Documentation: pack.compression: explain how to recompress
[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         setup_unpack_trees_porcelain(&opts, "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 ? LL_OPT_VIRTUAL_ANCESTOR : 0) |
648                                  (o->renormalize ? LL_OPT_RENORMALIZE : 0) |
649                                  create_ll_flag(favor)));
650
651         free(name1);
652         free(name2);
653         free(orig.ptr);
654         free(src1.ptr);
655         free(src2.ptr);
656         return merge_status;
657 }
658
659 static struct merge_file_info merge_file(struct merge_options *o,
660                                          struct diff_filespec *one,
661                                          struct diff_filespec *a,
662                                          struct diff_filespec *b,
663                                          const char *branch1,
664                                          const char *branch2)
665 {
666         struct merge_file_info result;
667         result.merge = 0;
668         result.clean = 1;
669
670         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
671                 result.clean = 0;
672                 if (S_ISREG(a->mode)) {
673                         result.mode = a->mode;
674                         hashcpy(result.sha, a->sha1);
675                 } else {
676                         result.mode = b->mode;
677                         hashcpy(result.sha, b->sha1);
678                 }
679         } else {
680                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
681                         result.merge = 1;
682
683                 /*
684                  * Merge modes
685                  */
686                 if (a->mode == b->mode || a->mode == one->mode)
687                         result.mode = b->mode;
688                 else {
689                         result.mode = a->mode;
690                         if (b->mode != one->mode) {
691                                 result.clean = 0;
692                                 result.merge = 1;
693                         }
694                 }
695
696                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
697                         hashcpy(result.sha, b->sha1);
698                 else if (sha_eq(b->sha1, one->sha1))
699                         hashcpy(result.sha, a->sha1);
700                 else if (S_ISREG(a->mode)) {
701                         mmbuffer_t result_buf;
702                         int merge_status;
703
704                         merge_status = merge_3way(o, &result_buf, one, a, b,
705                                                   branch1, branch2);
706
707                         if ((merge_status < 0) || !result_buf.ptr)
708                                 die("Failed to execute internal merge");
709
710                         if (write_sha1_file(result_buf.ptr, result_buf.size,
711                                             blob_type, result.sha))
712                                 die("Unable to add %s to database",
713                                     a->path);
714
715                         free(result_buf.ptr);
716                         result.clean = (merge_status == 0);
717                 } else if (S_ISGITLINK(a->mode)) {
718                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
719                                                        a->sha1, b->sha1);
720                 } else if (S_ISLNK(a->mode)) {
721                         hashcpy(result.sha, a->sha1);
722
723                         if (!sha_eq(a->sha1, b->sha1))
724                                 result.clean = 0;
725                 } else {
726                         die("unsupported object type in the tree");
727                 }
728         }
729
730         return result;
731 }
732
733 static void conflict_rename_rename(struct merge_options *o,
734                                    struct rename *ren1,
735                                    const char *branch1,
736                                    struct rename *ren2,
737                                    const char *branch2)
738 {
739         char *del[2];
740         int delp = 0;
741         const char *ren1_dst = ren1->pair->two->path;
742         const char *ren2_dst = ren2->pair->two->path;
743         const char *dst_name1 = ren1_dst;
744         const char *dst_name2 = ren2_dst;
745         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
746                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
747                 output(o, 1, "%s is a directory in %s adding as %s instead",
748                        ren1_dst, branch2, dst_name1);
749                 remove_file(o, 0, ren1_dst, 0);
750         }
751         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
752                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
753                 output(o, 1, "%s is a directory in %s adding as %s instead",
754                        ren2_dst, branch1, dst_name2);
755                 remove_file(o, 0, ren2_dst, 0);
756         }
757         if (o->call_depth) {
758                 remove_file_from_cache(dst_name1);
759                 remove_file_from_cache(dst_name2);
760                 /*
761                  * Uncomment to leave the conflicting names in the resulting tree
762                  *
763                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
764                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
765                  */
766         } else {
767                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
768                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
769         }
770         while (delp--)
771                 free(del[delp]);
772 }
773
774 static void conflict_rename_dir(struct merge_options *o,
775                                 struct rename *ren1,
