Merge branch 'maint'
[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 enum rename_type {
67         RENAME_NORMAL = 0,
68         RENAME_DELETE,
69         RENAME_ONE_FILE_TO_TWO
70 };
71
72 struct rename_df_conflict_info {
73         enum rename_type rename_type;
74         struct diff_filepair *pair1;
75         struct diff_filepair *pair2;
76         const char *branch1;
77         const char *branch2;
78         struct stage_data *dst_entry1;
79         struct stage_data *dst_entry2;
80 };
81
82 /*
83  * Since we want to write the index eventually, we cannot reuse the index
84  * for these (temporary) data.
85  */
86 struct stage_data
87 {
88         struct
89         {
90                 unsigned mode;
91                 unsigned char sha[20];
92         } stages[4];
93         struct rename_df_conflict_info *rename_df_conflict_info;
94         unsigned processed:1;
95 };
96
97 static inline void setup_rename_df_conflict_info(enum rename_type rename_type,
98                                                  struct diff_filepair *pair1,
99                                                  struct diff_filepair *pair2,
100                                                  const char *branch1,
101                                                  const char *branch2,
102                                                  struct stage_data *dst_entry1,
103                                                  struct stage_data *dst_entry2)
104 {
105         struct rename_df_conflict_info *ci = xcalloc(1, sizeof(struct rename_df_conflict_info));
106         ci->rename_type = rename_type;
107         ci->pair1 = pair1;
108         ci->branch1 = branch1;
109         ci->branch2 = branch2;
110
111         ci->dst_entry1 = dst_entry1;
112         dst_entry1->rename_df_conflict_info = ci;
113         dst_entry1->processed = 0;
114
115         assert(!pair2 == !dst_entry2);
116         if (dst_entry2) {
117                 ci->dst_entry2 = dst_entry2;
118                 ci->pair2 = pair2;
119                 dst_entry2->rename_df_conflict_info = ci;
120                 dst_entry2->processed = 0;
121         }
122 }
123
124 static int show(struct merge_options *o, int v)
125 {
126         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
127 }
128
129 static void flush_output(struct merge_options *o)
130 {
131         if (o->obuf.len) {
132                 fputs(o->obuf.buf, stdout);
133                 strbuf_reset(&o->obuf);
134         }
135 }
136
137 __attribute__((format (printf, 3, 4)))
138 static void output(struct merge_options *o, int v, const char *fmt, ...)
139 {
140         int len;
141         va_list ap;
142
143         if (!show(o, v))
144                 return;
145
146         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
147         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
148         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
149
150         va_start(ap, fmt);
151         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
152         va_end(ap);
153
154         if (len < 0)
155                 len = 0;
156         if (len >= strbuf_avail(&o->obuf)) {
157                 strbuf_grow(&o->obuf, len + 2);
158                 va_start(ap, fmt);
159                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
160                 va_end(ap);
161                 if (len >= strbuf_avail(&o->obuf)) {
162                         die("this should not happen, your snprintf is broken");
163                 }
164         }
165         strbuf_setlen(&o->obuf, o->obuf.len + len);
166         strbuf_add(&o->obuf, "\n", 1);
167         if (!o->buffer_output)
168                 flush_output(o);
169 }
170
171 static void output_commit_title(struct merge_options *o, struct commit *commit)
172 {
173         int i;
174         flush_output(o);
175         for (i = o->call_depth; i--;)
176                 fputs("  ", stdout);
177         if (commit->util)
178                 printf("virtual %s\n", (char *)commit->util);
179         else {
180                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
181                 if (parse_commit(commit) != 0)
182                         printf("(bad commit)\n");
183                 else {
184                         const char *title;
185                         int len = find_commit_subject(commit->buffer, &title);
186                         if (len)
187                                 printf("%.*s\n", len, title);
188                 }
189         }
190 }
191
192 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
193                 const char *path, int stage, int refresh, int options)
194 {
195         struct cache_entry *ce;
196         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
197         if (!ce)
198                 return error("addinfo_cache failed for path '%s'", path);
199         return add_cache_entry(ce, options);
200 }
201
202 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
203 {
204         parse_tree(tree);
205         init_tree_desc(desc, tree->buffer, tree->size);
206 }
207
208 static int git_merge_trees(int index_only,
209                            struct tree *common,
210                            struct tree *head,
211                            struct tree *merge)
212 {
213         int rc;
214         struct tree_desc t[3];
215         struct unpack_trees_options opts;
216
217         memset(&opts, 0, sizeof(opts));
218         if (index_only)
219                 opts.index_only = 1;
220         else
221                 opts.update = 1;
222         opts.merge = 1;
223         opts.head_idx = 2;
224         opts.fn = threeway_merge;
225         opts.src_index = &the_index;
226         opts.dst_index = &the_index;
227         setup_unpack_trees_porcelain(&opts, "merge");
228
229         init_tree_desc_from_tree(t+0, common);
230         init_tree_desc_from_tree(t+1, head);
231         init_tree_desc_from_tree(t+2, merge);
232
233         rc = unpack_trees(3, t, &opts);
234         cache_tree_free(&active_cache_tree);
235         return rc;
236 }
237
238 struct tree *write_tree_from_memory(struct merge_options *o)
239 {
240         struct tree *result = NULL;
241
242         if (unmerged_cache()) {
243                 int i;
244                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
245                 for (i = 0; i < active_nr; i++) {
246                         struct cache_entry *ce = active_cache[i];
247                         if (ce_stage(ce))
248                                 fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
249                                         (int)ce_namelen(ce), ce->name);
250                 }
251                 die("Bug in merge-recursive.c");
252         }
253
254         if (!active_cache_tree)
255                 active_cache_tree = cache_tree();
256
257         if (!cache_tree_fully_valid(active_cache_tree) &&
258             cache_tree_update(active_cache_tree,
259                               active_cache, active_nr, 0, 0) < 0)
260                 die("error building trees");
261
262         result = lookup_tree(active_cache_tree->sha1);
263
264         return result;
265 }
266
267 static int save_files_dirs(const unsigned char *sha1,
268                 const char *base, int baselen, const char *path,
269                 unsigned int mode, int stage, void *context)
270 {
271         int len = strlen(path);
272         char *newpath = xmalloc(baselen + len + 1);
273         struct merge_options *o = context;
274
275         memcpy(newpath, base, baselen);
276         memcpy(newpath + baselen, path, len);
277         newpath[baselen + len] = '\0';
278
279         if (S_ISDIR(mode))
280                 string_list_insert(&o->current_directory_set, newpath);
281         else
282                 string_list_insert(&o->current_file_set, newpath);
283         free(newpath);
284
285         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
286 }
287
288 static int get_files_dirs(struct merge_options *o, struct tree *tree)
289 {
290         int n;
291         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
292                 return 0;
293         n = o->current_file_set.nr + o->current_directory_set.nr;
294         return n;
295 }
296
297 /*
298  * Returns an index_entry instance which doesn't have to correspond to
299  * a real cache entry in Git's index.
