merge-recursive: split low-level merge functions out.
[git] / merge-recursive.c
1 /*
2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
3  * Fredrik Kuivinen.
4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
5  */
6 #include "cache.h"
7 #include "cache-tree.h"
8 #include "commit.h"
9 #include "blob.h"
10 #include "tree-walk.h"
11 #include "diff.h"
12 #include "diffcore.h"
13 #include "tag.h"
14 #include "unpack-trees.h"
15 #include "path-list.h"
16 #include "xdiff-interface.h"
17 #include "ll-merge.h"
18
19 static int subtree_merge;
20
21 static struct tree *shift_tree_object(struct tree *one, struct tree *two)
22 {
23         unsigned char shifted[20];
24
25         /*
26          * NEEDSWORK: this limits the recursion depth to hardcoded
27          * value '2' to avoid excessive overhead.
28          */
29         shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
30         if (!hashcmp(two->object.sha1, shifted))
31                 return two;
32         return lookup_tree(shifted);
33 }
34
35 /*
36  * A virtual commit has
37  * - (const char *)commit->util set to the name, and
38  * - *(int *)commit->object.sha1 set to the virtual id.
39  */
40
41 static unsigned commit_list_count(const struct commit_list *l)
42 {
43         unsigned c = 0;
44         for (; l; l = l->next )
45                 c++;
46         return c;
47 }
48
49 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
50 {
51         struct commit *commit = xcalloc(1, sizeof(struct commit));
52         static unsigned virtual_id = 1;
53         commit->tree = tree;
54         commit->util = (void*)comment;
55         *(int*)commit->object.sha1 = virtual_id++;
56         /* avoid warnings */
57         commit->object.parsed = 1;
58         return commit;
59 }
60
61 /*
62  * Since we use get_tree_entry(), which does not put the read object into
63  * the object pool, we cannot rely on a == b.
64  */
65 static int sha_eq(const unsigned char *a, const unsigned char *b)
66 {
67         if (!a && !b)
68                 return 2;
69         return a && b && hashcmp(a, b) == 0;
70 }
71
72 /*
73  * Since we want to write the index eventually, we cannot reuse the index
74  * for these (temporary) data.
75  */
76 struct stage_data
77 {
78         struct
79         {
80                 unsigned mode;
81                 unsigned char sha[20];
82         } stages[4];
83         unsigned processed:1;
84 };
85
86 static struct path_list current_file_set = {NULL, 0, 0, 1};
87 static struct path_list current_directory_set = {NULL, 0, 0, 1};
88
89 static int call_depth = 0;
90 static int verbosity = 2;
91 static int rename_limit = -1;
92 static int buffer_output = 1;
93 static struct strbuf obuf = STRBUF_INIT;
94
95 static int show(int v)
96 {
97         return (!call_depth && verbosity >= v) || verbosity >= 5;
98 }
99
100 static void flush_output(void)
101 {
102         if (obuf.len) {
103                 fputs(obuf.buf, stdout);
104                 strbuf_reset(&obuf);
105         }
106 }
107
108 static void output(int v, const char *fmt, ...)
109 {
110         int len;
111         va_list ap;
112
113         if (!show(v))
114                 return;
115
116         strbuf_grow(&obuf, call_depth * 2 + 2);
117         memset(obuf.buf + obuf.len, ' ', call_depth * 2);
118         strbuf_setlen(&obuf, obuf.len + call_depth * 2);
119
120         va_start(ap, fmt);
121         len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
122         va_end(ap);
123
124         if (len < 0)
125                 len = 0;
126         if (len >= strbuf_avail(&obuf)) {
127                 strbuf_grow(&obuf, len + 2);
128                 va_start(ap, fmt);
129                 len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
130                 va_end(ap);
131                 if (len >= strbuf_avail(&obuf)) {
132                         die("this should not happen, your snprintf is broken");
133                 }
134         }
135         strbuf_setlen(&obuf, obuf.len + len);
136         strbuf_add(&obuf, "\n", 1);
137         if (!buffer_output)
138                 flush_output();
139 }
140
141 static void output_commit_title(struct commit *commit)
142 {
143         int i;
144         flush_output();
145         for (i = call_depth; i--;)
146                 fputs("  ", stdout);
147         if (commit->util)
148                 printf("virtual %s\n", (char *)commit->util);
149         else {
150                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
151                 if (parse_commit(commit) != 0)
152                         printf("(bad commit)\n");
153                 else {
154                         const char *s;
155                         int len;
156                         for (s = commit->buffer; *s; s++)
157                                 if (*s == '\n' && s[1] == '\n') {
158                                         s += 2;
159                                         break;
160                                 }
161                         for (len = 0; s[len] && '\n' != s[len]; len++)
162                                 ; /* do nothing */
163                         printf("%.*s\n", len, s);
164                 }
165         }
166 }
167
168 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
169                 const char *path, int stage, int refresh, int options)
170 {
171         struct cache_entry *ce;
172         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
173         if (!ce)
174                 return error("addinfo_cache failed for path '%s'", path);
175         return add_cache_entry(ce, options);
176 }
177
178 /*
179  * This is a global variable which is used in a number of places but
180  * only written to in the 'merge' function.
181  *
182  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
183  *                       don't update the working directory.
184  *               0    => Leave unmerged entries in the cache and update
185  *                       the working directory.
