Merge branch 'en/d-f-conflict-fix'
[git] / merge-recursive.c
1 /*
2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
3  * Fredrik Kuivinen.
4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
5  */
6 #include "advice.h"
7 #include "cache.h"
8 #include "cache-tree.h"
9 #include "commit.h"
10 #include "blob.h"
11 #include "builtin.h"
12 #include "tree-walk.h"
13 #include "diff.h"
14 #include "diffcore.h"
15 #include "tag.h"
16 #include "unpack-trees.h"
17 #include "string-list.h"
18 #include "xdiff-interface.h"
19 #include "ll-merge.h"
20 #include "attr.h"
21 #include "merge-recursive.h"
22 #include "dir.h"
23 #include "submodule.h"
24
25 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
26                                       const char *subtree_shift)
27 {
28         unsigned char shifted[20];
29
30         if (!*subtree_shift) {
31                 shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
32         } else {
33                 shift_tree_by(one->object.sha1, two->object.sha1, shifted,
34                               subtree_shift);
35         }
36         if (!hashcmp(two->object.sha1, shifted))
37                 return two;
38         return lookup_tree(shifted);
39 }
40
41 /*
42  * A virtual commit has (const char *)commit->util set to the name.
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         commit->tree = tree;
49         commit->util = (void*)comment;
50         /* avoid warnings */
51         commit->object.parsed = 1;
52         return commit;
53 }
54
55 /*
56  * Since we use get_tree_entry(), which does not put the read object into
57  * the object pool, we cannot rely on a == b.
58  */
59 static int sha_eq(const unsigned char *a, const unsigned char *b)
60 {
61         if (!a && !b)
62                 return 2;
63         return a && b && hashcmp(a, b) == 0;
64 }
65
66 /*
67  * Since we want to write the index eventually, we cannot reuse the index
68  * for these (temporary) data.
69  */
70 struct stage_data
71 {
72         struct
73         {
74                 unsigned mode;
75                 unsigned char sha[20];
76         } stages[4];
77         unsigned processed:1;
78 };
79
80 static int show(struct merge_options *o, int v)
81 {
82         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
83 }
84
85 static void flush_output(struct merge_options *o)
86 {
87         if (o->obuf.len) {
88                 fputs(o->obuf.buf, stdout);
89                 strbuf_reset(&o->obuf);
90         }
91 }
92
93 __attribute__((format (printf, 3, 4)))
94 static void output(struct merge_options *o, int v, const char *fmt, ...)
95 {
96         int len;
97         va_list ap;
98
99         if (!show(o, v))
100                 return;
101
102         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
103         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
104         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
105
106         va_start(ap, fmt);
107         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
108         va_end(ap);
109
110         if (len < 0)
111                 len = 0;
112         if (len >= strbuf_avail(&o->obuf)) {
113                 strbuf_grow(&o->obuf, len + 2);
114                 va_start(ap, fmt);
115                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
116                 va_end(ap);
117                 if (len >= strbuf_avail(&o->obuf)) {
118                         die("this should not happen, your snprintf is broken");
119                 }
120         }
121         strbuf_setlen(&o->obuf, o->obuf.len + len);
122         strbuf_add(&o->obuf, "\n", 1);
123         if (!o->buffer_output)
124                 flush_output(o);
125 }
126
127 static void output_commit_title(struct merge_options *o, struct commit *commit)
128 {
129         int i;
130         flush_output(o);
131         for (i = o->call_depth; i--;)
132                 fputs("  ", stdout);
133         if (commit->util)
134                 printf("virtual %s\n", (char *)commit->util);
135         else {
136                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
137                 if (parse_commit(commit) != 0)
138                         printf("(bad commit)\n");
139                 else {
140                         const char *title;
141                         int len = find_commit_subject(commit->buffer, &title);
142                         if (len)
143                                 printf("%.*s\n", len, title);
144                 }
145         }
146 }
147
148 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
149                 const char *path, int stage, int refresh, int options)
150 {
151         struct cache_entry *ce;
152         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
153         if (!ce)
154                 return error("addinfo_cache failed for path '%s'", path);
155         return add_cache_entry(ce, options);
156 }
157
158 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
159 {
160         parse_tree(tree);
161         init_tree_desc(desc, tree->buffer, tree->size);
162 }
163
164 static int git_merge_trees(int index_only,
165                            struct tree *common,
166                            struct tree *head,
167                            struct tree *merge)
168 {
169         int rc;
170         struct tree_desc t[3];
171         struct unpack_trees_options opts;
172
173         memset(&opts, 0, sizeof(opts));
174         if (index_only)
175                 opts.index_only = 1;
176         else
177                 opts.update = 1;
178         opts.merge = 1;
179         opts.head_idx = 2;
180         opts.fn = threeway_merge;
181         opts.src_index = &the_index;
182         opts.dst_index = &the_index;
183         set_porcelain_error_msgs(opts.msgs, "merge");
184
185         init_tree_desc_from_tree(t+0, common);
186         init_tree_desc_from_tree(t+1, head);
187         init_tree_desc_from_tree(t+2, merge);
188
189         rc = unpack_trees(3, t, &opts);
190         cache_tree_free(&active_cache_tree);
191         return rc;
192 }
193
194 struct tree *write_tree_from_memory(struct merge_options *o)
195 {
196         struct tree *result = NULL;
197
198         if (unmerged_cache()) {
199                 int i;
200                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
201                 for (i = 0; i < active_nr; i++) {
202                         struct cache_entry *ce = active_cache[i];
203                         if (ce_stage(ce))
204                                 fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
205                                         (int)ce_namelen(ce), ce->name);
206                 }
207                 die("Bug in merge-recursive.c");
208         }
209
210         if (!active_cache_tree)
211                 active_cache_tree = cache_tree();
212
213         if (!cache_tree_fully_valid(active_cache_tree) &&
214             cache_tree_update(active_cache_tree,
215                               active_cache, active_nr, 0, 0) < 0)
216                 die("error building trees");
217
218         result = lookup_tree(active_cache_tree->sha1);
219
220         return result;
221 }
222
223 static int save_files_dirs(const unsigned char *sha1,
224                 const char *base, int baselen, const char *path,
225                 unsigned int mode, int stage, void *context)
226 {
227         int len = strlen(path);
228         char *newpath = xmalloc(baselen + len + 1);
229         struct merge_options *o = context;
230
231         memcpy(newpath, base, baselen);
232         memcpy(newpath + baselen, path, len);
233         newpath[baselen + len] = '\0';
234
235         if (S_ISDIR(mode))
236                 string_list_insert(&o->current_directory_set, newpath);
237         else
238                 string_list_insert(&o->current_file_set, newpath);
239         free(newpath);
240
241         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
242 }
243
244 static int get_files_dirs(struct merge_options *o, struct tree *tree)
245 {
246         int n;
247         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
248                 return 0;
249         n = o->current_file_set.nr + o->current_directory_set.nr;
250         return n;
251 }
252
253 /*
254  * Returns an index_entry instance which doesn't have to correspond to
255  * a real cache entry in Git's index.