300  */
301 static struct stage_data *insert_stage_data(const char *path,
302                 struct tree *o, struct tree *a, struct tree *b,
303                 struct string_list *entries)
304 {
305         struct string_list_item *item;
306         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
307         get_tree_entry(o->object.sha1, path,
308                         e->stages[1].sha, &e->stages[1].mode);
309         get_tree_entry(a->object.sha1, path,
310                         e->stages[2].sha, &e->stages[2].mode);
311         get_tree_entry(b->object.sha1, path,
312                         e->stages[3].sha, &e->stages[3].mode);
313         item = string_list_insert(entries, path);
314         item->util = e;
315         return e;
316 }
317
318 /*
319  * Create a dictionary mapping file names to stage_data objects. The
320  * dictionary contains one entry for every path with a non-zero stage entry.
321  */
322 static struct string_list *get_unmerged(void)
323 {
324         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
325         int i;
326
327         unmerged->strdup_strings = 1;
328
329         for (i = 0; i < active_nr; i++) {
330                 struct string_list_item *item;
331                 struct stage_data *e;
332                 struct cache_entry *ce = active_cache[i];
333                 if (!ce_stage(ce))
334                         continue;
335
336                 item = string_list_lookup(unmerged, ce->name);
337                 if (!item) {
338                         item = string_list_insert(unmerged, ce->name);
339                         item->util = xcalloc(1, sizeof(struct stage_data));
340                 }
341                 e = item->util;
342                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
343                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
344         }
345
346         return unmerged;
347 }
348
349 static void make_room_for_directories_of_df_conflicts(struct merge_options *o,
350                                                       struct string_list *entries)
351 {
352         /* If there are D/F conflicts, and the paths currently exist
353          * in the working copy as a file, we want to remove them to
354          * make room for the corresponding directory.  Such paths will
355          * later be processed in process_df_entry() at the end.  If
356          * the corresponding directory ends up being removed by the
357          * merge, then the file will be reinstated at that time;
358          * otherwise, if the file is not supposed to be removed by the
359          * merge, the contents of the file will be placed in another
360          * unique filename.
361          *
362          * NOTE: This function relies on the fact that entries for a
363          * D/F conflict will appear adjacent in the index, with the
364          * entries for the file appearing before entries for paths
365          * below the corresponding directory.
366          */
367         const char *last_file = NULL;
368         int last_len = 0;
369         struct stage_data *last_e;
370         int i;
371
372         for (i = 0; i < entries->nr; i++) {
373                 const char *path = entries->items[i].string;
374                 int len = strlen(path);
375                 struct stage_data *e = entries->items[i].util;
376
377                 /*
378                  * Check if last_file & path correspond to a D/F conflict;
379                  * i.e. whether path is last_file+'/'+<something>.
380                  * If so, remove last_file to make room for path and friends.
381                  */
382                 if (last_file &&
383                     len > last_len &&
384                     memcmp(path, last_file, last_len) == 0 &&
385                     path[last_len] == '/') {
386                         output(o, 3, "Removing %s to make room for subdirectory; may re-add later.", last_file);
387                         unlink(last_file);
388                 }
389
390                 /*
391                  * Determine whether path could exist as a file in the
392                  * working directory as a possible D/F conflict.  This
393                  * will only occur when it exists in stage 2 as a
394                  * file.
395                  */
396                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
397                         last_file = path;
398                         last_len = len;
399                         last_e = e;
400                 } else {
401                         last_file = NULL;
402                 }
403         }
404 }
405
406 struct rename
407 {
408         struct diff_filepair *pair;
409         struct stage_data *src_entry;
410         struct stage_data *dst_entry;
411         unsigned processed:1;
412 };
413
414 /*
415  * Get information of all renames which occurred between 'o_tree' and
416  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
417  * 'b_tree') to be able to associate the correct cache entries with
418  * the rename information. 'tree' is always equal to either a_tree or b_tree.
419  */
420 static struct string_list *get_renames(struct merge_options *o,
421                                        struct tree *tree,
422                                        struct tree *o_tree,
423                                        struct tree *a_tree,
424                                        struct tree *b_tree,
425                                        struct string_list *entries)
426 {
427         int i;
428         struct string_list *renames;
429         struct diff_options opts;
430
431         renames = xcalloc(1, sizeof(struct string_list));
432         diff_setup(&opts);
433         DIFF_OPT_SET(&opts, RECURSIVE);
434         opts.detect_rename = DIFF_DETECT_RENAME;
435         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
436                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
437                             500;
438         opts.rename_score = o->rename_score;
439         opts.warn_on_too_large_rename = 1;
440         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
441         if (diff_setup_done(&opts) < 0)
442                 die("diff setup failed");
443         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
444         diffcore_std(&opts);
445         for (i = 0; i < diff_queued_diff.nr; ++i) {
446                 struct string_list_item *item;
447                 struct rename *re;
448                 struct diff_filepair *pair = diff_queued_diff.queue[i];
449                 if (pair->status != 'R') {
450                         diff_free_filepair(pair);
451                         continue;
452                 }
453                 re = xmalloc(sizeof(*re));
454                 re->processed = 0;
455                 re->pair = pair;
456                 item = string_list_lookup(entries, re->pair->one->path);
457                 if (!item)
458                         re->src_entry = insert_stage_data(re->pair->one->path,
459                                         o_tree, a_tree, b_tree, entries);
460                 else
461                         re->src_entry = item->util;
462
463                 item = string_list_lookup(entries, re->pair->two->path);
464                 if (!item)
465                         re->dst_entry = insert_stage_data(re->pair->two->path,
466                                         o_tree, a_tree, b_tree, entries);
467                 else
468                         re->dst_entry = item->util;
469                 item = string_list_insert(renames, pair->one->path);
470                 item->util = re;
471         }
472         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
473         diff_queued_diff.nr = 0;
474         diff_flush(&opts);
475         return renames;
476 }
477
478 static int update_stages_options(const char *path, struct diff_filespec *o,
479                          struct diff_filespec *a, struct diff_filespec *b,
480                          int clear, int options)
481 {
482         if (clear)
483                 if (remove_file_from_cache(path))
484                         return -1;
485         if (o)
486                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
487                         return -1;
488         if (a)
489                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
490                         return -1;
491         if (b)
492                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
493                         return -1;
494         return 0;
495 }
496
497 static int update_stages(const char *path, struct diff_filespec *o,
498                          struct diff_filespec *a, struct diff_filespec *b,
499                          int clear)
500 {
501         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
502         return update_stages_options(path, o, a, b, clear, options);
503 }
504
505 static int update_stages_and_entry(const char *path,
506                                    struct stage_data *entry,
507                                    struct diff_filespec *o,
508                                    struct diff_filespec *a,
509                                    struct diff_filespec *b,
510                                    int clear)
511 {
512         int options;
513
514         entry->processed = 0;
515         entry->stages[1].mode = o->mode;
516         entry->stages[2].mode = a->mode;
517         entry->stages[3].mode = b->mode;
518         hashcpy(entry->stages[1].sha, o->sha1);
519         hashcpy(entry->stages[2].sha, a->sha1);
520         hashcpy(entry->stages[3].sha, b->sha1);
521         options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
522         return update_stages_options(path, o, a, b, clear, options);
523 }
524
525 static int remove_file(struct merge_options *o, int clean,
526                        const char *path, int no_wd)
527 {
528         int update_cache = o->call_depth || clean;
529         int update_working_directory = !o->call_depth && !no_wd;
530
531         if (update_cache) {
532                 if (remove_file_from_cache(path))
533                         return -1;
534         }
535         if (update_working_directory) {
536                 if (remove_path(path))
537                         return -1;
538         }
539         return 0;
540 }
541
542 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
543 {
544         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
545         int suffix = 0;
546         struct stat st;
547         char *p = newpath + strlen(path);
548         strcpy(newpath, path);
549         *(p++) = '~';
550         strcpy(p, branch);
551         for (; *p; ++p)
552                 if ('/' == *p)
553                         *p = '_';
554         while (string_list_has_string(&o->current_file_set, newpath) ||
555                string_list_has_string(&o->current_directory_set, newpath) ||
556                lstat(newpath, &st) == 0)
557                 sprintf(p, "_%d", suffix++);
558
559         string_list_insert(&o->current_file_set, newpath);
560         return newpath;
561 }
562
563 static void flush_buffer(int fd, const char *buf, unsigned long size)
564 {
565         while (size > 0) {
566                 long ret = write_in_full(fd, buf, size);
567                 if (ret < 0) {
568                         /* Ignore epipe */
569                         if (errno == EPIPE)
570                                 break;
571                         die_errno("merge-recursive");
572                 } else if (!ret) {
573                         die("merge-recursive: disk full?");
574                 }
575                 size -= ret;
576                 buf += ret;
577         }
578 }
579
580 static int would_lose_untracked(const char *path)
581 {
582         int pos = cache_name_pos(path, strlen(path));
583
584         if (pos < 0)
585                 pos = -1 - pos;
586         while (pos < active_nr &&
587                !strcmp(path, active_cache[pos]->name)) {
588                 /*
589                  * If stage #0, it is definitely tracked.
