git-worktree.txt: recommend 'git worktree remove' over manual deletion
[git] / merge-recursive.c
1 /*
2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
3  * Fredrik Kuivinen.
4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
5  */
6 #include "cache.h"
7 #include "config.h"
8 #include "advice.h"
9 #include "lockfile.h"
10 #include "cache-tree.h"
11 #include "commit.h"
12 #include "blob.h"
13 #include "builtin.h"
14 #include "tree-walk.h"
15 #include "diff.h"
16 #include "diffcore.h"
17 #include "tag.h"
18 #include "unpack-trees.h"
19 #include "string-list.h"
20 #include "xdiff-interface.h"
21 #include "ll-merge.h"
22 #include "attr.h"
23 #include "merge-recursive.h"
24 #include "dir.h"
25 #include "submodule.h"
26
27 struct path_hashmap_entry {
28         struct hashmap_entry e;
29         char path[FLEX_ARRAY];
30 };
31
32 static int path_hashmap_cmp(const void *cmp_data,
33                             const void *entry,
34                             const void *entry_or_key,
35                             const void *keydata)
36 {
37         const struct path_hashmap_entry *a = entry;
38         const struct path_hashmap_entry *b = entry_or_key;
39         const char *key = keydata;
40
41         if (ignore_case)
42                 return strcasecmp(a->path, key ? key : b->path);
43         else
44                 return strcmp(a->path, key ? key : b->path);
45 }
46
47 static unsigned int path_hash(const char *path)
48 {
49         return ignore_case ? strihash(path) : strhash(path);
50 }
51
52 static void flush_output(struct merge_options *o)
53 {
54         if (o->buffer_output < 2 && o->obuf.len) {
55                 fputs(o->obuf.buf, stdout);
56                 strbuf_reset(&o->obuf);
57         }
58 }
59
60 static int err(struct merge_options *o, const char *err, ...)
61 {
62         va_list params;
63
64         if (o->buffer_output < 2)
65                 flush_output(o);
66         else {
67                 strbuf_complete(&o->obuf, '\n');
68                 strbuf_addstr(&o->obuf, "error: ");
69         }
70         va_start(params, err);
71         strbuf_vaddf(&o->obuf, err, params);
72         va_end(params);
73         if (o->buffer_output > 1)
74                 strbuf_addch(&o->obuf, '\n');
75         else {
76                 error("%s", o->obuf.buf);
77                 strbuf_reset(&o->obuf);
78         }
79
80         return -1;
81 }
82
83 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
84                                       const char *subtree_shift)
85 {
86         struct object_id shifted;
87
88         if (!*subtree_shift) {
89                 shift_tree(&one->object.oid, &two->object.oid, &shifted, 0);
90         } else {
91                 shift_tree_by(&one->object.oid, &two->object.oid, &shifted,
92                               subtree_shift);
93         }
94         if (!oidcmp(&two->object.oid, &shifted))
95                 return two;
96         return lookup_tree(&shifted);
97 }
98
99 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
100 {
101         struct commit *commit = alloc_commit_node();
102
103         set_merge_remote_desc(commit, comment, (struct object *)commit);
104         commit->tree = tree;
105         commit->object.parsed = 1;
106         return commit;
107 }
108
109 /*
110  * Since we use get_tree_entry(), which does not put the read object into
111  * the object pool, we cannot rely on a == b.
112  */
113 static int oid_eq(const struct object_id *a, const struct object_id *b)
114 {
115         if (!a && !b)
116                 return 2;
117         return a && b && oidcmp(a, b) == 0;
118 }
119
120 enum rename_type {
121         RENAME_NORMAL = 0,
122         RENAME_DELETE,
123         RENAME_ONE_FILE_TO_ONE,
124         RENAME_ONE_FILE_TO_TWO,
125         RENAME_TWO_FILES_TO_ONE
126 };
127
128 struct rename_conflict_info {
129         enum rename_type rename_type;
130         struct diff_filepair *pair1;
131         struct diff_filepair *pair2;
132         const char *branch1;
133         const char *branch2;
134         struct stage_data *dst_entry1;
135         struct stage_data *dst_entry2;
136         struct diff_filespec ren1_other;
137         struct diff_filespec ren2_other;
138 };
139
140 /*
141  * Since we want to write the index eventually, we cannot reuse the index
142  * for these (temporary) data.
143  */
144 struct stage_data {
145         struct {
146                 unsigned mode;
147                 struct object_id oid;
148         } stages[4];
149         struct rename_conflict_info *rename_conflict_info;
150         unsigned processed:1;
151 };
152
153 static inline void setup_rename_conflict_info(enum rename_type rename_type,
154                                               struct diff_filepair *pair1,
155                                               struct diff_filepair *pair2,
156                                               const char *branch1,
157                                               const char *branch2,
158                                               struct stage_data *dst_entry1,
159                                               struct stage_data *dst_entry2,
160                                               struct merge_options *o,
161                                               struct stage_data *src_entry1,
162                                               struct stage_data *src_entry2)
163 {
164         struct rename_conflict_info *ci = xcalloc(1, sizeof(struct rename_conflict_info));
165         ci->rename_type = rename_type;
166         ci->pair1 = pair1;
167         ci->branch1 = branch1;
168         ci->branch2 = branch2;
169
170         ci->dst_entry1 = dst_entry1;
171         dst_entry1->rename_conflict_info = ci;
172         dst_entry1->processed = 0;
173
174         assert(!pair2 == !dst_entry2);
175         if (dst_entry2) {
176                 ci->dst_entry2 = dst_entry2;
177                 ci->pair2 = pair2;
178                 dst_entry2->rename_conflict_info = ci;
179         }
180
181         if (rename_type == RENAME_TWO_FILES_TO_ONE) {
182                 /*
183                  * For each rename, there could have been
184                  * modifications on the side of history where that
185                  * file was not renamed.
186                  */
187                 int ostage1 = o->branch1 == branch1 ? 3 : 2;
188                 int ostage2 = ostage1 ^ 1;
189
190                 ci->ren1_other.path = pair1->one->path;
191                 oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
192                 ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
193
194                 ci->ren2_other.path = pair2->one->path;
195                 oidcpy(&ci->ren2_other.oid, &src_entry2->stages[ostage2].oid);
196                 ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
197         }
198 }
199
200 static int show(struct merge_options *o, int v)
201 {
202         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
203 }
204
205 __attribute__((format (printf, 3, 4)))
206 static void output(struct merge_options *o, int v, const char *fmt, ...)
207 {
208         va_list ap;
209
210         if (!show(o, v))
211                 return;
212
213         strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
214
215         va_start(ap, fmt);
216         strbuf_vaddf(&o->obuf, fmt, ap);
217         va_end(ap);
218
219         strbuf_addch(&o->obuf, '\n');
220         if (!o->buffer_output)
221                 flush_output(o);
222 }
223
224 static void output_commit_title(struct merge_options *o, struct commit *commit)
225 {
226         strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
227         if (commit->util)
228                 strbuf_addf(&o->obuf, "virtual %s\n",
229                         merge_remote_util(commit)->name);
230         else {
231                 strbuf_add_unique_abbrev(&o->obuf, commit->object.oid.hash,
232                                          DEFAULT_ABBREV);
233                 strbuf_addch(&o->obuf, ' ');
234                 if (parse_commit(commit) != 0)
235                         strbuf_addstr(&o->obuf, _("(bad commit)\n"));
236                 else {
237                         const char *title;
238                         const char *msg = get_commit_buffer(commit, NULL);
239                         int len = find_commit_subject(msg, &title);
240                         if (len)
241                                 strbuf_addf(&o->obuf, "%.*s\n", len, title);
242                         unuse_commit_buffer(commit, msg);
243                 }
244         }
245         flush_output(o);
246 }
247
248 static int add_cacheinfo(struct merge_options *o,
249                 unsigned int mode, const struct object_id *oid,
250                 const char *path, int stage, int refresh, int options)
251 {
252         struct cache_entry *ce;
253         int ret;
254
255         ce = make_cache_entry(mode, oid ? oid->hash : null_sha1, path, stage, 0);
256         if (!ce)
257                 return err(o, _("addinfo_cache failed for path '%s'"), path);
258
259         ret = add_cache_entry(ce, options);
260         if (refresh) {
261                 struct cache_entry *nce;
262
263                 nce = refresh_cache_entry(ce, CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
264                 if (!nce)
265                         return err(o, _("addinfo_cache failed for path '%s'"), path);
266                 if (nce != ce)
267                         ret = add_cache_entry(nce, options);
268         }
269         return ret;
270 }
271
272 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
273 {
274         parse_tree(tree);
275         init_tree_desc(desc, tree->buffer, tree->size);
276 }
277
278 static int git_merge_trees(int index_only,
279                            struct tree *common,
280                            struct tree *head,
281                            struct tree *merge)
282 {
283         int rc;
284         struct tree_desc t[3];
285         struct unpack_trees_options opts;
286
287         memset(&opts, 0, sizeof(opts));
288         if (index_only)
289                 opts.index_only = 1;
290         else
291                 opts.update = 1;
292         opts.merge = 1;
293         opts.head_idx = 2;
294         opts.fn = threeway_merge;
295         opts.src_index = &the_index;
296         opts.dst_index = &the_index;
297         setup_unpack_trees_porcelain(&opts, "merge");
298
299         init_tree_desc_from_tree(t+0, common);
300         init_tree_desc_from_tree(t+1, head);
301         init_tree_desc_from_tree(t+2, merge);
302
303         rc = unpack_trees(3, t, &opts);
304         cache_tree_free(&active_cache_tree);
305         return rc;
306 }
307
308 struct tree *write_tree_from_memory(struct merge_options *o)
309 {
310         struct tree *result = NULL;
311
312         if (unmerged_cache()) {
313                 int i;
314                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
315                 for (i = 0; i < active_nr; i++) {
316                         const struct cache_entry *ce = active_cache[i];
317                         if (ce_stage(ce))
318                                 fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
319                                         (int)ce_namelen(ce), ce->name);
320                 }
321                 die("BUG: unmerged index entries in merge-recursive.c");
322         }
323
324         if (!active_cache_tree)
325                 active_cache_tree = cache_tree();
326
327         if (!cache_tree_fully_valid(active_cache_tree) &&
328             cache_tree_update(&the_index, 0) < 0) {
329                 err(o, _("error building trees"));
330                 return NULL;
331         }
332
333         result = lookup_tree(&active_cache_tree->oid);
334
335         return result;
336 }
337
338 static int save_files_dirs(const unsigned char *sha1,
339                 struct strbuf *base, const char *path,
340                 unsigned int mode, int stage, void *context)
341 {
342         struct path_hashmap_entry *entry;
343         int baselen = base->len;
344         struct merge_options *o = context;
345
346         strbuf_addstr(base, path);
347
348         FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
349         hashmap_entry_init(entry, path_hash(entry->path));
350         hashmap_add(&o->current_file_dir_set, entry);
351
352         strbuf_setlen(base, baselen);
353         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
354 }
355
356 static void get_files_dirs(struct merge_options *o, struct tree *tree)
357 {
358         struct pathspec match_all;
359         memset(&match_all, 0, sizeof(match_all));
360         read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o);
361 }
362
363 /*
364  * Returns an index_entry instance which doesn't have to correspond to
365  * a real cache entry in Git's index.