776                                 const char *branch1)
777 {
778         char *new_path = unique_path(o, ren1->pair->two->path, branch1);
779         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
780         remove_file(o, 0, ren1->pair->two->path, 0);
781         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
782         free(new_path);
783 }
784
785 static void conflict_rename_rename_2(struct merge_options *o,
786                                      struct rename *ren1,
787                                      const char *branch1,
788                                      struct rename *ren2,
789                                      const char *branch2)
790 {
791         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
792         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
793         output(o, 1, "Renaming %s to %s and %s to %s instead",
794                ren1->pair->one->path, new_path1,
795                ren2->pair->one->path, new_path2);
796         remove_file(o, 0, ren1->pair->two->path, 0);
797         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
798         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
799         free(new_path2);
800         free(new_path1);
801 }
802
803 static int process_renames(struct merge_options *o,
804                            struct string_list *a_renames,
805                            struct string_list *b_renames)
806 {
807         int clean_merge = 1, i, j;
808         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
809         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
810         const struct rename *sre;
811
812         for (i = 0; i < a_renames->nr; i++) {
813                 sre = a_renames->items[i].util;
814                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
815                         = sre->dst_entry;
816         }
817         for (i = 0; i < b_renames->nr; i++) {
818                 sre = b_renames->items[i].util;
819                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
820                         = sre->dst_entry;
821         }
822
823         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
824                 char *src;
825                 struct string_list *renames1, *renames2Dst;
826                 struct rename *ren1 = NULL, *ren2 = NULL;
827                 const char *branch1, *branch2;
828                 const char *ren1_src, *ren1_dst;
829
830                 if (i >= a_renames->nr) {
831                         ren2 = b_renames->items[j++].util;
832                 } else if (j >= b_renames->nr) {
833                         ren1 = a_renames->items[i++].util;
834                 } else {
835                         int compare = strcmp(a_renames->items[i].string,
836                                              b_renames->items[j].string);
837                         if (compare <= 0)
838                                 ren1 = a_renames->items[i++].util;
839                         if (compare >= 0)
840                                 ren2 = b_renames->items[j++].util;
841                 }
842
843                 /* TODO: refactor, so that 1/2 are not needed */
844                 if (ren1) {
845                         renames1 = a_renames;
846                         renames2Dst = &b_by_dst;
847                         branch1 = o->branch1;
848                         branch2 = o->branch2;
849                 } else {
850                         struct rename *tmp;
851                         renames1 = b_renames;
852                         renames2Dst = &a_by_dst;
853                         branch1 = o->branch2;
854                         branch2 = o->branch1;
855                         tmp = ren2;
856                         ren2 = ren1;
857                         ren1 = tmp;
858                 }
859                 src = ren1->pair->one->path;
860
861                 ren1->dst_entry->processed = 1;
862                 ren1->src_entry->processed = 1;
863
864                 if (ren1->processed)
865                         continue;
866                 ren1->processed = 1;
867
868                 ren1_src = ren1->pair->one->path;
869                 ren1_dst = ren1->pair->two->path;
870
871                 if (ren2) {
872                         const char *ren2_src = ren2->pair->one->path;
873                         const char *ren2_dst = ren2->pair->two->path;
874                         /* Renamed in 1 and renamed in 2 */
875                         if (strcmp(ren1_src, ren2_src) != 0)
876                                 die("ren1.src != ren2.src");
877                         ren2->dst_entry->processed = 1;
878                         ren2->processed = 1;
879                         if (strcmp(ren1_dst, ren2_dst) != 0) {
880                                 clean_merge = 0;
881                                 output(o, 1, "CONFLICT (rename/rename): "
882                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
883                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
884                                        src, ren1_dst, branch1,
885                                        src, ren2_dst, branch2,
886                                        o->call_depth ? " (left unresolved)": "");
887                                 if (o->call_depth) {
888                                         remove_file_from_cache(src);
889                                         update_file(o, 0, ren1->pair->one->sha1,
890                                                     ren1->pair->one->mode, src);
891                                 }
892                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
893                         } else {
894                                 struct merge_file_info mfi;
895                                 remove_file(o, 1, ren1_src, 1);
896                                 mfi = merge_file(o,
897                                                  ren1->pair->one,