590                  * If it has stage #2 then it was tracked
591                  * before this merge started.  All other
592                  * cases the path was not tracked.
593                  */
594                 switch (ce_stage(active_cache[pos])) {
595                 case 0:
596                 case 2:
597                         return 0;
598                 }
599                 pos++;
600         }
601         return file_exists(path);
602 }
603
604 static int make_room_for_path(const char *path)
605 {
606         int status;
607         const char *msg = "failed to create path '%s'%s";
608
609         status = safe_create_leading_directories_const(path);
610         if (status) {
611                 if (status == -3) {
612                         /* something else exists */
613                         error(msg, path, ": perhaps a D/F conflict?");
614                         return -1;
615                 }
616                 die(msg, path, "");
617         }
618
619         /*
620          * Do not unlink a file in the work tree if we are not
621          * tracking it.
622          */
623         if (would_lose_untracked(path))
624                 return error("refusing to lose untracked file at '%s'",
625                              path);
626
627         /* Successful unlink is good.. */
628         if (!unlink(path))
629                 return 0;
630         /* .. and so is no existing file */
631         if (errno == ENOENT)
632                 return 0;
633         /* .. but not some other error (who really cares what?) */
634         return error(msg, path, ": perhaps a D/F conflict?");
635 }
636
637 static void update_file_flags(struct merge_options *o,
638                               const unsigned char *sha,
639                               unsigned mode,
640                               const char *path,
641                               int update_cache,
642                               int update_wd)
643 {
644         if (o->call_depth)
645                 update_wd = 0;
646
647         if (update_wd) {
648                 enum object_type type;
649                 void *buf;
650                 unsigned long size;
651
652                 if (S_ISGITLINK(mode)) {
653                         /*
654                          * We may later decide to recursively descend into
655                          * the submodule directory and update its index
656                          * and/or work tree, but we do not do that now.
657                          */
658                         update_wd = 0;
659                         goto update_index;
660                 }
661
662                 buf = read_sha1_file(sha, &type, &size);
663                 if (!buf)
664                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
665                 if (type != OBJ_BLOB)
666                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
667                 if (S_ISREG(mode)) {
668                         struct strbuf strbuf = STRBUF_INIT;
669                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
670                                 free(buf);
671                                 size = strbuf.len;
672                                 buf = strbuf_detach(&strbuf, NULL);
673                         }
674                 }
675
676                 if (make_room_for_path(path) < 0) {
677                         update_wd = 0;
678                         free(buf);
679                         goto update_index;
680                 }
681                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
682                         int fd;
683                         if (mode & 0100)
684                                 mode = 0777;
685                         else
686                                 mode = 0666;
687                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
688                         if (fd < 0)
689                                 die_errno("failed to open '%s'", path);
690                         flush_buffer(fd, buf, size);
691                         close(fd);
692                 } else if (S_ISLNK(mode)) {
693                         char *lnk = xmemdupz(buf, size);
694                         safe_create_leading_directories_const(path);
695                         unlink(path);
696                         if (symlink(lnk, path))
697                                 die_errno("failed to symlink '%s'", path);
698                         free(lnk);
699                 } else
700                         die("do not know what to do with %06o %s '%s'",
701                             mode, sha1_to_hex(sha), path);
702                 free(buf);
703         }
704  update_index:
705         if (update_cache)
706                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
707 }
708
709 static void update_file(struct merge_options *o,
710                         int clean,
711                         const unsigned char *sha,
712                         unsigned mode,
713                         const char *path)
714 {
715         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
716 }
717
718 /* Low level file merging, update and removal */
719
720 struct merge_file_info
721 {
722         unsigned char sha[20];
723         unsigned mode;
724         unsigned clean:1,
725                  merge:1;
726 };
727
728 static int merge_3way(struct merge_options *o,
729                       mmbuffer_t *result_buf,
730                       struct diff_filespec *one,
731                       struct diff_filespec *a,
732                       struct diff_filespec *b,
733                       const char *branch1,
734                       const char *branch2)
735 {
736         mmfile_t orig, src1, src2;
737         struct ll_merge_options ll_opts = {0};
738         char *base_name, *name1, *name2;
739         int merge_status;
740
741         ll_opts.renormalize = o->renormalize;
742         ll_opts.xdl_opts = o->xdl_opts;
743
744         if (o->call_depth) {
745                 ll_opts.virtual_ancestor = 1;
746                 ll_opts.variant = 0;
747         } else {
748                 switch (o->recursive_variant) {
749                 case MERGE_RECURSIVE_OURS:
750                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
751                         break;
752                 case MERGE_RECURSIVE_THEIRS:
753                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
754                         break;
755                 default:
756                         ll_opts.variant = 0;
757                         break;
758                 }
759         }
760
761         if (strcmp(a->path, b->path) ||
762             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
763                 base_name = o->ancestor == NULL ? NULL :
764                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
765                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
766                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
767         } else {
768                 base_name = o->ancestor == NULL ? NULL :
769                         xstrdup(mkpath("%s", o->ancestor));
770                 name1 = xstrdup(mkpath("%s", branch1));
771                 name2 = xstrdup(mkpath("%s", branch2));
772         }
773
774         read_mmblob(&orig, one->sha1);
775         read_mmblob(&src1, a->sha1);
776         read_mmblob(&src2, b->sha1);
777
778         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
779                                 &src1, name1, &src2, name2, &ll_opts);
780
781         free(name1);
782         free(name2);
783         free(orig.ptr);
784         free(src1.ptr);
785         free(src2.ptr);
786         return merge_status;
787 }
788
789 static struct merge_file_info merge_file(struct merge_options *o,
790                                          struct diff_filespec *one,
791                                          struct diff_filespec *a,
792                                          struct diff_filespec *b,
793                                          const char *branch1,
794                                          const char *branch2)
795 {
796         struct merge_file_info result;
797         result.merge = 0;
798         result.clean = 1;
799
800         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
801                 result.clean = 0;
802                 if (S_ISREG(a->mode)) {
803                         result.mode = a->mode;
804                         hashcpy(result.sha, a->sha1);
805                 } else {
806                         result.mode = b->mode;
807                         hashcpy(result.sha, b->sha1);
808                 }
809         } else {
810                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
811                         result.merge = 1;
812
813                 /*
814                  * Merge modes
815                  */
816                 if (a->mode == b->mode || a->mode == one->mode)
817                         result.mode = b->mode;
818                 else {
819                         result.mode = a->mode;
820                         if (b->mode != one->mode) {
821                                 result.clean = 0;
822                                 result.merge = 1;
823                         }
824                 }
825
826                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
827                         hashcpy(result.sha, b->sha1);
828                 else if (sha_eq(b->sha1, one->sha1))
829                         hashcpy(result.sha, a->sha1);
830                 else if (S_ISREG(a->mode)) {
831                         mmbuffer_t result_buf;
832                         int merge_status;
833
834                         merge_status = merge_3way(o, &result_buf, one, a, b,
835                                                   branch1, branch2);
836
837                         if ((merge_status < 0) || !result_buf.ptr)
838                                 die("Failed to execute internal merge");
839
840                         if (write_sha1_file(result_buf.ptr, result_buf.size,
841                                             blob_type, result.sha))
842                                 die("Unable to add %s to database",
843                                     a->path);
844
845                         free(result_buf.ptr);
