren2_src");
1334                         ren2->dst_entry->processed = 1;
1335                         ren2->processed = 1;
1336                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1337                                 rename_type = RENAME_ONE_FILE_TO_TWO;
1338                                 clean_merge = 0;
1339                         } else {
1340                                 rename_type = RENAME_ONE_FILE_TO_ONE;
1341                                 /* BUG: We should only remove ren1_src in
1342                                  * the base stage (think of rename +
1343                                  * add-source cases).
1344                                  */
1345                                 remove_file(o, 1, ren1_src, 1);
1346                                 update_entry(ren1->dst_entry,
1347                                              ren1->pair->one,
1348                                              ren1->pair->two,
1349                                              ren2->pair->two);
1350                         }
1351                         setup_rename_conflict_info(rename_type,
1352                                                    ren1->pair,
1353                                                    ren2->pair,
1354                                                    branch1,
1355                                                    branch2,
1356                                                    ren1->dst_entry,
1357                                                    ren2->dst_entry,
1358                                                    o,
1359                                                    NULL,
1360                                                    NULL);
1361                 } else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
1362                         /* Two different files renamed to the same thing */
1363                         char *ren2_dst;
1364                         ren2 = lookup->util;
1365                         ren2_dst = ren2->pair->two->path;
1366                         if (strcmp(ren1_dst, ren2_dst) != 0)
1367                                 die("ren1_dst != ren2_dst");
1368
1369                         clean_merge = 0;
1370                         ren2->processed = 1;
1371                         /*
1372                          * BUG: We should only mark src_entry as processed
1373                          * if we are not dealing with a rename + add-source
1374                          * case.
1375                          */
1376                         ren2->src_entry->processed = 1;
1377
1378                         setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
1379                                                    ren1->pair,
1380                                                    ren2->pair,
1381                                                    branch1,
1382                                                    branch2,
1383                                                    ren1->dst_entry,
1384                                                    ren2->dst_entry,
1385                                                    o,
1386                                                    ren1->src_entry,
1387                                                    ren2->src_entry);
1388
1389                 } else {
1390                         /* Renamed in 1, maybe changed in 2 */
1391                         /* we only use sha1 and mode of these */
1392                         struct diff_filespec src_other, dst_other;
1393                         int try_merge;
1394
1395                         /*
1396                          * unpack_trees loads entries from common-commit
1397                          * into stage 1, from head-commit into stage 2, and
1398                          * from merge-commit into stage 3.  We keep track
1399                          * of which side corresponds to the rename.
1400                          */
1401                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1402                         int other_stage =   a_renames == renames1 ? 3 : 2;
1403
1404                         /* BUG: We should only remove ren1_src in the base
1405                          * stage and in other_stage (think of rename +
1406                          * add-source case).
1407                          */
1408                         remove_file(o, 1, ren1_src,
1409                                     renamed_stage == 2 || !was_tracked(ren1_src));
1410
1411                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1412                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1413                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1414                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1415                         try_merge = 0;
1416
1417                         if (sha_eq(src_other.sha1, null_sha1)) {
1418                                 setup_rename_conflict_info(RENAME_DELETE,
1419                                                            ren1->pair,
1420                                                            NULL,
1421                                                            branch1,
1422                                                            branch2,
1423                                                            ren1->dst_entry,
1424                                                            NULL,
1425                                                            o,
1426                                                            NULL,
1427                                                            NULL);
1428                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1429                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1430                                 /*
1431                                  * Added file on the other side identical to
1432                                  * the file being renamed: clean merge.
1433                                  * Also, there is no need to overwrite the
1434                                  * file already in the working copy, so call
1435                                  * update_file_flags() instead of
1436                                  * update_file().
