Merge branch 'ph/enable-threaded'
[git] / builtin-merge-recursive.c
1 /*
2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
3  * Fredrik Kuivinen.
4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
5  */
6 #include "cache.h"
7 #include "cache-tree.h"
8 #include "commit.h"
9 #include "blob.h"
10 #include "builtin.h"
11 #include "tree-walk.h"
12 #include "diff.h"
13 #include "diffcore.h"
14 #include "tag.h"
15 #include "unpack-trees.h"
16 #include "string-list.h"
17 #include "xdiff-interface.h"
18 #include "ll-merge.h"
19 #include "interpolate.h"
20 #include "attr.h"
21 #include "merge-recursive.h"
22
23 static int subtree_merge;
24
25 static struct tree *shift_tree_object(struct tree *one, struct tree *two)
26 {
27         unsigned char shifted[20];
28
29         /*
30          * NEEDSWORK: this limits the recursion depth to hardcoded
31          * value '2' to avoid excessive overhead.
32          */
33         shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
34         if (!hashcmp(two->object.sha1, shifted))
35                 return two;
36         return lookup_tree(shifted);
37 }
38
39 /*
40  * A virtual commit has
41  * - (const char *)commit->util set to the name, and
42  * - *(int *)commit->object.sha1 set to the virtual id.
43  */
44
45 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
46 {
47         struct commit *commit = xcalloc(1, sizeof(struct commit));
48         static unsigned virtual_id = 1;
49         commit->tree = tree;
50         commit->util = (void*)comment;
51         *(int*)commit->object.sha1 = virtual_id++;
52         /* avoid warnings */
53         commit->object.parsed = 1;
54         return commit;
55 }
56
57 /*
58  * Since we use get_tree_entry(), which does not put the read object into
59  * the object pool, we cannot rely on a == b.
60  */
61 static int sha_eq(const unsigned char *a, const unsigned char *b)
62 {
63         if (!a && !b)
64                 return 2;
65         return a && b && hashcmp(a, b) == 0;
66 }
67
68 /*
69  * Since we want to write the index eventually, we cannot reuse the index
70  * for these (temporary) data.
71  */
72 struct stage_data
73 {
74         struct
75         {
76                 unsigned mode;
77                 unsigned char sha[20];
78         } stages[4];
79         unsigned processed:1;
80 };
81
82 static struct string_list current_file_set = {NULL, 0, 0, 1};
83 static struct string_list current_directory_set = {NULL, 0, 0, 1};
84
85 static int call_depth = 0;
86 static int verbosity = 2;
87 static int diff_rename_limit = -1;
88 static int merge_rename_limit = -1;
89 static int buffer_output = 1;
90 static struct strbuf obuf = STRBUF_INIT;
91
92 static int show(int v)
93 {
94         return (!call_depth && verbosity >= v) || verbosity >= 5;
95 }
96
97 static void flush_output(void)
98 {
99         if (obuf.len) {
100                 fputs(obuf.buf, stdout);
101                 strbuf_reset(&obuf);
102         }
103 }
104
105 static void output(int v, const char *fmt, ...)
106 {
107         int len;
108         va_list ap;
109
110         if (!show(v))
111                 return;
112
113         strbuf_grow(&obuf, call_depth * 2 + 2);
114         memset(obuf.buf + obuf.len, ' ', call_depth * 2);
115         strbuf_setlen(&obuf, obuf.len + call_depth * 2);
116
117         va_start(ap, fmt);
118         len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
119         va_end(ap);
120
121         if (len < 0)
122                 len = 0;
123         if (len >= strbuf_avail(&obuf)) {
124                 strbuf_grow(&obuf, len + 2);
125                 va_start(ap, fmt);
126                 len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
127                 va_end(ap);
128                 if (len >= strbuf_avail(&obuf)) {
129                         die("this should not happen, your snprintf is broken");
130                 }
131         }
132         strbuf_setlen(&obuf, obuf.len + len);
133         strbuf_add(&obuf, "\n", 1);
134         if (!buffer_output)
135                 flush_output();
136 }
137
138 static void output_commit_title(struct commit *commit)
139 {
140         int i;
141         flush_output();
142         for (i = call_depth; i--;)
143                 fputs("  ", stdout);
144         if (commit->util)
145                 printf("virtual %s\n", (char *)commit->util);
146         else {
147                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
148                 if (parse_commit(commit) != 0)
149                         printf("(bad commit)\n");
150                 else {
151                         const char *s;
152                         int len;
153                         for (s = commit->buffer; *s; s++)
154                                 if (*s == '\n' && s[1] == '\n') {
155                                         s += 2;
156                                         break;
157                                 }
158                         for (len = 0; s[len] && '\n' != s[len]; len++)
159                                 ; /* do nothing */
160                         printf("%.*s\n", len, s);
161                 }
162         }
163 }
164
165 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
166                 const char *path, int stage, int refresh, int options)
167 {
168         struct cache_entry *ce;
169         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
170         if (!ce)
171                 return error("addinfo_cache failed for path '%s'", path);
172         return add_cache_entry(ce, options);
173 }
174
175 /*
176  * This is a global variable which is used in a number of places but
177  * only written to in the 'merge' function.
178  *
179  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
180  *                       don't update the working directory.
181  *               0    => Leave unmerged entries in the cache and update
182  *                       the working directory.