898                                                  ren1->pair->two,
899                                                  ren2->pair->two,
900                                                  branch1,
901                                                  branch2);
902                                 if (mfi.merge || !mfi.clean)
903                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
904
905                                 if (mfi.merge)
906                                         output(o, 2, "Auto-merging %s", ren1_dst);
907
908                                 if (!mfi.clean) {
909                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
910                                                ren1_dst);
911                                         clean_merge = 0;
912
913                                         if (!o->call_depth)
914                                                 update_stages(ren1_dst,
915                                                               ren1->pair->one,
916                                                               ren1->pair->two,
917                                                               ren2->pair->two,
918                                                               1 /* clear */);
919                                 }
920                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
921                         }
922                 } else {
923                         /* Renamed in 1, maybe changed in 2 */
924                         struct string_list_item *item;
925                         /* we only use sha1 and mode of these */
926                         struct diff_filespec src_other, dst_other;
927                         int try_merge, stage = a_renames == renames1 ? 3: 2;
928
929                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
930
931                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
932                         src_other.mode = ren1->src_entry->stages[stage].mode;
933                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
934                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
935
936                         try_merge = 0;
937
938                         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
939                                 clean_merge = 0;
940                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
941                                        " directory %s added in %s",
942                                        ren1_src, ren1_dst, branch1,
943                                        ren1_dst, branch2);
944                                 conflict_rename_dir(o, ren1, branch1);
945                         } else if (sha_eq(src_other.sha1, null_sha1)) {
946                                 clean_merge = 0;
947                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
948                                        "and deleted in %s",
949                                        ren1_src, ren1_dst, branch1,
950                                        branch2);
951                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
952                                 if (!o->call_depth)
953                                         update_stages(ren1_dst, NULL,
954                                                         branch1 == o->branch1 ?
955                                                         ren1->pair->two : NULL,
956                                                         branch1 == o->branch1 ?
957                                                         NULL : ren1->pair->two, 1);
958                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
959                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
960                                 /* Added file on the other side
961                                    identical to the file being
962                                    renamed: clean merge */
963                                 update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
964                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
965                                 const char *new_path;
966                                 clean_merge = 0;
967                                 try_merge = 1;
968                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
969                                        "%s added in %s",
970                                        ren1_src, ren1_dst, branch1,
971                                        ren1_dst, branch2);
972                                 if (o->call_depth) {
973                                         struct merge_file_info mfi;
974                                         struct diff_filespec one, a, b;
975
976                                         one.path = a.path = b.path =
977                                                 (char *)ren1_dst;
978                                         hashcpy(one.sha1, null_sha1);
979                                         one.mode = 0;
980                                         hashcpy(a.sha1, ren1->pair->two->sha1);
981                                         a.mode = ren1->pair->two->mode;
982                                         hashcpy(b.sha1, dst_other.sha1);
983                                         b.mode = dst_other.mode;
984                                         mfi = merge_file(o, &one, &a, &b,
985                                                          branch1,
986                                                          branch2);
987                                         output(o, 1, "Adding merged %s", ren1_dst);
988                                         update_file(o, 0,
989                                                     mfi.sha,
990                                                     mfi.mode,
991                                                     ren1_dst);