186  */
187 static int index_only = 0;
188
189 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
190 {
191         parse_tree(tree);
192         init_tree_desc(desc, tree->buffer, tree->size);
193 }
194
195 static int git_merge_trees(int index_only,
196                            struct tree *common,
197                            struct tree *head,
198                            struct tree *merge)
199 {
200         int rc;
201         struct tree_desc t[3];
202         struct unpack_trees_options opts;
203
204         memset(&opts, 0, sizeof(opts));
205         if (index_only)
206                 opts.index_only = 1;
207         else
208                 opts.update = 1;
209         opts.merge = 1;
210         opts.head_idx = 2;
211         opts.fn = threeway_merge;
212
213         init_tree_desc_from_tree(t+0, common);
214         init_tree_desc_from_tree(t+1, head);
215         init_tree_desc_from_tree(t+2, merge);
216
217         rc = unpack_trees(3, t, &opts);
218         cache_tree_free(&active_cache_tree);
219         return rc;
220 }
221
222 static int unmerged_index(void)
223 {
224         int i;
225         for (i = 0; i < active_nr; i++) {
226                 struct cache_entry *ce = active_cache[i];
227                 if (ce_stage(ce))
228                         return 1;
229         }
230         return 0;
231 }
232
233 static struct tree *git_write_tree(void)
234 {
235         struct tree *result = NULL;
236
237         if (unmerged_index()) {
238                 int i;
239                 output(0, "There are unmerged index entries:");
240                 for (i = 0; i < active_nr; i++) {
241                         struct cache_entry *ce = active_cache[i];
242                         if (ce_stage(ce))
243                                 output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
244                 }
245                 return NULL;
246         }
247
248         if (!active_cache_tree)
249                 active_cache_tree = cache_tree();
250
251         if (!cache_tree_fully_valid(active_cache_tree) &&
252             cache_tree_update(active_cache_tree,
253                               active_cache, active_nr, 0, 0) < 0)
254                 die("error building trees");
255
256         result = lookup_tree(active_cache_tree->sha1);
257
258         return result;
259 }
260
261 static int save_files_dirs(const unsigned char *sha1,
262                 const char *base, int baselen, const char *path,
263                 unsigned int mode, int stage)
264 {
265         int len = strlen(path);
266         char *newpath = xmalloc(baselen + len + 1);
267         memcpy(newpath, base, baselen);
268         memcpy(newpath + baselen, path, len);
269         newpath[baselen + len] = '\0';
270
271         if (S_ISDIR(mode))
272                 path_list_insert(newpath, &current_directory_set);
273         else
274                 path_list_insert(newpath, &current_file_set);
275         free(newpath);
276
277         return READ_TREE_RECURSIVE;
278 }
279
280 static int get_files_dirs(struct tree *tree)
281 {
282         int n;
283         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
284                 return 0;
285         n = current_file_set.nr + current_directory_set.nr;
286         return n;
287 }
288
289 /*
290  * Returns an index_entry instance which doesn't have to correspond to
291  * a real cache entry in Git's index.
292  */
293 static struct stage_data *insert_stage_data(const char *path,
294                 struct tree *o, struct tree *a, struct tree *b,
295                 struct path_list *entries)
296 {
297         struct path_list_item *item;
298         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
299         get_tree_entry(o->object.sha1, path,
300                         e->stages[1].sha, &e->stages[1].mode);
301         get_tree_entry(a->object.sha1, path,
302                         e->stages[2].sha, &e->stages[2].mode);
303         get_tree_entry(b->object.sha1, path,
304                         e->stages[3].sha, &e->stages[3].mode);
305         item = path_list_insert(path, entries);
306         item->util = e;
307         return e;
308 }
309
310 /*
311  * Create a dictionary mapping file names to stage_data objects. The
312  * dictionary contains one entry for every path with a non-zero stage entry.
313  */
314 static struct path_list *get_unmerged(void)
315 {
316         struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
317         int i;
318
319         unmerged->strdup_paths = 1;
320
321         for (i = 0; i < active_nr; i++) {
322                 struct path_list_item *item;
323                 struct stage_data *e;
324                 struct cache_entry *ce = active_cache[i];
325                 if (!ce_stage(ce))
326                         continue;
327
328                 item = path_list_lookup(ce->name, unmerged);
329                 if (!item) {
330                         item = path_list_insert(ce->name, unmerged);
331                         item->util = xcalloc(1, sizeof(struct stage_data));
332                 }
333                 e = item->util;
334                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
335                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
336         }
337
338         return unmerged;
339 }
340
341 struct rename
342 {
343         struct diff_filepair *pair;
344         struct stage_data *src_entry;
345         struct stage_data *dst_entry;
346         unsigned processed:1;
347 };
348
349 /*
350  * Get information of all renames which occurred between 'o_tree' and
351  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
352  * 'b_tree') to be able to associate the correct cache entries with
353  * the rename information. 'tree' is always equal to either a_tree or b_tree.