183  */
184 static int index_only = 0;
185
186 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
187 {
188         parse_tree(tree);
189         init_tree_desc(desc, tree->buffer, tree->size);
190 }
191
192 static int git_merge_trees(int index_only,
193                            struct tree *common,
194                            struct tree *head,
195                            struct tree *merge)
196 {
197         int rc;
198         struct tree_desc t[3];
199         struct unpack_trees_options opts;
200
201         memset(&opts, 0, sizeof(opts));
202         if (index_only)
203                 opts.index_only = 1;
204         else
205                 opts.update = 1;
206         opts.merge = 1;
207         opts.head_idx = 2;
208         opts.fn = threeway_merge;
209         opts.src_index = &the_index;
210         opts.dst_index = &the_index;
211
212         init_tree_desc_from_tree(t+0, common);
213         init_tree_desc_from_tree(t+1, head);
214         init_tree_desc_from_tree(t+2, merge);
215
216         rc = unpack_trees(3, t, &opts);
217         cache_tree_free(&active_cache_tree);
218         return rc;
219 }
220
221 struct tree *write_tree_from_memory(void)
222 {
223         struct tree *result = NULL;
224
225         if (unmerged_cache()) {
226                 int i;
227                 output(0, "There are unmerged index entries:");
228                 for (i = 0; i < active_nr; i++) {
229                         struct cache_entry *ce = active_cache[i];
230                         if (ce_stage(ce))
231                                 output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
232                 }
233                 return NULL;
234         }
235
236         if (!active_cache_tree)
237                 active_cache_tree = cache_tree();
238
239         if (!cache_tree_fully_valid(active_cache_tree) &&
240             cache_tree_update(active_cache_tree,
241                               active_cache, active_nr, 0, 0) < 0)
242                 die("error building trees");
243
244         result = lookup_tree(active_cache_tree->sha1);
245
246         return result;
247 }
248
249 static int save_files_dirs(const unsigned char *sha1,
250                 const char *base, int baselen, const char *path,
251                 unsigned int mode, int stage, void *context)
252 {
253         int len = strlen(path);
254         char *newpath = xmalloc(baselen + len + 1);
255         memcpy(newpath, base, baselen);
256         memcpy(newpath + baselen, path, len);
257         newpath[baselen + len] = '\0';
258
259         if (S_ISDIR(mode))
260                 string_list_insert(newpath, &current_directory_set);
261         else
262                 string_list_insert(newpath, &current_file_set);
263         free(newpath);
264
265         return READ_TREE_RECURSIVE;
266 }
267
268 static int get_files_dirs(struct tree *tree)
269 {
270         int n;
271         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, NULL))
272                 return 0;
273         n = current_file_set.nr + current_directory_set.nr;
274         return n;
275 }
276
277 /*
278  * Returns an index_entry instance which doesn't have to correspond to
279  * a real cache entry in Git's index.
280  */
281 static struct stage_data *insert_stage_data(const char *path,
282                 struct tree *o, struct tree *a, struct tree *b,
283                 struct string_list *entries)
284 {
285         struct string_list_item *item;
286         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
287         get_tree_entry(o->object.sha1, path,
288                         e->stages[1].sha, &e->stages[1].mode);
289         get_tree_entry(a->object.sha1, path,
290                         e->stages[2].sha, &e->stages[2].mode);
291         get_tree_entry(b->object.sha1, path,
292                         e->stages[3].sha, &e->stages[3].mode);
293         item = string_list_insert(path, entries);
294         item->util = e;
295         return e;
296 }
297
298 /*
299  * Create a dictionary mapping file names to stage_data objects. The
300  * dictionary contains one entry for every path with a non-zero stage entry.
301  */
302 static struct string_list *get_unmerged(void)
303 {
304         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
305         int i;
306
307         unmerged->strdup_strings = 1;
308
309         for (i = 0; i < active_nr; i++) {
310                 struct string_list_item *item;
311                 struct stage_data *e;
312                 struct cache_entry *ce = active_cache[i];
313                 if (!ce_stage(ce))
314                         continue;
315
316                 item = string_list_lookup(ce->name, unmerged);
317                 if (!item) {
318                         item = string_list_insert(ce->name, unmerged);
319                         item->util = xcalloc(1, sizeof(struct stage_data));
320                 }
321                 e = item->util;
322                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
323                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
324         }
325
326         return unmerged;
327 }
328
329 struct rename
330 {
331         struct diff_filepair *pair;
332         struct stage_data *src_entry;
333         struct stage_data *dst_entry;
334         unsigned processed:1;
335 };
336
337 /*
338  * Get information of all renames which occurred between 'o_tree' and
339  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
340  * 'b_tree') to be able to associate the correct cache entries with
341  * the rename information. 'tree' is always equal to either a_tree or b_tree.