846                         result.clean = (merge_status == 0);
847                 } else if (S_ISGITLINK(a->mode)) {
848                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
849                                                        a->sha1, b->sha1);
850                 } else if (S_ISLNK(a->mode)) {
851                         hashcpy(result.sha, a->sha1);
852
853                         if (!sha_eq(a->sha1, b->sha1))
854                                 result.clean = 0;
855                 } else {
856                         die("unsupported object type in the tree");
857                 }
858         }
859
860         return result;
861 }
862
863 static void conflict_rename_delete(struct merge_options *o,
864                                    struct diff_filepair *pair,
865                                    const char *rename_branch,
866                                    const char *other_branch)
867 {
868         char *dest_name = pair->two->path;
869         int df_conflict = 0;
870         struct stat st;
871
872         output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
873                "and deleted in %s",
874                pair->one->path, pair->two->path, rename_branch,
875                other_branch);
876         if (!o->call_depth)
877                 update_stages(dest_name, NULL,
878                               rename_branch == o->branch1 ? pair->two : NULL,
879                               rename_branch == o->branch1 ? NULL : pair->two,
880                               1);
881         if (lstat(dest_name, &st) == 0 && S_ISDIR(st.st_mode)) {
882                 dest_name = unique_path(o, dest_name, rename_branch);
883                 df_conflict = 1;
884         }
885         update_file(o, 0, pair->two->sha1, pair->two->mode, dest_name);
886         if (df_conflict)
887                 free(dest_name);
888 }
889
890 static void conflict_rename_rename_1to2(struct merge_options *o,
891                                         struct diff_filepair *pair1,
892                                         const char *branch1,
893                                         struct diff_filepair *pair2,
894                                         const char *branch2)
895 {
896         /* One file was renamed in both branches, but to different names. */
897         char *del[2];
898         int delp = 0;
899         const char *ren1_dst = pair1->two->path;
900         const char *ren2_dst = pair2->two->path;
901         const char *dst_name1 = ren1_dst;
902         const char *dst_name2 = ren2_dst;
903         struct stat st;
904         if (lstat(ren1_dst, &st) == 0 && S_ISDIR(st.st_mode)) {
905                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
906                 output(o, 1, "%s is a directory in %s adding as %s instead",
907                        ren1_dst, branch2, dst_name1);
908         }
909         if (lstat(ren2_dst, &st) == 0 && S_ISDIR(st.st_mode)) {
910                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
911                 output(o, 1, "%s is a directory in %s adding as %s instead",
912                        ren2_dst, branch1, dst_name2);
913         }
914         if (o->call_depth) {
915                 remove_file_from_cache(dst_name1);
916                 remove_file_from_cache(dst_name2);
917                 /*
918                  * Uncomment to leave the conflicting names in the resulting tree
919                  *
920                  * update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
921                  * update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
922                  */
923         } else {
924                 update_stages(ren1_dst, NULL, pair1->two, NULL, 1);
925                 update_stages(ren2_dst, NULL, NULL, pair2->two, 1);
926
927                 update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
928                 update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
929         }
930         while (delp--)
931                 free(del[delp]);
932 }
933
934 static void conflict_rename_rename_2to1(struct merge_options *o,
935                                         struct rename *ren1,
936                                         const char *branch1,
937                                         struct rename *ren2,
938                                         const char *branch2)
939 {
940         /* Two files were renamed to the same thing. */
941         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
942         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
943         output(o, 1, "Renaming %s to %s and %s to %s instead",
944                ren1->pair->one->path, new_path1,
945                ren2->pair->one->path, new_path2);
946         remove_file(o, 0, ren1->pair->two->path, 0);
947         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
948         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
949         free(new_path2);
950         free(new_path1);
951 }
952
953 static int process_renames(struct merge_options *o,
954                            struct string_list *a_renames,
955                            struct string_list *b_renames)
956 {
957         int clean_merge = 1, i, j;
958         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
959         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
960         const struct rename *sre;
961
962         for (i = 0; i < a_renames->nr; i++) {
963                 sre = a_renames->items[i].util;
964                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
965                         = sre->dst_entry;
966         }
967         for (i = 0; i < b_renames->nr; i++) {
968                 sre = b_renames->items[i].util;
969                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
970                         = sre->dst_entry;
971         }
972
973         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
974                 char *src;
975                 struct string_list *renames1, *renames2Dst;
976                 struct rename *ren1 = NULL, *ren2 = NULL;
977                 const char *branch1, *branch2;
978                 const char *ren1_src, *ren1_dst;
979
980                 if (i >= a_renames->nr) {
981                         ren2 = b_renames->items[j++].util;
982                 } else if (j >= b_renames->nr) {
983                         ren1 = a_renames->items[i++].util;
984                 } else {
985                         int compare = strcmp(a_renames->items[i].string,
986                                              b_renames->items[j].string);
987                         if (compare <= 0)
988                                 ren1 = a_renames->items[i++].util;
989                         if (compare >= 0)
990                                 ren2 = b_renames->items[j++].util;
991                 }
992
993                 /* TODO: refactor, so that 1/2 are not needed */
994                 if (ren1) {
995                         renames1 = a_renames;
996                         renames2Dst = &b_by_dst;
997                         branch1 = o->branch1;
998                         branch2 = o->branch2;
999                 } else {
1000                         struct rename *tmp;
1001                         renames1 = b_renames;
1002                         renames2Dst = &a_by_dst;
1003                         branch1 = o->branch2;
1004                         branch2 = o->branch1;
1005                         tmp = ren2;
1006                         ren2 = ren1;
1007                         ren1 = tmp;
1008                 }
1009                 src = ren1->pair->one->path;
1010
1011                 ren1->dst_entry->processed = 1;
1012                 ren1->src_entry->processed = 1;
1013
1014                 if (ren1->processed)
1015                         continue;
1016                 ren1->processed = 1;
1017
1018                 ren1_src = ren1->pair->one->path;
1019                 ren1_dst = ren1->pair->two->path;
1020
1021                 if (ren2) {
1022                         const char *ren2_src = ren2->pair->one->path;
1023                         const char *ren2_dst = ren2->pair->two->path;
1024                         /* Renamed in 1 and renamed in 2 */
1025                         if (strcmp(ren1_src, ren2_src) != 0)
1026                                 die("ren1.src != ren2.src");
1027                         ren2->dst_entry->processed = 1;
1028                         ren2->processed = 1;
1029                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1030                                 setup_rename_df_conflict_info(RENAME_ONE_FILE_TO_TWO,
1031                                                               ren1->pair,
1032                                                               ren2->pair,
1033                                                               branch1,
1034                                                               branch2,
1035                                                               ren1->dst_entry,
1036                                                               ren2->dst_entry);
1037                         } else {
1038                                 remove_file(o, 1, ren1_src, 1);
1039                                 update_stages_and_entry(ren1_dst,
1040                                                         ren1->dst_entry,
1041                                                         ren1->pair->one,
1042                                                         ren1->pair->two,
1043                                                         ren2->pair->two,
1044                                                         1 /* clear */);
1045                         }
1046                 } else {
1047                         /* Renamed in 1, maybe changed in 2 */
1048                         struct string_list_item *item;
1049                         /* we only use sha1 and mode of these */
1050                         struct diff_filespec src_other, dst_other;
1051                         int try_merge;
1052
1053                         /*
1054                          * unpack_trees loads entries from common-commit
1055                          * into stage 1, from head-commit into stage 2, and
1056                          * from merge-commit into stage 3.  We keep track
1057                          * of which side corresponds to the rename.