992                                 } else {
993                                         new_path = unique_path(o, ren1_dst, branch2);
994                                         output(o, 1, "Adding as %s instead", new_path);
995                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
996                                 }
997                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
998                                 ren2 = item->util;
999                                 clean_merge = 0;
1000                                 ren2->processed = 1;
1001                                 output(o, 1, "CONFLICT (rename/rename): "
1002                                        "Rename %s->%s in %s. "
1003                                        "Rename %s->%s in %s",
1004                                        ren1_src, ren1_dst, branch1,
1005                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1006                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
1007                         } else
1008                                 try_merge = 1;
1009
1010                         if (try_merge) {
1011                                 struct diff_filespec *one, *a, *b;
1012                                 struct merge_file_info mfi;
1013                                 src_other.path = (char *)ren1_src;
1014
1015                                 one = ren1->pair->one;
1016                                 if (a_renames == renames1) {
1017                                         a = ren1->pair->two;
1018                                         b = &src_other;
1019                                 } else {
1020                                         b = ren1->pair->two;
1021                                         a = &src_other;
1022                                 }
1023                                 mfi = merge_file(o, one, a, b,
1024                                                 o->branch1, o->branch2);
1025
1026                                 if (mfi.clean &&
1027                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1028                                     mfi.mode == ren1->pair->two->mode) {
1029                                         /*
1030                                          * This message is part of
1031                                          * t6022 test. If you change
1032                                          * it update the test too.
1033                                          */
1034                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1035
1036                                         /* There may be higher stage entries left
1037                                          * in the index (e.g. due to a D/F
1038                                          * conflict) that need to be resolved.
1039                                          */
1040                                         if (!ren1->dst_entry->stages[2].mode !=
1041                                             !ren1->dst_entry->stages[3].mode)
1042                                                 ren1->dst_entry->processed = 0;
1043                                 } else {
1044                                         if (mfi.merge || !mfi.clean)
1045                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1046                                         if (mfi.merge)
1047                                                 output(o, 2, "Auto-merging %s", ren1_dst);
1048                                         if (!mfi.clean) {
1049                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1050                                                        ren1_dst);
1051                                                 clean_merge = 0;
1052
1053                                                 if (!o->call_depth)
1054                                                         update_stages(ren1_dst,
1055                                                                       one, a, b, 1);
1056                                         }
1057                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1058                                 }
1059                         }
1060                 }
1061         }
1062         string_list_clear(&a_by_dst, 0);
1063         string_list_clear(&b_by_dst, 0);
1064
1065         return clean_merge;
1066 }
1067
1068 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1069 {
1070         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1071 }
1072
1073 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1074 {
1075         void *buf;
1076         enum object_type type;
1077         unsigned long size;
1078         buf = read_sha1_file(sha1, &type, &size);
1079         if (!buf)
1080                 return error("cannot read object %s", sha1_to_hex(sha1));
1081         if (type != OBJ_BLOB) {
1082                 free(buf);
1083                 return error("object %s is not a blob", sha1_to_hex(sha1));
1084         }
1085         strbuf_attach(dst, buf, size, size + 1);
1086         return 0;
1087 }
1088
1089 static int blob_unchanged(const unsigned char *o_sha,
1090                           const unsigned char *a_sha,
1091                           int renormalize, const char *path)
1092 {
1093         struct strbuf o = STRBUF_INIT;
1094         struct strbuf a = STRBUF_INIT;
1095         int ret = 0; /* assume changed for safety */
1096
1097         if (sha_eq(o_sha, a_sha))
1098                 return 1;
1099         if (!renormalize)
1100                 return 0;
1101
1102         assert(o_sha && a_sha);
1103         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1104                 goto error_return;
1105         /*
1106          * Note: binary | is used so that both renormalizations are
1107          * performed.  Comparison can be skipped if both files are
1108          * unchanged since their sha1s have already been compared.