354  */
355 static struct path_list *get_renames(struct tree *tree,
356                                         struct tree *o_tree,
357                                         struct tree *a_tree,
358                                         struct tree *b_tree,
359                                         struct path_list *entries)
360 {
361         int i;
362         struct path_list *renames;
363         struct diff_options opts;
364
365         renames = xcalloc(1, sizeof(struct path_list));
366         diff_setup(&opts);
367         DIFF_OPT_SET(&opts, RECURSIVE);
368         opts.detect_rename = DIFF_DETECT_RENAME;
369         opts.rename_limit = rename_limit;
370         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
371         if (diff_setup_done(&opts) < 0)
372                 die("diff setup failed");
373         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
374         diffcore_std(&opts);
375         for (i = 0; i < diff_queued_diff.nr; ++i) {
376                 struct path_list_item *item;
377                 struct rename *re;
378                 struct diff_filepair *pair = diff_queued_diff.queue[i];
379                 if (pair->status != 'R') {
380                         diff_free_filepair(pair);
381                         continue;
382                 }
383                 re = xmalloc(sizeof(*re));
384                 re->processed = 0;
385                 re->pair = pair;
386                 item = path_list_lookup(re->pair->one->path, entries);
387                 if (!item)
388                         re->src_entry = insert_stage_data(re->pair->one->path,
389                                         o_tree, a_tree, b_tree, entries);
390                 else
391                         re->src_entry = item->util;
392
393                 item = path_list_lookup(re->pair->two->path, entries);
394                 if (!item)
395                         re->dst_entry = insert_stage_data(re->pair->two->path,
396                                         o_tree, a_tree, b_tree, entries);
397                 else
398                         re->dst_entry = item->util;
399                 item = path_list_insert(pair->one->path, renames);
400                 item->util = re;
401         }
402         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
403         diff_queued_diff.nr = 0;
404         diff_flush(&opts);
405         return renames;
406 }
407
408 static int update_stages(const char *path, struct diff_filespec *o,
409                          struct diff_filespec *a, struct diff_filespec *b,
410                          int clear)
411 {
412         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
413         if (clear)
414                 if (remove_file_from_cache(path))
415                         return -1;
416         if (o)
417                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
418                         return -1;
419         if (a)
420                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
421                         return -1;
422         if (b)
423                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
424                         return -1;
425         return 0;
426 }
427
428 static int remove_path(const char *name)
429 {
430         int ret;
431         char *slash, *dirs;
432
433         ret = unlink(name);
434         if (ret)
435                 return ret;
436         dirs = xstrdup(name);
437         while ((slash = strrchr(name, '/'))) {
438                 *slash = '\0';
439                 if (rmdir(name) != 0)
440                         break;
441         }
442         free(dirs);
443         return ret;
444 }
445
446 static int remove_file(int clean, const char *path, int no_wd)
447 {
448         int update_cache = index_only || clean;
449         int update_working_directory = !index_only && !no_wd;
450
451         if (update_cache) {
452                 if (remove_file_from_cache(path))
453                         return -1;
454         }
455         if (update_working_directory) {
456                 unlink(path);
457                 if (errno != ENOENT || errno != EISDIR)
458                         return -1;
459                 remove_path(path);
460         }
461         return 0;
462 }
463
464 static char *unique_path(const char *path, const char *branch)
465 {
466         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
467         int suffix = 0;
468         struct stat st;
469         char *p = newpath + strlen(path);
470         strcpy(newpath, path);
471         *(p++) = '~';
472         strcpy(p, branch);
473         for (; *p; ++p)
474                 if ('/' == *p)
475                         *p = '_';
476         while (path_list_has_path(&current_file_set, newpath) ||
477                path_list_has_path(&current_directory_set, newpath) ||
478                lstat(newpath, &st) == 0)
479                 sprintf(p, "_%d", suffix++);
480
481         path_list_insert(newpath, &current_file_set);
482         return newpath;
483 }
484
485 static int mkdir_p(const char *path, unsigned long mode)
486 {
487         /* path points to cache entries, so xstrdup before messing with it */
488         char *buf = xstrdup(path);
489         int result = safe_create_leading_directories(buf);
490         free(buf);
491         return result;
492 }
493
494 static void flush_buffer(int fd, const char *buf, unsigned long size)
495 {
496         while (size > 0) {
497                 long ret = write_in_full(fd, buf, size);
498                 if (ret < 0) {
499                         /* Ignore epipe */
500                         if (errno == EPIPE)
501                                 break;
502                         die("merge-recursive: %s", strerror(errno));
503                 } else if (!ret) {
504                         die("merge-recursive: disk full?");
505                 }
506                 size -= ret;
507                 buf += ret;
508         }
509 }
510
511 static int make_room_for_path(const char *path)
512 {
513         int status;
514         const char *msg = "failed to create path '%s'%s";
515
516         status = mkdir_p(path, 0777);
517         if (status) {
518                 if (status == -3) {
519                         /* something else exists */
520                         error(msg, path, ": perhaps a D/F conflict?");
521                         return -1;
522                 }
523                 die(msg, path, "");
524         }
525
526         /* Successful unlink is good.. */
527         if (!unlink(path))
528                 return 0;
529         /* .. and so is no existing file */
530         if (errno == ENOENT)
531                 return 0;
532         /* .. but not some other error (who really cares what?) */
533         return error(msg, path, ": perhaps a D/F conflict?");
534 }
535
536 static void update_file_flags(const unsigned char *sha,
537                               unsigned mode,
538                               const char *path,
539                               int update_cache,
540                               int update_wd)
541 {
542         if (index_only)
543                 update_wd = 0;
544
545         if (update_wd) {
546                 enum object_type type;
547                 void *buf;
548                 unsigned long size;
549
550                 if (S_ISGITLINK(mode))
551                         die("cannot read object %s '%s': It is a submodule!",
552                             sha1_to_hex(sha), path);
553
554                 buf = read_sha1_file(sha, &type, &size);
555                 if (!buf)
556                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
557                 if (type != OBJ_BLOB)
558                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