366  */
367 static struct stage_data *insert_stage_data(const char *path,
368                 struct tree *o, struct tree *a, struct tree *b,
369                 struct string_list *entries)
370 {
371         struct string_list_item *item;
372         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
373         get_tree_entry(o->object.oid.hash, path,
374                         e->stages[1].oid.hash, &e->stages[1].mode);
375         get_tree_entry(a->object.oid.hash, path,
376                         e->stages[2].oid.hash, &e->stages[2].mode);
377         get_tree_entry(b->object.oid.hash, path,
378                         e->stages[3].oid.hash, &e->stages[3].mode);
379         item = string_list_insert(entries, path);
380         item->util = e;
381         return e;
382 }
383
384 /*
385  * Create a dictionary mapping file names to stage_data objects. The
386  * dictionary contains one entry for every path with a non-zero stage entry.
387  */
388 static struct string_list *get_unmerged(void)
389 {
390         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
391         int i;
392
393         unmerged->strdup_strings = 1;
394
395         for (i = 0; i < active_nr; i++) {
396                 struct string_list_item *item;
397                 struct stage_data *e;
398                 const struct cache_entry *ce = active_cache[i];
399                 if (!ce_stage(ce))
400                         continue;
401
402                 item = string_list_lookup(unmerged, ce->name);
403                 if (!item) {
404                         item = string_list_insert(unmerged, ce->name);
405                         item->util = xcalloc(1, sizeof(struct stage_data));
406                 }
407                 e = item->util;
408                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
409                 oidcpy(&e->stages[ce_stage(ce)].oid, &ce->oid);
410         }
411
412         return unmerged;
413 }
414
415 static int string_list_df_name_compare(const char *one, const char *two)
416 {
417         int onelen = strlen(one);
418         int twolen = strlen(two);
419         /*
420          * Here we only care that entries for D/F conflicts are
421          * adjacent, in particular with the file of the D/F conflict
422          * appearing before files below the corresponding directory.
423          * The order of the rest of the list is irrelevant for us.
424          *
425          * To achieve this, we sort with df_name_compare and provide
426          * the mode S_IFDIR so that D/F conflicts will sort correctly.
427          * We use the mode S_IFDIR for everything else for simplicity,
428          * since in other cases any changes in their order due to
429          * sorting cause no problems for us.
430          */
431         int cmp = df_name_compare(one, onelen, S_IFDIR,
432                                   two, twolen, S_IFDIR);
433         /*
434          * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
435          * that 'foo' comes before 'foo/bar'.
436          */
437         if (cmp)
438                 return cmp;
439         return onelen - twolen;
440 }
441
442 static void record_df_conflict_files(struct merge_options *o,
443                                      struct string_list *entries)
444 {
445         /* If there is a D/F conflict and the file for such a conflict
446          * currently exist in the working tree, we want to allow it to be
447          * removed to make room for the corresponding directory if needed.
448          * The files underneath the directories of such D/F conflicts will
449          * be processed before the corresponding file involved in the D/F
450          * conflict.  If the D/F directory ends up being removed by the
451          * merge, then we won't have to touch the D/F file.  If the D/F
452          * directory needs to be written to the working copy, then the D/F
453          * file will simply be removed (in make_room_for_path()) to make
454          * room for the necessary paths.  Note that if both the directory
455          * and the file need to be present, then the D/F file will be
456          * reinstated with a new unique name at the time it is processed.
457          */
458         struct string_list df_sorted_entries = STRING_LIST_INIT_NODUP;
459         const char *last_file = NULL;
460         int last_len = 0;
461         int i;
462
463         /*
464          * If we're merging merge-bases, we don't want to bother with
465          * any working directory changes.
466          */
467         if (o->call_depth)
468                 return;
469
470         /* Ensure D/F conflicts are adjacent in the entries list. */
471         for (i = 0; i < entries->nr; i++) {
472                 struct string_list_item *next = &entries->items[i];
473                 string_list_append(&df_sorted_entries, next->string)->util =
474                                    next->util;
475         }
476         df_sorted_entries.cmp = string_list_df_name_compare;
477         string_list_sort(&df_sorted_entries);
478
479         string_list_clear(&o->df_conflict_file_set, 1);
480         for (i = 0; i < df_sorted_entries.nr; i++) {
481                 const char *path = df_sorted_entries.items[i].string;
482                 int len = strlen(path);
483                 struct stage_data *e = df_sorted_entries.items[i].util;
484
485                 /*
486                  * Check if last_file & path correspond to a D/F conflict;
487                  * i.e. whether path is last_file+'/'+<something>.
488                  * If so, record that it's okay to remove last_file to make
489                  * room for path and friends if needed.
490                  */
491                 if (last_file &&
492                     len > last_len &&
493                     memcmp(path, last_file, last_len) == 0 &&
494                     path[last_len] == '/') {
495                         string_list_insert(&o->df_conflict_file_set, last_file);
496                 }
497
498                 /*
499                  * Determine whether path could exist as a file in the
500                  * working directory as a possible D/F conflict.  This
501                  * will only occur when it exists in stage 2 as a
502                  * file.
503                  */
504                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
505                         last_file = path;
506                         last_len = len;
507                 } else {
508                         last_file = NULL;
509                 }
510         }
511         string_list_clear(&df_sorted_entries, 0);
512 }
513
514 struct rename {
515         struct diff_filepair *pair;
516         struct stage_data *src_entry;
517         struct stage_data *dst_entry;
518         unsigned processed:1;
519 };
520
521 /*
522  * Get information of all renames which occurred between 'o_tree' and
523  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
524  * 'b_tree') to be able to associate the correct cache entries with
525  * the rename information. 'tree' is always equal to either a_tree or b_tree.
526  */
527 static struct string_list *get_renames(struct merge_options *o,
528                                        struct tree *tree,
529                                        struct tree *o_tree,
530                                        struct tree *a_tree,
531                                        struct tree *b_tree,
532                                        struct string_list *entries)
533 {
534         int i;
535         struct string_list *renames;
536         struct diff_options opts;
537
538         renames = xcalloc(1, sizeof(struct string_list));
539         if (!o->detect_rename)
540                 return renames;
541
542         diff_setup(&opts);
543         opts.flags.recursive = 1;
544         opts.flags.rename_empty = 0;
545         opts.detect_rename = DIFF_DETECT_RENAME;
546         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
547                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
548                             1000;
549         opts.rename_score = o->rename_score;
550         opts.show_rename_progress = o->show_rename_progress;
551         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
552         diff_setup_done(&opts);
553         diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
554         diffcore_std(&opts);
555         if (opts.needed_rename_limit > o->needed_rename_limit)
556                 o->needed_rename_limit = opts.needed_rename_limit;
557         for (i = 0; i < diff_queued_diff.nr; ++i) {
558                 struct string_list_item *item;
559                 struct rename *re;
560                 struct diff_filepair *pair = diff_queued_diff.queue[i];
561                 if (pair->status != 'R') {
562                         diff_free_filepair(pair);
563                         continue;
564                 }
565                 re = xmalloc(sizeof(*re));
566                 re->processed = 0;
567                 re->pair = pair;
568                 item = string_list_lookup(entries, re->pair->one->path);
569                 if (!item)
570                         re->src_entry = insert_stage_data(re->pair->one->path,
571                                         o_tree, a_tree, b_tree, entries);
572                 else
573                         re->src_entry = item->util;
574
575                 item = string_list_lookup(entries, re->pair->two->path);
576                 if (!item)
577                         re->dst_entry = insert_stage_data(re->pair->two->path,
578                                         o_tree, a_tree, b_tree, entries);
579                 else
580                         re->dst_entry = item->util;
581                 item = string_list_insert(renames, pair->one->path);
582                 item->util = re;
583         }
584         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
585         diff_queued_diff.nr = 0;
586         diff_flush(&opts);
587         return renames;
588 }
589
590 static int update_stages(struct merge_options *opt, const char *path,
591                          const struct diff_filespec *o,
592                          const struct diff_filespec *a,
593                          const struct diff_filespec *b)
594 {
595
596         /*
597          * NOTE: It is usually a bad idea to call update_stages on a path
598          * before calling update_file on that same path, since it can
599          * sometimes lead to spurious "refusing to lose untracked file..."
600          * messages from update_file (via make_room_for path via
601          * would_lose_untracked).  Instead, reverse the order of the calls
602          * (executing update_file first and then update_stages).
