ll-merge: replace flag argument with options struct
[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
24 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
25                                       const char *subtree_shift)
26 {
27         unsigned char shifted[20];
28
29         if (!*subtree_shift) {
30                 shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
31         } else {
32                 shift_tree_by(one->object.sha1, two->object.sha1, shifted,
33                               subtree_shift);
34         }
35         if (!hashcmp(two->object.sha1, shifted))
36                 return two;
37         return lookup_tree(shifted);
38 }
39
40 /*
41  * A virtual commit has (const char *)commit->util set to the name.
42  */
43
44 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
45 {
46         struct commit *commit = xcalloc(1, sizeof(struct commit));
47         commit->tree = tree;
48         commit->util = (void*)comment;
49         /* avoid warnings */
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 /*
66  * Since we want to write the index eventually, we cannot reuse the index
67  * for these (temporary) data.
68  */
69 struct stage_data
70 {
71         struct
72         {
73                 unsigned mode;
74                 unsigned char sha[20];
75         } stages[4];
76         unsigned processed:1;
77 };
78
79 static int show(struct merge_options *o, int v)
80 {
81         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
82 }
83
84 static void flush_output(struct merge_options *o)
85 {
86         if (o->obuf.len) {
87                 fputs(o->obuf.buf, stdout);
88                 strbuf_reset(&o->obuf);
89         }
90 }
91
92 __attribute__((format (printf, 3, 4)))
93 static void output(struct merge_options *o, int v, const char *fmt, ...)
94 {
95         int len;
96         va_list ap;
97
98         if (!show(o, v))
99                 return;
100
101         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
102         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
103         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
104
105         va_start(ap, fmt);
106         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
107         va_end(ap);
108
109         if (len < 0)
110                 len = 0;
111         if (len >= strbuf_avail(&o->obuf)) {
112                 strbuf_grow(&o->obuf, len + 2);
113                 va_start(ap, fmt);
114                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
115                 va_end(ap);
116                 if (len >= strbuf_avail(&o->obuf)) {
117                         die("this should not happen, your snprintf is broken");
118                 }
119         }
120         strbuf_setlen(&o->obuf, o->obuf.len + len);
121         strbuf_add(&o->obuf, "\n", 1);
122         if (!o->buffer_output)
123                 flush_output(o);
124 }
125
126 static void output_commit_title(struct merge_options *o, struct commit *commit)
127 {
128         int i;
129         flush_output(o);
130         for (i = o->call_depth; i--;)
131                 fputs("  ", stdout);
132         if (commit->util)
133                 printf("virtual %s\n", (char *)commit->util);
134         else {
135                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
136                 if (parse_commit(commit) != 0)
137                         printf("(bad commit)\n");
138                 else {
139                         const char *s;
140                         int len;
141                         for (s = commit->buffer; *s; s++)
142                                 if (*s == '\n' && s[1] == '\n') {
143                                         s += 2;
144                                         break;
145                                 }
146                         for (len = 0; s[len] && '\n' != s[len]; len++)
147                                 ; /* do nothing */
148                         printf("%.*s\n", len, s);
149                 }
150         }
151 }
152
153 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
154                 const char *path, int stage, int refresh, int options)
155 {
156         struct cache_entry *ce;
157         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
158         if (!ce)
159                 return error("addinfo_cache failed for path '%s'", path);
160         return add_cache_entry(ce, options);
161 }
162
163 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
164 {
165         parse_tree(tree);
166         init_tree_desc(desc, tree->buffer, tree->size);
167 }
168
169 static int git_merge_trees(int index_only,
170                            struct tree *common,
171                            struct tree *head,
172                            struct tree *merge)
173 {
174         int rc;
175         struct tree_desc t[3];
176         struct unpack_trees_options opts;
177
178         memset(&opts, 0, sizeof(opts));
179         if (index_only)
180                 opts.index_only = 1;
181         else
182                 opts.update = 1;
183         opts.merge = 1;
184         opts.head_idx = 2;
185         opts.fn = threeway_merge;
186         opts.src_index = &the_index;
187         opts.dst_index = &the_index;
188         opts.msgs = get_porcelain_error_msgs();
189
190         init_tree_desc_from_tree(t+0, common);
191         init_tree_desc_from_tree(t+1, head);
192         init_tree_desc_from_tree(t+2, merge);
193
194         rc = unpack_trees(3, t, &opts);
195         cache_tree_free(&active_cache_tree);
196         return rc;
197 }
198
199 struct tree *write_tree_from_memory(struct merge_options *o)
200 {
201         struct tree *result = NULL;
202
203         if (unmerged_cache()) {
204                 int i;
205                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
206                 for (i = 0; i < active_nr; i++) {
207                         struct cache_entry *ce = active_cache[i];
208                         if (ce_stage(ce))
209                                 fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
210                                         (int)ce_namelen(ce), ce->name);
211                 }
212                 die("Bug in merge-recursive.c");
213         }
214
215         if (!active_cache_tree)
216                 active_cache_tree = cache_tree();
217
218         if (!cache_tree_fully_valid(active_cache_tree) &&
219             cache_tree_update(active_cache_tree,
220                               active_cache, active_nr, 0, 0) < 0)
221                 die("error building trees");
222
223         result = lookup_tree(active_cache_tree->sha1);
224
225         return result;
226 }
227
228 static int save_files_dirs(const unsigned char *sha1,
229                 const char *base, int baselen, const char *path,
230                 unsigned int mode, int stage, void *context)
231 {
232         int len = strlen(path);
233         char *newpath = xmalloc(baselen + len + 1);
234         struct merge_options *o = context;
235
236         memcpy(newpath, base, baselen);
237         memcpy(newpath + baselen, path, len);
238         newpath[baselen + len] = '\0';
239
240         if (S_ISDIR(mode))
241                 string_list_insert(newpath, &o->current_directory_set);
242         else
243                 string_list_insert(newpath, &o->current_file_set);
244         free(newpath);
245
246         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
247 }
248
249 static int get_files_dirs(struct merge_options *o, struct tree *tree)
250 {
251         int n;
252         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
253                 return 0;
254         n = o->current_file_set.nr + o->current_directory_set.nr;
255         return n;
256 }
257
258 /*
259  * Returns an index_entry instance which doesn't have to correspond to
260  * a real cache entry in Git's index.