342  */
343 static struct string_list *get_renames(struct tree *tree,
344                                         struct tree *o_tree,
345                                         struct tree *a_tree,
346                                         struct tree *b_tree,
347                                         struct string_list *entries)
348 {
349         int i;
350         struct string_list *renames;
351         struct diff_options opts;
352
353         renames = xcalloc(1, sizeof(struct string_list));
354         diff_setup(&opts);
355         DIFF_OPT_SET(&opts, RECURSIVE);
356         opts.detect_rename = DIFF_DETECT_RENAME;
357         opts.rename_limit = merge_rename_limit >= 0 ? merge_rename_limit :
358                             diff_rename_limit >= 0 ? diff_rename_limit :
359                             500;
360         opts.warn_on_too_large_rename = 1;
361         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
362         if (diff_setup_done(&opts) < 0)
363                 die("diff setup failed");
364         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
365         diffcore_std(&opts);
366         for (i = 0; i < diff_queued_diff.nr; ++i) {
367                 struct string_list_item *item;
368                 struct rename *re;
369                 struct diff_filepair *pair = diff_queued_diff.queue[i];
370                 if (pair->status != 'R') {
371                         diff_free_filepair(pair);
372                         continue;
373                 }
374                 re = xmalloc(sizeof(*re));
375                 re->processed = 0;
376                 re->pair = pair;
377                 item = string_list_lookup(re->pair->one->path, entries);
378                 if (!item)
379                         re->src_entry = insert_stage_data(re->pair->one->path,
380                                         o_tree, a_tree, b_tree, entries);
381                 else
382                         re->src_entry = item->util;
383
384                 item = string_list_lookup(re->pair->two->path, entries);
385                 if (!item)
386                         re->dst_entry = insert_stage_data(re->pair->two->path,
387                                         o_tree, a_tree, b_tree, entries);
388                 else
389                         re->dst_entry = item->util;
390                 item = string_list_insert(pair->one->path, renames);
391                 item->util = re;
392         }
393         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
394         diff_queued_diff.nr = 0;
395         diff_flush(&opts);
396         return renames;
397 }
398
399 static int update_stages(const char *path, struct diff_filespec *o,
400                          struct diff_filespec *a, struct diff_filespec *b,
401                          int clear)
402 {
403         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
404         if (clear)
405                 if (remove_file_from_cache(path))
406                         return -1;
407         if (o)
408                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
409                         return -1;
410         if (a)
411                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
412                         return -1;
413         if (b)
414                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
415                         return -1;
416         return 0;
417 }
418
419 static int remove_path(const char *name)
420 {
421         int ret;
422         char *slash, *dirs;
423
424         ret = unlink(name);
425         if (ret)
426                 return ret;
427         dirs = xstrdup(name);
428         while ((slash = strrchr(name, '/'))) {
429                 *slash = '\0';
430                 if (rmdir(name) != 0)
431                         break;
432         }
433         free(dirs);
434         return ret;
435 }
436
437 static int remove_file(int clean, const char *path, int no_wd)
438 {
439         int update_cache = index_only || clean;
440         int update_working_directory = !index_only && !no_wd;
441
442         if (update_cache) {
443                 if (remove_file_from_cache(path))
444                         return -1;
445         }
446         if (update_working_directory) {
447                 unlink(path);
448                 if (errno != ENOENT || errno != EISDIR)
449                         return -1;
450                 remove_path(path);
451         }
452         return 0;
453 }
454
455 static char *unique_path(const char *path, const char *branch)
456 {
457         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
458         int suffix = 0;
459         struct stat st;
460         char *p = newpath + strlen(path);
461         strcpy(newpath, path);
462         *(p++) = '~';
463         strcpy(p, branch);
464         for (; *p; ++p)
465                 if ('/' == *p)
466                         *p = '_';
467         while (string_list_has_string(&current_file_set, newpath) ||
468                string_list_has_string(&current_directory_set, newpath) ||
469                lstat(newpath, &st) == 0)
470                 sprintf(p, "_%d", suffix++);
471
472         string_list_insert(newpath, &current_file_set);
473         return newpath;
474 }
475
476 static void flush_buffer(int fd, const char *buf, unsigned long size)
477 {
478         while (size > 0) {
479                 long ret = write_in_full(fd, buf, size);
480                 if (ret < 0) {
481                         /* Ignore epipe */
482                         if (errno == EPIPE)
483                                 break;
484                         die("merge-recursive: %s", strerror(errno));
485                 } else if (!ret) {
486                         die("merge-recursive: disk full?");
487                 }
488                 size -= ret;
489                 buf += ret;
490         }
491 }
492
493 static int make_room_for_path(const char *path)
494 {
495         int status;
496         const char *msg = "failed to create path '%s'%s";
497
498         status = safe_create_leading_directories_const(path);
499         if (status) {
500                 if (status == -3) {
501                         /* something else exists */
502                         error(msg, path, ": perhaps a D/F conflict?");
503                         return -1;
504                 }
505                 die(msg, path, "");
506         }
507
508         /* Successful unlink is good.. */
509         if (!unlink(path))
510                 return 0;
511         /* .. and so is no existing file */
512         if (errno == ENOENT)
513                 return 0;
514         /* .. but not some other error (who really cares what?) */
515         return error(msg, path, ": perhaps a D/F conflict?");
516 }
517
518 static void update_file_flags(const unsigned char *sha,
519                               unsigned mode,
520                               const char *path,
521                               int update_cache,
522                               int update_wd)
523 {
524         if (index_only)
525                 update_wd = 0;
526
527         if (update_wd) {
528                 enum object_type type;
529                 void *buf;
530                 unsigned long size;
531
532                 if (S_ISGITLINK(mode))
533                         die("cannot read object %s '%s': It is a submodule!",
534                             sha1_to_hex(sha), path);
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;
543                         strbuf_init(&strbuf, 0);
544                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
545                                 free(buf);
546                                 size = strbuf.len;
547                                 buf = strbuf_detach(&strbuf, NULL);
548                         }