603          */
604         int clear = 1;
605         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
606         if (clear)
607                 if (remove_file_from_cache(path))
608                         return -1;
609         if (o)
610                 if (add_cacheinfo(opt, o->mode, &o->oid, path, 1, 0, options))
611                         return -1;
612         if (a)
613                 if (add_cacheinfo(opt, a->mode, &a->oid, path, 2, 0, options))
614                         return -1;
615         if (b)
616                 if (add_cacheinfo(opt, b->mode, &b->oid, path, 3, 0, options))
617                         return -1;
618         return 0;
619 }
620
621 static void update_entry(struct stage_data *entry,
622                          struct diff_filespec *o,
623                          struct diff_filespec *a,
624                          struct diff_filespec *b)
625 {
626         entry->processed = 0;
627         entry->stages[1].mode = o->mode;
628         entry->stages[2].mode = a->mode;
629         entry->stages[3].mode = b->mode;
630         oidcpy(&entry->stages[1].oid, &o->oid);
631         oidcpy(&entry->stages[2].oid, &a->oid);
632         oidcpy(&entry->stages[3].oid, &b->oid);
633 }
634
635 static int remove_file(struct merge_options *o, int clean,
636                        const char *path, int no_wd)
637 {
638         int update_cache = o->call_depth || clean;
639         int update_working_directory = !o->call_depth && !no_wd;
640
641         if (update_cache) {
642                 if (remove_file_from_cache(path))
643                         return -1;
644         }
645         if (update_working_directory) {
646                 if (ignore_case) {
647                         struct cache_entry *ce;
648                         ce = cache_file_exists(path, strlen(path), ignore_case);
649                         if (ce && ce_stage(ce) == 0 && strcmp(path, ce->name))
650                                 return 0;
651                 }
652                 if (remove_path(path))
653                         return -1;
654         }
655         return 0;
656 }
657
658 /* add a string to a strbuf, but converting "/" to "_" */
659 static void add_flattened_path(struct strbuf *out, const char *s)
660 {
661         size_t i = out->len;
662         strbuf_addstr(out, s);
663         for (; i < out->len; i++)
664                 if (out->buf[i] == '/')
665                         out->buf[i] = '_';
666 }
667
668 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
669 {
670         struct path_hashmap_entry *entry;
671         struct strbuf newpath = STRBUF_INIT;
672         int suffix = 0;
673         size_t base_len;
674
675         strbuf_addf(&newpath, "%s~", path);
676         add_flattened_path(&newpath, branch);
677
678         base_len = newpath.len;
679         while (hashmap_get_from_hash(&o->current_file_dir_set,
680                                      path_hash(newpath.buf), newpath.buf) ||
681                (!o->call_depth && file_exists(newpath.buf))) {
682                 strbuf_setlen(&newpath, base_len);
683                 strbuf_addf(&newpath, "_%d", suffix++);
684         }
685
686         FLEX_ALLOC_MEM(entry, path, newpath.buf, newpath.len);
687         hashmap_entry_init(entry, path_hash(entry->path));
688         hashmap_add(&o->current_file_dir_set, entry);
689         return strbuf_detach(&newpath, NULL);
690 }
691
692 /**
693  * Check whether a directory in the index is in the way of an incoming
694  * file.  Return 1 if so.  If check_working_copy is non-zero, also
695  * check the working directory.  If empty_ok is non-zero, also return
696  * 0 in the case where the working-tree dir exists but is empty.
697  */
698 static int dir_in_way(const char *path, int check_working_copy, int empty_ok)
699 {
700         int pos;
701         struct strbuf dirpath = STRBUF_INIT;
702         struct stat st;
703
704         strbuf_addstr(&dirpath, path);
705         strbuf_addch(&dirpath, '/');
706
707         pos = cache_name_pos(dirpath.buf, dirpath.len);
708
709         if (pos < 0)
710                 pos = -1 - pos;
711         if (pos < active_nr &&
712             !strncmp(dirpath.buf, active_cache[pos]->name, dirpath.len)) {
713                 strbuf_release(&dirpath);
714                 return 1;
715         }
716
717         strbuf_release(&dirpath);
718         return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode) &&
719                 !(empty_ok && is_empty_dir(path));
720 }
721
722 static int was_tracked(const char *path)
723 {
724         int pos = cache_name_pos(path, strlen(path));
725
726         if (0 <= pos)
727                 /* we have been tracking this path */
728                 return 1;
729
730         /*
731          * Look for an unmerged entry for the path,
732          * specifically stage #2, which would indicate
733          * that "our" side before the merge started
734          * had the path tracked (and resulted in a conflict).
735          */
736         for (pos = -1 - pos;
737              pos < active_nr && !strcmp(path, active_cache[pos]->name);
738              pos++)
739                 if (ce_stage(active_cache[pos]) == 2)
740                         return 1;
741         return 0;
742 }
743
744 static int would_lose_untracked(const char *path)
745 {
746         return !was_tracked(path) && file_exists(path);
747 }
748
749 static int make_room_for_path(struct merge_options *o, const char *path)
750 {
751         int status, i;
752         const char *msg = _("failed to create path '%s'%s");
753
754         /* Unlink any D/F conflict files that are in the way */
755         for (i = 0; i < o->df_conflict_file_set.nr; i++) {
756                 const char *df_path = o->df_conflict_file_set.items[i].string;
757                 size_t pathlen = strlen(path);
758                 size_t df_pathlen = strlen(df_path);
759                 if (df_pathlen < pathlen &&
760                     path[df_pathlen] == '/' &&
761                     strncmp(path, df_path, df_pathlen) == 0) {
762                         output(o, 3,
763                                _("Removing %s to make room for subdirectory\n"),
764                                df_path);
765                         unlink(df_path);
766                         unsorted_string_list_delete_item(&o->df_conflict_file_set,
767                                                          i, 0);
768                         break;
769                 }
770         }
771
772         /* Make sure leading directories are created */
773         status = safe_create_leading_directories_const(path);
774         if (status) {
775                 if (status == SCLD_EXISTS)
776                         /* something else exists */
777                         return err(o, msg, path, _(": perhaps a D/F conflict?"));
778                 return err(o, msg, path, "");
779         }
780
781         /*
782          * Do not unlink a file in the work tree if we are not
783          * tracking it.
784          */
785         if (would_lose_untracked(path))
786                 return err(o, _("refusing to lose untracked file at '%s'"),
787                              path);
788
789         /* Successful unlink is good.. */
790         if (!unlink(path))
791                 return 0;
792         /* .. and so is no existing file */
793         if (errno == ENOENT)
794                 return 0;
795         /* .. but not some other error (who really cares what?) */
796         return err(o, msg, path, _(": perhaps a D/F conflict?"));
797 }
798
799 static int update_file_flags(struct merge_options *o,
800                              const struct object_id *oid,
801                              unsigned mode,
802                              const char *path,
803                              int update_cache,
804                              int update_wd)
805 {
806         int ret = 0;
807
808         if (o->call_depth)
809                 update_wd = 0;
810
811         if (update_wd) {
812                 enum object_type type;
813                 void *buf;
814                 unsigned long size;
815
816                 if (S_ISGITLINK(mode)) {
817                         /*
818                          * We may later decide to recursively descend into
819                          * the submodule directory and update its index
820                          * and/or work tree, but we do not do that now.
821                          */
822                         update_wd = 0;
823                         goto update_index;
824                 }
825
826                 buf = read_sha1_file(oid->hash, &type, &size);
827                 if (!buf)
828                         return err(o, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
829                 if (type != OBJ_BLOB) {
830                         ret = err(o, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
831                         goto free_buf;
832                 }
833                 if (S_ISREG(mode)) {
834                         struct strbuf strbuf = STRBUF_INIT;
835                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
836                                 free(buf);
837                                 size = strbuf.len;
838                                 buf = strbuf_detach(&strbuf, NULL);
839                         }
840                 }
841
842                 if (make_room_for_path(o, path) < 0) {
843                         update_wd = 0;
844                         goto free_buf;
845                 }
846                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
847                         int fd;
848                         if (mode & 0100)
849                                 mode = 0777;
850                         else
851                                 mode = 0666;
852                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
853                         if (fd < 0) {
854                                 ret = err(o, _("failed to open '%s': %s"),
855                                           path, strerror(errno));
856                                 goto free_buf;
857                         }
858                         write_in_full(fd, buf, size);
859                         close(fd);
860                 } else if (S_ISLNK(mode)) {
861                         char *lnk = xmemdupz(buf, size);
862                         safe_create_leading_directories_const(path);
863                         unlink(path);
864                         if (symlink(lnk, path))
865                                 ret = err(o, _("failed to symlink '%s': %s"),
866                                         path, strerror(errno));
867                         free(lnk);
868                 } else
869                         ret = err(o,
870                                   _("do not know what to do with %06o %s '%s'"),
871                                   mode, oid_to_hex(oid), path);
872  free_buf:
873                 free(buf);
874         }
875  update_index:
876         if (!ret && update_cache)
877                 add_cacheinfo(o, mode, oid, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
878         return ret;
879 }
880
881 static int update_file(struct merge_options *o,
882                        int clean,
883                        const struct object_id *oid,
884                        unsigned mode,
885                        const char *path)
886 {
887         return update_file_flags(o, oid, mode, path, o->call_depth || clean, !o->call_depth);
888 }
889
890 /* Low level file merging, update and removal */
891
892 struct merge_file_info {
893         struct object_id oid;
894         unsigned mode;
895         unsigned clean:1,
896                  merge:1;
897 };
898