1437                                  */
1438                                 update_file_flags(o,
1439                                                   ren1->pair->two->sha1,
1440                                                   ren1->pair->two->mode,
1441                                                   ren1_dst,
1442                                                   1, /* update_cache */
1443                                                   0  /* update_wd    */);
1444                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1445                                 clean_merge = 0;
1446                                 try_merge = 1;
1447                                 output(o, 1, _("CONFLICT (rename/add): Rename %s->%s in %s. "
1448                                        "%s added in %s"),
1449                                        ren1_src, ren1_dst, branch1,
1450                                        ren1_dst, branch2);
1451                                 if (o->call_depth) {
1452                                         struct merge_file_info mfi;
1453                                         mfi = merge_file_one(o, ren1_dst, null_sha1, 0,
1454                                                          ren1->pair->two->sha1, ren1->pair->two->mode,
1455                                                          dst_other.sha1, dst_other.mode,
1456                                                          branch1, branch2);
1457                                         output(o, 1, _("Adding merged %s"), ren1_dst);
1458                                         update_file(o, 0, mfi.sha, mfi.mode, ren1_dst);
1459                                         try_merge = 0;
1460                                 } else {
1461                                         char *new_path = unique_path(o, ren1_dst, branch2);
1462                                         output(o, 1, _("Adding as %s instead"), new_path);
1463                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1464                                         free(new_path);
1465                                 }
1466                         } else
1467                                 try_merge = 1;
1468
1469                         if (try_merge) {
1470                                 struct diff_filespec *one, *a, *b;
1471                                 src_other.path = (char *)ren1_src;
1472
1473                                 one = ren1->pair->one;
1474                                 if (a_renames == renames1) {
1475                                         a = ren1->pair->two;
1476                                         b = &src_other;
1477                                 } else {
1478                                         b = ren1->pair->two;
1479                                         a = &src_other;
1480                                 }
1481                                 update_entry(ren1->dst_entry, one, a, b);
1482                                 setup_rename_conflict_info(RENAME_NORMAL,
1483                                                            ren1->pair,
1484                                                            NULL,
1485                                                            branch1,
1486                                                            NULL,
1487                                                            ren1->dst_entry,
1488                                                            NULL,
1489                                                            o,
1490                                                            NULL,
1491                                                            NULL);
1492                         }
1493                 }
1494         }
1495         string_list_clear(&a_by_dst, 0);
1496         string_list_clear(&b_by_dst, 0);
1497
1498         return clean_merge;
1499 }
1500
1501 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1502 {
1503         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1504 }
1505
1506 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1507 {
1508         void *buf;
1509         enum object_type type;
1510         unsigned long size;
1511         buf = read_sha1_file(sha1, &type, &size);
1512         if (!buf)
1513                 return error(_("cannot read object %s"), sha1_to_hex(sha1));
1514         if (type != OBJ_BLOB) {
1515                 free(buf);
1516                 return error(_("object %s is not a blob"), sha1_to_hex(sha1));
1517         }
1518         strbuf_attach(dst, buf, size, size + 1);
1519         return 0;
1520 }
1521
1522 static int blob_unchanged(const unsigned char *o_sha,
1523                           const unsigned char *a_sha,
1524                           int renormalize, const char *path)
1525 {
1526         struct strbuf o = STRBUF_INIT;
1527         struct strbuf a = STRBUF_INIT;
1528         int ret = 0; /* assume changed for safety */
1529
1530         if (sha_eq(o_sha, a_sha))
1531                 return 1;
1532         if (!renormalize)
1533                 return 0;
1534
1535         assert(o_sha && a_sha);
1536         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1537                 goto error_return;
1538         /*
1539          * Note: binary | is used so that both renormalizations are
1540          * performed.  Comparison can be skipped if both files are
1541          * unchanged since their sha1s have already been compared.