1058                          */
1059                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1060                         int other_stage =   a_renames == renames1 ? 3 : 2;
1061
1062                         remove_file(o, 1, ren1_src, o->call_depth || renamed_stage == 2);
1063
1064                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1065                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1066                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1067                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1068                         try_merge = 0;
1069
1070                         if (sha_eq(src_other.sha1, null_sha1)) {
1071                                 if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
1072                                         ren1->dst_entry->processed = 0;
1073                                         setup_rename_df_conflict_info(RENAME_DELETE,
1074                                                                       ren1->pair,
1075                                                                       NULL,
1076                                                                       branch1,
1077                                                                       branch2,
1078                                                                       ren1->dst_entry,
1079                                                                       NULL);
1080                                 } else {
1081                                         clean_merge = 0;
1082                                         conflict_rename_delete(o, ren1->pair, branch1, branch2);
1083                                 }
1084                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1085                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1086                                 /* Added file on the other side
1087                                    identical to the file being
1088                                    renamed: clean merge */
1089                                 update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
1090                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1091                                 const char *new_path;
1092                                 clean_merge = 0;
1093                                 try_merge = 1;
1094                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
1095                                        "%s added in %s",
1096                                        ren1_src, ren1_dst, branch1,
1097                                        ren1_dst, branch2);
1098                                 if (o->call_depth) {
1099                                         struct merge_file_info mfi;
1100                                         struct diff_filespec one, a, b;
1101
1102                                         one.path = a.path = b.path =
1103                                                 (char *)ren1_dst;
1104                                         hashcpy(one.sha1, null_sha1);
1105                                         one.mode = 0;
1106                                         hashcpy(a.sha1, ren1->pair->two->sha1);
1107                                         a.mode = ren1->pair->two->mode;
1108                                         hashcpy(b.sha1, dst_other.sha1);
1109                                         b.mode = dst_other.mode;
1110                                         mfi = merge_file(o, &one, &a, &b,
1111                                                          branch1,
1112                                                          branch2);
1113                                         output(o, 1, "Adding merged %s", ren1_dst);
1114                                         update_file(o, 0,
1115                                                     mfi.sha,
1116                                                     mfi.mode,
1117                                                     ren1_dst);
1118                                         try_merge = 0;
1119                                 } else {
1120                                         new_path = unique_path(o, ren1_dst, branch2);
1121                                         output(o, 1, "Adding as %s instead", new_path);
1122                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1123                                 }
1124                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
1125                                 ren2 = item->util;
1126                                 clean_merge = 0;
1127                                 ren2->processed = 1;
1128                                 output(o, 1, "CONFLICT (rename/rename): "
1129                                        "Rename %s->%s in %s. "
1130                                        "Rename %s->%s in %s",
1131                                        ren1_src, ren1_dst, branch1,
1132                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1133                                 conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
1134                         } else
1135                                 try_merge = 1;
1136
1137                         if (try_merge) {
1138                                 struct diff_filespec *one, *a, *b;
1139                                 src_other.path = (char *)ren1_src;
1140
1141                                 one = ren1->pair->one;
1142                                 if (a_renames == renames1) {
1143                                         a = ren1->pair->two;
1144                                         b = &src_other;
1145                                 } else {
1146                                         b = ren1->pair->two;
1147                                         a = &src_other;
1148                                 }
1149                                 update_stages_and_entry(ren1_dst, ren1->dst_entry, one, a, b, 1);
1150                                 if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
1151                                         setup_rename_df_conflict_info(RENAME_NORMAL,
1152                                                                       ren1->pair,
1153                                                                       NULL,
1154                                                                       branch1,
1155                                                                       NULL,
1156                                                                       ren1->dst_entry,
1157                                                                       NULL);
1158                                 }
1159                         }
1160                 }
1161         }
1162         string_list_clear(&a_by_dst, 0);
1163         string_list_clear(&b_by_dst, 0);
1164
1165         return clean_merge;
1166 }
1167
1168 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1169 {
1170         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1171 }
1172
1173 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1174 {
1175         void *buf;
1176         enum object_type type;
1177         unsigned long size;
1178         buf = read_sha1_file(sha1, &type, &size);
1179         if (!buf)
1180                 return error("cannot read object %s", sha1_to_hex(sha1));
1181         if (type != OBJ_BLOB) {
1182                 free(buf);
1183                 return error("object %s is not a blob", sha1_to_hex(sha1));
1184         }
1185         strbuf_attach(dst, buf, size, size + 1);
1186         return 0;
1187 }
1188
1189 static int blob_unchanged(const unsigned char *o_sha,
1190                           const unsigned char *a_sha,
1191                           int renormalize, const char *path)
1192 {
1193         struct strbuf o = STRBUF_INIT;
1194         struct strbuf a = STRBUF_INIT;
1195         int ret = 0; /* assume changed for safety */
1196
1197         if (sha_eq(o_sha, a_sha))
1198                 return 1;
1199         if (!renormalize)
1200                 return 0;
1201
1202         assert(o_sha && a_sha);
1203         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1204                 goto error_return;
1205         /*
1206          * Note: binary | is used so that both renormalizations are
1207          * performed.  Comparison can be skipped if both files are
1208          * unchanged since their sha1s have already been compared.