1109          */
1110         if (renormalize_buffer(path, o.buf, o.len, &o) |
1111             renormalize_buffer(path, a.buf, o.len, &a))
1112                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1113
1114 error_return:
1115         strbuf_release(&o);
1116         strbuf_release(&a);
1117         return ret;
1118 }
1119
1120 /* Per entry merge function */
1121 static int process_entry(struct merge_options *o,
1122                          const char *path, struct stage_data *entry)
1123 {
1124         /*
1125         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1126         print_index_entry("\tpath: ", entry);
1127         */
1128         int clean_merge = 1;
1129         int normalize = o->renormalize;
1130         unsigned o_mode = entry->stages[1].mode;
1131         unsigned a_mode = entry->stages[2].mode;
1132         unsigned b_mode = entry->stages[3].mode;
1133         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1134         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1135         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1136
1137         entry->processed = 1;
1138         if (o_sha && (!a_sha || !b_sha)) {
1139                 /* Case A: Deleted in one */
1140                 if ((!a_sha && !b_sha) ||
1141                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1142                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1143                         /* Deleted in both or deleted in one and
1144                          * unchanged in the other */
1145                         if (a_sha)
1146                                 output(o, 2, "Removing %s", path);
1147                         /* do not touch working file if it did not exist */
1148                         remove_file(o, 1, path, !a_sha);
1149                 } else {
1150                         /* Deleted in one and changed in the other */
1151                         clean_merge = 0;
1152                         if (!a_sha) {
1153                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1154                                        "and modified in %s. Version %s of %s left in tree.",
1155                                        path, o->branch1,
1156                                        o->branch2, o->branch2, path);
1157                                 update_file(o, 0, b_sha, b_mode, path);
1158                         } else {
1159                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1160                                        "and modified in %s. Version %s of %s left in tree.",
1161                                        path, o->branch2,
1162                                        o->branch1, o->branch1, path);
1163                                 update_file(o, 0, a_sha, a_mode, path);
1164                         }
1165                 }
1166
1167         } else if ((!o_sha && a_sha && !b_sha) ||
1168                    (!o_sha && !a_sha && b_sha)) {
1169                 /* Case B: Added in one. */
1170                 unsigned mode;
1171                 const unsigned char *sha;
1172
1173                 if (a_sha) {
1174                         mode = a_mode;
1175                         sha = a_sha;
1176                 } else {
1177                         mode = b_mode;
1178                         sha = b_sha;
1179                 }
1180                 if (string_list_has_string(&o->current_directory_set, path)) {
1181                         /* Handle D->F conflicts after all subfiles */
1182                         entry->processed = 0;
1183                         /* But get any file out of the way now, so conflicted
1184                          * entries below the directory of the same name can
1185                          * be put in the working directory.
1186                          */
1187                         if (a_sha)
1188                                 output(o, 2, "Removing %s", path);
1189                         /* do not touch working file if it did not exist */
1190                         remove_file(o, 0, path, !a_sha);
1191                         return 1; /* Assume clean till processed */
1192                 } else {
1193                         output(o, 2, "Adding %s", path);
1194                         update_file(o, 1, sha, mode, path);
1195                 }
1196         } else if (a_sha && b_sha) {
1197                 /* Case C: Added in both (check for same permissions) and */
1198                 /* case D: Modified in both, but differently. */
1199                 const char *reason = "content";
1200                 struct merge_file_info mfi;
1201                 struct diff_filespec one, a, b;
1202
1203                 if (!o_sha) {
1204                         reason = "add/add";
1205                         o_sha = (unsigned char *)null_sha1;
1206                 }
1207                 output(o, 2, "Auto-merging %s", path);
1208                 one.path = a.path = b.path = (char *)path;
1209                 hashcpy(one.sha1, o_sha);
1210                 one.mode = o_mode;
1211                 hashcpy(a.sha1, a_sha);
1212                 a.mode = a_mode;
1213                 hashcpy(b.sha1, b_sha);
1214                 b.mode = b_mode;
1215
1216                 mfi = merge_file(o, &one, &a, &b,
1217                                  o->branch1, o->branch2);
1218
1219                 clean_merge = mfi.clean;
1220                 if (!mfi.clean) {
1221                         if (S_ISGITLINK(mfi.mode))
1222                                 reason = "submodule";
1223                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1224                                         reason, path);
1225                 }
1226                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1227         } else if (!o_sha && !a_sha && !b_sha) {
1228                 /*
1229                  * this entry was deleted altogether. a_mode == 0 means
1230                  * we had that path and want to actively remove it.