1542          */
1543         if (renormalize_buffer(path, o.buf, o.len, &o) |
1544             renormalize_buffer(path, a.buf, o.len, &a))
1545                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1546
1547 error_return:
1548         strbuf_release(&o);
1549         strbuf_release(&a);
1550         return ret;
1551 }
1552
1553 static void handle_modify_delete(struct merge_options *o,
1554                                  const char *path,
1555                                  unsigned char *o_sha, int o_mode,
1556                                  unsigned char *a_sha, int a_mode,
1557                                  unsigned char *b_sha, int b_mode)
1558 {
1559         handle_change_delete(o,
1560                              path,
1561                              o_sha, o_mode,
1562                              a_sha, a_mode,
1563                              b_sha, b_mode,
1564                              _("modify"), _("modified"));
1565 }
1566
1567 static int merge_content(struct merge_options *o,
1568                          const char *path,
1569                          unsigned char *o_sha, int o_mode,
1570                          unsigned char *a_sha, int a_mode,
1571                          unsigned char *b_sha, int b_mode,
1572                          struct rename_conflict_info *rename_conflict_info)
1573 {
1574         const char *reason = _("content");
1575         const char *path1 = NULL, *path2 = NULL;
1576         struct merge_file_info mfi;
1577         struct diff_filespec one, a, b;
1578         unsigned df_conflict_remains = 0;
1579
1580         if (!o_sha) {
1581                 reason = _("add/add");
1582                 o_sha = (unsigned char *)null_sha1;
1583         }
1584         one.path = a.path = b.path = (char *)path;
1585         hashcpy(one.sha1, o_sha);
1586         one.mode = o_mode;
1587         hashcpy(a.sha1, a_sha);
1588         a.mode = a_mode;
1589         hashcpy(b.sha1, b_sha);
1590         b.mode = b_mode;
1591
1592         if (rename_conflict_info) {
1593                 struct diff_filepair *pair1 = rename_conflict_info->pair1;
1594
1595                 path1 = (o->branch1 == rename_conflict_info->branch1) ?
1596                         pair1->two->path : pair1->one->path;
1597                 /* If rename_conflict_info->pair2 != NULL, we are in
1598                  * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
1599                  * normal rename.
1600                  */
1601                 path2 = (rename_conflict_info->pair2 ||
1602                          o->branch2 == rename_conflict_info->branch1) ?
1603                         pair1->two->path : pair1->one->path;
1604
1605                 if (dir_in_way(path, !o->call_depth))
1606                         df_conflict_remains = 1;
1607         }
1608         mfi = merge_file_special_markers(o, &one, &a, &b,
1609                                          o->branch1, path1,
1610                                          o->branch2, path2);
1611
1612         if (mfi.clean && !df_conflict_remains &&
1613             sha_eq(mfi.sha, a_sha) && mfi.mode == a_mode) {
1614                 int path_renamed_outside_HEAD;
1615                 output(o, 3, _("Skipped %s (merged same as existing)"), path);
1616                 /*
1617                  * The content merge resulted in the same file contents we
1618                  * already had.  We can return early if those file contents
1619                  * are recorded at the correct path (which may not be true
1620                  * if the merge involves a rename).
1621                  */
1622                 path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
1623                 if (!path_renamed_outside_HEAD) {
1624                         add_cacheinfo(mfi.mode, mfi.sha, path,
1625                                       0, (!o->call_depth), 0);
1626                         return mfi.clean;
1627                 }
1628         } else
1629                 output(o, 2, _("Auto-merging %s"), path);
1630
1631         if (!mfi.clean) {
1632                 if (S_ISGITLINK(mfi.mode))
1633                         reason = _("submodule");
1634                 output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
1635                                 reason, path);
1636                 if (rename_conflict_info && !df_conflict_remains)
1637                         update_stages(path, &one, &a, &b);
1638         }
1639
1640         if (df_conflict_remains) {
1641                 char *new_path;
1642                 if (o->call_depth) {
1643                         remove_file_from_cache(path);
1644                 } else {
1645                         if (!mfi.clean)
1646                                 update_stages(path, &one, &a, &b);
1647                         else {
1648                                 int file_from_stage2 = was_tracked(path);
1649                                 struct diff_filespec merged;
1650                                 hashcpy(merged.sha1, mfi.sha);
1651                                 merged.mode = mfi.mode;
1652
1653                                 update_stages(path, NULL,
1654                                               file_from_stage2 ? &merged : NULL,
1655                                               file_from_stage2 ? NULL : &merged);
1656                         }
1657
1658                 }
1659                 new_path = unique_path(o, path, rename_conflict_info->branch1);
1660                 output(o, 1, _("Adding as %s instead"), new_path);
1661                 update_file(o, 0, mfi.sha, mfi.mode, new_path);
1662                 free(new_path);
1663                 mfi.clean = 0;
1664         } else {
1665                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1666         }
1667         return mfi.clean;
1668
1669 }
1670
1671 /* Per entry merge function */