549                 }
550
551                 if (make_room_for_path(path) < 0) {
552                         update_wd = 0;
553                         free(buf);
554                         goto update_index;
555                 }
556                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
557                         int fd;
558                         if (mode & 0100)
559                                 mode = 0777;
560                         else
561                                 mode = 0666;
562                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
563                         if (fd < 0)
564                                 die("failed to open %s: %s", path, strerror(errno));
565                         flush_buffer(fd, buf, size);
566                         close(fd);
567                 } else if (S_ISLNK(mode)) {
568                         char *lnk = xmemdupz(buf, size);
569                         safe_create_leading_directories_const(path);
570                         unlink(path);
571                         symlink(lnk, 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(int clean,
584                         const unsigned char *sha,
585                         unsigned mode,
586                         const char *path)
587 {
588         update_file_flags(sha, mode, path, index_only || clean, !index_only);
589 }
590
591 /* Low level file merging, update and removal */
592
593 struct merge_file_info
594 {
595         unsigned char sha[20];
596         unsigned mode;
597         unsigned clean:1,
598                  merge:1;
599 };
600
601 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
602 {
603         unsigned long size;
604         enum object_type type;
605
606         if (!hashcmp(sha1, null_sha1)) {
607                 mm->ptr = xstrdup("");
608                 mm->size = 0;
609                 return;
610         }
611
612         mm->ptr = read_sha1_file(sha1, &type, &size);
613         if (!mm->ptr || type != OBJ_BLOB)
614                 die("unable to read blob object %s", sha1_to_hex(sha1));
615         mm->size = size;
616 }
617
618 static int merge_3way(mmbuffer_t *result_buf,
619                       struct diff_filespec *o,
620                       struct diff_filespec *a,
621                       struct diff_filespec *b,
622                       const char *branch1,
623                       const char *branch2)
624 {
625         mmfile_t orig, src1, src2;
626         char *name1, *name2;
627         int merge_status;
628
629         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
630         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
631
632         fill_mm(o->sha1, &orig);
633         fill_mm(a->sha1, &src1);
634         fill_mm(b->sha1, &src2);
635
636         merge_status = ll_merge(result_buf, a->path, &orig,
637                                 &src1, name1, &src2, name2,
638                                 index_only);
639
640         free(name1);
641         free(name2);
642         free(orig.ptr);
643         free(src1.ptr);
644         free(src2.ptr);
645         return merge_status;
646 }
647
648 static struct merge_file_info merge_file(struct diff_filespec *o,
649                 struct diff_filespec *a, struct diff_filespec *b,
650                 const char *branch1, const char *branch2)
651 {
652         struct merge_file_info result;
653         result.merge = 0;
654         result.clean = 1;
655
656         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
657                 result.clean = 0;
658                 if (S_ISREG(a->mode)) {
659                         result.mode = a->mode;
660                         hashcpy(result.sha, a->sha1);
661                 } else {
662                         result.mode = b->mode;
663                         hashcpy(result.sha, b->sha1);
664                 }
665         } else {
666                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
667                         result.merge = 1;
668
669                 /*
670                  * Merge modes
671                  */
672                 if (a->mode == b->mode || a->mode == o->mode)
673                         result.mode = b->mode;
674                 else {
675                         result.mode = a->mode;
676                         if (b->mode != o->mode) {
677                                 result.clean = 0;
678                                 result.merge = 1;
679                         }
680                 }
681
682                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, o->sha1))
683                         hashcpy(result.sha, b->sha1);
684                 else if (sha_eq(b->sha1, o->sha1))
685                         hashcpy(result.sha, a->sha1);
686                 else if (S_ISREG(a->mode)) {
687                         mmbuffer_t result_buf;
688                         int merge_status;
689
690                         merge_status = merge_3way(&result_buf, o, a, b,
691                                                   branch1, branch2);
692
693                         if ((merge_status < 0) || !result_buf.ptr)
694                                 die("Failed to execute internal merge");
695
696                         if (write_sha1_file(result_buf.ptr, result_buf.size,
697                                             blob_type, result.sha))
698                                 die("Unable to add %s to database",
699                                     a->path);
700
701                         free(result_buf.ptr);
702                         result.clean = (merge_status == 0);
703                 } else if (S_ISGITLINK(a->mode)) {
704                         result.clean = 0;
705                         hashcpy(result.sha, a->sha1);
706                 } else if (S_ISLNK(a->mode)) {
707                         hashcpy(result.sha, a->sha1);
708
709                         if (!sha_eq(a->sha1, b->sha1))
710                                 result.clean = 0;
711                 } else {
712                         die("unsupported object type in the tree");
713                 }
714         }
715
716         return result;
717 }
718
719 static void conflict_rename_rename(struct rename *ren1,
720                                    const char *branch1,
721                                    struct rename *ren2,
722                                    const char *branch2)
723 {
724         char *del[2];
725         int delp = 0;
726         const char *ren1_dst = ren1->pair->two->path;
727         const char *ren2_dst = ren2->pair->two->path;
728         const char *dst_name1 = ren1_dst;
729         const char *dst_name2 = ren2_dst;
730         if (string_list_has_string(&current_directory_set, ren1_dst)) {
731                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
732                 output(1, "%s is a directory in %s added as %s instead",
733                        ren1_dst, branch2, dst_name1);
734                 remove_file(0, ren1_dst, 0);
735         }
736         if (string_list_has_string(&current_directory_set, ren2_dst)) {
737                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
738                 output(1, "%s is a directory in %s added as %s instead",
739                        ren2_dst, branch1, dst_name2);
740                 remove_file(0, ren2_dst, 0);
741         }
742         if (index_only) {
743                 remove_file_from_cache(dst_name1);
744                 remove_file_from_cache(dst_name2);
745                 /*
746                  * Uncomment to leave the conflicting names in the resulting tree
747                  *
748                  * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
749                  * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
750                  */
751         } else {