1209          */
1210         if (renormalize_buffer(path, o.buf, o.len, &o) |
1211             renormalize_buffer(path, a.buf, o.len, &a))
1212                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1213
1214 error_return:
1215         strbuf_release(&o);
1216         strbuf_release(&a);
1217         return ret;
1218 }
1219
1220 static void handle_delete_modify(struct merge_options *o,
1221                                  const char *path,
1222                                  const char *new_path,
1223                                  unsigned char *a_sha, int a_mode,
1224                                  unsigned char *b_sha, int b_mode)
1225 {
1226         if (!a_sha) {
1227                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1228                        "and modified in %s. Version %s of %s left in tree%s%s.",
1229                        path, o->branch1,
1230                        o->branch2, o->branch2, path,
1231                        path == new_path ? "" : " at ",
1232                        path == new_path ? "" : new_path);
1233                 update_file(o, 0, b_sha, b_mode, new_path);
1234         } else {
1235                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1236                        "and modified in %s. Version %s of %s left in tree%s%s.",
1237                        path, o->branch2,
1238                        o->branch1, o->branch1, path,
1239                        path == new_path ? "" : " at ",
1240                        path == new_path ? "" : new_path);
1241                 update_file(o, 0, a_sha, a_mode, new_path);
1242         }
1243 }
1244
1245 static int merge_content(struct merge_options *o,
1246                          const char *path,
1247                          unsigned char *o_sha, int o_mode,
1248                          unsigned char *a_sha, int a_mode,
1249                          unsigned char *b_sha, int b_mode,
1250                          const char *df_rename_conflict_branch)
1251 {
1252         const char *reason = "content";
1253         struct merge_file_info mfi;
1254         struct diff_filespec one, a, b;
1255         struct stat st;
1256         unsigned df_conflict_remains = 0;
1257
1258         if (!o_sha) {
1259                 reason = "add/add";
1260                 o_sha = (unsigned char *)null_sha1;
1261         }
1262         one.path = a.path = b.path = (char *)path;
1263         hashcpy(one.sha1, o_sha);
1264         one.mode = o_mode;
1265         hashcpy(a.sha1, a_sha);
1266         a.mode = a_mode;
1267         hashcpy(b.sha1, b_sha);
1268         b.mode = b_mode;
1269
1270         mfi = merge_file(o, &one, &a, &b, o->branch1, o->branch2);
1271         if (df_rename_conflict_branch &&
1272             lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1273                 df_conflict_remains = 1;
1274         }
1275
1276         if (mfi.clean && !df_conflict_remains &&
1277             sha_eq(mfi.sha, a_sha) && mfi.mode == a.mode)
1278                 output(o, 3, "Skipped %s (merged same as existing)", path);
1279         else
1280                 output(o, 2, "Auto-merging %s", path);
1281
1282         if (!mfi.clean) {
1283                 if (S_ISGITLINK(mfi.mode))
1284                         reason = "submodule";
1285                 output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1286                                 reason, path);
1287         }
1288
1289         if (df_conflict_remains) {
1290                 const char *new_path;
1291                 update_file_flags(o, mfi.sha, mfi.mode, path,
1292                                   o->call_depth || mfi.clean, 0);
1293                 new_path = unique_path(o, path, df_rename_conflict_branch);
1294                 mfi.clean = 0;
1295                 output(o, 1, "Adding as %s instead", new_path);
1296                 update_file_flags(o, mfi.sha, mfi.mode, new_path, 0, 1);
1297         } else {
1298                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1299         }
1300         return mfi.clean;
1301
1302 }
1303
1304 /* Per entry merge function */
1305 static int process_entry(struct merge_options *o,
1306                          const char *path, struct stage_data *entry)
1307 {
1308         /*
1309         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1310         print_index_entry("\tpath: ", entry);
1311         */
1312         int clean_merge = 1;
1313         int normalize = o->renormalize;
1314         unsigned o_mode = entry->stages[1].mode;
1315         unsigned a_mode = entry->stages[2].mode;
1316         unsigned b_mode = entry->stages[3].mode;
1317         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1318         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1319         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1320
1321         if (entry->rename_df_conflict_info)
1322                 return 1; /* Such cases are handled elsewhere. */
1323
1324         entry->processed = 1;
1325         if (o_sha && (!a_sha || !b_sha)) {
1326                 /* Case A: Deleted in one */
1327                 if ((!a_sha && !b_sha) ||
1328                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1329                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1330                         /* Deleted in both or deleted in one and
1331                          * unchanged in the other */
1332                         if (a_sha)
1333                                 output(o, 2, "Removing %s", path);
1334                         /* do not touch working file if it did not exist */
1335                         remove_file(o, 1, path, !a_sha);
1336                 } else if (string_list_has_string(&o->current_directory_set,
1337                                                   path)) {
1338                         entry->processed = 0;
1339                         return 1; /* Assume clean until processed */
1340                 } else {
1341                         /* Deleted in one and changed in the other */
1342                         clean_merge = 0;
1343                         handle_delete_modify(o, path, path,
1344                                              a_sha, a_mode, b_sha, b_mode);
1345                 }
1346
1347         } else if ((!o_sha && a_sha && !b_sha) ||
1348                    (!o_sha && !a_sha && b_sha)) {
1349                 /* Case B: Added in one. */
1350                 unsigned mode;
1351                 const unsigned char *sha;
1352
1353                 if (a_sha) {
1354                         mode = a_mode;
1355                         sha = a_sha;
1356                 } else {
1357                         mode = b_mode;
1358                         sha = b_sha;
1359                 }
1360                 if (string_list_has_string(&o->current_directory_set, path)) {
1361                         /* Handle D->F conflicts after all subfiles */
1362                         entry->processed = 0;
1363                         return 1; /* Assume clean until processed */
1364                 } else {
1365                         output(o, 2, "Adding %s", path);
1366                         update_file(o, 1, sha, mode, path);
1367                 }
1368         } else if (a_sha && b_sha) {
1369                 /* Case C: Added in both (check for same permissions) and */
1370                 /* case D: Modified in both, but differently. */
1371                 clean_merge = merge_content(o, path,
1372                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1373                                             NULL);
1374         } else if (!o_sha && !a_sha && !b_sha) {
1375                 /*
1376                  * this entry was deleted altogether. a_mode == 0 means
1377                  * we had that path and want to actively remove it.
1378                  */
1379                 remove_file(o, 1, path, !a_mode);
1380         } else
1381                 die("Fatal merge failure, shouldn't happen.");
1382
1383         return clean_merge;
1384 }
1385
1386 /*
1387  * Per entry merge function for D/F (and/or rename) conflicts.  In the
1388  * cases we can cleanly resolve D/F conflicts, process_entry() can
1389  * clean out all the files below the directory for us.  All D/F
1390  * conflict cases must be handled here at the end to make sure any
1391  * directories that can be cleaned out, are.
1392  *
1393  * Some rename conflicts may also be handled here that don't necessarily
1394  * involve D/F conflicts, since the code to handle them is generic enough
1395  * to handle those rename conflicts with or without D/F conflicts also
1396  * being involved.