1672 static int process_entry(struct merge_options *o,
1673                          const char *path, struct stage_data *entry)
1674 {
1675         /*
1676         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1677         print_index_entry("\tpath: ", entry);
1678         */
1679         int clean_merge = 1;
1680         int normalize = o->renormalize;
1681         unsigned o_mode = entry->stages[1].mode;
1682         unsigned a_mode = entry->stages[2].mode;
1683         unsigned b_mode = entry->stages[3].mode;
1684         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1685         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1686         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1687
1688         entry->processed = 1;
1689         if (entry->rename_conflict_info) {
1690                 struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
1691                 switch (conflict_info->rename_type) {
1692                 case RENAME_NORMAL:
1693                 case RENAME_ONE_FILE_TO_ONE:
1694                         clean_merge = merge_content(o, path,
1695                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1696                                                     conflict_info);
1697                         break;
1698                 case RENAME_DELETE:
1699                         clean_merge = 0;
1700                         conflict_rename_delete(o, conflict_info->pair1,
1701                                                conflict_info->branch1,
1702                                                conflict_info->branch2);
1703                         break;
1704                 case RENAME_ONE_FILE_TO_TWO:
1705                         clean_merge = 0;
1706                         conflict_rename_rename_1to2(o, conflict_info);
1707                         break;
1708                 case RENAME_TWO_FILES_TO_ONE:
1709                         clean_merge = 0;
1710                         conflict_rename_rename_2to1(o, conflict_info);
1711                         break;
1712                 default:
1713                         entry->processed = 0;
1714                         break;
1715                 }
1716         } else if (o_sha && (!a_sha || !b_sha)) {
1717                 /* Case A: Deleted in one */
1718                 if ((!a_sha && !b_sha) ||
1719                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1720                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1721                         /* Deleted in both or deleted in one and
1722                          * unchanged in the other */
1723                         if (a_sha)
1724                                 output(o, 2, _("Removing %s"), path);
1725                         /* do not touch working file if it did not exist */
1726                         remove_file(o, 1, path, !a_sha);
1727                 } else {
1728                         /* Modify/delete; deleted side may have put a directory in the way */
1729                         clean_merge = 0;
1730                         handle_modify_delete(o, path, o_sha, o_mode,
1731                                              a_sha, a_mode, b_sha, b_mode);
1732                 }
1733         } else if ((!o_sha && a_sha && !b_sha) ||
1734                    (!o_sha && !a_sha && b_sha)) {
1735                 /* Case B: Added in one. */
1736                 /* [nothing|directory] -> ([nothing|directory], file) */
1737
1738                 const char *add_branch;
1739                 const char *other_branch;
1740                 unsigned mode;
1741                 const unsigned char *sha;
1742                 const char *conf;
1743
1744                 if (a_sha) {
1745                         add_branch = o->branch1;
1746                         other_branch = o->branch2;
1747                         mode = a_mode;
1748                         sha = a_sha;
1749                         conf = _("file/directory");
1750                 } else {
1751                         add_branch = o->branch2;
1752                         other_branch = o->branch1;
1753                         mode = b_mode;
1754                         sha = b_sha;
1755                         conf = _("directory/file");
1756                 }
1757                 if (dir_in_way(path, !o->call_depth)) {
1758                         char *new_path = unique_path(o, path, add_branch);
1759                         clean_merge = 0;
1760                         output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
1761                                "Adding %s as %s"),
1762                                conf, path, other_branch, path, new_path);
1763                         if (o->call_depth)
1764                                 remove_file_from_cache(path);
1765                         update_file(o, 0, sha, mode, new_path);
1766                         if (o->call_depth)
1767                                 remove_file_from_cache(path);
1768                         free(new_path);
1769                 } else {
1770                         output(o, 2, _("Adding %s"), path);
1771                         /* do not overwrite file if already present */
1772                         update_file_flags(o, sha, mode, path, 1, !a_sha);
1773                 }
1774         } else if (a_sha && b_sha) {
1775                 /* Case C: Added in both (check for same permissions) and */
1776                 /* case D: Modified in both, but differently. */
1777                 clean_merge = merge_content(o, path,
1778                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1779                                             NULL);
1780         } else if (!o_sha && !a_sha && !b_sha) {
1781                 /*
1782                  * this entry was deleted altogether. a_mode == 0 means
1783                  * we had that path and want to actively remove it.