752                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
753                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
754         }
755         while (delp--)
756                 free(del[delp]);
757 }
758
759 static void conflict_rename_dir(struct rename *ren1,
760                                 const char *branch1)
761 {
762         char *new_path = unique_path(ren1->pair->two->path, branch1);
763         output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
764         remove_file(0, ren1->pair->two->path, 0);
765         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
766         free(new_path);
767 }
768
769 static void conflict_rename_rename_2(struct rename *ren1,
770                                      const char *branch1,
771                                      struct rename *ren2,
772                                      const char *branch2)
773 {
774         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
775         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
776         output(1, "Renamed %s to %s and %s to %s instead",
777                ren1->pair->one->path, new_path1,
778                ren2->pair->one->path, new_path2);
779         remove_file(0, ren1->pair->two->path, 0);
780         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
781         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
782         free(new_path2);
783         free(new_path1);
784 }
785
786 static int process_renames(struct string_list *a_renames,
787                            struct string_list *b_renames,
788                            const char *a_branch,
789                            const char *b_branch)
790 {
791         int clean_merge = 1, i, j;
792         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
793         const struct rename *sre;
794
795         for (i = 0; i < a_renames->nr; i++) {
796                 sre = a_renames->items[i].util;
797                 string_list_insert(sre->pair->two->path, &a_by_dst)->util
798                         = sre->dst_entry;
799         }
800         for (i = 0; i < b_renames->nr; i++) {
801                 sre = b_renames->items[i].util;
802                 string_list_insert(sre->pair->two->path, &b_by_dst)->util
803                         = sre->dst_entry;
804         }
805
806         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
807                 int compare;
808                 char *src;
809                 struct string_list *renames1, *renames2, *renames2Dst;
810                 struct rename *ren1 = NULL, *ren2 = NULL;
811                 const char *branch1, *branch2;
812                 const char *ren1_src, *ren1_dst;
813
814                 if (i >= a_renames->nr) {
815                         compare = 1;
816                         ren2 = b_renames->items[j++].util;
817                 } else if (j >= b_renames->nr) {
818                         compare = -1;
819                         ren1 = a_renames->items[i++].util;
820                 } else {
821                         compare = strcmp(a_renames->items[i].string,
822                                         b_renames->items[j].string);
823                         if (compare <= 0)
824                                 ren1 = a_renames->items[i++].util;
825                         if (compare >= 0)
826                                 ren2 = b_renames->items[j++].util;
827                 }
828
829                 /* TODO: refactor, so that 1/2 are not needed */
830                 if (ren1) {
831                         renames1 = a_renames;
832                         renames2 = b_renames;
833                         renames2Dst = &b_by_dst;
834                         branch1 = a_branch;
835                         branch2 = b_branch;
836                 } else {
837                         struct rename *tmp;
838                         renames1 = b_renames;
839                         renames2 = a_renames;
840                         renames2Dst = &a_by_dst;
841                         branch1 = b_branch;
842                         branch2 = a_branch;
843                         tmp = ren2;
844                         ren2 = ren1;
845                         ren1 = tmp;
846                 }
847                 src = ren1->pair->one->path;
848
849                 ren1->dst_entry->processed = 1;
850                 ren1->src_entry->processed = 1;
851
852                 if (ren1->processed)
853                         continue;
854                 ren1->processed = 1;
855
856                 ren1_src = ren1->pair->one->path;
857                 ren1_dst = ren1->pair->two->path;
858
859                 if (ren2) {
860                         const char *ren2_src = ren2->pair->one->path;
861                         const char *ren2_dst = ren2->pair->two->path;
862                         /* Renamed in 1 and renamed in 2 */
863                         if (strcmp(ren1_src, ren2_src) != 0)
864                                 die("ren1.src != ren2.src");
865                         ren2->dst_entry->processed = 1;
866                         ren2->processed = 1;
867                         if (strcmp(ren1_dst, ren2_dst) != 0) {
868                                 clean_merge = 0;
869                                 output(1, "CONFLICT (rename/rename): "
870                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
871                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
872                                        src, ren1_dst, branch1,
873                                        src, ren2_dst, branch2,
874                                        index_only ? " (left unresolved)": "");
875                                 if (index_only) {
876                                         remove_file_from_cache(src);
877                                         update_file(0, ren1->pair->one->sha1,
878                                                     ren1->pair->one->mode, src);
879                                 }
880                                 conflict_rename_rename(ren1, branch1, ren2, branch2);
881                         } else {
882                                 struct merge_file_info mfi;
883                                 remove_file(1, ren1_src, 1);
884                                 mfi = merge_file(ren1->pair->one,
885                                                  ren1->pair->two,
886                                                  ren2->pair->two,
887                                                  branch1,
888                                                  branch2);
889                                 if (mfi.merge || !mfi.clean)
890                                         output(1, "Renamed %s->%s", src, ren1_dst);
891
892                                 if (mfi.merge)
893                                         output(2, "Auto-merged %s", ren1_dst);
894
895                                 if (!mfi.clean) {
896                                         output(1, "CONFLICT (content): merge conflict in %s",
897                                                ren1_dst);
898                                         clean_merge = 0;
899
900                                         if (!index_only)
901                                                 update_stages(ren1_dst,
902                                                               ren1->pair->one,
903                                                               ren1->pair->two,
904                                                               ren2->pair->two,
905                                                               1 /* clear */);
906                                 }
907                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
908                         }
909                 } else {