1397  */
1398 static int process_df_entry(struct merge_options *o,
1399                             const char *path, struct stage_data *entry)
1400 {
1401         int clean_merge = 1;
1402         unsigned o_mode = entry->stages[1].mode;
1403         unsigned a_mode = entry->stages[2].mode;
1404         unsigned b_mode = entry->stages[3].mode;
1405         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1406         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1407         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1408         struct stat st;
1409
1410         entry->processed = 1;
1411         if (entry->rename_df_conflict_info) {
1412                 struct rename_df_conflict_info *conflict_info = entry->rename_df_conflict_info;
1413                 char *src;
1414                 switch (conflict_info->rename_type) {
1415                 case RENAME_NORMAL:
1416                         clean_merge = merge_content(o, path,
1417                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1418                                                     conflict_info->branch1);
1419                         break;
1420                 case RENAME_DELETE:
1421                         clean_merge = 0;
1422                         conflict_rename_delete(o, conflict_info->pair1,
1423                                                conflict_info->branch1,
1424                                                conflict_info->branch2);
1425                         break;
1426                 case RENAME_ONE_FILE_TO_TWO:
1427                         src = conflict_info->pair1->one->path;
1428                         clean_merge = 0;
1429                         output(o, 1, "CONFLICT (rename/rename): "
1430                                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1431                                "rename \"%s\"->\"%s\" in \"%s\"%s",
1432                                src, conflict_info->pair1->two->path, conflict_info->branch1,
1433                                src, conflict_info->pair2->two->path, conflict_info->branch2,
1434                                o->call_depth ? " (left unresolved)" : "");
1435                         if (o->call_depth) {
1436                                 remove_file_from_cache(src);
1437                                 update_file(o, 0, conflict_info->pair1->one->sha1,
1438                                             conflict_info->pair1->one->mode, src);
1439                         }
1440                         conflict_rename_rename_1to2(o, conflict_info->pair1,
1441                                                     conflict_info->branch1,
1442                                                     conflict_info->pair2,
1443                                                     conflict_info->branch2);
1444                         conflict_info->dst_entry2->processed = 1;
1445                         break;
1446                 default:
1447                         entry->processed = 0;
1448                         break;
1449                 }
1450         } else if (o_sha && (!a_sha || !b_sha)) {
1451                 /* Modify/delete; deleted side may have put a directory in the way */
1452                 const char *new_path = path;
1453                 if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode))
1454                         new_path = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1455                 clean_merge = 0;
1456                 handle_delete_modify(o, path, new_path,
1457                                      a_sha, a_mode, b_sha, b_mode);
1458         } else if (!o_sha && !!a_sha != !!b_sha) {
1459                 /* directory -> (directory, file) */
1460                 const char *add_branch;
1461                 const char *other_branch;
1462                 unsigned mode;
1463                 const unsigned char *sha;
1464                 const char *conf;
1465
1466                 if (a_sha) {
1467                         add_branch = o->branch1;
1468                         other_branch = o->branch2;
1469                         mode = a_mode;
1470                         sha = a_sha;
1471                         conf = "file/directory";
1472                 } else {
1473                         add_branch = o->branch2;
1474                         other_branch = o->branch1;
1475                         mode = b_mode;
1476                         sha = b_sha;
1477                         conf = "directory/file";
1478                 }
1479                 if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1480                         const char *new_path = unique_path(o, path, add_branch);
1481                         clean_merge = 0;
1482                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1483                                "Adding %s as %s",
1484                                conf, path, other_branch, path, new_path);
1485                         update_file(o, 0, sha, mode, new_path);
1486                 } else {
1487                         output(o, 2, "Adding %s", path);
1488                         update_file(o, 1, sha, mode, path);
1489                 }
1490         } else {
1491                 entry->processed = 0;
1492                 return 1; /* not handled; assume clean until processed */
1493         }
1494
1495         return clean_merge;
1496 }
1497
1498 int merge_trees(struct merge_options *o,
1499                 struct tree *head,
1500                 struct tree *merge,
1501                 struct tree *common,
1502                 struct tree **result)
1503 {
1504         int code, clean;
1505
1506         if (o->subtree_shift) {
1507                 merge = shift_tree_object(head, merge, o->subtree_shift);
1508                 common = shift_tree_object(head, common, o->subtree_shift);
1509         }
1510
1511         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1512                 output(o, 0, "Already up-to-date!");
1513                 *result = head;
1514                 return 1;
1515         }
1516
1517         code = git_merge_trees(o->call_depth, common, head, merge);
1518
1519         if (code != 0) {
1520                 if (show(o, 4) || o->call_depth)
1521                         die("merging of trees %s and %s failed",
1522                             sha1_to_hex(head->object.sha1),
1523                             sha1_to_hex(merge->object.sha1));
1524                 else
1525                         exit(128);
1526         }
1527
1528         if (unmerged_cache()) {
1529                 struct string_list *entries, *re_head, *re_merge;
1530                 int i;
1531                 string_list_clear(&o->current_file_set, 1);
1532                 string_list_clear(&o->current_directory_set, 1);
1533                 get_files_dirs(o, head);
1534                 get_files_dirs(o, merge);
1535
1536                 entries = get_unmerged();
1537                 make_room_for_directories_of_df_conflicts(o, entries);
1538                 re_head  = get_renames(o, head, common, head, merge, entries);
1539                 re_merge = get_renames(o, merge, common, head, merge, entries);
1540                 clean = process_renames(o, re_head, re_merge);
1541                 for (i = 0; i < entries->nr; i++) {
1542                         const char *path = entries->items[i].string;
1543                         struct stage_data *e = entries->items[i].util;
1544                         if (!e->processed
1545                                 && !process_entry(o, path, e))
1546                                 clean = 0;
1547                 }
1548                 for (i = 0; i < entries->nr; i++) {
1549                         const char *path = entries->items[i].string;
1550                         struct stage_data *e = entries->items[i].util;
1551                         if (!e->processed
1552                                 && !process_df_entry(o, path, e))
1553                                 clean = 0;
1554                 }
1555                 for (i = 0; i < entries->nr; i++) {
1556                         struct stage_data *e = entries->items[i].util;
1557                         if (!e->processed)
1558                                 die("Unprocessed path??? %s",
1559                                     entries->items[i].string);
1560                 }
1561
1562                 string_list_clear(re_merge, 0);
1563                 string_list_clear(re_head, 0);
1564                 string_list_clear(entries, 1);
1565
1566         }
1567         else
1568                 clean = 1;
1569
1570         if (o->call_depth)
1571                 *result = write_tree_from_memory(o);
1572
1573         return clean;
1574 }
1575
1576 static struct commit_list *reverse_commit_list(struct commit_list *list)
1577 {
1578         struct commit_list *next = NULL, *current, *backup;
1579         for (current = list; current; current = backup) {
1580                 backup = current->next;
1581                 current->next = next;
1582                 next = current;
1583         }
1584         return next;
1585 }
1586
1587 /*
1588  * Merge the commits h1 and h2, return the resulting virtual
1589  * commit object and a flag indicating the cleanness of the merge.