261  */
262 static struct stage_data *insert_stage_data(const char *path,
263                 struct tree *o, struct tree *a, struct tree *b,
264                 struct string_list *entries)
265 {
266         struct string_list_item *item;
267         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
268         get_tree_entry(o->object.sha1, path,
269                         e->stages[1].sha, &e->stages[1].mode);
270         get_tree_entry(a->object.sha1, path,
271                         e->stages[2].sha, &e->stages[2].mode);
272         get_tree_entry(b->object.sha1, path,
273                         e->stages[3].sha, &e->stages[3].mode);
274         item = string_list_insert(path, entries);
275         item->util = e;
276         return e;
277 }
278
279 /*
280  * Create a dictionary mapping file names to stage_data objects. The
281  * dictionary contains one entry for every path with a non-zero stage entry.
282  */
283 static struct string_list *get_unmerged(void)
284 {
285         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
286         int i;
287
288         unmerged->strdup_strings = 1;
289
290         for (i = 0; i < active_nr; i++) {
291                 struct string_list_item *item;
292                 struct stage_data *e;
293                 struct cache_entry *ce = active_cache[i];
294                 if (!ce_stage(ce))
295                         continue;
296
297                 item = string_list_lookup(ce->name, unmerged);
298                 if (!item) {
299                         item = string_list_insert(ce->name, unmerged);
300                         item->util = xcalloc(1, sizeof(struct stage_data));
301                 }
302                 e = item->util;
303                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
304                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
305         }
306
307         return unmerged;
308 }
309
310 struct rename
311 {
312         struct diff_filepair *pair;
313         struct stage_data *src_entry;
314         struct stage_data *dst_entry;
315         unsigned processed:1;
316 };
317
318 /*
319  * Get information of all renames which occurred between 'o_tree' and
320  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
321  * 'b_tree') to be able to associate the correct cache entries with
322  * the rename information. 'tree' is always equal to either a_tree or b_tree.
323  */
324 static struct string_list *get_renames(struct merge_options *o,
325                                        struct tree *tree,
326                                        struct tree *o_tree,
327                                        struct tree *a_tree,
328                                        struct tree *b_tree,
329                                        struct string_list *entries)
330 {
331         int i;
332         struct string_list *renames;
333         struct diff_options opts;
334
335         renames = xcalloc(1, sizeof(struct string_list));
336         diff_setup(&opts);
337         DIFF_OPT_SET(&opts, RECURSIVE);
338         opts.detect_rename = DIFF_DETECT_RENAME;
339         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
340                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
341                             500;
342         opts.warn_on_too_large_rename = 1;
343         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
344         if (diff_setup_done(&opts) < 0)
345                 die("diff setup failed");
346         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
347         diffcore_std(&opts);
348         for (i = 0; i < diff_queued_diff.nr; ++i) {
349                 struct string_list_item *item;
350                 struct rename *re;
351                 struct diff_filepair *pair = diff_queued_diff.queue[i];
352                 if (pair->status != 'R') {
353                         diff_free_filepair(pair);
354                         continue;
355                 }
356                 re = xmalloc(sizeof(*re));
357                 re->processed = 0;
358                 re->pair = pair;
359                 item = string_list_lookup(re->pair->one->path, entries);
360                 if (!item)
361                         re->src_entry = insert_stage_data(re->pair->one->path,
362                                         o_tree, a_tree, b_tree, entries);
363                 else
364                         re->src_entry = item->util;
365
366                 item = string_list_lookup(re->pair->two->path, entries);
367                 if (!item)
368                         re->dst_entry = insert_stage_data(re->pair->two->path,
369                                         o_tree, a_tree, b_tree, entries);
370                 else
371                         re->dst_entry = item->util;
372                 item = string_list_insert(pair->one->path, renames);
373                 item->util = re;
374         }
375         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
376         diff_queued_diff.nr = 0;
377         diff_flush(&opts);
378         return renames;
379 }
380
381 static int update_stages(const char *path, struct diff_filespec *o,
382                          struct diff_filespec *a, struct diff_filespec *b,
383                          int clear)
384 {
385         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
386         if (clear)
387                 if (remove_file_from_cache(path))
388                         return -1;
389         if (o)
390                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
391                         return -1;
392         if (a)
393                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
394                         return -1;
395         if (b)
396                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
397                         return -1;
398         return 0;
399 }
400
401 static int remove_file(struct merge_options *o, int clean,
402                        const char *path, int no_wd)
403 {
404         int update_cache = o->call_depth || clean;
405         int update_working_directory = !o->call_depth && !no_wd;
406
407         if (update_cache) {
408                 if (remove_file_from_cache(path))
409                         return -1;
410         }
411         if (update_working_directory) {
412                 if (remove_path(path))
413                         return -1;
414         }
415         return 0;
416 }
417
418 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
419 {
420         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
421         int suffix = 0;
422         struct stat st;
423         char *p = newpath + strlen(path);
424         strcpy(newpath, path);
425         *(p++) = '~';
426         strcpy(p, branch);
427         for (; *p; ++p)
428                 if ('/' == *p)
429                         *p = '_';
430         while (string_list_has_string(&o->current_file_set, newpath) ||
431                string_list_has_string(&o->current_directory_set, newpath) ||
432                lstat(newpath, &st) == 0)
433                 sprintf(p, "_%d", suffix++);
434
435         string_list_insert(newpath, &o->current_file_set);
436         return newpath;
437 }
438
439 static void flush_buffer(int fd, const char *buf, unsigned long size)
440 {
441         while (size > 0) {
442                 long ret = write_in_full(fd, buf, size);
443                 if (ret < 0) {
444                         /* Ignore epipe */
445                         if (errno == EPIPE)
446                                 break;
447                         die_errno("merge-recursive");
448                 } else if (!ret) {
449                         die("merge-recursive: disk full?");
450                 }
451                 size -= ret;
452                 buf += ret;
453         }
454 }
455
456 static int would_lose_untracked(const char *path)
457 {
458         int pos = cache_name_pos(path, strlen(path));
459
460         if (pos < 0)
461                 pos = -1 - pos;
462         while (pos < active_nr &&
463                !strcmp(path, active_cache[pos]->name)) {
464                 /*
465                  * If stage #0, it is definitely tracked.