1784                  */
1785                 remove_file(o, 1, path, !a_mode);
1786         } else
1787                 die(_("Fatal merge failure, shouldn't happen."));
1788
1789         return clean_merge;
1790 }
1791
1792 int merge_trees(struct merge_options *o,
1793                 struct tree *head,
1794                 struct tree *merge,
1795                 struct tree *common,
1796                 struct tree **result)
1797 {
1798         int code, clean;
1799
1800         if (o->subtree_shift) {
1801                 merge = shift_tree_object(head, merge, o->subtree_shift);
1802                 common = shift_tree_object(head, common, o->subtree_shift);
1803         }
1804
1805         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1806                 output(o, 0, _("Already up-to-date!"));
1807                 *result = head;
1808                 return 1;
1809         }
1810
1811         code = git_merge_trees(o->call_depth, common, head, merge);
1812
1813         if (code != 0) {
1814                 if (show(o, 4) || o->call_depth)
1815                         die(_("merging of trees %s and %s failed"),
1816                             sha1_to_hex(head->object.sha1),
1817                             sha1_to_hex(merge->object.sha1));
1818                 else
1819                         exit(128);
1820         }
1821
1822         if (unmerged_cache()) {
1823                 struct string_list *entries, *re_head, *re_merge;
1824                 int i;
1825                 string_list_clear(&o->current_file_set, 1);
1826                 string_list_clear(&o->current_directory_set, 1);
1827                 get_files_dirs(o, head);
1828                 get_files_dirs(o, merge);
1829
1830                 entries = get_unmerged();
1831                 record_df_conflict_files(o, entries);
1832                 re_head  = get_renames(o, head, common, head, merge, entries);
1833                 re_merge = get_renames(o, merge, common, head, merge, entries);
1834                 clean = process_renames(o, re_head, re_merge);
1835                 for (i = entries->nr-1; 0 <= i; i--) {
1836                         const char *path = entries->items[i].string;
1837                         struct stage_data *e = entries->items[i].util;
1838                         if (!e->processed
1839                                 && !process_entry(o, path, e))
1840                                 clean = 0;
1841                 }
1842                 for (i = 0; i < entries->nr; i++) {
1843                         struct stage_data *e = entries->items[i].util;
1844                         if (!e->processed)
1845                                 die(_("Unprocessed path??? %s"),
1846                                     entries->items[i].string);
1847                 }
1848
1849                 string_list_clear(re_merge, 0);
1850                 string_list_clear(re_head, 0);
1851                 string_list_clear(entries, 1);
1852
1853         }
1854         else
1855                 clean = 1;
1856
1857         if (o->call_depth)
1858                 *result = write_tree_from_memory(o);
1859
1860         return clean;
1861 }
1862
1863 static struct commit_list *reverse_commit_list(struct commit_list *list)
1864 {
1865         struct commit_list *next = NULL, *current, *backup;
1866         for (current = list; current; current = backup) {
1867                 backup = current->next;
1868                 current->next = next;
1869                 next = current;
1870         }
1871         return next;
1872 }
1873
1874 /*
1875  * Merge the commits h1 and h2, return the resulting virtual
1876  * commit object and a flag indicating the cleanness of the merge.