1231                  */
1232                 remove_file(o, 1, path, !a_mode);
1233         } else
1234                 die("Fatal merge failure, shouldn't happen.");
1235
1236         return clean_merge;
1237 }
1238
1239 /*
1240  * Per entry merge function for D/F conflicts, to be called only after
1241  * all files below dir have been processed.  We do this because in the
1242  * cases we can cleanly resolve D/F conflicts, process_entry() can clean
1243  * out all the files below the directory for us.
1244  */
1245 static int process_df_entry(struct merge_options *o,
1246                          const char *path, struct stage_data *entry)
1247 {
1248         int clean_merge = 1;
1249         unsigned o_mode = entry->stages[1].mode;
1250         unsigned a_mode = entry->stages[2].mode;
1251         unsigned b_mode = entry->stages[3].mode;
1252         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1253         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1254         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1255         const char *add_branch;
1256         const char *other_branch;
1257         unsigned mode;
1258         const unsigned char *sha;
1259         const char *conf;
1260         struct stat st;
1261
1262         /* We currently only handle D->F cases */
1263         assert((!o_sha && a_sha && !b_sha) ||
1264                (!o_sha && !a_sha && b_sha));
1265
1266         entry->processed = 1;
1267
1268         if (a_sha) {
1269                 add_branch = o->branch1;
1270                 other_branch = o->branch2;
1271                 mode = a_mode;
1272                 sha = a_sha;
1273                 conf = "file/directory";
1274         } else {
1275                 add_branch = o->branch2;
1276                 other_branch = o->branch1;
1277                 mode = b_mode;
1278                 sha = b_sha;
1279                 conf = "directory/file";
1280         }
1281         if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1282                 const char *new_path = unique_path(o, path, add_branch);
1283                 clean_merge = 0;
1284                 output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1285                        "Adding %s as %s",
1286                        conf, path, other_branch, path, new_path);
1287                 remove_file(o, 0, path, 0);
1288                 update_file(o, 0, sha, mode, new_path);
1289         } else {
1290                 output(o, 2, "Adding %s", path);
1291                 update_file(o, 1, sha, mode, path);
1292         }
1293
1294         return clean_merge;
1295 }
1296
1297 int merge_trees(struct merge_options *o,
1298                 struct tree *head,
1299                 struct tree *merge,
1300                 struct tree *common,
1301                 struct tree **result)
1302 {
1303         int code, clean;
1304
1305         if (o->subtree_shift) {
1306                 merge = shift_tree_object(head, merge, o->subtree_shift);
1307                 common = shift_tree_object(head, common, o->subtree_shift);
1308         }
1309
1310         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1311                 output(o, 0, "Already up-to-date!");
1312                 *result = head;
1313                 return 1;
1314         }
1315
1316         code = git_merge_trees(o->call_depth, common, head, merge);
1317
1318         if (code != 0) {
1319                 if (show(o, 4) || o->call_depth)
1320                         die("merging of trees %s and %s failed",
1321                             sha1_to_hex(head->object.sha1),
1322                             sha1_to_hex(merge->object.sha1));
1323                 else
1324                         exit(128);
1325         }
1326
1327         if (unmerged_cache()) {
1328                 struct string_list *entries, *re_head, *re_merge;
1329                 int i;
1330                 string_list_clear(&o->current_file_set, 1);
1331                 string_list_clear(&o->current_directory_set, 1);
1332                 get_files_dirs(o, head);