910                         /* Renamed in 1, maybe changed in 2 */
911                         struct string_list_item *item;
912                         /* we only use sha1 and mode of these */
913                         struct diff_filespec src_other, dst_other;
914                         int try_merge, stage = a_renames == renames1 ? 3: 2;
915
916                         remove_file(1, ren1_src, index_only || stage == 3);
917
918                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
919                         src_other.mode = ren1->src_entry->stages[stage].mode;
920                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
921                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
922
923                         try_merge = 0;
924
925                         if (string_list_has_string(&current_directory_set, ren1_dst)) {
926                                 clean_merge = 0;
927                                 output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
928                                        " directory %s added in %s",
929                                        ren1_src, ren1_dst, branch1,
930                                        ren1_dst, branch2);
931                                 conflict_rename_dir(ren1, branch1);
932                         } else if (sha_eq(src_other.sha1, null_sha1)) {
933                                 clean_merge = 0;
934                                 output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
935                                        "and deleted in %s",
936                                        ren1_src, ren1_dst, branch1,
937                                        branch2);
938                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
939                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
940                                 const char *new_path;
941                                 clean_merge = 0;
942                                 try_merge = 1;
943                                 output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
944                                        "%s added in %s",
945                                        ren1_src, ren1_dst, branch1,
946                                        ren1_dst, branch2);
947                                 new_path = unique_path(ren1_dst, branch2);
948                                 output(1, "Added as %s instead", new_path);
949                                 update_file(0, dst_other.sha1, dst_other.mode, new_path);
950                         } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
951                                 ren2 = item->util;
952                                 clean_merge = 0;
953                                 ren2->processed = 1;
954                                 output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
955                                        "Renamed %s->%s in %s",
956                                        ren1_src, ren1_dst, branch1,
957                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
958                                 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
959                         } else
960                                 try_merge = 1;
961
962                         if (try_merge) {
963                                 struct diff_filespec *o, *a, *b;
964                                 struct merge_file_info mfi;
965                                 src_other.path = (char *)ren1_src;
966
967                                 o = ren1->pair->one;
968                                 if (a_renames == renames1) {
969                                         a = ren1->pair->two;
970                                         b = &src_other;
971                                 } else {
972                                         b = ren1->pair->two;
973                                         a = &src_other;
974                                 }
975                                 mfi = merge_file(o, a, b,
976                                                 a_branch, b_branch);
977
978                                 if (mfi.clean &&
979                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
980                                     mfi.mode == ren1->pair->two->mode)
981                                         /*
982                                          * This messaged is part of
983                                          * t6022 test. If you change
984                                          * it update the test too.
985                                          */
986                                         output(3, "Skipped %s (merged same as existing)", ren1_dst);
987                                 else {
988                                         if (mfi.merge || !mfi.clean)
989                                                 output(1, "Renamed %s => %s", ren1_src, ren1_dst);
990                                         if (mfi.merge)
991                                                 output(2, "Auto-merged %s", ren1_dst);
992                                         if (!mfi.clean) {
993                                                 output(1, "CONFLICT (rename/modify): Merge conflict in %s",
994                                                        ren1_dst);
995                                                 clean_merge = 0;
996
997                                                 if (!index_only)
998                                                         update_stages(ren1_dst,
999                                                                       o, a, b, 1);
1000                                         }
1001                                         update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1002                                 }
1003                         }
1004                 }
1005         }
1006         string_list_clear(&a_by_dst, 0);
1007         string_list_clear(&b_by_dst, 0);
1008
1009         return clean_merge;
1010 }
1011
1012 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1013 {
1014         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1015 }
1016
1017 /* Per entry merge function */
1018 static int process_entry(const char *path, struct stage_data *entry,
1019                          const char *branch1,
1020                          const char *branch2)
1021 {
1022         /*
1023         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1024         print_index_entry("\tpath: ", entry);
1025         */
1026         int clean_merge = 1;
1027         unsigned o_mode = entry->stages[1].mode;
1028         unsigned a_mode = entry->stages[2].mode;
1029         unsigned b_mode = entry->stages[3].mode;
1030         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1031         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1032         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1033
1034         if (o_sha && (!a_sha || !b_sha)) {
1035                 /* Case A: Deleted in one */
1036                 if ((!a_sha && !b_sha) ||
1037                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1038                     (!a_sha && sha_eq(b_sha, o_sha))) {
1039                         /* Deleted in both or deleted in one and
1040                          * unchanged in the other */
1041                         if (a_sha)
1042                                 output(2, "Removed %s", path);
1043                         /* do not touch working file if it did not exist */
1044                         remove_file(1, path, !a_sha);
1045                 } else {
1046                         /* Deleted in one and changed in the other */
1047                         clean_merge = 0;
1048                         if (!a_sha) {