559
560                 if (make_room_for_path(path) < 0) {
561                         update_wd = 0;
562                         goto update_index;
563                 }
564                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
565                         int fd;
566                         if (mode & 0100)
567                                 mode = 0777;
568                         else
569                                 mode = 0666;
570                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
571                         if (fd < 0)
572                                 die("failed to open %s: %s", path, strerror(errno));
573                         flush_buffer(fd, buf, size);
574                         close(fd);
575                 } else if (S_ISLNK(mode)) {
576                         char *lnk = xmemdupz(buf, size);
577                         mkdir_p(path, 0777);
578                         unlink(path);
579                         symlink(lnk, path);
580                         free(lnk);
581                 } else
582                         die("do not know what to do with %06o %s '%s'",
583                             mode, sha1_to_hex(sha), path);
584         }
585  update_index:
586         if (update_cache)
587                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
588 }
589
590 static void update_file(int clean,
591                         const unsigned char *sha,
592                         unsigned mode,
593                         const char *path)
594 {
595         update_file_flags(sha, mode, path, index_only || clean, !index_only);
596 }
597
598 /* Low level file merging, update and removal */
599
600 struct merge_file_info
601 {
602         unsigned char sha[20];
603         unsigned mode;
604         unsigned clean:1,
605                  merge:1;
606 };
607
608 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
609 {
610         unsigned long size;
611         enum object_type type;
612
613         if (!hashcmp(sha1, null_sha1)) {
614                 mm->ptr = xstrdup("");
615                 mm->size = 0;
616                 return;
617         }
618
619         mm->ptr = read_sha1_file(sha1, &type, &size);
620         if (!mm->ptr || type != OBJ_BLOB)
621                 die("unable to read blob object %s", sha1_to_hex(sha1));
622         mm->size = size;
623 }
624
625 static int merge_3way(mmbuffer_t *result_buf,
626                       struct diff_filespec *o,
627                       struct diff_filespec *a,
628                       struct diff_filespec *b,
629                       const char *branch1,
630                       const char *branch2)
631 {
632         mmfile_t orig, src1, src2;
633         char *name1, *name2;
634         int merge_status;
635
636         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
637         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
638
639         fill_mm(o->sha1, &orig);
640         fill_mm(a->sha1, &src1);
641         fill_mm(b->sha1, &src2);
642
643         merge_status = ll_merge(result_buf, a->path, &orig,
644                                 &src1, name1, &src2, name2,
645                                 index_only);
646
647         free(name1);
648         free(name2);
649         free(orig.ptr);
650         free(src1.ptr);
651         free(src2.ptr);
652         return merge_status;
653 }
654
655 static struct merge_file_info merge_file(struct diff_filespec *o,
656                 struct diff_filespec *a, struct diff_filespec *b,
657                 const char *branch1, const char *branch2)
658 {
659         struct merge_file_info result;
660         result.merge = 0;
661         result.clean = 1;
662
663         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
664                 result.clean = 0;
665                 if (S_ISREG(a->mode)) {
666                         result.mode = a->mode;
667                         hashcpy(result.sha, a->sha1);
668                 } else {
669                         result.mode = b->mode;
670                         hashcpy(result.sha, b->sha1);
671                 }
672         } else {
673                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
674                         result.merge = 1;
675
676                 result.mode = a->mode == o->mode ? b->mode: a->mode;
677
678                 if (sha_eq(a->sha1, o->sha1))
679                         hashcpy(result.sha, b->sha1);
680                 else if (sha_eq(b->sha1, o->sha1))
681                         hashcpy(result.sha, a->sha1);
682                 else if (S_ISREG(a->mode)) {
683                         mmbuffer_t result_buf;
684                         int merge_status;
685
686                         merge_status = merge_3way(&result_buf, o, a, b,
687                                                   branch1, branch2);
688
689                         if ((merge_status < 0) || !result_buf.ptr)
690                                 die("Failed to execute internal merge");
691
692                         if (write_sha1_file(result_buf.ptr, result_buf.size,
693                                             blob_type, result.sha))
694                                 die("Unable to add %s to database",
695                                     a->path);
696
697                         free(result_buf.ptr);
698                         result.clean = (merge_status == 0);
699                 } else if (S_ISGITLINK(a->mode)) {
700                         result.clean = 0;
701                         hashcpy(result.sha, a->sha1);
702                 } else if (S_ISLNK(a->mode)) {
703                         hashcpy(result.sha, a->sha1);
704
705                         if (!sha_eq(a->sha1, b->sha1))
706                                 result.clean = 0;
707                 } else {
708                         die("unsupported object type in the tree");
709                 }
710         }
711
712         return result;
713 }
714
715 static void conflict_rename_rename(struct rename *ren1,
716                                    const char *branch1,
717                                    struct rename *ren2,
718                                    const char *branch2)
719 {
720         char *del[2];
721         int delp = 0;
722         const char *ren1_dst = ren1->pair->two->path;
723         const char *ren2_dst = ren2->pair->two->path;
724         const char *dst_name1 = ren1_dst;
725         const char *dst_name2 = ren2_dst;
726         if (path_list_has_path(&current_directory_set, ren1_dst)) {
727                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
728                 output(1, "%s is a directory in %s added as %s instead",
729                        ren1_dst, branch2, dst_name1);
730                 remove_file(0, ren1_dst, 0);
731         }
732         if (path_list_has_path(&current_directory_set, ren2_dst)) {
733                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
734                 output(1, "%s is a directory in %s added as %s instead",
735                        ren2_dst, branch1, dst_name2);
736                 remove_file(0, ren2_dst, 0);
737         }
738         if (index_only) {
739                 remove_file_from_cache(dst_name1);
740                 remove_file_from_cache(dst_name2);
741                 /*
742                  * Uncomment to leave the conflicting names in the resulting tree
743                  *
744                  * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
745                  * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
746                  */
747         } else {
748                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
749                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