1333                 get_files_dirs(o, merge);
1334
1335                 entries = get_unmerged();
1336                 re_head  = get_renames(o, head, common, head, merge, entries);
1337                 re_merge = get_renames(o, merge, common, head, merge, entries);
1338                 clean = process_renames(o, re_head, re_merge);
1339                 for (i = 0; i < entries->nr; i++) {
1340                         const char *path = entries->items[i].string;
1341                         struct stage_data *e = entries->items[i].util;
1342                         if (!e->processed
1343                                 && !process_entry(o, path, e))
1344                                 clean = 0;
1345                 }
1346                 for (i = 0; i < entries->nr; i++) {
1347                         const char *path = entries->items[i].string;
1348                         struct stage_data *e = entries->items[i].util;
1349                         if (!e->processed
1350                                 && !process_df_entry(o, path, e))
1351                                 clean = 0;
1352                 }
1353
1354                 string_list_clear(re_merge, 0);
1355                 string_list_clear(re_head, 0);
1356                 string_list_clear(entries, 1);
1357
1358         }
1359         else
1360                 clean = 1;
1361
1362         if (o->call_depth)
1363                 *result = write_tree_from_memory(o);
1364
1365         return clean;
1366 }
1367
1368 static struct commit_list *reverse_commit_list(struct commit_list *list)
1369 {
1370         struct commit_list *next = NULL, *current, *backup;
1371         for (current = list; current; current = backup) {
1372                 backup = current->next;
1373                 current->next = next;
1374                 next = current;
1375         }
1376         return next;
1377 }
1378
1379 /*
1380  * Merge the commits h1 and h2, return the resulting virtual
1381  * commit object and a flag indicating the cleanness of the merge.
1382  */
1383 int merge_recursive(struct merge_options *o,
1384                     struct commit *h1,
1385                     struct commit *h2,
1386                     struct commit_list *ca,
1387                     struct commit **result)
1388 {
1389         struct commit_list *iter;
1390         struct commit *merged_common_ancestors;
1391         struct tree *mrtree = mrtree;
1392         int clean;
1393
1394         if (show(o, 4)) {
1395                 output(o, 4, "Merging:");
1396                 output_commit_title(o, h1);
1397                 output_commit_title(o, h2);
1398         }
1399
1400         if (!ca) {
1401                 ca = get_merge_bases(h1, h2, 1);
1402                 ca = reverse_commit_list(ca);
1403         }
1404
1405         if (show(o, 5)) {
1406                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1407                 for (iter = ca; iter; iter = iter->next)
1408                         output_commit_title(o, iter->item);
1409         }
1410
1411         merged_common_ancestors = pop_commit(&ca);
1412         if (merged_common_ancestors == NULL) {
1413                 /* if there is no common ancestor, make an empty tree */
1414                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1415
1416                 tree->object.parsed = 1;
1417                 tree->object.type = OBJ_TREE;
1418                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1419                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1420         }
1421
1422         for (iter = ca; iter; iter = iter->next) {
1423                 const char *saved_b1, *saved_b2;
1424                 o->call_depth++;
1425                 /*
1426                  * When the merge fails, the result contains files
1427                  * with conflict markers. The cleanness flag is
1428                  * ignored, it was never actually used, as result of
1429                  * merge_trees has always overwritten it: the committed
1430                  * "conflicts" were already resolved.