466                  * If it has stage #2 then it was tracked
467                  * before this merge started.  All other
468                  * cases the path was not tracked.
469                  */
470                 switch (ce_stage(active_cache[pos])) {
471                 case 0:
472                 case 2:
473                         return 0;
474                 }
475                 pos++;
476         }
477         return file_exists(path);
478 }
479
480 static int make_room_for_path(const char *path)
481 {
482         int status;
483         const char *msg = "failed to create path '%s'%s";
484
485         status = safe_create_leading_directories_const(path);
486         if (status) {
487                 if (status == -3) {
488                         /* something else exists */
489                         error(msg, path, ": perhaps a D/F conflict?");
490                         return -1;
491                 }
492                 die(msg, path, "");
493         }
494
495         /*
496          * Do not unlink a file in the work tree if we are not
497          * tracking it.
498          */
499         if (would_lose_untracked(path))
500                 return error("refusing to lose untracked file at '%s'",
501                              path);
502
503         /* Successful unlink is good.. */
504         if (!unlink(path))
505                 return 0;
506         /* .. and so is no existing file */
507         if (errno == ENOENT)
508                 return 0;
509         /* .. but not some other error (who really cares what?) */
510         return error(msg, path, ": perhaps a D/F conflict?");
511 }
512
513 static void update_file_flags(struct merge_options *o,
514                               const unsigned char *sha,
515                               unsigned mode,
516                               const char *path,
517                               int update_cache,
518                               int update_wd)
519 {
520         if (o->call_depth)
521                 update_wd = 0;
522
523         if (update_wd) {
524                 enum object_type type;
525                 void *buf;
526                 unsigned long size;
527
528                 if (S_ISGITLINK(mode))
529                         /*
530                          * We may later decide to recursively descend into
531                          * the submodule directory and update its index
532                          * and/or work tree, but we do not do that now.
533                          */
534                         goto update_index;
535
536                 buf = read_sha1_file(sha, &type, &size);
537                 if (!buf)
538                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
539                 if (type != OBJ_BLOB)
540                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
541                 if (S_ISREG(mode)) {
542                         struct strbuf strbuf = STRBUF_INIT;
543                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
544                                 free(buf);
545                                 size = strbuf.len;
546                                 buf = strbuf_detach(&strbuf, NULL);
547                         }
548                 }
549
550                 if (make_room_for_path(path) < 0) {
551                         update_wd = 0;
552                         free(buf);
553                         goto update_index;
554                 }
555                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
556                         int fd;
557                         if (mode & 0100)
558                                 mode = 0777;
559                         else
560                                 mode = 0666;
561                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
562                         if (fd < 0)
563                                 die_errno("failed to open '%s'", path);
564                         flush_buffer(fd, buf, size);
565                         close(fd);
566                 } else if (S_ISLNK(mode)) {
567                         char *lnk = xmemdupz(buf, size);
568                         safe_create_leading_directories_const(path);
569                         unlink(path);
570                         if (symlink(lnk, path))
571                                 die_errno("failed to symlink '%s'", path);
572                         free(lnk);
573                 } else
574                         die("do not know what to do with %06o %s '%s'",
575                             mode, sha1_to_hex(sha), path);
576                 free(buf);
577         }
578  update_index:
579         if (update_cache)
580                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
581 }
582
583 static void update_file(struct merge_options *o,
584                         int clean,
585                         const unsigned char *sha,
586                         unsigned mode,
587                         const char *path)
588 {
589         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
590 }
591
592 /* Low level file merging, update and removal */
593
594 struct merge_file_info
595 {
596         unsigned char sha[20];
597         unsigned mode;
598         unsigned clean:1,
599                  merge:1;
600 };
601
602 static int merge_3way(struct merge_options *o,
603                       mmbuffer_t *result_buf,
604                       struct diff_filespec *one,
605                       struct diff_filespec *a,
606                       struct diff_filespec *b,
607                       const char *branch1,
608                       const char *branch2)
609 {
610         mmfile_t orig, src1, src2;
611         struct ll_merge_options ll_opts = {0};
612         char *base_name, *name1, *name2;
613         int merge_status;
614
615         ll_opts.renormalize = o->renormalize;
616
617         if (o->call_depth) {
618                 ll_opts.virtual_ancestor = 1;
619                 ll_opts.variant = 0;
620         } else {
621                 switch (o->recursive_variant) {
622                 case MERGE_RECURSIVE_OURS:
623                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
624                         break;
625                 case MERGE_RECURSIVE_THEIRS:
626                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
627                         break;
628                 default:
629                         ll_opts.variant = 0;
630                         break;
631                 }
632         }
633
634         if (strcmp(a->path, b->path) ||
635             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
636                 base_name = o->ancestor == NULL ? NULL :
637                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
638                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
639                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
640         } else {
641                 base_name = o->ancestor == NULL ? NULL :
642                         xstrdup(mkpath("%s", o->ancestor));
643                 name1 = xstrdup(mkpath("%s", branch1));
644                 name2 = xstrdup(mkpath("%s", branch2));
645         }
646
647         read_mmblob(&orig, one->sha1);
648         read_mmblob(&src1, a->sha1);
649         read_mmblob(&src2, b->sha1);
650
651         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
652                                 &src1, name1, &src2, name2, &ll_opts);
653
654         free(name1);
655         free(name2);
656         free(orig.ptr);
657         free(src1.ptr);
658         free(src2.ptr);
659         return merge_status;
660 }
661
662 static struct merge_file_info merge_file(struct merge_options *o,
663                                          struct diff_filespec *one,
664                                          struct diff_filespec *a,
665                                          struct diff_filespec *b,
666                                          const char *branch1,
667                                          const char *branch2)
668 {
669         struct merge_file_info result;
670         result.merge = 0;
671         result.clean = 1;
672
673         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
674                 result.clean = 0;
675                 if (S_ISREG(a->mode)) {
676                         result.mode = a->mode;
677                         hashcpy(result.sha, a->sha1);
678                 } else {
679                         result.mode = b->mode;
680                         hashcpy(result.sha, b->sha1);
681                 }
682         } else {
683                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
684                         result.merge = 1;
685
686                 /*
687                  * Merge modes
688                  */
689                 if (a->mode == b->mode || a->mode == one->mode)
690                         result.mode = b->mode;