750         }
751         while (delp--)
752                 free(del[delp]);
753 }
754
755 static void conflict_rename_dir(struct rename *ren1,
756                                 const char *branch1)
757 {
758         char *new_path = unique_path(ren1->pair->two->path, branch1);
759         output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
760         remove_file(0, ren1->pair->two->path, 0);
761         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
762         free(new_path);
763 }
764
765 static void conflict_rename_rename_2(struct rename *ren1,
766                                      const char *branch1,
767                                      struct rename *ren2,
768                                      const char *branch2)
769 {
770         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
771         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
772         output(1, "Renamed %s to %s and %s to %s instead",
773                ren1->pair->one->path, new_path1,
774                ren2->pair->one->path, new_path2);
775         remove_file(0, ren1->pair->two->path, 0);
776         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
777         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
778         free(new_path2);
779         free(new_path1);
780 }
781
782 static int process_renames(struct path_list *a_renames,
783                            struct path_list *b_renames,
784                            const char *a_branch,
785                            const char *b_branch)
786 {
787         int clean_merge = 1, i, j;
788         struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
789         const struct rename *sre;
790
791         for (i = 0; i < a_renames->nr; i++) {
792                 sre = a_renames->items[i].util;
793                 path_list_insert(sre->pair->two->path, &a_by_dst)->util
794                         = sre->dst_entry;
795         }
796         for (i = 0; i < b_renames->nr; i++) {
797                 sre = b_renames->items[i].util;
798                 path_list_insert(sre->pair->two->path, &b_by_dst)->util
799                         = sre->dst_entry;
800         }
801
802         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
803                 int compare;
804                 char *src;
805                 struct path_list *renames1, *renames2, *renames2Dst;
806                 struct rename *ren1 = NULL, *ren2 = NULL;
807                 const char *branch1, *branch2;
808                 const char *ren1_src, *ren1_dst;
809
810                 if (i >= a_renames->nr) {
811                         compare = 1;
812                         ren2 = b_renames->items[j++].util;
813                 } else if (j >= b_renames->nr) {
814                         compare = -1;
815                         ren1 = a_renames->items[i++].util;
816                 } else {
817                         compare = strcmp(a_renames->items[i].path,
818                                         b_renames->items[j].path);
819                         if (compare <= 0)
820                                 ren1 = a_renames->items[i++].util;
821                         if (compare >= 0)
822                                 ren2 = b_renames->items[j++].util;
823                 }
824
825                 /* TODO: refactor, so that 1/2 are not needed */
826                 if (ren1) {
827                         renames1 = a_renames;
828                         renames2 = b_renames;
829                         renames2Dst = &b_by_dst;
830                         branch1 = a_branch;
831                         branch2 = b_branch;
832                 } else {
833                         struct rename *tmp;
834                         renames1 = b_renames;
835                         renames2 = a_renames;
836                         renames2Dst = &a_by_dst;
837                         branch1 = b_branch;
838                         branch2 = a_branch;
839                         tmp = ren2;
840                         ren2 = ren1;
841                         ren1 = tmp;
842                 }
843                 src = ren1->pair->one->path;
844
845                 ren1->dst_entry->processed = 1;
846                 ren1->src_entry->processed = 1;
847
848                 if (ren1->processed)
849                         continue;
850                 ren1->processed = 1;
851
852                 ren1_src = ren1->pair->one->path;
853                 ren1_dst = ren1->pair->two->path;
854
855                 if (ren2) {
856                         const char *ren2_src = ren2->pair->one->path;
857                         const char *ren2_dst = ren2->pair->two->path;
858                         /* Renamed in 1 and renamed in 2 */
859                         if (strcmp(ren1_src, ren2_src) != 0)
860                                 die("ren1.src != ren2.src");
861                         ren2->dst_entry->processed = 1;
862                         ren2->processed = 1;
863                         if (strcmp(ren1_dst, ren2_dst) != 0) {
864                                 clean_merge = 0;
865                                 output(1, "CONFLICT (rename/rename): "
866                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
867                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
868                                        src, ren1_dst, branch1,
869                                        src, ren2_dst, branch2,
870                                        index_only ? " (left unresolved)": "");
871                                 if (index_only) {
872                                         remove_file_from_cache(src);
873                                         update_file(0, ren1->pair->one->sha1,
874                                                     ren1->pair->one->mode, src);
875                                 }
876                                 conflict_rename_rename(ren1, branch1, ren2, branch2);
877                         } else {
878                                 struct merge_file_info mfi;
879                                 remove_file(1, ren1_src, 1);
880                                 mfi = merge_file(ren1->pair->one,
881                                                  ren1->pair->two,
882                                                  ren2->pair->two,
883                                                  branch1,
884                                                  branch2);
885                                 if (mfi.merge || !mfi.clean)
886                                         output(1, "Renamed %s->%s", src, ren1_dst);
887
888                                 if (mfi.merge)
889                                         output(2, "Auto-merged %s", ren1_dst);
890
891                                 if (!mfi.clean) {
892                                         output(1, "CONFLICT (content): merge conflict in %s",
893                                                ren1_dst);
894                                         clean_merge = 0;
895
896                                         if (!index_only)
897                                                 update_stages(ren1_dst,
898                                                               ren1->pair->one,
899                                                               ren1->pair->two,
900                                                               ren2->pair->two,
901                                                               1 /* clear */);
902                                 }
903                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
904                         }
905                 } else {
906                         /* Renamed in 1, maybe changed in 2 */
907                         struct path_list_item *item;