899 static int merge_3way(struct merge_options *o,
900                       mmbuffer_t *result_buf,
901                       const struct diff_filespec *one,
902                       const struct diff_filespec *a,
903                       const struct diff_filespec *b,
904                       const char *branch1,
905                       const char *branch2)
906 {
907         mmfile_t orig, src1, src2;
908         struct ll_merge_options ll_opts = {0};
909         char *base_name, *name1, *name2;
910         int merge_status;
911
912         ll_opts.renormalize = o->renormalize;
913         ll_opts.xdl_opts = o->xdl_opts;
914
915         if (o->call_depth) {
916                 ll_opts.virtual_ancestor = 1;
917                 ll_opts.variant = 0;
918         } else {
919                 switch (o->recursive_variant) {
920                 case MERGE_RECURSIVE_OURS:
921                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
922                         break;
923                 case MERGE_RECURSIVE_THEIRS:
924                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
925                         break;
926                 default:
927                         ll_opts.variant = 0;
928                         break;
929                 }
930         }
931
932         if (strcmp(a->path, b->path) ||
933             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
934                 base_name = o->ancestor == NULL ? NULL :
935                         mkpathdup("%s:%s", o->ancestor, one->path);
936                 name1 = mkpathdup("%s:%s", branch1, a->path);
937                 name2 = mkpathdup("%s:%s", branch2, b->path);
938         } else {
939                 base_name = o->ancestor == NULL ? NULL :
940                         mkpathdup("%s", o->ancestor);
941                 name1 = mkpathdup("%s", branch1);
942                 name2 = mkpathdup("%s", branch2);
943         }
944
945         read_mmblob(&orig, &one->oid);
946         read_mmblob(&src1, &a->oid);
947         read_mmblob(&src2, &b->oid);
948
949         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
950                                 &src1, name1, &src2, name2, &ll_opts);
951
952         free(base_name);
953         free(name1);
954         free(name2);
955         free(orig.ptr);
956         free(src1.ptr);
957         free(src2.ptr);
958         return merge_status;
959 }
960
961 static int merge_file_1(struct merge_options *o,
962                                            const struct diff_filespec *one,
963                                            const struct diff_filespec *a,
964                                            const struct diff_filespec *b,
965                                            const char *branch1,
966                                            const char *branch2,
967                                            struct merge_file_info *result)
968 {
969         result->merge = 0;
970         result->clean = 1;
971
972         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
973                 result->clean = 0;
974                 if (S_ISREG(a->mode)) {
975                         result->mode = a->mode;
976                         oidcpy(&result->oid, &a->oid);
977                 } else {
978                         result->mode = b->mode;
979                         oidcpy(&result->oid, &b->oid);
980                 }
981         } else {
982                 if (!oid_eq(&a->oid, &one->oid) && !oid_eq(&b->oid, &one->oid))
983                         result->merge = 1;
984
985                 /*
986                  * Merge modes
987                  */
988                 if (a->mode == b->mode || a->mode == one->mode)
989                         result->mode = b->mode;
990                 else {
991                         result->mode = a->mode;
992                         if (b->mode != one->mode) {
993                                 result->clean = 0;
994                                 result->merge = 1;
995                         }
996                 }
997
998                 if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &one->oid))
999                         oidcpy(&result->oid, &b->oid);
1000                 else if (oid_eq(&b->oid, &one->oid))
1001                         oidcpy(&result->oid, &a->oid);
1002                 else if (S_ISREG(a->mode)) {
1003                         mmbuffer_t result_buf;
1004                         int ret = 0, merge_status;
1005
1006                         merge_status = merge_3way(o, &result_buf, one, a, b,
1007                                                   branch1, branch2);
1008
1009                         if ((merge_status < 0) || !result_buf.ptr)
1010                                 ret = err(o, _("Failed to execute internal merge"));
1011
1012                         if (!ret && write_sha1_file(result_buf.ptr, result_buf.size,
1013                                                     blob_type, result->oid.hash))
1014                                 ret = err(o, _("Unable to add %s to database"),
1015                                           a->path);
1016
1017                         free(result_buf.ptr);
1018                         if (ret)
1019                                 return ret;
1020                         result->clean = (merge_status == 0);
1021                 } else if (S_ISGITLINK(a->mode)) {
1022                         result->clean = merge_submodule(&result->oid,
1023                                                        one->path,
1024                                                        &one->oid,
1025                                                        &a->oid,
1026                                                        &b->oid,
1027                                                        !o->call_depth);
1028                 } else if (S_ISLNK(a->mode)) {
1029                         oidcpy(&result->oid, &a->oid);
1030
1031                         if (!oid_eq(&a->oid, &b->oid))
1032                                 result->clean = 0;
1033                 } else
1034                         die("BUG: unsupported object type in the tree");
1035         }
1036
1037         return 0;
1038 }
1039
1040 static int merge_file_special_markers(struct merge_options *o,
1041                            const struct diff_filespec *one,
1042                            const struct diff_filespec *a,
1043                            const struct diff_filespec *b,
1044                            const char *branch1,
1045                            const char *filename1,
1046                            const char *branch2,
1047                            const char *filename2,
1048                            struct merge_file_info *mfi)
1049 {
1050         char *side1 = NULL;
1051         char *side2 = NULL;
1052         int ret;
1053
1054         if (filename1)
1055                 side1 = xstrfmt("%s:%s", branch1, filename1);
1056         if (filename2)
1057                 side2 = xstrfmt("%s:%s", branch2, filename2);
1058
1059         ret = merge_file_1(o, one, a, b,
1060                            side1 ? side1 : branch1,
1061                            side2 ? side2 : branch2, mfi);
1062         free(side1);
1063         free(side2);
1064         return ret;
1065 }
1066
1067 static int merge_file_one(struct merge_options *o,
1068                                          const char *path,
1069                                          const struct object_id *o_oid, int o_mode,
1070                                          const struct object_id *a_oid, int a_mode,
1071                                          const struct object_id *b_oid, int b_mode,
1072                                          const char *branch1,
1073                                          const char *branch2,
1074                                          struct merge_file_info *mfi)
1075 {
1076         struct diff_filespec one, a, b;
1077
1078         one.path = a.path = b.path = (char *)path;
1079         oidcpy(&one.oid, o_oid);
1080         one.mode = o_mode;
1081         oidcpy(&a.oid, a_oid);
1082         a.mode = a_mode;
1083         oidcpy(&b.oid, b_oid);
1084         b.mode = b_mode;
1085         return merge_file_1(o, &one, &a, &b, branch1, branch2, mfi);
1086 }
1087
1088 static int handle_change_delete(struct merge_options *o,
1089                                  const char *path, const char *old_path,
1090                                  const struct object_id *o_oid, int o_mode,
1091                                  const struct object_id *changed_oid,
1092                                  int changed_mode,
1093                                  const char *change_branch,
1094                                  const char *delete_branch,
1095                                  const char *change, const char *change_past)
1096 {
1097         char *alt_path = NULL;
1098         const char *update_path = path;
1099         int ret = 0;
1100
1101         if (dir_in_way(path, !o->call_depth, 0)) {
1102                 update_path = alt_path = unique_path(o, path, change_branch);
1103         }
1104
1105         if (o->call_depth) {
1106                 /*
1107                  * We cannot arbitrarily accept either a_sha or b_sha as
1108                  * correct; since there is no true "middle point" between
1109                  * them, simply reuse the base version for virtual merge base.
1110                  */
1111                 ret = remove_file_from_cache(path);
1112                 if (!ret)
1113                         ret = update_file(o, 0, o_oid, o_mode, update_path);
1114         } else {
1115                 if (!alt_path) {
1116                         if (!old_path) {
1117                                 output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1118                                        "and %s in %s. Version %s of %s left in tree."),
1119                                        change, path, delete_branch, change_past,
1120                                        change_branch, change_branch, path);
1121                         } else {
1122                                 output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1123                                        "and %s to %s in %s. Version %s of %s left in tree."),
1124                                        change, old_path, delete_branch, change_past, path,
1125                                        change_branch, change_branch, path);
1126                         }
1127                 } else {
1128                         if (!old_path) {
1129                                 output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1130                                        "and %s in %s. Version %s of %s left in tree at %s."),
1131                                        change, path, delete_branch, change_past,
1132                                        change_branch, change_branch, path, alt_path);
1133                         } else {
1134                                 output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1135                                        "and %s to %s in %s. Version %s of %s left in tree at %s."),
1136                                        change, old_path, delete_branch, change_past, path,
1137                                        change_branch, change_branch, path, alt_path);
1138                         }
1139                 }
1140                 /*
1141                  * No need to call update_file() on path when change_branch ==
1142                  * o->branch1 && !alt_path, since that would needlessly touch
1143                  * path.  We could call update_file_flags() with update_cache=0
1144                  * and update_wd=0, but that's a no-op.