691                 else {
692                         result.mode = a->mode;
693                         if (b->mode != one->mode) {
694                                 result.clean = 0;
695                                 result.merge = 1;
696                         }
697                 }
698
699                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
700                         hashcpy(result.sha, b->sha1);
701                 else if (sha_eq(b->sha1, one->sha1))
702                         hashcpy(result.sha, a->sha1);
703                 else if (S_ISREG(a->mode)) {
704                         mmbuffer_t result_buf;
705                         int merge_status;
706
707                         merge_status = merge_3way(o, &result_buf, one, a, b,
708                                                   branch1, branch2);
709
710                         if ((merge_status < 0) || !result_buf.ptr)
711                                 die("Failed to execute internal merge");
712
713                         if (write_sha1_file(result_buf.ptr, result_buf.size,
714                                             blob_type, result.sha))
715                                 die("Unable to add %s to database",
716                                     a->path);
717
718                         free(result_buf.ptr);
719                         result.clean = (merge_status == 0);
720                 } else if (S_ISGITLINK(a->mode)) {
721                         result.clean = 0;
722                         hashcpy(result.sha, a->sha1);
723                 } else if (S_ISLNK(a->mode)) {
724                         hashcpy(result.sha, a->sha1);
725
726                         if (!sha_eq(a->sha1, b->sha1))
727                                 result.clean = 0;
728                 } else {
729                         die("unsupported object type in the tree");
730                 }
731         }
732
733         return result;
734 }
735
736 static void conflict_rename_rename(struct merge_options *o,
737                                    struct rename *ren1,
738                                    const char *branch1,
739                                    struct rename *ren2,
740                                    const char *branch2)
741 {
742         char *del[2];
743         int delp = 0;
744         const char *ren1_dst = ren1->pair->two->path;
745         const char *ren2_dst = ren2->pair->two->path;
746         const char *dst_name1 = ren1_dst;
747         const char *dst_name2 = ren2_dst;
748         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
749                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
750                 output(o, 1, "%s is a directory in %s adding as %s instead",
751                        ren1_dst, branch2, dst_name1);
752                 remove_file(o, 0, ren1_dst, 0);
753         }
754         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
755                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
756                 output(o, 1, "%s is a directory in %s adding as %s instead",
757                        ren2_dst, branch1, dst_name2);
758                 remove_file(o, 0, ren2_dst, 0);
759         }
760         if (o->call_depth) {
761                 remove_file_from_cache(dst_name1);
762                 remove_file_from_cache(dst_name2);
763                 /*
764                  * Uncomment to leave the conflicting names in the resulting tree
765                  *
766                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
767                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
768                  */
769         } else {
770                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
771                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
772         }
773         while (delp--)
774                 free(del[delp]);
775 }
776
777 static void conflict_rename_dir(struct merge_options *o,
778                                 struct rename *ren1,
779                                 const char *branch1)
780 {
781         char *new_path = unique_path(o, ren1->pair->two->path, branch1);
782         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
783         remove_file(o, 0, ren1->pair->two->path, 0);
784         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
785         free(new_path);
786 }
787
788 static void conflict_rename_rename_2(struct merge_options *o,
789                                      struct rename *ren1,
790                                      const char *branch1,
791                                      struct rename *ren2,
792                                      const char *branch2)
793 {
794         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
795         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
796         output(o, 1, "Renaming %s to %s and %s to %s instead",
797                ren1->pair->one->path, new_path1,
798                ren2->pair->one->path, new_path2);
799         remove_file(o, 0, ren1->pair->two->path, 0);
800         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
801         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
802         free(new_path2);
803         free(new_path1);
804 }
805
806 static int process_renames(struct merge_options *o,
807                            struct string_list *a_renames,
808                            struct string_list *b_renames)
809 {
810         int clean_merge = 1, i, j;
811         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
812         const struct rename *sre;
813
814         for (i = 0; i < a_renames->nr; i++) {
815                 sre = a_renames->items[i].util;
816                 string_list_insert(sre->pair->two->path, &a_by_dst)->util
817                         = sre->dst_entry;
818         }
819         for (i = 0; i < b_renames->nr; i++) {
820                 sre = b_renames->items[i].util;
821                 string_list_insert(sre->pair->two->path, &b_by_dst)->util
822                         = sre->dst_entry;
823         }
824
825         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
826                 char *src;
827                 struct string_list *renames1, *renames2Dst;
828                 struct rename *ren1 = NULL, *ren2 = NULL;
829                 const char *branch1, *branch2;
830                 const char *ren1_src, *ren1_dst;
831
832                 if (i >= a_renames->nr) {
833                         ren2 = b_renames->items[j++].util;
834                 } else if (j >= b_renames->nr) {
835                         ren1 = a_renames->items[i++].util;
836                 } else {
837                         int compare = strcmp(a_renames->items[i].string,
838                                              b_renames->items[j].string);
839                         if (compare <= 0)
840                                 ren1 = a_renames->items[i++].util;
841                         if (compare >= 0)
842                                 ren2 = b_renames->items[j++].util;
843                 }
844
845                 /* TODO: refactor, so that 1/2 are not needed */
846                 if (ren1) {
847                         renames1 = a_renames;
848                         renames2Dst = &b_by_dst;
849                         branch1 = o->branch1;
850                         branch2 = o->branch2;
851                 } else {
852                         struct rename *tmp;
853                         renames1 = b_renames;
854                         renames2Dst = &a_by_dst;
855                         branch1 = o->branch2;
856                         branch2 = o->branch1;
857                         tmp = ren2;
858                         ren2 = ren1;
859                         ren1 = tmp;
860                 }
861                 src = ren1->pair->one->path;
862
863                 ren1->dst_entry->processed = 1;
864                 ren1->src_entry->processed = 1;
865
866                 if (ren1->processed)
867                         continue;
868                 ren1->processed = 1;
869
870                 ren1_src = ren1->pair->one->path;
871                 ren1_dst = ren1->pair->two->path;
872
873                 if (ren2) {
874                         const char *ren2_src = ren2->pair->one->path;
875                         const char *ren2_dst = ren2->pair->two->path;
876                         /* Renamed in 1 and renamed in 2 */
877                         if (strcmp(ren1_src, ren2_src) != 0)
878                                 die("ren1.src != ren2.src");
879                         ren2->dst_entry->processed = 1;
880                         ren2->processed = 1;
881                         if (strcmp(ren1_dst, ren2_dst) != 0) {
882                                 clean_merge = 0;
883                                 output(o, 1, "CONFLICT (rename/rename): "
884                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