908                         /* we only use sha1 and mode of these */
909                         struct diff_filespec src_other, dst_other;
910                         int try_merge, stage = a_renames == renames1 ? 3: 2;
911
912                         remove_file(1, ren1_src, index_only || stage == 3);
913
914                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
915                         src_other.mode = ren1->src_entry->stages[stage].mode;
916                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
917                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
918
919                         try_merge = 0;
920
921                         if (path_list_has_path(&current_directory_set, ren1_dst)) {
922                                 clean_merge = 0;
923                                 output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
924                                        " directory %s added in %s",
925                                        ren1_src, ren1_dst, branch1,
926                                        ren1_dst, branch2);
927                                 conflict_rename_dir(ren1, branch1);
928                         } else if (sha_eq(src_other.sha1, null_sha1)) {
929                                 clean_merge = 0;
930                                 output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
931                                        "and deleted in %s",
932                                        ren1_src, ren1_dst, branch1,
933                                        branch2);
934                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
935                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
936                                 const char *new_path;
937                                 clean_merge = 0;
938                                 try_merge = 1;
939                                 output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
940                                        "%s added in %s",
941                                        ren1_src, ren1_dst, branch1,
942                                        ren1_dst, branch2);
943                                 new_path = unique_path(ren1_dst, branch2);
944                                 output(1, "Added as %s instead", new_path);
945                                 update_file(0, dst_other.sha1, dst_other.mode, new_path);
946                         } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
947                                 ren2 = item->util;
948                                 clean_merge = 0;
949                                 ren2->processed = 1;
950                                 output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
951                                        "Renamed %s->%s in %s",
952                                        ren1_src, ren1_dst, branch1,
953                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
954                                 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
955                         } else
956                                 try_merge = 1;
957
958                         if (try_merge) {
959                                 struct diff_filespec *o, *a, *b;
960                                 struct merge_file_info mfi;
961                                 src_other.path = (char *)ren1_src;
962
963                                 o = ren1->pair->one;
964                                 if (a_renames == renames1) {
965                                         a = ren1->pair->two;
966                                         b = &src_other;
967                                 } else {
968                                         b = ren1->pair->two;
969                                         a = &src_other;
970                                 }
971                                 mfi = merge_file(o, a, b,
972                                                 a_branch, b_branch);
973
974                                 if (mfi.clean &&
975                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
976                                     mfi.mode == ren1->pair->two->mode)
977                                         /*
978                                          * This messaged is part of
979                                          * t6022 test. If you change
980                                          * it update the test too.
981                                          */
982                                         output(3, "Skipped %s (merged same as existing)", ren1_dst);
983                                 else {
984                                         if (mfi.merge || !mfi.clean)
985                                                 output(1, "Renamed %s => %s", ren1_src, ren1_dst);
986                                         if (mfi.merge)
987                                                 output(2, "Auto-merged %s", ren1_dst);
988                                         if (!mfi.clean) {
989                                                 output(1, "CONFLICT (rename/modify): Merge conflict in %s",
990                                                        ren1_dst);
991                                                 clean_merge = 0;
992
993                                                 if (!index_only)
994                                                         update_stages(ren1_dst,
995                                                                       o, a, b, 1);
996                                         }
997                                         update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
998                                 }
999                         }
1000                 }
1001         }
1002         path_list_clear(&a_by_dst, 0);
1003         path_list_clear(&b_by_dst, 0);
1004
1005         return clean_merge;
1006 }
1007
1008 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1009 {
1010         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1011 }
1012
1013 /* Per entry merge function */
1014 static int process_entry(const char *path, struct stage_data *entry,
1015                          const char *branch1,
1016                          const char *branch2)
1017 {
1018         /*
1019         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1020         print_index_entry("\tpath: ", entry);
1021         */
1022         int clean_merge = 1;
1023         unsigned o_mode = entry->stages[1].mode;
1024         unsigned a_mode = entry->stages[2].mode;
1025         unsigned b_mode = entry->stages[3].mode;
1026         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1027         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1028         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1029
1030         if (o_sha && (!a_sha || !b_sha)) {
1031                 /* Case A: Deleted in one */
1032                 if ((!a_sha && !b_sha) ||
1033                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1034                     (!a_sha && sha_eq(b_sha, o_sha))) {
1035                         /* Deleted in both or deleted in one and
1036                          * unchanged in the other */
1037                         if (a_sha)
1038                                 output(2, "Removed %s", path);
1039                         /* do not touch working file if it did not exist */
1040                         remove_file(1, path, !a_sha);
1041                 } else {
1042                         /* Deleted in one and changed in the other */
1043                         clean_merge = 0;
1044                         if (!a_sha) {