1049                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1050                                        "and modified in %s. Version %s of %s left in tree.",
1051                                        path, branch1,
1052                                        branch2, branch2, path);
1053                                 update_file(0, b_sha, b_mode, path);
1054                         } else {
1055                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1056                                        "and modified in %s. Version %s of %s left in tree.",
1057                                        path, branch2,
1058                                        branch1, branch1, path);
1059                                 update_file(0, a_sha, a_mode, path);
1060                         }
1061                 }
1062
1063         } else if ((!o_sha && a_sha && !b_sha) ||
1064                    (!o_sha && !a_sha && b_sha)) {
1065                 /* Case B: Added in one. */
1066                 const char *add_branch;
1067                 const char *other_branch;
1068                 unsigned mode;
1069                 const unsigned char *sha;
1070                 const char *conf;
1071
1072                 if (a_sha) {
1073                         add_branch = branch1;
1074                         other_branch = branch2;
1075                         mode = a_mode;
1076                         sha = a_sha;
1077                         conf = "file/directory";
1078                 } else {
1079                         add_branch = branch2;
1080                         other_branch = branch1;
1081                         mode = b_mode;
1082                         sha = b_sha;
1083                         conf = "directory/file";
1084                 }
1085                 if (string_list_has_string(&current_directory_set, path)) {
1086                         const char *new_path = unique_path(path, add_branch);
1087                         clean_merge = 0;
1088                         output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
1089                                "Added %s as %s",
1090                                conf, path, other_branch, path, new_path);
1091                         remove_file(0, path, 0);
1092                         update_file(0, sha, mode, new_path);
1093                 } else {
1094                         output(2, "Added %s", path);
1095                         update_file(1, sha, mode, path);
1096                 }
1097         } else if (a_sha && b_sha) {
1098                 /* Case C: Added in both (check for same permissions) and */
1099                 /* case D: Modified in both, but differently. */
1100                 const char *reason = "content";
1101                 struct merge_file_info mfi;
1102                 struct diff_filespec o, a, b;
1103
1104                 if (!o_sha) {
1105                         reason = "add/add";
1106                         o_sha = (unsigned char *)null_sha1;
1107                 }
1108                 output(2, "Auto-merged %s", path);
1109                 o.path = a.path = b.path = (char *)path;
1110                 hashcpy(o.sha1, o_sha);
1111                 o.mode = o_mode;
1112                 hashcpy(a.sha1, a_sha);
1113                 a.mode = a_mode;
1114                 hashcpy(b.sha1, b_sha);
1115                 b.mode = b_mode;
1116
1117                 mfi = merge_file(&o, &a, &b,
1118                                  branch1, branch2);
1119
1120                 clean_merge = mfi.clean;
1121                 if (mfi.clean)
1122                         update_file(1, mfi.sha, mfi.mode, path);
1123                 else if (S_ISGITLINK(mfi.mode))
1124                         output(1, "CONFLICT (submodule): Merge conflict in %s "
1125                                "- needs %s", path, sha1_to_hex(b.sha1));
1126                 else {
1127                         output(1, "CONFLICT (%s): Merge conflict in %s",
1128                                         reason, path);
1129
1130                         if (index_only)
1131                                 update_file(0, mfi.sha, mfi.mode, path);
1132                         else
1133                                 update_file_flags(mfi.sha, mfi.mode, path,
1134                                               0 /* update_cache */, 1 /* update_working_directory */);
1135                 }
1136         } else if (!o_sha && !a_sha && !b_sha) {
1137                 /*
1138                  * this entry was deleted altogether. a_mode == 0 means
1139                  * we had that path and want to actively remove it.
1140                  */
1141                 remove_file(1, path, !a_mode);
1142         } else
1143                 die("Fatal merge failure, shouldn't happen.");
1144
1145         return clean_merge;
1146 }
1147
1148 int merge_trees(struct tree *head,
1149                 struct tree *merge,
1150                 struct tree *common,
1151                 const char *branch1,
1152                 const char *branch2,
1153                 struct tree **result)
1154 {
1155         int code, clean;
1156
1157         if (subtree_merge) {
1158                 merge = shift_tree_object(head, merge);
1159                 common = shift_tree_object(head, common);
1160         }
1161
1162         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1163                 output(0, "Already uptodate!");
1164                 *result = head;
1165                 return 1;
1166         }
1167
1168         code = git_merge_trees(index_only, common, head, merge);
1169
1170         if (code != 0)
1171                 die("merging of trees %s and %s failed",
1172                     sha1_to_hex(head->object.sha1),
1173                     sha1_to_hex(merge->object.sha1));
1174
1175         if (unmerged_cache()) {
1176                 struct string_list *entries, *re_head, *re_merge;
1177                 int i;
1178                 string_list_clear(&current_file_set, 1);
1179                 string_list_clear(&current_directory_set, 1);
1180                 get_files_dirs(head);
1181                 get_files_dirs(merge);
1182
1183                 entries = get_unmerged();
1184                 re_head  = get_renames(head, common, head, merge, entries);
1185                 re_merge = get_renames(merge, common, head, merge, entries);
1186                 clean = process_renames(re_head, re_merge,
1187                                 branch1, branch2);
1188                 for (i = 0; i < entries->nr; i++) {
1189                         const char *path = entries->items[i].string;
1190                         struct stage_data *e = entries->items[i].util;
1191                         if (!e->processed
1192                                 && !process_entry(path, e, branch1, branch2))
1193                                 clean = 0;
1194                 }
1195
1196                 string_list_clear(re_merge, 0);
1197                 string_list_clear(re_head, 0);
1198                 string_list_clear(entries, 1);
1199
1200         }
1201         else
1202                 clean = 1;
1203
1204         if (index_only)
1205                 *result = write_tree_from_memory();
1206
1207         return clean;
1208 }
1209
1210 static struct commit_list *reverse_commit_list(struct commit_list *list)
1211 {
1212         struct commit_list *next = NULL, *current, *backup;
1213         for (current = list; current; current = backup) {
1214                 backup = current->next;
1215                 current->next = next;
1216                 next = current;
1217         }
1218         return next;
1219 }
1220
1221 /*
1222  * Merge the commits h1 and h2, return the resulting virtual
1223  * commit object and a flag indicating the cleanness of the merge.