1431                  */
1432                 discard_cache();
1433                 saved_b1 = o->branch1;
1434                 saved_b2 = o->branch2;
1435                 o->branch1 = "Temporary merge branch 1";
1436                 o->branch2 = "Temporary merge branch 2";
1437                 merge_recursive(o, merged_common_ancestors, iter->item,
1438                                 NULL, &merged_common_ancestors);
1439                 o->branch1 = saved_b1;
1440                 o->branch2 = saved_b2;
1441                 o->call_depth--;
1442
1443                 if (!merged_common_ancestors)
1444                         die("merge returned no commit");
1445         }
1446
1447         discard_cache();
1448         if (!o->call_depth)
1449                 read_cache();
1450
1451         o->ancestor = "merged common ancestors";
1452         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1453                             &mrtree);
1454
1455         if (o->call_depth) {
1456                 *result = make_virtual_commit(mrtree, "merged tree");
1457                 commit_list_insert(h1, &(*result)->parents);
1458                 commit_list_insert(h2, &(*result)->parents->next);
1459         }
1460         flush_output(o);
1461         return clean;
1462 }
1463
1464 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1465 {
1466         struct object *object;
1467
1468         object = deref_tag(parse_object(sha1), name, strlen(name));
1469         if (!object)
1470                 return NULL;
1471         if (object->type == OBJ_TREE)
1472                 return make_virtual_commit((struct tree*)object, name);
1473         if (object->type != OBJ_COMMIT)
1474                 return NULL;
1475         if (parse_commit((struct commit *)object))
1476                 return NULL;
1477         return (struct commit *)object;
1478 }
1479
1480 int merge_recursive_generic(struct merge_options *o,
1481                             const unsigned char *head,
1482                             const unsigned char *merge,
1483                             int num_base_list,
1484                             const unsigned char **base_list,
1485                             struct commit **result)
1486 {
1487         int clean, index_fd;
1488         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1489         struct commit *head_commit = get_ref(head, o->branch1);
1490         struct commit *next_commit = get_ref(merge, o->branch2);
1491         struct commit_list *ca = NULL;
1492
1493         if (base_list) {
1494                 int i;
1495                 for (i = 0; i < num_base_list; ++i) {
1496                         struct commit *base;
1497                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1498                                 return error("Could not parse object '%s'",
1499                                         sha1_to_hex(base_list[i]));
1500                         commit_list_insert(base, &ca);
1501                 }
1502         }
1503
1504         index_fd = hold_locked_index(lock, 1);
1505         clean = merge_recursive(o, head_commit, next_commit, ca,
1506                         result);
1507         if (active_cache_changed &&
1508                         (write_cache(index_fd, active_cache, active_nr) ||
1509                          commit_locked_index(lock)))
1510                 return error("Unable to write index.");
1511
1512         return clean ? 0 : 1;
1513 }
1514
1515 static int merge_recursive_config(const char *var, const char *value, void *cb)
1516 {
1517         struct merge_options *o = cb;
1518         if (!strcasecmp(var, "merge.verbosity")) {
1519                 o->verbosity = git_config_int(var, value);
1520                 return 0;
1521         }
1522         if (!strcasecmp(var, "diff.renamelimit")) {
1523                 o->diff_rename_limit = git_config_int(var, value);
1524                 return 0;
1525         }
1526         if (!strcasecmp(var, "merge.renamelimit")) {
1527                 o->merge_rename_limit = git_config_int(var, value);
1528                 return 0;
1529         }
1530         return git_xmerge_config(var, value, cb);
1531 }
1532
1533 void init_merge_options(struct merge_options *o)
1534 {
1535         memset(o, 0, sizeof(struct merge_options));
1536         o->verbosity = 2;
1537         o->buffer_output = 1;
1538         o->diff_rename_limit = -1;
1539         o->merge_rename_limit = -1;
1540         o->renormalize = 0;
1541         git_config(merge_recursive_config, o);
1542         if (getenv("GIT_MERGE_VERBOSITY"))
1543                 o->verbosity =
1544                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1545         if (o->verbosity >= 5)
1546                 o->buffer_output = 0;
1547         strbuf_init(&o->obuf, 0);
1548         memset(&o->current_file_set, 0, sizeof(struct string_list));
1549         o->current_file_set.strdup_strings = 1;
1550         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1551         o->current_directory_set.strdup_strings = 1;
1552 }