885                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
886                                        src, ren1_dst, branch1,
887                                        src, ren2_dst, branch2,
888                                        o->call_depth ? " (left unresolved)": "");
889                                 if (o->call_depth) {
890                                         remove_file_from_cache(src);
891                                         update_file(o, 0, ren1->pair->one->sha1,
892                                                     ren1->pair->one->mode, src);
893                                 }
894                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
895                         } else {
896                                 struct merge_file_info mfi;
897                                 remove_file(o, 1, ren1_src, 1);
898                                 mfi = merge_file(o,
899                                                  ren1->pair->one,
900                                                  ren1->pair->two,
901                                                  ren2->pair->two,
902                                                  branch1,
903                                                  branch2);
904                                 if (mfi.merge || !mfi.clean)
905                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
906
907                                 if (mfi.merge)
908                                         output(o, 2, "Auto-merging %s", ren1_dst);
909
910                                 if (!mfi.clean) {
911                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
912                                                ren1_dst);
913                                         clean_merge = 0;
914
915                                         if (!o->call_depth)
916                                                 update_stages(ren1_dst,
917                                                               ren1->pair->one,
918                                                               ren1->pair->two,
919                                                               ren2->pair->two,
920                                                               1 /* clear */);
921                                 }
922                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
923                         }
924                 } else {
925                         /* Renamed in 1, maybe changed in 2 */
926                         struct string_list_item *item;
927                         /* we only use sha1 and mode of these */
928                         struct diff_filespec src_other, dst_other;
929                         int try_merge, stage = a_renames == renames1 ? 3: 2;
930
931                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
932
933                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
934                         src_other.mode = ren1->src_entry->stages[stage].mode;
935                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
936                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
937
938                         try_merge = 0;
939
940                         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
941                                 clean_merge = 0;
942                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
943                                        " directory %s added in %s",
944                                        ren1_src, ren1_dst, branch1,
945                                        ren1_dst, branch2);
946                                 conflict_rename_dir(o, ren1, branch1);
947                         } else if (sha_eq(src_other.sha1, null_sha1)) {
948                                 clean_merge = 0;
949                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
950                                        "and deleted in %s",
951                                        ren1_src, ren1_dst, branch1,
952                                        branch2);
953                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
954                                 if (!o->call_depth)
955                                         update_stages(ren1_dst, NULL,
956                                                         branch1 == o->branch1 ?
957                                                         ren1->pair->two : NULL,
958                                                         branch1 == o->branch1 ?
959                                                         NULL : ren1->pair->two, 1);
960                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
961                                 const char *new_path;
962                                 clean_merge = 0;
963                                 try_merge = 1;
964                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
965                                        "%s added in %s",
966                                        ren1_src, ren1_dst, branch1,
967                                        ren1_dst, branch2);
968                                 if (o->call_depth) {
969                                         struct merge_file_info mfi;
970                                         struct diff_filespec one, a, b;
971
972                                         one.path = a.path = b.path =
973                                                 (char *)ren1_dst;
974                                         hashcpy(one.sha1, null_sha1);
975                                         one.mode = 0;
976                                         hashcpy(a.sha1, ren1->pair->two->sha1);
977                                         a.mode = ren1->pair->two->mode;
978                                         hashcpy(b.sha1, dst_other.sha1);
979                                         b.mode = dst_other.mode;
980                                         mfi = merge_file(o, &one, &a, &b,
981                                                          branch1,
982                                                          branch2);
983                                         output(o, 1, "Adding merged %s", ren1_dst);
984                                         update_file(o, 0,
985                                                     mfi.sha,
986                                                     mfi.mode,
987                                                     ren1_dst);
988                                 } else {
989                                         new_path = unique_path(o, ren1_dst, branch2);
990                                         output(o, 1, "Adding as %s instead", new_path);
991                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
992                                 }
993                         } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
994                                 ren2 = item->util;
995                                 clean_merge = 0;
996                                 ren2->processed = 1;
997                                 output(o, 1, "CONFLICT (rename/rename): "
998                                        "Rename %s->%s in %s. "
999                                        "Rename %s->%s in %s",
1000                                        ren1_src, ren1_dst, branch1,
1001                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1002                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
1003                         } else
1004                                 try_merge = 1;
1005
1006                         if (try_merge) {
1007                                 struct diff_filespec *one, *a, *b;
1008                                 struct merge_file_info mfi;
1009                                 src_other.path = (char *)ren1_src;
1010
1011                                 one = ren1->pair->one;
1012                                 if (a_renames == renames1) {
1013                                         a = ren1->pair->two;
1014                                         b = &src_other;
1015                                 } else {
1016                                         b = ren1->pair->two;
1017                                         a = &src_other;
1018                                 }
1019                                 mfi = merge_file(o, one, a, b,
1020                                                 o->branch1, o->branch2);
1021
1022                                 if (mfi.clean &&
1023                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1024                                     mfi.mode == ren1->pair->two->mode)
1025                                         /*
1026                                          * This messaged is part of
1027                                          * t6022 test. If you change
1028                                          * it update the test too.