1877  */
1878 int merge_recursive(struct merge_options *o,
1879                     struct commit *h1,
1880                     struct commit *h2,
1881                     struct commit_list *ca,
1882                     struct commit **result)
1883 {
1884         struct commit_list *iter;
1885         struct commit *merged_common_ancestors;
1886         struct tree *mrtree = mrtree;
1887         int clean;
1888
1889         if (show(o, 4)) {
1890                 output(o, 4, _("Merging:"));
1891                 output_commit_title(o, h1);
1892                 output_commit_title(o, h2);
1893         }
1894
1895         if (!ca) {
1896                 ca = get_merge_bases(h1, h2, 1);
1897                 ca = reverse_commit_list(ca);
1898         }
1899
1900         if (show(o, 5)) {
1901                 unsigned cnt = commit_list_count(ca);
1902
1903                 output(o, 5, Q_("found %u common ancestor:",
1904                                 "found %u common ancestors:", cnt), cnt);
1905                 for (iter = ca; iter; iter = iter->next)
1906                         output_commit_title(o, iter->item);
1907         }
1908
1909         merged_common_ancestors = pop_commit(&ca);
1910         if (merged_common_ancestors == NULL) {
1911                 /* if there is no common ancestor, use an empty tree */
1912                 struct tree *tree;
1913
1914                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1915                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1916         }
1917
1918         for (iter = ca; iter; iter = iter->next) {
1919                 const char *saved_b1, *saved_b2;
1920                 o->call_depth++;
1921                 /*
1922                  * When the merge fails, the result contains files
1923                  * with conflict markers. The cleanness flag is
1924                  * ignored, it was never actually used, as result of
1925                  * merge_trees has always overwritten it: the committed
1926                  * "conflicts" were already resolved.
1927                  */
1928                 discard_cache();
1929                 saved_b1 = o->branch1;
1930                 saved_b2 = o->branch2;
1931                 o->branch1 = "Temporary merge branch 1";
1932                 o->branch2 = "Temporary merge branch 2";
1933                 merge_recursive(o, merged_common_ancestors, iter->item,
1934                                 NULL, &merged_common_ancestors);
1935                 o->branch1 = saved_b1;
1936                 o->branch2 = saved_b2;
1937                 o->call_depth--;
1938
1939                 if (!merged_common_ancestors)
1940                         die(_("merge returned no commit"));
1941         }
1942
1943         discard_cache();
1944         if (!o->call_depth)
1945                 read_cache();
1946
1947         o->ancestor = "merged common ancestors";
1948         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1949                             &mrtree);
1950
1951         if (o->call_depth) {
1952                 *result = make_virtual_commit(mrtree, "merged tree");
1953                 commit_list_insert(h1, &(*result)->parents);
1954                 commit_list_insert(h2, &(*result)->parents->next);
1955         }
1956         flush_output(o);
1957         if (show(o, 2))
1958                 diff_warn_rename_limit("merge.renamelimit",
1959                                        o->needed_rename_limit, 0);
1960         return clean;
1961 }
1962
1963 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1964 {
1965         struct object *object;
1966
1967         object = deref_tag(parse_object(sha1), name, strlen(name));
1968         if (!object)
1969                 return NULL;
1970         if (object->type == OBJ_TREE)
1971                 return make_virtual_commit((struct tree*)object, name);
1972         if (object->type != OBJ_COMMIT)
1973                 return NULL;
1974         if (parse_commit((struct commit *)object))
1975                 return NULL;
1976         return (struct commit *)object;
1977 }
1978
1979 int merge_recursive_generic(struct merge_options *o,
1980                             const unsigned char *head,
1981                             const unsigned char *merge,
1982                             int num_base_list,
1983                             const unsigned char **base_list,
1984                             struct commit **result)
1985 {
1986         int clean, index_fd;
1987         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1988         struct commit *head_commit = get_ref(head, o->branch1);
1989         struct commit *next_commit = get_ref(merge, o->branch2);
1990         struct commit_list *ca = NULL;
1991
1992         if (base_list) {
1993                 int i;