256  */
257 static struct stage_data *insert_stage_data(const char *path,
258                 struct tree *o, struct tree *a, struct tree *b,
259                 struct string_list *entries)
260 {
261         struct string_list_item *item;
262         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
263         get_tree_entry(o->object.sha1, path,
264                         e->stages[1].sha, &e->stages[1].mode);
265         get_tree_entry(a->object.sha1, path,
266                         e->stages[2].sha, &e->stages[2].mode);
267         get_tree_entry(b->object.sha1, path,
268                         e->stages[3].sha, &e->stages[3].mode);
269         item = string_list_insert(entries, path);
270         item->util = e;
271         return e;
272 }
273
274 /*
275  * Create a dictionary mapping file names to stage_data objects. The
276  * dictionary contains one entry for every path with a non-zero stage entry.
277  */
278 static struct string_list *get_unmerged(void)
279 {
280         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
281         int i;
282
283         unmerged->strdup_strings = 1;
284
285         for (i = 0; i < active_nr; i++) {
286                 struct string_list_item *item;
287                 struct stage_data *e;
288                 struct cache_entry *ce = active_cache[i];
289                 if (!ce_stage(ce))
290                         continue;
291
292                 item = string_list_lookup(unmerged, ce->name);
293                 if (!item) {
294                         item = string_list_insert(unmerged, ce->name);
295                         item->util = xcalloc(1, sizeof(struct stage_data));
296                 }
297                 e = item->util;
298                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
299                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
300         }
301
302         return unmerged;
303 }
304
305 struct rename
306 {
307         struct diff_filepair *pair;
308         struct stage_data *src_entry;
309         struct stage_data *dst_entry;
310         unsigned processed:1;
311 };
312
313 /*
314  * Get information of all renames which occurred between 'o_tree' and
315  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
316  * 'b_tree') to be able to associate the correct cache entries with
317  * the rename information. 'tree' is always equal to either a_tree or b_tree.
318  */
319 static struct string_list *get_renames(struct merge_options *o,
320                                        struct tree *tree,
321                                        struct tree *o_tree,
322                                        struct tree *a_tree,
323                                        struct tree *b_tree,
324                                        struct string_list *entries)
325 {
326         int i;
327         struct string_list *renames;
328         struct diff_options opts;
329
330         renames = xcalloc(1, sizeof(struct string_list));
331         diff_setup(&opts);
332         DIFF_OPT_SET(&opts, RECURSIVE);
333         opts.detect_rename = DIFF_DETECT_RENAME;
334         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
335                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
336                             500;
337         opts.warn_on_too_large_rename = 1;
338         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
339         if (diff_setup_done(&opts) < 0)
340                 die("diff setup failed");
341         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
342         diffcore_std(&opts);
343         for (i = 0; i < diff_queued_diff.nr; ++i) {
344                 struct string_list_item *item;
345                 struct rename *re;
346                 struct diff_filepair *pair = diff_queued_diff.queue[i];
347                 if (pair->status != 'R') {
348                         diff_free_filepair(pair);
349                         continue;
350                 }
351                 re = xmalloc(sizeof(*re));
352                 re->processed = 0;
353                 re->pair = pair;
354                 item = string_list_lookup(entries, re->pair->one->path);
355                 if (!item)
356                         re->src_entry = insert_stage_data(re->pair->one->path,
357                                         o_tree, a_tree, b_tree, entries);
358                 else
359                         re->src_entry = item->util;
360
361                 item = string_list_lookup(entries, re->pair->two->path);
362                 if (!item)
363                         re->dst_entry = insert_stage_data(re->pair->two->path,
364                                         o_tree, a_tree, b_tree, entries);
365                 else
366                         re->dst_entry = item->util;
367                 item = string_list_insert(renames, pair->one->path);
368                 item->util = re;
369         }
370         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
371         diff_queued_diff.nr = 0;
372         diff_flush(&opts);
373         return renames;
374 }
375
376 static int update_stages(const char *path, struct diff_filespec *o,
377                          struct diff_filespec *a, struct diff_filespec *b,
378                          int clear)
379 {
380         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
381         if (clear)
382                 if (remove_file_from_cache(path))
383                         return -1;
384         if (o)
385                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
386                         return -1;
387         if (a)
388                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
389                         return -1;
390         if (b)
391                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
392                         return -1;
393         return 0;
394 }
395
396 static int remove_file(struct merge_options *o, int clean,
397                        const char *path, int no_wd)
398 {
399         int update_cache = o->call_depth || clean;
400         int update_working_directory = !o->call_depth && !no_wd;
401
402         if (update_cache) {
403                 if (remove_file_from_cache(path))
404                         return -1;
405         }
406         if (update_working_directory) {
407                 if (remove_path(path))
408                         return -1;
409         }
410         return 0;
411 }
412
413 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
414 {
415         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
416         int suffix = 0;
417         struct stat st;
418         char *p = newpath + strlen(path);
419         strcpy(newpath, path);
420         *(p++) = '~';
421         strcpy(p, branch);
422         for (; *p; ++p)
423                 if ('/' == *p)
424                         *p = '_';
425         while (string_list_has_string(&o->current_file_set, newpath) ||
426                string_list_has_string(&o->current_directory_set, newpath) ||
427                lstat(newpath, &st) == 0)
428                 sprintf(p, "_%d", suffix++);
429
430         string_list_insert(&o->current_file_set, newpath);
431         return newpath;
432 }
433
434 static void flush_buffer(int fd, const char *buf, unsigned long size)
435 {
436         while (size > 0) {
437                 long ret = write_in_full(fd, buf, size);
438                 if (ret < 0) {
439                         /* Ignore epipe */
440                         if (errno == EPIPE)
441                                 break;
442                         die_errno("merge-recursive");
443                 } else if (!ret) {
444                         die("merge-recursive: disk full?");
445                 }
446                 size -= ret;
447                 buf += ret;
448         }
449 }
450
451 static int would_lose_untracked(const char *path)
452 {
453         int pos = cache_name_pos(path, strlen(path));
454
455         if (pos < 0)
456                 pos = -1 - pos;
457         while (pos < active_nr &&
458                !strcmp(path, active_cache[pos]->name)) {
459                 /*
460                  * If stage #0, it is definitely tracked.