1224  */
1225 int merge_recursive(struct commit *h1,
1226                     struct commit *h2,
1227                     const char *branch1,
1228                     const char *branch2,
1229                     struct commit_list *ca,
1230                     struct commit **result)
1231 {
1232         struct commit_list *iter;
1233         struct commit *merged_common_ancestors;
1234         struct tree *mrtree = mrtree;
1235         int clean;
1236
1237         if (show(4)) {
1238                 output(4, "Merging:");
1239                 output_commit_title(h1);
1240                 output_commit_title(h2);
1241         }
1242
1243         if (!ca) {
1244                 ca = get_merge_bases(h1, h2, 1);
1245                 ca = reverse_commit_list(ca);
1246         }
1247
1248         if (show(5)) {
1249                 output(5, "found %u common ancestor(s):", commit_list_count(ca));
1250                 for (iter = ca; iter; iter = iter->next)
1251                         output_commit_title(iter->item);
1252         }
1253
1254         merged_common_ancestors = pop_commit(&ca);
1255         if (merged_common_ancestors == NULL) {
1256                 /* if there is no common ancestor, make an empty tree */
1257                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1258
1259                 tree->object.parsed = 1;
1260                 tree->object.type = OBJ_TREE;
1261                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1262                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1263         }
1264
1265         for (iter = ca; iter; iter = iter->next) {
1266                 call_depth++;
1267                 /*
1268                  * When the merge fails, the result contains files
1269                  * with conflict markers. The cleanness flag is
1270                  * ignored, it was never actually used, as result of
1271                  * merge_trees has always overwritten it: the committed
1272                  * "conflicts" were already resolved.
1273                  */
1274                 discard_cache();
1275                 merge_recursive(merged_common_ancestors, iter->item,
1276                                 "Temporary merge branch 1",
1277                                 "Temporary merge branch 2",
1278                                 NULL,
1279                                 &merged_common_ancestors);
1280                 call_depth--;
1281
1282                 if (!merged_common_ancestors)
1283                         die("merge returned no commit");
1284         }
1285
1286         discard_cache();
1287         if (!call_depth) {
1288                 read_cache();
1289                 index_only = 0;
1290         } else
1291                 index_only = 1;
1292
1293         clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1294                             branch1, branch2, &mrtree);
1295
1296         if (index_only) {
1297                 *result = make_virtual_commit(mrtree, "merged tree");
1298                 commit_list_insert(h1, &(*result)->parents);
1299                 commit_list_insert(h2, &(*result)->parents->next);
1300         }
1301         flush_output();
1302         return clean;
1303 }
1304
1305 static const char *better_branch_name(const char *branch)
1306 {
1307         static char githead_env[8 + 40 + 1];
1308         char *name;
1309
1310         if (strlen(branch) != 40)
1311                 return branch;
1312         sprintf(githead_env, "GITHEAD_%s", branch);
1313         name = getenv(githead_env);
1314         return name ? name : branch;
1315 }
1316
1317 static struct commit *get_ref(const char *ref)
1318 {
1319         unsigned char sha1[20];
1320         struct object *object;
1321
1322         if (get_sha1(ref, sha1))
1323                 die("Could not resolve ref '%s'", ref);
1324         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1325         if (!object)
1326                 return NULL;
1327         if (object->type == OBJ_TREE)
1328                 return make_virtual_commit((struct tree*)object,
1329                         better_branch_name(ref));
1330         if (object->type != OBJ_COMMIT)
1331                 return NULL;
1332         if (parse_commit((struct commit *)object))
1333                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1334         return (struct commit *)object;
1335 }
1336
1337 static int merge_config(const char *var, const char *value, void *cb)
1338 {
1339         if (!strcasecmp(var, "merge.verbosity")) {
1340                 verbosity = git_config_int(var, value);
1341                 return 0;
1342         }
1343         if (!strcasecmp(var, "diff.renamelimit")) {
1344                 diff_rename_limit = git_config_int(var, value);
1345                 return 0;
1346         }
1347         if (!strcasecmp(var, "merge.renamelimit")) {
1348                 merge_rename_limit = git_config_int(var, value);
1349                 return 0;
1350         }
1351         return git_default_config(var, value, cb);
1352 }
1353
1354 int cmd_merge_recursive(int argc, const char **argv, const char *prefix)
1355 {
1356         static const char *bases[20];
1357         static unsigned bases_count = 0;
1358         int i, clean;
1359         const char *branch1, *branch2;
1360         struct commit *result, *h1, *h2;
1361         struct commit_list *ca = NULL;
1362         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1363         int index_fd;
1364
1365         if (argv[0]) {
1366                 int namelen = strlen(argv[0]);
1367                 if (8 < namelen &&
1368                     !strcmp(argv[0] + namelen - 8, "-subtree"))
1369                         subtree_merge = 1;
1370         }
1371
1372         git_config(merge_config, NULL);
1373         if (getenv("GIT_MERGE_VERBOSITY"))
1374                 verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1375
1376         if (argc < 4)
1377                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1378
1379         for (i = 1; i < argc; ++i) {
1380                 if (!strcmp(argv[i], "--"))
1381                         break;
1382                 if (bases_count < sizeof(bases)/sizeof(*bases))
1383                         bases[bases_count++] = argv[i];
1384         }
1385         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1386                 die("Not handling anything other than two heads merge.");
1387         if (verbosity >= 5)
1388                 buffer_output = 0;
1389
1390         branch1 = argv[++i];
1391         branch2 = argv[++i];
1392
1393         h1 = get_ref(branch1);
1394         h2 = get_ref(branch2);
1395
1396         branch1 = better_branch_name(branch1);
1397         branch2 = better_branch_name(branch2);
1398
1399         if (show(3))
1400                 printf("Merging %s with %s\n", branch1, branch2);
1401
1402         index_fd = hold_locked_index(lock, 1);
1403
1404         for (i = 0; i < bases_count; i++) {
1405                 struct commit *ancestor = get_ref(bases[i]);
1406                 ca = commit_list_insert(ancestor, &ca);
1407         }
1408         clean = merge_recursive(h1, h2, branch1, branch2, ca, &result);
1409
1410         if (active_cache_changed &&
1411             (write_cache(index_fd, active_cache, active_nr) ||
1412              commit_locked_index(lock)))
1413                         die ("unable to write %s", get_index_file());
1414
1415         return clean ? 0: 1;
1416 }