1029                                          */
1030                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1031                                 else {
1032                                         if (mfi.merge || !mfi.clean)
1033                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1034                                         if (mfi.merge)
1035                                                 output(o, 2, "Auto-merging %s", ren1_dst);
1036                                         if (!mfi.clean) {
1037                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1038                                                        ren1_dst);
1039                                                 clean_merge = 0;
1040
1041                                                 if (!o->call_depth)
1042                                                         update_stages(ren1_dst,
1043                                                                       one, a, b, 1);
1044                                         }
1045                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1046                                 }
1047                         }
1048                 }
1049         }
1050         string_list_clear(&a_by_dst, 0);
1051         string_list_clear(&b_by_dst, 0);
1052
1053         return clean_merge;
1054 }
1055
1056 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1057 {
1058         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1059 }
1060
1061 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1062 {
1063         void *buf;
1064         enum object_type type;
1065         unsigned long size;
1066         buf = read_sha1_file(sha1, &type, &size);
1067         if (!buf)
1068                 return error("cannot read object %s", sha1_to_hex(sha1));
1069         if (type != OBJ_BLOB) {
1070                 free(buf);
1071                 return error("object %s is not a blob", sha1_to_hex(sha1));
1072         }
1073         strbuf_attach(dst, buf, size, size + 1);
1074         return 0;
1075 }
1076
1077 static int blob_unchanged(const unsigned char *o_sha,
1078                           const unsigned char *a_sha,
1079                           int renormalize, const char *path)
1080 {
1081         struct strbuf o = STRBUF_INIT;
1082         struct strbuf a = STRBUF_INIT;
1083         int ret = 0; /* assume changed for safety */
1084
1085         if (sha_eq(o_sha, a_sha))
1086                 return 1;
1087         if (!renormalize)
1088                 return 0;
1089
1090         assert(o_sha && a_sha);
1091         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1092                 goto error_return;
1093         /*
1094          * Note: binary | is used so that both renormalizations are
1095          * performed.  Comparison can be skipped if both files are
1096          * unchanged since their sha1s have already been compared.
1097          */
1098         if (renormalize_buffer(path, o.buf, o.len, &o) |
1099             renormalize_buffer(path, a.buf, o.len, &a))
1100                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1101
1102 error_return:
1103         strbuf_release(&o);
1104         strbuf_release(&a);
1105         return ret;
1106 }
1107
1108 /* Per entry merge function */
1109 static int process_entry(struct merge_options *o,
1110                          const char *path, struct stage_data *entry)
1111 {
1112         /*
1113         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1114         print_index_entry("\tpath: ", entry);
1115         */
1116         int clean_merge = 1;
1117         int normalize = o->renormalize;
1118         unsigned o_mode = entry->stages[1].mode;
1119         unsigned a_mode = entry->stages[2].mode;
1120         unsigned b_mode = entry->stages[3].mode;
1121         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1122         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1123         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1124
1125         if (o_sha && (!a_sha || !b_sha)) {
1126                 /* Case A: Deleted in one */
1127                 if ((!a_sha && !b_sha) ||
1128                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1129                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1130                         /* Deleted in both or deleted in one and
1131                          * unchanged in the other */
1132                         if (a_sha)
1133                                 output(o, 2, "Removing %s", path);
1134                         /* do not touch working file if it did not exist */
1135                         remove_file(o, 1, path, !a_sha);
1136                 } else {
1137                         /* Deleted in one and changed in the other */
1138                         clean_merge = 0;
1139                         if (!a_sha) {
1140                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1141                                        "and modified in %s. Version %s of %s left in tree.",
1142                                        path, o->branch1,
1143                                        o->branch2, o->branch2, path);
1144                                 update_file(o, 0, b_sha, b_mode, path);
1145                         } else {
1146                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1147                                        "and modified in %s. Version %s of %s left in tree.",
1148                                        path, o->branch2,
1149                                        o->branch1, o->branch1, path);
1150                                 update_file(o, 0, a_sha, a_mode, path);
1151                         }
1152                 }
1153
1154         } else if ((!o_sha && a_sha && !b_sha) ||
1155                    (!o_sha && !a_sha && b_sha)) {
1156                 /* Case B: Added in one. */
1157                 const char *add_branch;
1158                 const char *other_branch;
1159                 unsigned mode;
1160                 const unsigned char *sha;
1161                 const char *conf;
1162
1163                 if (a_sha) {
1164                         add_branch = o->branch1;
1165                         other_branch = o->branch2;
1166                         mode = a_mode;
1167                         sha = a_sha;
1168                         conf = "file/directory";
1169                 } else {
1170                         add_branch = o->branch2;
1171                         other_branch = o->branch1;
1172                         mode = b_mode;
1173                         sha = b_sha;
1174                         conf = "directory/file";
1175                 }
1176                 if (string_list_has_string(&o->current_directory_set, path)) {
1177                         const char *new_path = unique_path(o, path, add_branch);
1178                         clean_merge = 0;
1179                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1180                                "Adding %s as %s",
1181                                conf, path, other_branch, path, new_path);
1182                         remove_file(o, 0, path, 0);
1183                         update_file(o, 0, sha, mode, new_path);
1184                 } else {
1185                         output(o, 2, "Adding %s", path);
1186                         update_file(o, 1, sha, mode, path);
1187                 }
1188         } else if (a_sha && b_sha) {
1189                 /* Case C: Added in both (check for same permissions) and */
1190                 /* case D: Modified in both, but differently. */
1191                 const char *reason = "content";
1192                 struct merge_file_info mfi;
1193                 struct diff_filespec one, a, b;
1194
1195                 if (!o_sha) {
1196                         reason = "add/add";
1197                         o_sha = (unsigned char *)null_sha1;
1198                 }
1199                 output(o, 2, "Auto-merging %s", path);
1200                 one.path = a.path = b.path = (char *)path;
1201                 hashcpy(one.sha1, o_sha);
1202                 one.mode = o_mode;
1203                 hashcpy(a.sha1, a_sha);
1204                 a.mode = a_mode;
1205                 hashcpy(b.sha1, b_sha);
1206                 b.mode = b_mode;
1207
1208                 mfi = merge_file(o, &one, &a, &b,
1209                                  o->branch1, o->branch2);
1210
1211                 clean_merge = mfi.clean;
1212                 if (!mfi.clean) {
1213                         if (S_ISGITLINK(mfi.mode))
1214                                 reason = "submodule";
1215                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1216                                         reason, path);
1217                 }
1218                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1219         } else if (!o_sha && !a_sha && !b_sha) {
1220                 /*
1221                  * this entry was deleted altogether. a_mode == 0 means
1222                  * we had that path and want to actively remove it.