461                  * If it has stage #2 then it was tracked
462                  * before this merge started.  All other
463                  * cases the path was not tracked.
464                  */
465                 switch (ce_stage(active_cache[pos])) {
466                 case 0:
467                 case 2:
468                         return 0;
469                 }
470                 pos++;
471         }
472         return file_exists(path);
473 }
474
475 static int make_room_for_path(const char *path)
476 {
477         int status;
478         const char *msg = "failed to create path '%s'%s";
479
480         status = safe_create_leading_directories_const(path);
481         if (status) {
482                 if (status == -3) {
483                         /* something else exists */
484                         error(msg, path, ": perhaps a D/F conflict?");
485                         return -1;
486                 }
487                 die(msg, path, "");
488         }
489
490         /*
491          * Do not unlink a file in the work tree if we are not
492          * tracking it.
493          */
494         if (would_lose_untracked(path))
495                 return error("refusing to lose untracked file at '%s'",
496                              path);
497
498         /* Successful unlink is good.. */
499         if (!unlink(path))
500                 return 0;
501         /* .. and so is no existing file */
502         if (errno == ENOENT)
503                 return 0;
504         /* .. but not some other error (who really cares what?) */
505         return error(msg, path, ": perhaps a D/F conflict?");
506 }
507
508 static void update_file_flags(struct merge_options *o,
509                               const unsigned char *sha,
510                               unsigned mode,
511                               const char *path,
512                               int update_cache,
513                               int update_wd)
514 {
515         if (o->call_depth)
516                 update_wd = 0;
517
518         if (update_wd) {
519                 enum object_type type;
520                 void *buf;
521                 unsigned long size;
522
523                 if (S_ISGITLINK(mode)) {
524                         /*
525                          * We may later decide to recursively descend into
526                          * the submodule directory and update its index
527                          * and/or work tree, but we do not do that now.
528                          */
529                         update_wd = 0;
530                         goto update_index;
531                 }
532
533                 buf = read_sha1_file(sha, &type, &size);
534                 if (!buf)
535                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
536                 if (type != OBJ_BLOB)
537                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
538                 if (S_ISREG(mode)) {
539                         struct strbuf strbuf = STRBUF_INIT;
540                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
541                                 free(buf);
542                                 size = strbuf.len;
543                                 buf = strbuf_detach(&strbuf, NULL);
544                         }
545                 }
546
547                 if (make_room_for_path(path) < 0) {
548                         update_wd = 0;
549                         free(buf);
550                         goto update_index;
551                 }
552                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
553                         int fd;
554                         if (mode & 0100)
555                                 mode = 0777;
556                         else
557                                 mode = 0666;
558                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
559                         if (fd < 0)
560                                 die_errno("failed to open '%s'", path);
561                         flush_buffer(fd, buf, size);
562                         close(fd);
563                 } else if (S_ISLNK(mode)) {
564                         char *lnk = xmemdupz(buf, size);
565                         safe_create_leading_directories_const(path);
566                         unlink(path);
567                         if (symlink(lnk, path))
568                                 die_errno("failed to symlink '%s'", path);
569                         free(lnk);
570                 } else
571                         die("do not know what to do with %06o %s '%s'",
572                             mode, sha1_to_hex(sha), path);
573                 free(buf);
574         }
575  update_index:
576         if (update_cache)
577                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
578 }
579
580 static void update_file(struct merge_options *o,
581                         int clean,
582                         const unsigned char *sha,
583                         unsigned mode,
584                         const char *path)
585 {
586         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
587 }
588
589 /* Low level file merging, update and removal */
590
591 struct merge_file_info
592 {
593         unsigned char sha[20];
594         unsigned mode;
595         unsigned clean:1,
596                  merge:1;
597 };
598
599 static int merge_3way(struct merge_options *o,
600                       mmbuffer_t *result_buf,
601                       struct diff_filespec *one,
602                       struct diff_filespec *a,
603                       struct diff_filespec *b,
604                       const char *branch1,
605                       const char *branch2)
606 {
607         mmfile_t orig, src1, src2;
608         char *base_name, *name1, *name2;
609         int merge_status;
610         int favor;
611
612         if (o->call_depth)
613                 favor = 0;
614         else {
615                 switch (o->recursive_variant) {
616                 case MERGE_RECURSIVE_OURS:
617                         favor = XDL_MERGE_FAVOR_OURS;
618                         break;
619                 case MERGE_RECURSIVE_THEIRS:
620                         favor = XDL_MERGE_FAVOR_THEIRS;
621                         break;
622                 default:
623                         favor = 0;
624                         break;
625                 }
626         }
627
628         if (strcmp(a->path, b->path) ||
629             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
630                 base_name = o->ancestor == NULL ? NULL :
631                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
632                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
633                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
634         } else {
635                 base_name = o->ancestor == NULL ? NULL :
636                         xstrdup(mkpath("%s", o->ancestor));
637                 name1 = xstrdup(mkpath("%s", branch1));
638                 name2 = xstrdup(mkpath("%s", branch2));
639         }
640
641         read_mmblob(&orig, one->sha1);
642         read_mmblob(&src1, a->sha1);
643         read_mmblob(&src2, b->sha1);
644
645         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
646                                 &src1, name1, &src2, name2,
647                                 (!!o->call_depth) | (favor << 1));
648
649         free(name1);
650         free(name2);
651         free(orig.ptr);
652         free(src1.ptr);
653         free(src2.ptr);
654         return merge_status;
655 }
656
657 static struct merge_file_info merge_file(struct merge_options *o,
658                                          struct diff_filespec *one,
659                                          struct diff_filespec *a,
660                                          struct diff_filespec *b,
661                                          const char *branch1,
662                                          const char *branch2)
663 {
664         struct merge_file_info result;
665         result.merge = 0;
666         result.clean = 1;
667
668         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
669                 result.clean = 0;
670                 if (S_ISREG(a->mode)) {
671                         result.mode = a->mode;
672                         hashcpy(result.sha, a->sha1);
673                 } else {
674                         result.mode = b->mode;
675                         hashcpy(result.sha, b->sha1);
676                 }
677         } else {
678                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
679                         result.merge = 1;
680
681                 /*
682                  * Merge modes
683                  */
684                 if (a->mode == b->mode || a->mode == one->mode)
685                         result.mode = b->mode;
686                 else {
687                         result.mode = a->mode;
688                         if (b->mode != one->mode) {
689                                 result.clean = 0;