1045                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1046                                        "and modified in %s. Version %s of %s left in tree.",
1047                                        path, branch1,
1048                                        branch2, branch2, path);
1049                                 update_file(0, b_sha, b_mode, path);
1050                         } else {
1051                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1052                                        "and modified in %s. Version %s of %s left in tree.",
1053                                        path, branch2,
1054                                        branch1, branch1, path);
1055                                 update_file(0, a_sha, a_mode, path);
1056                         }
1057                 }
1058
1059         } else if ((!o_sha && a_sha && !b_sha) ||
1060                    (!o_sha && !a_sha && b_sha)) {
1061                 /* Case B: Added in one. */
1062                 const char *add_branch;
1063                 const char *other_branch;
1064                 unsigned mode;
1065                 const unsigned char *sha;
1066                 const char *conf;
1067
1068                 if (a_sha) {
1069                         add_branch = branch1;
1070                         other_branch = branch2;
1071                         mode = a_mode;
1072                         sha = a_sha;
1073                         conf = "file/directory";
1074                 } else {
1075                         add_branch = branch2;
1076                         other_branch = branch1;
1077                         mode = b_mode;
1078                         sha = b_sha;
1079                         conf = "directory/file";
1080                 }
1081                 if (path_list_has_path(&current_directory_set, path)) {
1082                         const char *new_path = unique_path(path, add_branch);
1083                         clean_merge = 0;
1084                         output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
1085                                "Added %s as %s",
1086                                conf, path, other_branch, path, new_path);
1087                         remove_file(0, path, 0);
1088                         update_file(0, sha, mode, new_path);
1089                 } else {
1090                         output(2, "Added %s", path);
1091                         update_file(1, sha, mode, path);
1092                 }
1093         } else if (a_sha && b_sha) {
1094                 /* Case C: Added in both (check for same permissions) and */
1095                 /* case D: Modified in both, but differently. */
1096                 const char *reason = "content";
1097                 struct merge_file_info mfi;
1098                 struct diff_filespec o, a, b;
1099
1100                 if (!o_sha) {
1101                         reason = "add/add";
1102                         o_sha = (unsigned char *)null_sha1;
1103                 }
1104                 output(2, "Auto-merged %s", path);
1105                 o.path = a.path = b.path = (char *)path;
1106                 hashcpy(o.sha1, o_sha);
1107                 o.mode = o_mode;
1108                 hashcpy(a.sha1, a_sha);
1109                 a.mode = a_mode;
1110                 hashcpy(b.sha1, b_sha);
1111                 b.mode = b_mode;
1112
1113                 mfi = merge_file(&o, &a, &b,
1114                                  branch1, branch2);
1115
1116                 clean_merge = mfi.clean;
1117                 if (mfi.clean)
1118                         update_file(1, mfi.sha, mfi.mode, path);
1119                 else if (S_ISGITLINK(mfi.mode))
1120                         output(1, "CONFLICT (submodule): Merge conflict in %s "
1121                                "- needs %s", path, sha1_to_hex(b.sha1));
1122                 else {
1123                         output(1, "CONFLICT (%s): Merge conflict in %s",
1124                                         reason, path);
1125
1126                         if (index_only)
1127                                 update_file(0, mfi.sha, mfi.mode, path);
1128                         else
1129                                 update_file_flags(mfi.sha, mfi.mode, path,
1130                                               0 /* update_cache */, 1 /* update_working_directory */);
1131                 }
1132         } else if (!o_sha && !a_sha && !b_sha) {
1133                 /*
1134                  * this entry was deleted altogether. a_mode == 0 means
1135                  * we had that path and want to actively remove it.
1136                  */
1137                 remove_file(1, path, !a_mode);
1138         } else
1139                 die("Fatal merge failure, shouldn't happen.");
1140
1141         return clean_merge;
1142 }
1143
1144 static int merge_trees(struct tree *head,
1145                        struct tree *merge,
1146                        struct tree *common,
1147                        const char *branch1,
1148                        const char *branch2,
1149                        struct tree **result)
1150 {
1151         int code, clean;
1152
1153         if (subtree_merge) {
1154                 merge = shift_tree_object(head, merge);
1155                 common = shift_tree_object(head, common);
1156         }
1157
1158         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1159                 output(0, "Already uptodate!");
1160                 *result = head;
1161                 return 1;
1162         }
1163
1164         code = git_merge_trees(index_only, common, head, merge);
1165
1166         if (code != 0)
1167                 die("merging of trees %s and %s failed",
1168                     sha1_to_hex(head->object.sha1),
1169                     sha1_to_hex(merge->object.sha1));
1170
1171         if (unmerged_index()) {
1172                 struct path_list *entries, *re_head, *re_merge;
1173                 int i;
1174                 path_list_clear(&current_file_set, 1);
1175                 path_list_clear(&current_directory_set, 1);
1176                 get_files_dirs(head);
1177                 get_files_dirs(merge);
1178
1179                 entries = get_unmerged();
1180                 re_head  = get_renames(head, common, head, merge, entries);
1181                 re_merge = get_renames(merge, common, head, merge, entries);
1182                 clean = process_renames(re_head, re_merge,
1183                                 branch1, branch2);
1184                 for (i = 0; i < entries->nr; i++) {
1185                         const char *path = entries->items[i].path;
1186                         struct stage_data *e = entries->items[i].util;
1187                         if (!e->processed
1188                                 && !process_entry(path, e, branch1, branch2))
1189                                 clean = 0;
1190                 }
1191
1192                 path_list_clear(re_merge, 0);
1193                 path_list_clear(re_head, 0);
1194                 path_list_clear(entries, 1);
1195
1196         }
1197         else
1198                 clean = 1;
1199
1200         if (index_only)
1201                 *result = git_write_tree();
1202
1203         return clean;
1204 }
1205
1206 static struct commit_list *reverse_commit_list(struct commit_list *list)
1207 {
1208         struct commit_list *next = NULL, *current, *backup;
1209         for (current = list; current; current = backup) {
1210                 backup = current->next;
1211                 current->next = next;
1212                 next = current;
1213         }
1214         return next;
1215 }
1216
1217 /*
1218  * Merge the commits h1 and h2, return the resulting virtual
1219  * commit object and a flag indicating the cleanness of the merge.