1145                  */
1146                 if (change_branch != o->branch1 || alt_path)
1147                         ret = update_file(o, 0, changed_oid, changed_mode, update_path);
1148         }
1149         free(alt_path);
1150
1151         return ret;
1152 }
1153
1154 static int conflict_rename_delete(struct merge_options *o,
1155                                    struct diff_filepair *pair,
1156                                    const char *rename_branch,
1157                                    const char *delete_branch)
1158 {
1159         const struct diff_filespec *orig = pair->one;
1160         const struct diff_filespec *dest = pair->two;
1161
1162         if (handle_change_delete(o,
1163                                  o->call_depth ? orig->path : dest->path,
1164                                  o->call_depth ? NULL : orig->path,
1165                                  &orig->oid, orig->mode,
1166                                  &dest->oid, dest->mode,
1167                                  rename_branch, delete_branch,
1168                                  _("rename"), _("renamed")))
1169                 return -1;
1170
1171         if (o->call_depth)
1172                 return remove_file_from_cache(dest->path);
1173         else
1174                 return update_stages(o, dest->path, NULL,
1175                                      rename_branch == o->branch1 ? dest : NULL,
1176                                      rename_branch == o->branch1 ? NULL : dest);
1177 }
1178
1179 static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
1180                                                  struct stage_data *entry,
1181                                                  int stage)
1182 {
1183         struct object_id *oid = &entry->stages[stage].oid;
1184         unsigned mode = entry->stages[stage].mode;
1185         if (mode == 0 || is_null_oid(oid))
1186                 return NULL;
1187         oidcpy(&target->oid, oid);
1188         target->mode = mode;
1189         return target;
1190 }
1191
1192 static int handle_file(struct merge_options *o,
1193                         struct diff_filespec *rename,
1194                         int stage,
1195                         struct rename_conflict_info *ci)
1196 {
1197         char *dst_name = rename->path;
1198         struct stage_data *dst_entry;
1199         const char *cur_branch, *other_branch;
1200         struct diff_filespec other;
1201         struct diff_filespec *add;
1202         int ret;
1203
1204         if (stage == 2) {
1205                 dst_entry = ci->dst_entry1;
1206                 cur_branch = ci->branch1;
1207                 other_branch = ci->branch2;
1208         } else {
1209                 dst_entry = ci->dst_entry2;
1210                 cur_branch = ci->branch2;
1211                 other_branch = ci->branch1;
1212         }
1213
1214         add = filespec_from_entry(&other, dst_entry, stage ^ 1);
1215         if (add) {
1216                 char *add_name = unique_path(o, rename->path, other_branch);
1217                 if (update_file(o, 0, &add->oid, add->mode, add_name))
1218                         return -1;
1219
1220                 remove_file(o, 0, rename->path, 0);
1221                 dst_name = unique_path(o, rename->path, cur_branch);
1222         } else {
1223                 if (dir_in_way(rename->path, !o->call_depth, 0)) {
1224                         dst_name = unique_path(o, rename->path, cur_branch);
1225                         output(o, 1, _("%s is a directory in %s adding as %s instead"),
1226                                rename->path, other_branch, dst_name);
1227                 }
1228         }
1229         if ((ret = update_file(o, 0, &rename->oid, rename->mode, dst_name)))
1230                 ; /* fall through, do allow dst_name to be released */
1231         else if (stage == 2)
1232                 ret = update_stages(o, rename->path, NULL, rename, add);
1233         else
1234                 ret = update_stages(o, rename->path, NULL, add, rename);
1235
1236         if (dst_name != rename->path)
1237                 free(dst_name);
1238
1239         return ret;
1240 }
1241
1242 static int conflict_rename_rename_1to2(struct merge_options *o,
1243                                         struct rename_conflict_info *ci)
1244 {
1245         /* One file was renamed in both branches, but to different names. */
1246         struct diff_filespec *one = ci->pair1->one;
1247         struct diff_filespec *a = ci->pair1->two;
1248         struct diff_filespec *b = ci->pair2->two;
1249
1250         output(o, 1, _("CONFLICT (rename/rename): "
1251                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1252                "rename \"%s\"->\"%s\" in \"%s\"%s"),
1253                one->path, a->path, ci->branch1,
1254                one->path, b->path, ci->branch2,
1255                o->call_depth ? _(" (left unresolved)") : "");
1256         if (o->call_depth) {
1257                 struct merge_file_info mfi;
1258                 struct diff_filespec other;
1259                 struct diff_filespec *add;
1260                 if (merge_file_one(o, one->path,
1261                                  &one->oid, one->mode,
1262                                  &a->oid, a->mode,
1263                                  &b->oid, b->mode,
1264                                  ci->branch1, ci->branch2, &mfi))
1265                         return -1;
1266
1267                 /*
1268                  * FIXME: For rename/add-source conflicts (if we could detect
1269                  * such), this is wrong.  We should instead find a unique
1270                  * pathname and then either rename the add-source file to that
1271                  * unique path, or use that unique path instead of src here.
1272                  */
1273                 if (update_file(o, 0, &mfi.oid, mfi.mode, one->path))
1274                         return -1;
1275
1276                 /*
1277                  * Above, we put the merged content at the merge-base's
1278                  * path.  Now we usually need to delete both a->path and
1279                  * b->path.  However, the rename on each side of the merge
1280                  * could also be involved in a rename/add conflict.  In
1281                  * such cases, we should keep the added file around,
1282                  * resolving the conflict at that path in its favor.
1283                  */
1284                 add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
1285                 if (add) {
1286                         if (update_file(o, 0, &add->oid, add->mode, a->path))
1287                                 return -1;
1288                 }
1289                 else
1290                         remove_file_from_cache(a->path);
1291                 add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
1292                 if (add) {
1293                         if (update_file(o, 0, &add->oid, add->mode, b->path))
1294                                 return -1;
1295                 }
1296                 else
1297                         remove_file_from_cache(b->path);
1298         } else if (handle_file(o, a, 2, ci) || handle_file(o, b, 3, ci))
1299                 return -1;
1300
1301         return 0;
1302 }
1303
1304 static int conflict_rename_rename_2to1(struct merge_options *o,
1305                                         struct rename_conflict_info *ci)
1306 {
1307         /* Two files, a & b, were renamed to the same thing, c. */
1308         struct diff_filespec *a = ci->pair1->one;
1309         struct diff_filespec *b = ci->pair2->one;
1310         struct diff_filespec *c1 = ci->pair1->two;
1311         struct diff_filespec *c2 = ci->pair2->two;
1312         char *path = c1->path; /* == c2->path */
1313         struct merge_file_info mfi_c1;
1314         struct merge_file_info mfi_c2;
1315         int ret;
1316
1317         output(o, 1, _("CONFLICT (rename/rename): "
1318                "Rename %s->%s in %s. "
1319                "Rename %s->%s in %s"),
1320                a->path, c1->path, ci->branch1,
1321                b->path, c2->path, ci->branch2);
1322
1323         remove_file(o, 1, a->path, o->call_depth || would_lose_untracked(a->path));
1324         remove_file(o, 1, b->path, o->call_depth || would_lose_untracked(b->path));
1325
1326         if (merge_file_special_markers(o, a, c1, &ci->ren1_other,
1327                                        o->branch1, c1->path,
1328                                        o->branch2, ci->ren1_other.path, &mfi_c1) ||
1329             merge_file_special_markers(o, b, &ci->ren2_other, c2,
1330                                        o->branch1, ci->ren2_other.path,
1331                                        o->branch2, c2->path, &mfi_c2))
1332                 return -1;
1333
1334         if (o->call_depth) {
1335                 /*
1336                  * If mfi_c1.clean && mfi_c2.clean, then it might make
1337                  * sense to do a two-way merge of those results.  But, I
1338                  * think in all cases, it makes sense to have the virtual
1339                  * merge base just undo the renames; they can be detected
1340                  * again later for the non-recursive merge.
1341                  */
1342                 remove_file(o, 0, path, 0);
1343                 ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, a->path);
1344                 if (!ret)
1345                         ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
1346                                           b->path);
1347         } else {
1348                 char *new_path1 = unique_path(o, path, ci->branch1);
1349                 char *new_path2 = unique_path(o, path, ci->branch2);
1350                 output(o, 1, _("Renaming %s to %s and %s to %s instead"),
1351                        a->path, new_path1, b->path, new_path2);
1352                 remove_file(o, 0, path, 0);
1353                 ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, new_path1);
1354                 if (!ret)
1355                         ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
1356                                           new_path2);
1357                 free(new_path2);
1358                 free(new_path1);
1359         }
1360
1361         return ret;
1362 }
1363
1364 static int process_renames(struct merge_options *o,
1365                            struct string_list *a_renames,
1366                            struct string_list *b_renames)
1367 {
1368         int clean_merge = 1, i, j;
1369         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
1370         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
1371         const struct rename *sre;
1372
1373         for (i = 0; i < a_renames->nr; i++) {
1374                 sre = a_renames->items[i].util;
1375                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
1376                         = (void *)sre;
1377         }
1378         for (i = 0; i < b_renames->nr; i++) {
1379                 sre = b_renames->items[i].util;
1380                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
1381                         = (void *)sre;
1382         }
1383
1384         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1385                 struct string_list *renames1, *renames2Dst;
1386                 struct rename *ren1 = NULL, *ren2 = NULL;
1387                 const char *branch1, *branch2;
1388                 const char *ren1_src, *ren1_dst;
1389                 struct string_list_item *lookup;
1390
1391                 if (i >= a_renames->nr) {
1392                         ren2 = b_renames->items[j++].util;
1393                 } else if (j >= b_renames->nr) {
1394                         ren1 = a_renames->items[i++].util;
1395                 } else {
1396                         int compare = strcmp(a_renames->items[i].string,
1397                                              b_renames->items[j].string);
1398                         if (compare <= 0)
1399                                 ren1 = a_renames->items[i++].util;
1400                         if (compare >= 0)
1401                                 ren2 = b_renames->items[j++].util;
1402                 }
1403
1404                 /* TODO: refactor, so that 1/2 are not needed */
1405                 if (ren1) {
1406                         renames1 = a_renames;
1407                         renames2Dst = &b_by_dst;
1408                         branch1 = o->branch1;
1409                         branch2 = o->branch2;
1410                 } else {
1411                         renames1 = b_renames;
1412                         renames2Dst = &a_by_dst;
1413                         branch1 = o->branch2;
1414                         branch2 = o->branch1;
1415                         SWAP(ren2, ren1);
1416                 }
1417
1418                 if (ren1->processed)
1419                         continue;
1420                 ren1->processed = 1;
1421                 ren1->dst_entry->processed = 1;
1422                 /* BUG: We should only mark src_entry as processed if we
1423                  * are not dealing with a rename + add-source case.
1424                  */
1425                 ren1->src_entry->processed = 1;
1426
1427                 ren1_src = ren1->pair->one->path;
1428                 ren1_dst = ren1->pair->two->path;
1429
1430                 if (ren2) {
1431                         /* One file renamed on both sides */
1432                         const char *ren2_src = ren2->pair->one->path;
1433                         const char *ren2_dst = ren2->pair->two->path;
1434                         enum rename_type rename_type;
1435                         if (strcmp(ren1_src, ren2_src) != 0)
1436                                 die("BUG: ren1_src != ren2_src");
1437                         ren2->dst_entry->processed = 1;
1438                         ren2->processed = 1;
1439                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1440                                 rename_type = RENAME_ONE_FILE_TO_TWO;
1441                                 clean_merge = 0;
1442                         } else {
1443                                 rename_type = RENAME_ONE_FILE_TO_ONE;
1444                                 /* BUG: We should only remove ren1_src in
1445                                  * the base stage (think of rename +
1446                                  * add-source cases).
1447                                  */
1448                                 remove_file(o, 1, ren1_src, 1);
1449                                 update_entry(ren1->dst_entry,
1450                                              ren1->pair->one,
1451                                              ren1->pair->two,
1452                                              ren2->pair->two);
1453                         }
1454                         setup_rename_conflict_info(rename_type,
1455                                                    ren1->pair,
1456                                                    ren2->pair,
1457                                                    branch1,
1458                                                    branch2,
1459                                                    ren1->dst_entry,
1460                                                    ren2->dst_entry,
1461                                                    o,
1462                                                    NULL,
1463                                                    NULL);
1464                 } else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
1465                         /* Two different files renamed to the same thing */
1466                         char *ren2_dst;
1467                         ren2 = lookup->util;
1468                         ren2_dst = ren2->pair->two->path;
1469                         if (strcmp(ren1_dst, ren2_dst) != 0)
1470                                 die("BUG: ren1_dst != ren2_dst");
1471
1472                         clean_merge = 0;
1473                         ren2->processed = 1;
1474                         /*
1475                          * BUG: We should only mark src_entry as processed
1476                          * if we are not dealing with a rename + add-source
1477                          * case.