690                                 result.merge = 1;
691                         }
692                 }
693
694                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
695                         hashcpy(result.sha, b->sha1);
696                 else if (sha_eq(b->sha1, one->sha1))
697                         hashcpy(result.sha, a->sha1);
698                 else if (S_ISREG(a->mode)) {
699                         mmbuffer_t result_buf;
700                         int merge_status;
701
702                         merge_status = merge_3way(o, &result_buf, one, a, b,
703                                                   branch1, branch2);
704
705                         if ((merge_status < 0) || !result_buf.ptr)
706                                 die("Failed to execute internal merge");
707
708                         if (write_sha1_file(result_buf.ptr, result_buf.size,
709                                             blob_type, result.sha))
710                                 die("Unable to add %s to database",
711                                     a->path);
712
713                         free(result_buf.ptr);
714                         result.clean = (merge_status == 0);
715                 } else if (S_ISGITLINK(a->mode)) {
716                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
717                                                        a->sha1, b->sha1);
718                 } else if (S_ISLNK(a->mode)) {
719                         hashcpy(result.sha, a->sha1);
720
721                         if (!sha_eq(a->sha1, b->sha1))
722                                 result.clean = 0;
723                 } else {
724                         die("unsupported object type in the tree");
725                 }
726         }
727
728         return result;
729 }
730
731 static void conflict_rename_rename(struct merge_options *o,
732                                    struct rename *ren1,
733                                    const char *branch1,
734                                    struct rename *ren2,
735                                    const char *branch2)
736 {
737         char *del[2];
738         int delp = 0;
739         const char *ren1_dst = ren1->pair->two->path;
740         const char *ren2_dst = ren2->pair->two->path;
741         const char *dst_name1 = ren1_dst;
742         const char *dst_name2 = ren2_dst;
743         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
744                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
745                 output(o, 1, "%s is a directory in %s adding as %s instead",
746                        ren1_dst, branch2, dst_name1);
747                 remove_file(o, 0, ren1_dst, 0);
748         }
749         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
750                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
751                 output(o, 1, "%s is a directory in %s adding as %s instead",
752                        ren2_dst, branch1, dst_name2);
753                 remove_file(o, 0, ren2_dst, 0);
754         }
755         if (o->call_depth) {
756                 remove_file_from_cache(dst_name1);
757                 remove_file_from_cache(dst_name2);
758                 /*
759                  * Uncomment to leave the conflicting names in the resulting tree
760                  *
761                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
762                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
763                  */
764         } else {
765                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
766                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
767         }
768         while (delp--)
769                 free(del[delp]);
770 }
771
772 static void conflict_rename_dir(struct merge_options *o,
773                                 struct rename *ren1,
774                                 const char *branch1)
775 {
776         char *new_path = unique_path(o, ren1->pair->two->path, branch1);
777         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
778         remove_file(o, 0, ren1->pair->two->path, 0);
779         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
780         free(new_path);
781 }
782
783 static void conflict_rename_rename_2(struct merge_options *o,
784                                      struct rename *ren1,
785                                      const char *branch1,
786                                      struct rename *ren2,
787                                      const char *branch2)
788 {
789         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
790         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
791         output(o, 1, "Renaming %s to %s and %s to %s instead",
792                ren1->pair->one->path, new_path1,
793                ren2->pair->one->path, new_path2);
794         remove_file(o, 0, ren1->pair->two->path, 0);
795         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
796         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
797         free(new_path2);
798         free(new_path1);
799 }
800
801 static int process_renames(struct merge_options *o,
802                            struct string_list *a_renames,
803                            struct string_list *b_renames)
804 {
805         int clean_merge = 1, i, j;
806         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
807         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
808         const struct rename *sre;
809
810         for (i = 0; i < a_renames->nr; i++) {
811                 sre = a_renames->items[i].util;
812                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
813                         = sre->dst_entry;
814         }
815         for (i = 0; i < b_renames->nr; i++) {
816                 sre = b_renames->items[i].util;
817                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
818                         = sre->dst_entry;
819         }
820
821         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
822                 char *src;
823                 struct string_list *renames1, *renames2Dst;
824                 struct rename *ren1 = NULL, *ren2 = NULL;
825                 const char *branch1, *branch2;
826                 const char *ren1_src, *ren1_dst;
827
828                 if (i >= a_renames->nr) {
829                         ren2 = b_renames->items[j++].util;
830                 } else if (j >= b_renames->nr) {
831                         ren1 = a_renames->items[i++].util;
832                 } else {
833                         int compare = strcmp(a_renames->items[i].string,
834                                              b_renames->items[j].string);
835                         if (compare <= 0)
836                                 ren1 = a_renames->items[i++].util;
837                         if (compare >= 0)
838                                 ren2 = b_renames->items[j++].util;
839                 }
840
841                 /* TODO: refactor, so that 1/2 are not needed */
842                 if (ren1) {
843                         renames1 = a_renames;
844                         renames2Dst = &b_by_dst;
845                         branch1 = o->branch1;
846                         branch2 = o->branch2;
847                 } else {
848                         struct rename *tmp;
849                         renames1 = b_renames;
850                         renames2Dst = &a_by_dst;
851                         branch1 = o->branch2;
852                         branch2 = o->branch1;
853                         tmp = ren2;
854                         ren2 = ren1;
855                         ren1 = tmp;
856                 }
857                 src = ren1->pair->one->path;
858
859                 ren1->dst_entry->processed = 1;
860                 ren1->src_entry->processed = 1;
861
862                 if (ren1->processed)
863                         continue;
864                 ren1->processed = 1;
865
866                 ren1_src = ren1->pair->one->path;
867                 ren1_dst = ren1->pair->two->path;
868
869                 if (ren2) {
870                         const char *ren2_src = ren2->pair->one->path;
871                         const char *ren2_dst = ren2->pair->two->path;
872                         /* Renamed in 1 and renamed in 2 */
873                         if (strcmp(ren1_src, ren2_src) != 0)
874                                 die("ren1.src != ren2.src");
875                         ren2->dst_entry->processed = 1;
876                         ren2->processed = 1;
877                         if (strcmp(ren1_dst, ren2_dst) != 0) {
878                                 clean_merge = 0;
879                                 output(o, 1, "CONFLICT (rename/rename): "
880                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
881                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
882                                        src, ren1_dst, branch1,
883                                        src, ren2_dst, branch2,