1590  */
1591 int merge_recursive(struct merge_options *o,
1592                     struct commit *h1,
1593                     struct commit *h2,
1594                     struct commit_list *ca,
1595                     struct commit **result)
1596 {
1597         struct commit_list *iter;
1598         struct commit *merged_common_ancestors;
1599         struct tree *mrtree = mrtree;
1600         int clean;
1601
1602         if (show(o, 4)) {
1603                 output(o, 4, "Merging:");
1604                 output_commit_title(o, h1);
1605                 output_commit_title(o, h2);
1606         }
1607
1608         if (!ca) {
1609                 ca = get_merge_bases(h1, h2, 1);
1610                 ca = reverse_commit_list(ca);
1611         }
1612
1613         if (show(o, 5)) {
1614                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1615                 for (iter = ca; iter; iter = iter->next)
1616                         output_commit_title(o, iter->item);
1617         }
1618
1619         merged_common_ancestors = pop_commit(&ca);
1620         if (merged_common_ancestors == NULL) {
1621                 /* if there is no common ancestor, make an empty tree */
1622                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1623
1624                 tree->object.parsed = 1;
1625                 tree->object.type = OBJ_TREE;
1626                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1627                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1628         }
1629
1630         for (iter = ca; iter; iter = iter->next) {
1631                 const char *saved_b1, *saved_b2;
1632                 o->call_depth++;
1633                 /*
1634                  * When the merge fails, the result contains files
1635                  * with conflict markers. The cleanness flag is
1636                  * ignored, it was never actually used, as result of
1637                  * merge_trees has always overwritten it: the committed
1638                  * "conflicts" were already resolved.
1639                  */
1640                 discard_cache();
1641                 saved_b1 = o->branch1;
1642                 saved_b2 = o->branch2;
1643                 o->branch1 = "Temporary merge branch 1";
1644                 o->branch2 = "Temporary merge branch 2";
1645                 merge_recursive(o, merged_common_ancestors, iter->item,
1646                                 NULL, &merged_common_ancestors);
1647                 o->branch1 = saved_b1;
1648                 o->branch2 = saved_b2;
1649                 o->call_depth--;
1650
1651                 if (!merged_common_ancestors)
1652                         die("merge returned no commit");
1653         }
1654
1655         discard_cache();
1656         if (!o->call_depth)
1657                 read_cache();
1658
1659         o->ancestor = "merged common ancestors";
1660         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1661                             &mrtree);
1662
1663         if (o->call_depth) {
1664                 *result = make_virtual_commit(mrtree, "merged tree");
1665                 commit_list_insert(h1, &(*result)->parents);
1666                 commit_list_insert(h2, &(*result)->parents->next);
1667         }
1668         flush_output(o);
1669         return clean;
1670 }
1671
1672 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1673 {
1674         struct object *object;
1675
1676         object = deref_tag(parse_object(sha1), name, strlen(name));
1677         if (!object)
1678                 return NULL;
1679         if (object->type == OBJ_TREE)
1680                 return make_virtual_commit((struct tree*)object, name);
1681         if (object->type != OBJ_COMMIT)
1682                 return NULL;
1683         if (parse_commit((struct commit *)object))
1684                 return NULL;
1685         return (struct commit *)object;
1686 }
1687
1688 int merge_recursive_generic(struct merge_options *o,
1689                             const unsigned char *head,
1690                             const unsigned char *merge,
1691                             int num_base_list,
1692                             const unsigned char **base_list,
1693                             struct commit **result)
1694 {
1695         int clean, index_fd;
1696         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1697         struct commit *head_commit = get_ref(head, o->branch1);
1698         struct commit *next_commit = get_ref(merge, o->branch2);
1699         struct commit_list *ca = NULL;
1700
1701         if (base_list) {
1702                 int i;
1703                 for (i = 0; i < num_base_list; ++i) {
1704                         struct commit *base;
1705                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1706                                 return error("Could not parse object '%s'",
1707                                         sha1_to_hex(base_list[i]));
1708                         commit_list_insert(base, &ca);
1709                 }
1710         }
1711
1712         index_fd = hold_locked_index(lock, 1);
1713         clean = merge_recursive(o, head_commit, next_commit, ca,
1714                         result);
1715         if (active_cache_changed &&
1716                         (write_cache(index_fd, active_cache, active_nr) ||
1717                          commit_locked_index(lock)))
1718                 return error("Unable to write index.");
1719
1720         return clean ? 0 : 1;
1721 }
1722
1723 static int merge_recursive_config(const char *var, const char *value, void *cb)
1724 {
1725         struct merge_options *o = cb;
1726         if (!strcasecmp(var, "merge.verbosity")) {
1727                 o->verbosity = git_config_int(var, value);
1728                 return 0;
1729         }
1730         if (!strcasecmp(var, "diff.renamelimit")) {
1731                 o->diff_rename_limit = git_config_int(var, value);
1732                 return 0;
1733         }
1734         if (!strcasecmp(var, "merge.renamelimit")) {
1735                 o->merge_rename_limit = git_config_int(var, value);
1736                 return 0;
1737         }
1738         return git_xmerge_config(var, value, cb);
1739 }
1740
1741 void init_merge_options(struct merge_options *o)
1742 {
1743         memset(o, 0, sizeof(struct merge_options));
1744         o->verbosity = 2;
1745         o->buffer_output = 1;
1746         o->diff_rename_limit = -1;
1747         o->merge_rename_limit = -1;
1748         o->renormalize = 0;
1749         git_config(merge_recursive_config, o);
1750         if (getenv("GIT_MERGE_VERBOSITY"))
1751                 o->verbosity =
1752                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1753         if (o->verbosity >= 5)
1754                 o->buffer_output = 0;
1755         strbuf_init(&o->obuf, 0);
1756         memset(&o->current_file_set, 0, sizeof(struct string_list));
1757         o->current_file_set.strdup_strings = 1;
1758         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1759         o->current_directory_set.strdup_strings = 1;
1760 }
1761
1762 int parse_merge_opt(struct merge_options *o, const char *s)
1763 {
1764         if (!s || !*s)
1765                 return -1;
1766         if (!strcmp(s, "ours"))
1767                 o->recursive_variant = MERGE_RECURSIVE_OURS;
1768         else if (!strcmp(s, "theirs"))
1769                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
1770         else if (!strcmp(s, "subtree"))
1771                 o->subtree_shift = "";
1772         else if (!prefixcmp(s, "subtree="))
1773                 o->subtree_shift = s + strlen("subtree=");
1774         else if (!strcmp(s, "patience"))
1775                 o->xdl_opts |= XDF_PATIENCE_DIFF;
1776         else if (!strcmp(s, "ignore-space-change"))
1777                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
1778         else if (!strcmp(s, "ignore-all-space"))
1779                 o->xdl_opts |= XDF_IGNORE_WHITESPACE;
1780         else if (!strcmp(s, "ignore-space-at-eol"))
1781                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
1782         else if (!strcmp(s, "renormalize"))
1783                 o->renormalize = 1;
1784         else if (!strcmp(s, "no-renormalize"))
1785                 o->renormalize = 0;
1786         else if (!prefixcmp(s, "rename-threshold=")) {
1787                 const char *score = s + strlen("rename-threshold=");
1788                 if ((o->rename_score = parse_rename_score(&score)) == -1 || *score != 0)
1789                         return -1;
1790         }
1791         else
1792                 return -1;
1793         return 0;
1794 }