1478                          */
1479                         ren2->src_entry->processed = 1;
1480
1481                         setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
1482                                                    ren1->pair,
1483                                                    ren2->pair,
1484                                                    branch1,
1485                                                    branch2,
1486                                                    ren1->dst_entry,
1487                                                    ren2->dst_entry,
1488                                                    o,
1489                                                    ren1->src_entry,
1490                                                    ren2->src_entry);
1491
1492                 } else {
1493                         /* Renamed in 1, maybe changed in 2 */
1494                         /* we only use sha1 and mode of these */
1495                         struct diff_filespec src_other, dst_other;
1496                         int try_merge;
1497
1498                         /*
1499                          * unpack_trees loads entries from common-commit
1500                          * into stage 1, from head-commit into stage 2, and
1501                          * from merge-commit into stage 3.  We keep track
1502                          * of which side corresponds to the rename.
1503                          */
1504                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1505                         int other_stage =   a_renames == renames1 ? 3 : 2;
1506
1507                         /* BUG: We should only remove ren1_src in the base
1508                          * stage and in other_stage (think of rename +
1509                          * add-source case).
1510                          */
1511                         remove_file(o, 1, ren1_src,
1512                                     renamed_stage == 2 || !was_tracked(ren1_src));
1513
1514                         oidcpy(&src_other.oid,
1515                                &ren1->src_entry->stages[other_stage].oid);
1516                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1517                         oidcpy(&dst_other.oid,
1518                                &ren1->dst_entry->stages[other_stage].oid);
1519                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1520                         try_merge = 0;
1521
1522                         if (oid_eq(&src_other.oid, &null_oid)) {
1523                                 setup_rename_conflict_info(RENAME_DELETE,
1524                                                            ren1->pair,
1525                                                            NULL,
1526                                                            branch1,
1527                                                            branch2,
1528                                                            ren1->dst_entry,
1529                                                            NULL,
1530                                                            o,
1531                                                            NULL,
1532                                                            NULL);
1533                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1534                                    oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
1535                                 /*
1536                                  * Added file on the other side identical to
1537                                  * the file being renamed: clean merge.
1538                                  * Also, there is no need to overwrite the
1539                                  * file already in the working copy, so call
1540                                  * update_file_flags() instead of
1541                                  * update_file().
1542                                  */
1543                                 if (update_file_flags(o,
1544                                                       &ren1->pair->two->oid,
1545                                                       ren1->pair->two->mode,
1546                                                       ren1_dst,
1547                                                       1, /* update_cache */
1548                                                       0  /* update_wd    */))
1549                                         clean_merge = -1;
1550                         } else if (!oid_eq(&dst_other.oid, &null_oid)) {
1551                                 clean_merge = 0;
1552                                 try_merge = 1;
1553                                 output(o, 1, _("CONFLICT (rename/add): Rename %s->%s in %s. "
1554                                        "%s added in %s"),
1555                                        ren1_src, ren1_dst, branch1,
1556                                        ren1_dst, branch2);
1557                                 if (o->call_depth) {
1558                                         struct merge_file_info mfi;
1559                                         if (merge_file_one(o, ren1_dst, &null_oid, 0,
1560                                                            &ren1->pair->two->oid,
1561                                                            ren1->pair->two->mode,
1562                                                            &dst_other.oid,
1563                                                            dst_other.mode,
1564                                                            branch1, branch2, &mfi)) {
1565                                                 clean_merge = -1;
1566                                                 goto cleanup_and_return;
1567                                         }
1568                                         output(o, 1, _("Adding merged %s"), ren1_dst);
1569                                         if (update_file(o, 0, &mfi.oid,
1570                                                         mfi.mode, ren1_dst))
1571                                                 clean_merge = -1;
1572                                         try_merge = 0;
1573                                 } else {
1574                                         char *new_path = unique_path(o, ren1_dst, branch2);
1575                                         output(o, 1, _("Adding as %s instead"), new_path);
1576                                         if (update_file(o, 0, &dst_other.oid,
1577                                                         dst_other.mode, new_path))
1578                                                 clean_merge = -1;
1579                                         free(new_path);
1580                                 }
1581                         } else
1582                                 try_merge = 1;
1583
1584                         if (clean_merge < 0)
1585                                 goto cleanup_and_return;
1586                         if (try_merge) {
1587                                 struct diff_filespec *one, *a, *b;
1588                                 src_other.path = (char *)ren1_src;
1589
1590                                 one = ren1->pair->one;
1591                                 if (a_renames == renames1) {
1592                                         a = ren1->pair->two;
1593                                         b = &src_other;
1594                                 } else {
1595                                         b = ren1->pair->two;
1596                                         a = &src_other;
1597                                 }
1598                                 update_entry(ren1->dst_entry, one, a, b);
1599                                 setup_rename_conflict_info(RENAME_NORMAL,
1600                                                            ren1->pair,
1601                                                            NULL,
1602                                                            branch1,
1603                                                            NULL,
1604                                                            ren1->dst_entry,
1605                                                            NULL,
1606                                                            o,
1607                                                            NULL,
1608                                                            NULL);
1609                         }
1610                 }
1611         }
1612 cleanup_and_return:
1613         string_list_clear(&a_by_dst, 0);
1614         string_list_clear(&b_by_dst, 0);
1615
1616         return clean_merge;
1617 }
1618
1619 static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
1620 {
1621         return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
1622 }
1623
1624 static int read_oid_strbuf(struct merge_options *o,
1625         const struct object_id *oid, struct strbuf *dst)
1626 {
1627         void *buf;
1628         enum object_type type;
1629         unsigned long size;
1630         buf = read_sha1_file(oid->hash, &type, &size);
1631         if (!buf)
1632                 return err(o, _("cannot read object %s"), oid_to_hex(oid));
1633         if (type != OBJ_BLOB) {
1634                 free(buf);
1635                 return err(o, _("object %s is not a blob"), oid_to_hex(oid));
1636         }
1637         strbuf_attach(dst, buf, size, size + 1);
1638         return 0;
1639 }
1640
1641 static int blob_unchanged(struct merge_options *opt,
1642                           const struct object_id *o_oid,
1643                           unsigned o_mode,
1644                           const struct object_id *a_oid,
1645                           unsigned a_mode,
1646                           int renormalize, const char *path)
1647 {
1648         struct strbuf o = STRBUF_INIT;
1649         struct strbuf a = STRBUF_INIT;
1650         int ret = 0; /* assume changed for safety */
1651
1652         if (a_mode != o_mode)
1653                 return 0;
1654         if (oid_eq(o_oid, a_oid))
1655                 return 1;
1656         if (!renormalize)
1657                 return 0;
1658
1659         assert(o_oid && a_oid);
1660         if (read_oid_strbuf(opt, o_oid, &o) || read_oid_strbuf(opt, a_oid, &a))
1661                 goto error_return;
1662         /*
1663          * Note: binary | is used so that both renormalizations are
1664          * performed.  Comparison can be skipped if both files are
1665          * unchanged since their sha1s have already been compared.
1666          */
1667         if (renormalize_buffer(&the_index, path, o.buf, o.len, &o) |
1668             renormalize_buffer(&the_index, path, a.buf, a.len, &a))
1669                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1670
1671 error_return:
1672         strbuf_release(&o);
1673         strbuf_release(&a);
1674         return ret;
1675 }
1676
1677 static int handle_modify_delete(struct merge_options *o,
1678                                  const char *path,
1679                                  struct object_id *o_oid, int o_mode,
1680                                  struct object_id *a_oid, int a_mode,
1681                                  struct object_id *b_oid, int b_mode)
1682 {
1683         const char *modify_branch, *delete_branch;
1684         struct object_id *changed_oid;
1685         int changed_mode;
1686
1687         if (a_oid) {
1688                 modify_branch = o->branch1;
1689                 delete_branch = o->branch2;
1690                 changed_oid = a_oid;
1691                 changed_mode = a_mode;
1692         } else {
1693                 modify_branch = o->branch2;
1694                 delete_branch = o->branch1;
1695                 changed_oid = b_oid;
1696                 changed_mode = b_mode;
1697         }
1698
1699         return handle_change_delete(o,
1700                                     path, NULL,
1701                                     o_oid, o_mode,
1702                                     changed_oid, changed_mode,
1703                                     modify_branch, delete_branch,
1704                                     _("modify"), _("modified"));
1705 }
1706
1707 static int merge_content(struct merge_options *o,
1708                          const char *path,
1709                          struct object_id *o_oid, int o_mode,
1710                          struct object_id *a_oid, int a_mode,
1711                          struct object_id *b_oid, int b_mode,
1712                          struct rename_conflict_info *rename_conflict_info)
1713 {
1714         const char *reason = _("content");
1715         const char *path1 = NULL, *path2 = NULL;
1716         struct merge_file_info mfi;
1717         struct diff_filespec one, a, b;
1718         unsigned df_conflict_remains = 0;
1719
1720         if (!o_oid) {
1721                 reason = _("add/add");
1722                 o_oid = (struct object_id *)&null_oid;
1723         }
1724         one.path = a.path = b.path = (char *)path;
1725         oidcpy(&one.oid, o_oid);
1726         one.mode = o_mode;
1727         oidcpy(&a.oid, a_oid);
1728         a.mode = a_mode;
1729         oidcpy(&b.oid, b_oid);
1730         b.mode = b_mode;
1731
1732         if (rename_conflict_info) {
1733                 struct diff_filepair *pair1 = rename_conflict_info->pair1;
1734
1735                 path1 = (o->branch1 == rename_conflict_info->branch1) ?