884                                        o->call_depth ? " (left unresolved)": "");
885                                 if (o->call_depth) {
886                                         remove_file_from_cache(src);
887                                         update_file(o, 0, ren1->pair->one->sha1,
888                                                     ren1->pair->one->mode, src);
889                                 }
890                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
891                         } else {
892                                 struct merge_file_info mfi;
893                                 remove_file(o, 1, ren1_src, 1);
894                                 mfi = merge_file(o,
895                                                  ren1->pair->one,
896                                                  ren1->pair->two,
897                                                  ren2->pair->two,
898                                                  branch1,
899                                                  branch2);
900                                 if (mfi.merge || !mfi.clean)
901                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
902
903                                 if (mfi.merge)
904                                         output(o, 2, "Auto-merging %s", ren1_dst);
905
906                                 if (!mfi.clean) {
907                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
908                                                ren1_dst);
909                                         clean_merge = 0;
910
911                                         if (!o->call_depth)
912                                                 update_stages(ren1_dst,
913                                                               ren1->pair->one,
914                                                               ren1->pair->two,
915                                                               ren2->pair->two,
916                                                               1 /* clear */);
917                                 }
918                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
919                         }
920                 } else {
921                         /* Renamed in 1, maybe changed in 2 */
922                         struct string_list_item *item;
923                         /* we only use sha1 and mode of these */
924                         struct diff_filespec src_other, dst_other;
925                         int try_merge, stage = a_renames == renames1 ? 3: 2;
926
927                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
928
929                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
930                         src_other.mode = ren1->src_entry->stages[stage].mode;
931                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
932                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
933
934                         try_merge = 0;
935
936                         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
937                                 clean_merge = 0;
938                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
939                                        " directory %s added in %s",
940                                        ren1_src, ren1_dst, branch1,
941                                        ren1_dst, branch2);
942                                 conflict_rename_dir(o, ren1, branch1);
943                         } else if (sha_eq(src_other.sha1, null_sha1)) {
944                                 clean_merge = 0;
945                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
946                                        "and deleted in %s",
947                                        ren1_src, ren1_dst, branch1,
948                                        branch2);
949                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
950                                 if (!o->call_depth)
951                                         update_stages(ren1_dst, NULL,
952                                                         branch1 == o->branch1 ?
953                                                         ren1->pair->two : NULL,
954                                                         branch1 == o->branch1 ?
955                                                         NULL : ren1->pair->two, 1);
956                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
957                                 const char *new_path;
958                                 clean_merge = 0;
959                                 try_merge = 1;
960                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
961                                        "%s added in %s",
962                                        ren1_src, ren1_dst, branch1,
963                                        ren1_dst, branch2);
964                                 if (o->call_depth) {
965                                         struct merge_file_info mfi;
966                                         struct diff_filespec one, a, b;
967
968                                         one.path = a.path = b.path =
969                                                 (char *)ren1_dst;
970                                         hashcpy(one.sha1, null_sha1);
971                                         one.mode = 0;
972                                         hashcpy(a.sha1, ren1->pair->two->sha1);
973                                         a.mode = ren1->pair->two->mode;
974                                         hashcpy(b.sha1, dst_other.sha1);
975                                         b.mode = dst_other.mode;
976                                         mfi = merge_file(o, &one, &a, &b,
977                                                          branch1,
978                                                          branch2);
979                                         output(o, 1, "Adding merged %s", ren1_dst);
980                                         update_file(o, 0,
981                                                     mfi.sha,
982                                                     mfi.mode,
983                                                     ren1_dst);
984                                 } else {
985                                         new_path = unique_path(o, ren1_dst, branch2);
986                                         output(o, 1, "Adding as %s instead", new_path);
987                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
988                                 }
989                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
990                                 ren2 = item->util;
991                                 clean_merge = 0;
992                                 ren2->processed = 1;
993                                 output(o, 1, "CONFLICT (rename/rename): "
994                                        "Rename %s->%s in %s. "
995                                        "Rename %s->%s in %s",
996                                        ren1_src, ren1_dst, branch1,
997                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
998                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
999                         } else
1000                                 try_merge = 1;
1001
1002                         if (try_merge) {
1003                                 struct diff_filespec *one, *a, *b;
1004                                 struct merge_file_info mfi;
1005                                 src_other.path = (char *)ren1_src;
1006
1007                                 one = ren1->pair->one;
1008                                 if (a_renames == renames1) {
1009                                         a = ren1->pair->two;
1010                                         b = &src_other;
1011                                 } else {
1012                                         b = ren1->pair->two;
1013                                         a = &src_other;
1014                                 }
1015                                 mfi = merge_file(o, one, a, b,
1016                                                 o->branch1, o->branch2);
1017
1018                                 if (mfi.clean &&
1019                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1020                                     mfi.mode == ren1->pair->two->mode) {
1021                                         /*
1022                                          * This message is part of
1023                                          * t6022 test. If you change
1024                                          * it update the test too.
1025                                          */
1026                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1027
1028                                         /* There may be higher stage entries left
1029                                          * in the index (e.g. due to a D/F
1030                                          * conflict) that need to be resolved.