1223                  */
1224                 remove_file(o, 1, path, !a_mode);
1225         } else
1226                 die("Fatal merge failure, shouldn't happen.");
1227
1228         return clean_merge;
1229 }
1230
1231 struct unpack_trees_error_msgs get_porcelain_error_msgs(void)
1232 {
1233         struct unpack_trees_error_msgs msgs = {
1234                 /* would_overwrite */
1235                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
1236                 /* not_uptodate_file */
1237                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
1238                 /* not_uptodate_dir */
1239                 "Updating '%s' would lose untracked files in it.  Aborting.",
1240                 /* would_lose_untracked */
1241                 "Untracked working tree file '%s' would be %s by merge.  Aborting",
1242                 /* bind_overlap -- will not happen here */
1243                 NULL,
1244         };
1245         if (advice_commit_before_merge) {
1246                 msgs.would_overwrite = msgs.not_uptodate_file =
1247                         "Your local changes to '%s' would be overwritten by merge.  Aborting.\n"
1248                         "Please, commit your changes or stash them before you can merge.";
1249         }
1250         return msgs;
1251 }
1252
1253 int merge_trees(struct merge_options *o,
1254                 struct tree *head,
1255                 struct tree *merge,
1256                 struct tree *common,
1257                 struct tree **result)
1258 {
1259         int code, clean;
1260
1261         if (o->subtree_shift) {
1262                 merge = shift_tree_object(head, merge, o->subtree_shift);
1263                 common = shift_tree_object(head, common, o->subtree_shift);
1264         }
1265
1266         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1267                 output(o, 0, "Already uptodate!");
1268                 *result = head;
1269                 return 1;
1270         }
1271
1272         code = git_merge_trees(o->call_depth, common, head, merge);
1273
1274         if (code != 0) {
1275                 if (show(o, 4) || o->call_depth)
1276                         die("merging of trees %s and %s failed",
1277                             sha1_to_hex(head->object.sha1),
1278                             sha1_to_hex(merge->object.sha1));
1279                 else
1280                         exit(128);
1281         }
1282
1283         if (unmerged_cache()) {
1284                 struct string_list *entries, *re_head, *re_merge;
1285                 int i;
1286                 string_list_clear(&o->current_file_set, 1);
1287                 string_list_clear(&o->current_directory_set, 1);
1288                 get_files_dirs(o, head);
1289                 get_files_dirs(o, merge);
1290
1291                 entries = get_unmerged();
1292                 re_head  = get_renames(o, head, common, head, merge, entries);
1293                 re_merge = get_renames(o, merge, common, head, merge, entries);
1294                 clean = process_renames(o, re_head, re_merge);
1295                 for (i = 0; i < entries->nr; i++) {
1296                         const char *path = entries->items[i].string;
1297                         struct stage_data *e = entries->items[i].util;
1298                         if (!e->processed
1299                                 && !process_entry(o, path, e))
1300                                 clean = 0;
1301                 }
1302
1303                 string_list_clear(re_merge, 0);
1304                 string_list_clear(re_head, 0);
1305                 string_list_clear(entries, 1);
1306
1307         }
1308         else
1309                 clean = 1;
1310
1311         if (o->call_depth)
1312                 *result = write_tree_from_memory(o);
1313
1314         return clean;
1315 }
1316
1317 static struct commit_list *reverse_commit_list(struct commit_list *list)
1318 {
1319         struct commit_list *next = NULL, *current, *backup;
1320         for (current = list; current; current = backup) {
1321                 backup = current->next;
1322                 current->next = next;
1323                 next = current;
1324         }
1325         return next;
1326 }
1327
1328 /*
1329  * Merge the commits h1 and h2, return the resulting virtual
1330  * commit object and a flag indicating the cleanness of the merge.
1331  */
1332 int merge_recursive(struct merge_options *o,
1333                     struct commit *h1,
1334                     struct commit *h2,
1335                     struct commit_list *ca,
1336                     struct commit **result)
1337 {
1338         struct commit_list *iter;
1339         struct commit *merged_common_ancestors;
1340         struct tree *mrtree = mrtree;
1341         int clean;
1342
1343         if (show(o, 4)) {
1344                 output(o, 4, "Merging:");
1345                 output_commit_title(o, h1);
1346                 output_commit_title(o, h2);
1347         }
1348
1349         if (!ca) {
1350                 ca = get_merge_bases(h1, h2, 1);
1351                 ca = reverse_commit_list(ca);
1352         }
1353
1354         if (show(o, 5)) {
1355                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1356                 for (iter = ca; iter; iter = iter->next)
1357                         output_commit_title(o, iter->item);
1358         }
1359
1360         merged_common_ancestors = pop_commit(&ca);
1361         if (merged_common_ancestors == NULL) {
1362                 /* if there is no common ancestor, make an empty tree */
1363                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1364
1365                 tree->object.parsed = 1;
1366                 tree->object.type = OBJ_TREE;
1367                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1368                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1369         }
1370
1371         for (iter = ca; iter; iter = iter->next) {
1372                 const char *saved_b1, *saved_b2;
1373                 o->call_depth++;
1374                 /*
1375                  * When the merge fails, the result contains files
1376                  * with conflict markers. The cleanness flag is
1377                  * ignored, it was never actually used, as result of
1378                  * merge_trees has always overwritten it: the committed
1379                  * "conflicts" were already resolved.