1994                 for (i = 0; i < num_base_list; ++i) {
1995                         struct commit *base;
1996                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1997                                 return error(_("Could not parse object '%s'"),
1998                                         sha1_to_hex(base_list[i]));
1999                         commit_list_insert(base, &ca);
2000                 }
2001         }
2002
2003         index_fd = hold_locked_index(lock, 1);
2004         clean = merge_recursive(o, head_commit, next_commit, ca,
2005                         result);
2006         if (active_cache_changed &&
2007                         (write_cache(index_fd, active_cache, active_nr) ||
2008                          commit_locked_index(lock)))
2009                 return error(_("Unable to write index."));
2010
2011         return clean ? 0 : 1;
2012 }
2013
2014 static int merge_recursive_config(const char *var, const char *value, void *cb)
2015 {
2016         struct merge_options *o = cb;
2017         if (!strcmp(var, "merge.verbosity")) {
2018                 o->verbosity = git_config_int(var, value);
2019                 return 0;
2020         }
2021         if (!strcmp(var, "diff.renamelimit")) {
2022                 o->diff_rename_limit = git_config_int(var, value);
2023                 return 0;
2024         }
2025         if (!strcmp(var, "merge.renamelimit")) {
2026                 o->merge_rename_limit = git_config_int(var, value);
2027                 return 0;
2028         }
2029         return git_xmerge_config(var, value, cb);
2030 }
2031
2032 void init_merge_options(struct merge_options *o)
2033 {
2034         memset(o, 0, sizeof(struct merge_options));
2035         o->verbosity = 2;
2036         o->buffer_output = 1;
2037         o->diff_rename_limit = -1;
2038         o->merge_rename_limit = -1;
2039         o->renormalize = 0;
2040         git_config(merge_recursive_config, o);
2041         if (getenv("GIT_MERGE_VERBOSITY"))
2042                 o->verbosity =
2043                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
2044         if (o->verbosity >= 5)
2045                 o->buffer_output = 0;
2046         strbuf_init(&o->obuf, 0);
2047         memset(&o->current_file_set, 0, sizeof(struct string_list));
2048         o->current_file_set.strdup_strings = 1;
2049         memset(&o->current_directory_set, 0, sizeof(struct string_list));
2050         o->current_directory_set.strdup_strings = 1;
2051         memset(&o->df_conflict_file_set, 0, sizeof(struct string_list));
2052         o->df_conflict_file_set.strdup_strings = 1;
2053 }
2054
2055 int parse_merge_opt(struct merge_options *o, const char *s)
2056 {
2057         if (!s || !*s)
2058                 return -1;
2059         if (!strcmp(s, "ours"))
2060                 o->recursive_variant = MERGE_RECURSIVE_OURS;
2061         else if (!strcmp(s, "theirs"))
2062                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
2063         else if (!strcmp(s, "subtree"))
2064                 o->subtree_shift = "";
2065         else if (!prefixcmp(s, "subtree="))
2066                 o->subtree_shift = s + strlen("subtree=");
2067         else if (!strcmp(s, "patience"))
2068                 o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
2069         else if (!strcmp(s, "histogram"))
2070                 o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
2071         else if (!strcmp(s, "diff-algorithm=")) {
2072                 long value = parse_algorithm_value(s+15);
2073                 if (value < 0)
2074                         return -1;
2075                 /* clear out previous settings */
2076                 DIFF_XDL_CLR(o, NEED_MINIMAL);
2077                 o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
2078                 o->xdl_opts |= value;
2079         }
2080         else if (!strcmp(s, "ignore-space-change"))
2081                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2082         else if (!strcmp(s, "ignore-all-space"))
2083                 o->xdl_opts |= XDF_IGNORE_WHITESPACE;
2084         else if (!strcmp(s, "ignore-space-at-eol"))
2085                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2086         else if (!strcmp(s, "renormalize"))
2087                 o->renormalize = 1;
2088         else if (!strcmp(s, "no-renormalize"))
2089                 o->renormalize = 0;
2090         else if (!prefixcmp(s, "rename-threshold=")) {
2091                 const char *score = s + strlen("rename-threshold=");
2092                 if ((o->rename_score = parse_rename_score(&score)) == -1 || *score != 0)
2093                         return -1;
2094         }
2095         else
2096                 return -1;
2097         return 0;
2098 }