1031                                          */
1032                                         if (!ren1->dst_entry->stages[2].mode !=
1033                                             !ren1->dst_entry->stages[3].mode)
1034                                                 ren1->dst_entry->processed = 0;
1035                                 } else {
1036                                         if (mfi.merge || !mfi.clean)
1037                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1038                                         if (mfi.merge)
1039                                                 output(o, 2, "Auto-merging %s", ren1_dst);
1040                                         if (!mfi.clean) {
1041                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1042                                                        ren1_dst);
1043                                                 clean_merge = 0;
1044
1045                                                 if (!o->call_depth)
1046                                                         update_stages(ren1_dst,
1047                                                                       one, a, b, 1);
1048                                         }
1049                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1050                                 }
1051                         }
1052                 }
1053         }
1054         string_list_clear(&a_by_dst, 0);
1055         string_list_clear(&b_by_dst, 0);
1056
1057         return clean_merge;
1058 }
1059
1060 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1061 {
1062         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1063 }
1064
1065 /* Per entry merge function */
1066 static int process_entry(struct merge_options *o,
1067                          const char *path, struct stage_data *entry)
1068 {
1069         /*
1070         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1071         print_index_entry("\tpath: ", entry);
1072         */
1073         int clean_merge = 1;
1074         unsigned o_mode = entry->stages[1].mode;
1075         unsigned a_mode = entry->stages[2].mode;
1076         unsigned b_mode = entry->stages[3].mode;
1077         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1078         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1079         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1080
1081         entry->processed = 1;
1082         if (o_sha && (!a_sha || !b_sha)) {
1083                 /* Case A: Deleted in one */
1084                 if ((!a_sha && !b_sha) ||
1085                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1086                     (!a_sha && sha_eq(b_sha, o_sha))) {
1087                         /* Deleted in both or deleted in one and
1088                          * unchanged in the other */
1089                         if (a_sha)
1090                                 output(o, 2, "Removing %s", path);
1091                         /* do not touch working file if it did not exist */
1092                         remove_file(o, 1, path, !a_sha);
1093                 } else {
1094                         /* Deleted in one and changed in the other */
1095                         clean_merge = 0;
1096                         if (!a_sha) {
1097                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1098                                        "and modified in %s. Version %s of %s left in tree.",
1099                                        path, o->branch1,
1100                                        o->branch2, o->branch2, path);
1101                                 update_file(o, 0, b_sha, b_mode, path);
1102                         } else {
1103                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1104                                        "and modified in %s. Version %s of %s left in tree.",
1105                                        path, o->branch2,
1106                                        o->branch1, o->branch1, path);
1107                                 update_file(o, 0, a_sha, a_mode, path);
1108                         }
1109                 }
1110
1111         } else if ((!o_sha && a_sha && !b_sha) ||
1112                    (!o_sha && !a_sha && b_sha)) {
1113                 /* Case B: Added in one. */
1114                 unsigned mode;
1115                 const unsigned char *sha;
1116
1117                 if (a_sha) {
1118                         mode = a_mode;
1119                         sha = a_sha;
1120                 } else {
1121                         mode = b_mode;
1122                         sha = b_sha;
1123                 }
1124                 if (string_list_has_string(&o->current_directory_set, path)) {
1125                         /* Handle D->F conflicts after all subfiles */
1126                         entry->processed = 0;
1127                         /* But get any file out of the way now, so conflicted
1128                          * entries below the directory of the same name can
1129                          * be put in the working directory.
1130                          */
1131                         if (a_sha)
1132                                 output(o, 2, "Removing %s", path);
1133                         /* do not touch working file if it did not exist */
1134                         remove_file(o, 0, path, !a_sha);
1135                         return 1; /* Assume clean till processed */
1136                 } else {
1137                         output(o, 2, "Adding %s", path);
1138                         update_file(o, 1, sha, mode, path);
1139                 }
1140         } else if (a_sha && b_sha) {
1141                 /* Case C: Added in both (check for same permissions) and */
1142                 /* case D: Modified in both, but differently. */
1143                 const char *reason = "content";
1144                 struct merge_file_info mfi;
1145                 struct diff_filespec one, a, b;
1146
1147                 if (!o_sha) {
1148                         reason = "add/add";
1149                         o_sha = (unsigned char *)null_sha1;
1150                 }
1151                 output(o, 2, "Auto-merging %s", path);
1152                 one.path = a.path = b.path = (char *)path;
1153                 hashcpy(one.sha1, o_sha);
1154                 one.mode = o_mode;
1155                 hashcpy(a.sha1, a_sha);
1156                 a.mode = a_mode;
1157                 hashcpy(b.sha1, b_sha);
1158                 b.mode = b_mode;
1159
1160                 mfi = merge_file(o, &one, &a, &b,
1161                                  o->branch1, o->branch2);
1162
1163                 clean_merge = mfi.clean;
1164                 if (!mfi.clean) {
1165                         if (S_ISGITLINK(mfi.mode))
1166                                 reason = "submodule";
1167                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1168                                         reason, path);
1169                 }
1170                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1171         } else if (!o_sha && !a_sha && !b_sha) {
1172                 /*
1173                  * this entry was deleted altogether. a_mode == 0 means
1174                  * we had that path and want to actively remove it.
1175                  */
1176                 remove_file(o, 1, path, !a_mode);
1177         } else
1178                 die("Fatal merge failure, shouldn't happen.");
1179
1180         return clean_merge;
1181 }
1182
1183 /*
1184  * Per entry merge function for D/F conflicts, to be called only after
1185  * all files below dir have been processed.  We do this because in the
1186  * cases we can cleanly resolve D/F conflicts, process_entry() can clean
1187  * out all the files below the directory for us.