1736                         pair1->two->path : pair1->one->path;
1737                 /* If rename_conflict_info->pair2 != NULL, we are in
1738                  * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
1739                  * normal rename.
1740                  */
1741                 path2 = (rename_conflict_info->pair2 ||
1742                          o->branch2 == rename_conflict_info->branch1) ?
1743                         pair1->two->path : pair1->one->path;
1744
1745                 if (dir_in_way(path, !o->call_depth,
1746                                S_ISGITLINK(pair1->two->mode)))
1747                         df_conflict_remains = 1;
1748         }
1749         if (merge_file_special_markers(o, &one, &a, &b,
1750                                        o->branch1, path1,
1751                                        o->branch2, path2, &mfi))
1752                 return -1;
1753
1754         if (mfi.clean && !df_conflict_remains &&
1755             oid_eq(&mfi.oid, a_oid) && mfi.mode == a_mode) {
1756                 int path_renamed_outside_HEAD;
1757                 output(o, 3, _("Skipped %s (merged same as existing)"), path);
1758                 /*
1759                  * The content merge resulted in the same file contents we
1760                  * already had.  We can return early if those file contents
1761                  * are recorded at the correct path (which may not be true
1762                  * if the merge involves a rename).
1763                  */
1764                 path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
1765                 if (!path_renamed_outside_HEAD) {
1766                         add_cacheinfo(o, mfi.mode, &mfi.oid, path,
1767                                       0, (!o->call_depth), 0);
1768                         return mfi.clean;
1769                 }
1770         } else
1771                 output(o, 2, _("Auto-merging %s"), path);
1772
1773         if (!mfi.clean) {
1774                 if (S_ISGITLINK(mfi.mode))
1775                         reason = _("submodule");
1776                 output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
1777                                 reason, path);
1778                 if (rename_conflict_info && !df_conflict_remains)
1779                         if (update_stages(o, path, &one, &a, &b))
1780                                 return -1;
1781         }
1782
1783         if (df_conflict_remains) {
1784                 char *new_path;
1785                 if (o->call_depth) {
1786                         remove_file_from_cache(path);
1787                 } else {
1788                         if (!mfi.clean) {
1789                                 if (update_stages(o, path, &one, &a, &b))
1790                                         return -1;
1791                         } else {
1792                                 int file_from_stage2 = was_tracked(path);
1793                                 struct diff_filespec merged;
1794                                 oidcpy(&merged.oid, &mfi.oid);
1795                                 merged.mode = mfi.mode;
1796
1797                                 if (update_stages(o, path, NULL,
1798                                                   file_from_stage2 ? &merged : NULL,
1799                                                   file_from_stage2 ? NULL : &merged))
1800                                         return -1;
1801                         }
1802
1803                 }
1804                 new_path = unique_path(o, path, rename_conflict_info->branch1);
1805                 output(o, 1, _("Adding as %s instead"), new_path);
1806                 if (update_file(o, 0, &mfi.oid, mfi.mode, new_path)) {
1807                         free(new_path);
1808                         return -1;
1809                 }
1810                 free(new_path);
1811                 mfi.clean = 0;
1812         } else if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, path))
1813                 return -1;
1814         return mfi.clean;
1815 }
1816
1817 /* Per entry merge function */
1818 static int process_entry(struct merge_options *o,
1819                          const char *path, struct stage_data *entry)
1820 {
1821         int clean_merge = 1;
1822         int normalize = o->renormalize;
1823         unsigned o_mode = entry->stages[1].mode;
1824         unsigned a_mode = entry->stages[2].mode;
1825         unsigned b_mode = entry->stages[3].mode;
1826         struct object_id *o_oid = stage_oid(&entry->stages[1].oid, o_mode);
1827         struct object_id *a_oid = stage_oid(&entry->stages[2].oid, a_mode);
1828         struct object_id *b_oid = stage_oid(&entry->stages[3].oid, b_mode);
1829
1830         entry->processed = 1;
1831         if (entry->rename_conflict_info) {
1832                 struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
1833                 switch (conflict_info->rename_type) {
1834                 case RENAME_NORMAL:
1835                 case RENAME_ONE_FILE_TO_ONE:
1836                         clean_merge = merge_content(o, path,
1837                                                     o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
1838                                                     conflict_info);
1839                         break;
1840                 case RENAME_DELETE:
1841                         clean_merge = 0;
1842                         if (conflict_rename_delete(o,
1843                                                    conflict_info->pair1,
1844                                                    conflict_info->branch1,
1845                                                    conflict_info->branch2))
1846                                 clean_merge = -1;
1847                         break;
1848                 case RENAME_ONE_FILE_TO_TWO:
1849                         clean_merge = 0;
1850                         if (conflict_rename_rename_1to2(o, conflict_info))
1851                                 clean_merge = -1;
1852                         break;
1853                 case RENAME_TWO_FILES_TO_ONE:
1854                         clean_merge = 0;
1855                         if (conflict_rename_rename_2to1(o, conflict_info))
1856                                 clean_merge = -1;
1857                         break;
1858                 default:
1859                         entry->processed = 0;
1860                         break;
1861                 }
1862         } else if (o_oid && (!a_oid || !b_oid)) {
1863                 /* Case A: Deleted in one */
1864                 if ((!a_oid && !b_oid) ||
1865                     (!b_oid && blob_unchanged(o, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
1866                     (!a_oid && blob_unchanged(o, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
1867                         /* Deleted in both or deleted in one and
1868                          * unchanged in the other */
1869                         if (a_oid)
1870                                 output(o, 2, _("Removing %s"), path);
1871                         /* do not touch working file if it did not exist */
1872                         remove_file(o, 1, path, !a_oid);
1873                 } else {
1874                         /* Modify/delete; deleted side may have put a directory in the way */
1875                         clean_merge = 0;
1876                         if (handle_modify_delete(o, path, o_oid, o_mode,
1877                                                  a_oid, a_mode, b_oid, b_mode))
1878                                 clean_merge = -1;
1879                 }
1880         } else if ((!o_oid && a_oid && !b_oid) ||
1881                    (!o_oid && !a_oid && b_oid)) {
1882                 /* Case B: Added in one. */
1883                 /* [nothing|directory] -> ([nothing|directory], file) */
1884
1885                 const char *add_branch;
1886                 const char *other_branch;
1887                 unsigned mode;
1888                 const struct object_id *oid;
1889                 const char *conf;
1890
1891                 if (a_oid) {
1892                         add_branch = o->branch1;
1893                         other_branch = o->branch2;
1894                         mode = a_mode;
1895                         oid = a_oid;
1896                         conf = _("file/directory");
1897                 } else {
1898                         add_branch = o->branch2;
1899                         other_branch = o->branch1;
1900                         mode = b_mode;
1901                         oid = b_oid;
1902                         conf = _("directory/file");
1903                 }
1904                 if (dir_in_way(path,
1905                                !o->call_depth && !S_ISGITLINK(a_mode),
1906                                0)) {
1907                         char *new_path = unique_path(o, path, add_branch);
1908                         clean_merge = 0;
1909                         output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
1910                                "Adding %s as %s"),
1911                                conf, path, other_branch, path, new_path);
1912                         if (update_file(o, 0, oid, mode, new_path))
1913                                 clean_merge = -1;
1914                         else if (o->call_depth)
1915                                 remove_file_from_cache(path);
1916                         free(new_path);
1917                 } else {
1918                         output(o, 2, _("Adding %s"), path);
1919                         /* do not overwrite file if already present */
1920                         if (update_file_flags(o, oid, mode, path, 1, !a_oid))
1921                                 clean_merge = -1;
1922                 }
1923         } else if (a_oid && b_oid) {
1924                 /* Case C: Added in both (check for same permissions) and */
1925                 /* case D: Modified in both, but differently. */
1926                 clean_merge = merge_content(o, path,
1927                                             o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
1928                                             NULL);
1929         } else if (!o_oid && !a_oid && !b_oid) {
1930                 /*
1931                  * this entry was deleted altogether. a_mode == 0 means
1932                  * we had that path and want to actively remove it.
1933                  */
1934                 remove_file(o, 1, path, !a_mode);
1935         } else
1936                 die("BUG: fatal merge failure, shouldn't happen.");
1937
1938         return clean_merge;
1939 }
1940
1941 int merge_trees(struct merge_options *o,
1942                 struct tree *head,
1943                 struct tree *merge,
1944                 struct tree *common,
1945                 struct tree **result)
1946 {
1947         int code, clean;
1948
1949         if (o->subtree_shift) {
1950                 merge = shift_tree_object(head, merge, o->subtree_shift);
1951                 common = shift_tree_object(head, common, o->subtree_shift);
1952         }
1953
1954         if (oid_eq(&common->object.oid, &merge->object.oid)) {
1955                 struct strbuf sb = STRBUF_INIT;
1956
1957                 if (!o->call_depth && index_has_changes(&sb)) {
1958                         err(o, _("Dirty index: cannot merge (dirty: %s)"),
1959                             sb.buf);
1960                         return 0;
1961                 }
1962                 output(o, 0, _("Already up to date!"));
1963                 *result = head;
1964                 return 1;
1965         }
1966
1967         code = git_merge_trees(o->call_depth, common, head, merge);
1968
1969         if (code != 0) {
1970                 if (show(o, 4) || o->call_depth)
1971                         err(o, _("merging of trees %s and %s failed"),
1972                             oid_to_hex(&head->object.oid),
1973                             oid_to_hex(&merge->object.oid));
1974                 return -1;
1975         }
1976
1977         if (unmerged_cache()) {
1978                 struct string_list *entries, *re_head, *re_merge;
1979                 int i;
1980                 /*
1981                  * Only need the hashmap while processing entries, so
1982                  * initialize it here and free it when we are done running
1983                  * through the entries. Keeping it in the merge_options as
1984                  * opposed to decaring a local hashmap is for convenience
1985                  * so that we don't have to pass it to around.