1380                  */
1381                 discard_cache();
1382                 saved_b1 = o->branch1;
1383                 saved_b2 = o->branch2;
1384                 o->branch1 = "Temporary merge branch 1";
1385                 o->branch2 = "Temporary merge branch 2";
1386                 merge_recursive(o, merged_common_ancestors, iter->item,
1387                                 NULL, &merged_common_ancestors);
1388                 o->branch1 = saved_b1;
1389                 o->branch2 = saved_b2;
1390                 o->call_depth--;
1391
1392                 if (!merged_common_ancestors)
1393                         die("merge returned no commit");
1394         }
1395
1396         discard_cache();
1397         if (!o->call_depth)
1398                 read_cache();
1399
1400         o->ancestor = "merged common ancestors";
1401         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1402                             &mrtree);
1403
1404         if (o->call_depth) {
1405                 *result = make_virtual_commit(mrtree, "merged tree");
1406                 commit_list_insert(h1, &(*result)->parents);
1407                 commit_list_insert(h2, &(*result)->parents->next);
1408         }
1409         flush_output(o);
1410         return clean;
1411 }
1412
1413 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1414 {
1415         struct object *object;
1416
1417         object = deref_tag(parse_object(sha1), name, strlen(name));
1418         if (!object)
1419                 return NULL;
1420         if (object->type == OBJ_TREE)
1421                 return make_virtual_commit((struct tree*)object, name);
1422         if (object->type != OBJ_COMMIT)
1423                 return NULL;
1424         if (parse_commit((struct commit *)object))
1425                 return NULL;
1426         return (struct commit *)object;
1427 }
1428
1429 int merge_recursive_generic(struct merge_options *o,
1430                             const unsigned char *head,
1431                             const unsigned char *merge,
1432                             int num_base_list,
1433                             const unsigned char **base_list,
1434                             struct commit **result)
1435 {
1436         int clean, index_fd;
1437         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1438         struct commit *head_commit = get_ref(head, o->branch1);
1439         struct commit *next_commit = get_ref(merge, o->branch2);
1440         struct commit_list *ca = NULL;
1441
1442         if (base_list) {
1443                 int i;
1444                 for (i = 0; i < num_base_list; ++i) {
1445                         struct commit *base;
1446                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1447                                 return error("Could not parse object '%s'",
1448                                         sha1_to_hex(base_list[i]));
1449                         commit_list_insert(base, &ca);
1450                 }
1451         }
1452
1453         index_fd = hold_locked_index(lock, 1);
1454         clean = merge_recursive(o, head_commit, next_commit, ca,
1455                         result);
1456         if (active_cache_changed &&
1457                         (write_cache(index_fd, active_cache, active_nr) ||
1458                          commit_locked_index(lock)))
1459                 return error("Unable to write index.");
1460
1461         return clean ? 0 : 1;
1462 }
1463
1464 static int merge_recursive_config(const char *var, const char *value, void *cb)
1465 {
1466         struct merge_options *o = cb;
1467         if (!strcasecmp(var, "merge.verbosity")) {
1468                 o->verbosity = git_config_int(var, value);
1469                 return 0;
1470         }
1471         if (!strcasecmp(var, "diff.renamelimit")) {
1472                 o->diff_rename_limit = git_config_int(var, value);
1473                 return 0;
1474         }
1475         if (!strcasecmp(var, "merge.renamelimit")) {
1476                 o->merge_rename_limit = git_config_int(var, value);
1477                 return 0;
1478         }
1479         return git_xmerge_config(var, value, cb);
1480 }
1481
1482 void init_merge_options(struct merge_options *o)
1483 {
1484         memset(o, 0, sizeof(struct merge_options));
1485         o->verbosity = 2;
1486         o->buffer_output = 1;
1487         o->diff_rename_limit = -1;
1488         o->merge_rename_limit = -1;
1489         o->renormalize = 0;
1490         git_config(merge_recursive_config, o);
1491         if (getenv("GIT_MERGE_VERBOSITY"))
1492                 o->verbosity =
1493                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1494         if (o->verbosity >= 5)
1495                 o->buffer_output = 0;
1496         strbuf_init(&o->obuf, 0);
1497         memset(&o->current_file_set, 0, sizeof(struct string_list));
1498         o->current_file_set.strdup_strings = 1;
1499         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1500         o->current_directory_set.strdup_strings = 1;
1501 }
1502
1503 int parse_merge_opt(struct merge_options *o, const char *s)
1504 {
1505         if (!s || !*s)
1506                 return -1;
1507         if (!strcmp(s, "ours"))
1508                 o->recursive_variant = MERGE_RECURSIVE_OURS;
1509         else if (!strcmp(s, "theirs"))
1510                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
1511         else if (!strcmp(s, "subtree"))
1512                 o->subtree_shift = "";
1513         else if (!prefixcmp(s, "subtree="))
1514                 o->subtree_shift = s + strlen("subtree=");
1515         else if (!strcmp(s, "renormalize"))
1516                 o->renormalize = 1;
1517         else if (!strcmp(s, "no-renormalize"))
1518                 o->renormalize = 0;
1519         else
1520                 return -1;
1521         return 0;
1522 }