1188  */
1189 static int process_df_entry(struct merge_options *o,
1190                          const char *path, struct stage_data *entry)
1191 {
1192         int clean_merge = 1;
1193         unsigned o_mode = entry->stages[1].mode;
1194         unsigned a_mode = entry->stages[2].mode;
1195         unsigned b_mode = entry->stages[3].mode;
1196         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1197         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1198         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1199         const char *add_branch;
1200         const char *other_branch;
1201         unsigned mode;
1202         const unsigned char *sha;
1203         const char *conf;
1204         struct stat st;
1205
1206         /* We currently only handle D->F cases */
1207         assert((!o_sha && a_sha && !b_sha) ||
1208                (!o_sha && !a_sha && b_sha));
1209
1210         entry->processed = 1;
1211
1212         if (a_sha) {
1213                 add_branch = o->branch1;
1214                 other_branch = o->branch2;
1215                 mode = a_mode;
1216                 sha = a_sha;
1217                 conf = "file/directory";
1218         } else {
1219                 add_branch = o->branch2;
1220                 other_branch = o->branch1;
1221                 mode = b_mode;
1222                 sha = b_sha;
1223                 conf = "directory/file";
1224         }
1225         if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1226                 const char *new_path = unique_path(o, path, add_branch);
1227                 clean_merge = 0;
1228                 output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1229                        "Adding %s as %s",
1230                        conf, path, other_branch, path, new_path);
1231                 remove_file(o, 0, path, 0);
1232                 update_file(o, 0, sha, mode, new_path);
1233         } else {
1234                 output(o, 2, "Adding %s", path);
1235                 update_file(o, 1, sha, mode, path);
1236         }
1237
1238         return clean_merge;
1239 }
1240
1241 void set_porcelain_error_msgs(const char **msgs, const char *cmd)
1242 {
1243         const char *msg;
1244         char *tmp;
1245         const char *cmd2 = strcmp(cmd, "checkout") ? cmd : "switch branches";
1246         if (advice_commit_before_merge)
1247                 msg = "Your local changes to the following files would be overwritten by %s:\n%%s"
1248                         "Please, commit your changes or stash them before you can %s.";
1249         else
1250                 msg = "Your local changes to the following files would be overwritten by %s:\n%%s";
1251         tmp = xmalloc(strlen(msg) + strlen(cmd) + strlen(cmd2) - 2);
1252         sprintf(tmp, msg, cmd, cmd2);
1253         msgs[ERROR_WOULD_OVERWRITE] = tmp;
1254         msgs[ERROR_NOT_UPTODATE_FILE] = tmp;
1255
1256         msgs[ERROR_NOT_UPTODATE_DIR] =
1257                 "Updating the following directories would lose untracked files in it:\n%s";
1258
1259         if (advice_commit_before_merge)
1260                 msg = "The following untracked working tree files would be %s by %s:\n%%s"
1261                         "Please move or remove them before you can %s.";
1262         else
1263                 msg = "The following untracked working tree files would be %s by %s:\n%%s";
1264         tmp = xmalloc(strlen(msg) + strlen(cmd) + strlen("removed") + strlen(cmd2) - 4);
1265         sprintf(tmp, msg, "removed", cmd, cmd2);
1266         msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = tmp;
1267         tmp = xmalloc(strlen(msg) + strlen(cmd) + strlen("overwritten") + strlen(cmd2) - 4);
1268         sprintf(tmp, msg, "overwritten", cmd, cmd2);
1269         msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = tmp;
1270
1271         /*
1272          * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
1273          * cannot easily display it as a list.
1274          */
1275         msgs[ERROR_BIND_OVERLAP] = "Entry '%s' overlaps with '%s'.  Cannot bind.";
1276
1277         msgs[ERROR_SPARSE_NOT_UPTODATE_FILE] =
1278                 "Cannot update sparse checkout: the following entries are not up-to-date:\n%s";
1279         msgs[ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN] =
1280                 "The following Working tree files would be overwritten by sparse checkout update:\n%s";
1281         msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
1282                 "The following Working tree files would be removed by sparse checkout update:\n%s";
1283 }
1284
1285 int merge_trees(struct merge_options *o,
1286                 struct tree *head,
1287                 struct tree *merge,
1288                 struct tree *common,
1289                 struct tree **result)
1290 {
1291         int code, clean;
1292
1293         if (o->subtree_shift) {
1294                 merge = shift_tree_object(head, merge, o->subtree_shift);
1295                 common = shift_tree_object(head, common, o->subtree_shift);
1296         }
1297
1298         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1299                 output(o, 0, "Already up-to-date!");
1300                 *result = head;
1301                 return 1;
1302         }
1303
1304         code = git_merge_trees(o->call_depth, common, head, merge);
1305
1306         if (code != 0) {
1307                 if (show(o, 4) || o->call_depth)
1308                         die("merging of trees %s and %s failed",
1309                             sha1_to_hex(head->object.sha1),
1310                             sha1_to_hex(merge->object.sha1));
1311                 else
1312                         exit(128);
1313         }
1314
1315         if (unmerged_cache()) {
1316                 struct string_list *entries, *re_head, *re_merge;
1317                 int i;
1318                 string_list_clear(&o->current_file_set, 1);
1319                 string_list_clear(&o->current_directory_set, 1);
1320                 get_files_dirs(o, head);
1321                 get_files_dirs(o, merge);
1322
1323                 entries = get_unmerged();
1324                 re_head  = get_renames(o, head, common, head, merge, entries);
1325                 re_merge = get_renames(o, merge, common, head, merge, entries);
1326                 clean = process_renames(o, re_head, re_merge);
1327                 for (i = 0; i < entries->nr; i++) {
1328                         const char *path = entries->items[i].string;
1329                         struct stage_data *e = entries->items[i].util;
1330                         if (!e->processed
1331                                 && !process_entry(o, path, e))
1332                                 clean = 0;
1333                 }
1334                 for (i = 0; i < entries->nr; i++) {
1335                         const char *path = entries->items[i].string;
1336                         struct stage_data *e = entries->items[i].util;
1337                         if (!e->processed
1338                                 && !process_df_entry(o, path, e))
1339                                 clean = 0;
1340                 }
1341
1342                 string_list_clear(re_merge, 0);
1343                 string_list_clear(re_head, 0);
1344                 string_list_clear(entries, 1);
1345
1346         }
1347         else
1348                 clean = 1;
1349
1350         if (o->call_depth)
1351                 *result = write_tree_from_memory(o);
1352
1353         return clean;
1354 }
1355
1356 static struct commit_list *reverse_commit_list(struct commit_list *list)
1357 {
1358         struct commit_list *next = NULL, *current, *backup;
1359         for (current = list; current; current = backup) {
1360                 backup = current->next;
1361                 current->next = next;
1362                 next = current;
1363         }
1364         return next;
1365 }
1366
1367 /*
1368  * Merge the commits h1 and h2, return the resulting virtual
1369  * commit object and a flag indicating the cleanness of the merge.