1220  */
1221 static int merge(struct commit *h1,
1222                  struct commit *h2,
1223                  const char *branch1,
1224                  const char *branch2,
1225                  struct commit_list *ca,
1226                  struct commit **result)
1227 {
1228         struct commit_list *iter;
1229         struct commit *merged_common_ancestors;
1230         struct tree *mrtree = mrtree;
1231         int clean;
1232
1233         if (show(4)) {
1234                 output(4, "Merging:");
1235                 output_commit_title(h1);
1236                 output_commit_title(h2);
1237         }
1238
1239         if (!ca) {
1240                 ca = get_merge_bases(h1, h2, 1);
1241                 ca = reverse_commit_list(ca);
1242         }
1243
1244         if (show(5)) {
1245                 output(5, "found %u common ancestor(s):", commit_list_count(ca));
1246                 for (iter = ca; iter; iter = iter->next)
1247                         output_commit_title(iter->item);
1248         }
1249
1250         merged_common_ancestors = pop_commit(&ca);
1251         if (merged_common_ancestors == NULL) {
1252                 /* if there is no common ancestor, make an empty tree */
1253                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1254
1255                 tree->object.parsed = 1;
1256                 tree->object.type = OBJ_TREE;
1257                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1258                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1259         }
1260
1261         for (iter = ca; iter; iter = iter->next) {
1262                 call_depth++;
1263                 /*
1264                  * When the merge fails, the result contains files
1265                  * with conflict markers. The cleanness flag is
1266                  * ignored, it was never actually used, as result of
1267                  * merge_trees has always overwritten it: the committed
1268                  * "conflicts" were already resolved.
1269                  */
1270                 discard_cache();
1271                 merge(merged_common_ancestors, iter->item,
1272                       "Temporary merge branch 1",
1273                       "Temporary merge branch 2",
1274                       NULL,
1275                       &merged_common_ancestors);
1276                 call_depth--;
1277
1278                 if (!merged_common_ancestors)
1279                         die("merge returned no commit");
1280         }
1281
1282         discard_cache();
1283         if (!call_depth) {
1284                 read_cache();
1285                 index_only = 0;
1286         } else
1287                 index_only = 1;
1288
1289         clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1290                             branch1, branch2, &mrtree);
1291
1292         if (index_only) {
1293                 *result = make_virtual_commit(mrtree, "merged tree");
1294                 commit_list_insert(h1, &(*result)->parents);
1295                 commit_list_insert(h2, &(*result)->parents->next);
1296         }
1297         flush_output();
1298         return clean;
1299 }
1300
1301 static const char *better_branch_name(const char *branch)
1302 {
1303         static char githead_env[8 + 40 + 1];
1304         char *name;
1305
1306         if (strlen(branch) != 40)
1307                 return branch;
1308         sprintf(githead_env, "GITHEAD_%s", branch);
1309         name = getenv(githead_env);
1310         return name ? name : branch;
1311 }
1312
1313 static struct commit *get_ref(const char *ref)
1314 {
1315         unsigned char sha1[20];
1316         struct object *object;
1317
1318         if (get_sha1(ref, sha1))
1319                 die("Could not resolve ref '%s'", ref);
1320         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1321         if (!object)
1322                 return NULL;
1323         if (object->type == OBJ_TREE)
1324                 return make_virtual_commit((struct tree*)object,
1325                         better_branch_name(ref));
1326         if (object->type != OBJ_COMMIT)
1327                 return NULL;
1328         if (parse_commit((struct commit *)object))
1329                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1330         return (struct commit *)object;
1331 }
1332
1333 static int merge_config(const char *var, const char *value)
1334 {
1335         if (!strcasecmp(var, "merge.verbosity")) {
1336                 verbosity = git_config_int(var, value);
1337                 return 0;
1338         }
1339         if (!strcasecmp(var, "diff.renamelimit")) {
1340                 rename_limit = git_config_int(var, value);
1341                 return 0;
1342         }
1343         return git_default_config(var, value);
1344 }
1345
1346 int main(int argc, char *argv[])
1347 {
1348         static const char *bases[20];
1349         static unsigned bases_count = 0;
1350         int i, clean;
1351         const char *branch1, *branch2;
1352         struct commit *result, *h1, *h2;
1353         struct commit_list *ca = NULL;
1354         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1355         int index_fd;
1356
1357         if (argv[0]) {
1358                 int namelen = strlen(argv[0]);
1359                 if (8 < namelen &&
1360                     !strcmp(argv[0] + namelen - 8, "-subtree"))
1361                         subtree_merge = 1;
1362         }
1363
1364         git_config(merge_config);
1365         if (getenv("GIT_MERGE_VERBOSITY"))
1366                 verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1367
1368         if (argc < 4)
1369                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1370
1371         for (i = 1; i < argc; ++i) {
1372                 if (!strcmp(argv[i], "--"))
1373                         break;
1374                 if (bases_count < sizeof(bases)/sizeof(*bases))
1375                         bases[bases_count++] = argv[i];
1376         }
1377         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1378                 die("Not handling anything other than two heads merge.");
1379         if (verbosity >= 5)
1380                 buffer_output = 0;
1381
1382         branch1 = argv[++i];
1383         branch2 = argv[++i];
1384
1385         h1 = get_ref(branch1);
1386         h2 = get_ref(branch2);
1387
1388         branch1 = better_branch_name(branch1);
1389         branch2 = better_branch_name(branch2);
1390
1391         if (show(3))
1392                 printf("Merging %s with %s\n", branch1, branch2);
1393
1394         index_fd = hold_locked_index(lock, 1);
1395
1396         for (i = 0; i < bases_count; i++) {
1397                 struct commit *ancestor = get_ref(bases[i]);
1398                 ca = commit_list_insert(ancestor, &ca);
1399         }
1400         clean = merge(h1, h2, branch1, branch2, ca, &result);
1401
1402         if (active_cache_changed &&
1403             (write_cache(index_fd, active_cache, active_nr) ||
1404              commit_locked_index(lock)))
1405                         die ("unable to write %s", get_index_file());
1406
1407         return clean ? 0: 1;
1408 }