1370  */
1371 int merge_recursive(struct merge_options *o,
1372                     struct commit *h1,
1373                     struct commit *h2,
1374                     struct commit_list *ca,
1375                     struct commit **result)
1376 {
1377         struct commit_list *iter;
1378         struct commit *merged_common_ancestors;
1379         struct tree *mrtree = mrtree;
1380         int clean;
1381
1382         if (show(o, 4)) {
1383                 output(o, 4, "Merging:");
1384                 output_commit_title(o, h1);
1385                 output_commit_title(o, h2);
1386         }
1387
1388         if (!ca) {
1389                 ca = get_merge_bases(h1, h2, 1);
1390                 ca = reverse_commit_list(ca);
1391         }
1392
1393         if (show(o, 5)) {
1394                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1395                 for (iter = ca; iter; iter = iter->next)
1396                         output_commit_title(o, iter->item);
1397         }
1398
1399         merged_common_ancestors = pop_commit(&ca);
1400         if (merged_common_ancestors == NULL) {
1401                 /* if there is no common ancestor, make an empty tree */
1402                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1403
1404                 tree->object.parsed = 1;
1405                 tree->object.type = OBJ_TREE;
1406                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1407                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1408         }
1409
1410         for (iter = ca; iter; iter = iter->next) {
1411                 const char *saved_b1, *saved_b2;
1412                 o->call_depth++;
1413                 /*
1414                  * When the merge fails, the result contains files
1415                  * with conflict markers. The cleanness flag is
1416                  * ignored, it was never actually used, as result of
1417                  * merge_trees has always overwritten it: the committed
1418                  * "conflicts" were already resolved.
1419                  */
1420                 discard_cache();
1421                 saved_b1 = o->branch1;
1422                 saved_b2 = o->branch2;
1423                 o->branch1 = "Temporary merge branch 1";
1424                 o->branch2 = "Temporary merge branch 2";
1425                 merge_recursive(o, merged_common_ancestors, iter->item,
1426                                 NULL, &merged_common_ancestors);
1427                 o->branch1 = saved_b1;
1428                 o->branch2 = saved_b2;
1429                 o->call_depth--;
1430
1431                 if (!merged_common_ancestors)
1432                         die("merge returned no commit");
1433         }
1434
1435         discard_cache();
1436         if (!o->call_depth)
1437                 read_cache();
1438
1439         o->ancestor = "merged common ancestors";
1440         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1441                             &mrtree);
1442
1443         if (o->call_depth) {
1444                 *result = make_virtual_commit(mrtree, "merged tree");
1445                 commit_list_insert(h1, &(*result)->parents);
1446                 commit_list_insert(h2, &(*result)->parents->next);
1447         }
1448         flush_output(o);
1449         return clean;
1450 }
1451
1452 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1453 {
1454         struct object *object;
1455
1456         object = deref_tag(parse_object(sha1), name, strlen(name));
1457         if (!object)
1458                 return NULL;
1459         if (object->type == OBJ_TREE)
1460                 return make_virtual_commit((struct tree*)object, name);
1461         if (object->type != OBJ_COMMIT)
1462                 return NULL;
1463         if (parse_commit((struct commit *)object))
1464                 return NULL;
1465         return (struct commit *)object;
1466 }
1467
1468 int merge_recursive_generic(struct merge_options *o,
1469                             const unsigned char *head,
1470                             const unsigned char *merge,
1471                             int num_base_list,
1472                             const unsigned char **base_list,
1473                             struct commit **result)
1474 {
1475         int clean, index_fd;
1476         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1477         struct commit *head_commit = get_ref(head, o->branch1);
1478         struct commit *next_commit = get_ref(merge, o->branch2);
1479         struct commit_list *ca = NULL;
1480
1481         if (base_list) {
1482                 int i;
1483                 for (i = 0; i < num_base_list; ++i) {
1484                         struct commit *base;
1485                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1486                                 return error("Could not parse object '%s'",
1487                                         sha1_to_hex(base_list[i]));
1488                         commit_list_insert(base, &ca);
1489                 }
1490         }
1491
1492         index_fd = hold_locked_index(lock, 1);
1493         clean = merge_recursive(o, head_commit, next_commit, ca,
1494                         result);
1495         if (active_cache_changed &&
1496                         (write_cache(index_fd, active_cache, active_nr) ||
1497                          commit_locked_index(lock)))
1498                 return error("Unable to write index.");
1499
1500         return clean ? 0 : 1;
1501 }
1502
1503 static int merge_recursive_config(const char *var, const char *value, void *cb)
1504 {
1505         struct merge_options *o = cb;
1506         if (!strcasecmp(var, "merge.verbosity")) {
1507                 o->verbosity = git_config_int(var, value);
1508                 return 0;
1509         }
1510         if (!strcasecmp(var, "diff.renamelimit")) {
1511                 o->diff_rename_limit = git_config_int(var, value);
1512                 return 0;
1513         }
1514         if (!strcasecmp(var, "merge.renamelimit")) {
1515                 o->merge_rename_limit = git_config_int(var, value);
1516                 return 0;
1517         }
1518         return git_xmerge_config(var, value, cb);
1519 }
1520
1521 void init_merge_options(struct merge_options *o)
1522 {
1523         memset(o, 0, sizeof(struct merge_options));
1524         o->verbosity = 2;
1525         o->buffer_output = 1;
1526         o->diff_rename_limit = -1;
1527         o->merge_rename_limit = -1;
1528         git_config(merge_recursive_config, o);
1529         if (getenv("GIT_MERGE_VERBOSITY"))
1530                 o->verbosity =
1531                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1532         if (o->verbosity >= 5)
1533                 o->buffer_output = 0;
1534         strbuf_init(&o->obuf, 0);
1535         memset(&o->current_file_set, 0, sizeof(struct string_list));
1536         o->current_file_set.strdup_strings = 1;
1537         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1538         o->current_directory_set.strdup_strings = 1;
1539 }