1986                  */
1987                 hashmap_init(&o->current_file_dir_set, path_hashmap_cmp, NULL, 512);
1988                 get_files_dirs(o, head);
1989                 get_files_dirs(o, merge);
1990
1991                 entries = get_unmerged();
1992                 record_df_conflict_files(o, entries);
1993                 re_head  = get_renames(o, head, common, head, merge, entries);
1994                 re_merge = get_renames(o, merge, common, head, merge, entries);
1995                 clean = process_renames(o, re_head, re_merge);
1996                 if (clean < 0)
1997                         goto cleanup;
1998                 for (i = entries->nr-1; 0 <= i; i--) {
1999                         const char *path = entries->items[i].string;
2000                         struct stage_data *e = entries->items[i].util;
2001                         if (!e->processed) {
2002                                 int ret = process_entry(o, path, e);
2003                                 if (!ret)
2004                                         clean = 0;
2005                                 else if (ret < 0) {
2006                                         clean = ret;
2007                                         goto cleanup;
2008                                 }
2009                         }
2010                 }
2011                 for (i = 0; i < entries->nr; i++) {
2012                         struct stage_data *e = entries->items[i].util;
2013                         if (!e->processed)
2014                                 die("BUG: unprocessed path??? %s",
2015                                     entries->items[i].string);
2016                 }
2017
2018 cleanup:
2019                 string_list_clear(re_merge, 0);
2020                 string_list_clear(re_head, 0);
2021                 string_list_clear(entries, 1);
2022
2023                 hashmap_free(&o->current_file_dir_set, 1);
2024
2025                 free(re_merge);
2026                 free(re_head);
2027                 free(entries);
2028
2029                 if (clean < 0)
2030                         return clean;
2031         }
2032         else
2033                 clean = 1;
2034
2035         if (o->call_depth && !(*result = write_tree_from_memory(o)))
2036                 return -1;
2037
2038         return clean;
2039 }
2040
2041 static struct commit_list *reverse_commit_list(struct commit_list *list)
2042 {
2043         struct commit_list *next = NULL, *current, *backup;
2044         for (current = list; current; current = backup) {
2045                 backup = current->next;
2046                 current->next = next;
2047                 next = current;
2048         }
2049         return next;
2050 }
2051
2052 /*
2053  * Merge the commits h1 and h2, return the resulting virtual
2054  * commit object and a flag indicating the cleanness of the merge.
2055  */
2056 int merge_recursive(struct merge_options *o,
2057                     struct commit *h1,
2058                     struct commit *h2,
2059                     struct commit_list *ca,
2060                     struct commit **result)
2061 {
2062         struct commit_list *iter;
2063         struct commit *merged_common_ancestors;
2064         struct tree *mrtree = mrtree;
2065         int clean;
2066
2067         if (show(o, 4)) {
2068                 output(o, 4, _("Merging:"));
2069                 output_commit_title(o, h1);
2070                 output_commit_title(o, h2);
2071         }
2072
2073         if (!ca) {
2074                 ca = get_merge_bases(h1, h2);
2075                 ca = reverse_commit_list(ca);
2076         }
2077
2078         if (show(o, 5)) {
2079                 unsigned cnt = commit_list_count(ca);
2080
2081                 output(o, 5, Q_("found %u common ancestor:",
2082                                 "found %u common ancestors:", cnt), cnt);
2083                 for (iter = ca; iter; iter = iter->next)
2084                         output_commit_title(o, iter->item);
2085         }
2086
2087         merged_common_ancestors = pop_commit(&ca);
2088         if (merged_common_ancestors == NULL) {
2089                 /* if there is no common ancestor, use an empty tree */
2090                 struct tree *tree;
2091
2092                 tree = lookup_tree(the_hash_algo->empty_tree);
2093                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
2094         }
2095
2096         for (iter = ca; iter; iter = iter->next) {
2097                 const char *saved_b1, *saved_b2;
2098                 o->call_depth++;
2099                 /*
2100                  * When the merge fails, the result contains files
2101                  * with conflict markers. The cleanness flag is
2102                  * ignored (unless indicating an error), it was never
2103                  * actually used, as result of merge_trees has always
2104                  * overwritten it: the committed "conflicts" were
2105                  * already resolved.
2106                  */
2107                 discard_cache();
2108                 saved_b1 = o->branch1;
2109                 saved_b2 = o->branch2;
2110                 o->branch1 = "Temporary merge branch 1";
2111                 o->branch2 = "Temporary merge branch 2";
2112                 if (merge_recursive(o, merged_common_ancestors, iter->item,
2113                                     NULL, &merged_common_ancestors) < 0)
2114                         return -1;
2115                 o->branch1 = saved_b1;
2116                 o->branch2 = saved_b2;
2117                 o->call_depth--;
2118
2119                 if (!merged_common_ancestors)
2120                         return err(o, _("merge returned no commit"));
2121         }
2122
2123         discard_cache();
2124         if (!o->call_depth)
2125                 read_cache();
2126
2127         o->ancestor = "merged common ancestors";
2128         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
2129                             &mrtree);
2130         if (clean < 0) {
2131                 flush_output(o);
2132                 return clean;
2133         }
2134
2135         if (o->call_depth) {
2136                 *result = make_virtual_commit(mrtree, "merged tree");
2137                 commit_list_insert(h1, &(*result)->parents);
2138                 commit_list_insert(h2, &(*result)->parents->next);
2139         }
2140         flush_output(o);
2141         if (!o->call_depth && o->buffer_output < 2)
2142                 strbuf_release(&o->obuf);
2143         if (show(o, 2))
2144                 diff_warn_rename_limit("merge.renamelimit",
2145                                        o->needed_rename_limit, 0);
2146         return clean;
2147 }
2148
2149 static struct commit *get_ref(const struct object_id *oid, const char *name)
2150 {
2151         struct object *object;
2152
2153         object = deref_tag(parse_object(oid), name, strlen(name));
2154         if (!object)
2155                 return NULL;
2156         if (object->type == OBJ_TREE)
2157                 return make_virtual_commit((struct tree*)object, name);
2158         if (object->type != OBJ_COMMIT)
2159                 return NULL;
2160         if (parse_commit((struct commit *)object))
2161                 return NULL;
2162         return (struct commit *)object;
2163 }
2164
2165 int merge_recursive_generic(struct merge_options *o,
2166                             const struct object_id *head,
2167                             const struct object_id *merge,
2168                             int num_base_list,
2169                             const struct object_id **base_list,
2170                             struct commit **result)
2171 {
2172         int clean;
2173         struct lock_file lock = LOCK_INIT;
2174         struct commit *head_commit = get_ref(head, o->branch1);
2175         struct commit *next_commit = get_ref(merge, o->branch2);
2176         struct commit_list *ca = NULL;
2177
2178         if (base_list) {
2179                 int i;
2180                 for (i = 0; i < num_base_list; ++i) {
2181                         struct commit *base;
2182                         if (!(base = get_ref(base_list[i], oid_to_hex(base_list[i]))))
2183                                 return err(o, _("Could not parse object '%s'"),
2184                                         oid_to_hex(base_list[i]));
2185                         commit_list_insert(base, &ca);
2186                 }
2187         }
2188
2189         hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
2190         clean = merge_recursive(o, head_commit, next_commit, ca,
2191                         result);
2192         if (clean < 0)
2193                 return clean;
2194
2195         if (active_cache_changed &&
2196             write_locked_index(&the_index, &lock, COMMIT_LOCK))
2197                 return err(o, _("Unable to write index."));
2198
2199         return clean ? 0 : 1;
2200 }
2201
2202 static void merge_recursive_config(struct merge_options *o)
2203 {
2204         git_config_get_int("merge.verbosity", &o->verbosity);
2205         git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
2206         git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
2207         git_config(git_xmerge_config, NULL);
2208 }
2209
2210 void init_merge_options(struct merge_options *o)
2211 {
2212         const char *merge_verbosity;
2213         memset(o, 0, sizeof(struct merge_options));
2214         o->verbosity = 2;
2215         o->buffer_output = 1;
2216         o->diff_rename_limit = -1;
2217         o->merge_rename_limit = -1;
2218         o->renormalize = 0;
2219         o->detect_rename = 1;
2220         merge_recursive_config(o);
2221         merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
2222         if (merge_verbosity)
2223                 o->verbosity = strtol(merge_verbosity, NULL, 10);
2224         if (o->verbosity >= 5)
2225                 o->buffer_output = 0;
2226         strbuf_init(&o->obuf, 0);
2227         string_list_init(&o->df_conflict_file_set, 1);
2228 }
2229
2230 int parse_merge_opt(struct merge_options *o, const char *s)
2231 {
2232         const char *arg;
2233
2234         if (!s || !*s)
2235                 return -1;
2236         if (!strcmp(s, "ours"))
2237                 o->recursive_variant = MERGE_RECURSIVE_OURS;
2238         else if (!strcmp(s, "theirs"))
2239                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
2240         else if (!strcmp(s, "subtree"))
2241                 o->subtree_shift = "";
2242         else if (skip_prefix(s, "subtree=", &arg))
2243                 o->subtree_shift = arg;
2244         else if (!strcmp(s, "patience"))
2245                 o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
2246         else if (!strcmp(s, "histogram"))
2247                 o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
2248         else if (skip_prefix(s, "diff-algorithm=", &arg)) {
2249                 long value = parse_algorithm_value(arg);
2250                 if (value < 0)
2251                         return -1;
2252                 /* clear out previous settings */
2253                 DIFF_XDL_CLR(o, NEED_MINIMAL);
2254                 o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
2255                 o->xdl_opts |= value;
2256         }
2257         else if (!strcmp(s, "ignore-space-change"))
2258                 DIFF_XDL_SET(o, IGNORE_WHITESPACE_CHANGE);
2259         else if (!strcmp(s, "ignore-all-space"))
2260                 DIFF_XDL_SET(o, IGNORE_WHITESPACE);
2261         else if (!strcmp(s, "ignore-space-at-eol"))
2262                 DIFF_XDL_SET(o, IGNORE_WHITESPACE_AT_EOL);
2263         else if (!strcmp(s, "ignore-cr-at-eol"))
2264                 DIFF_XDL_SET(o, IGNORE_CR_AT_EOL);
2265         else if (!strcmp(s, "renormalize"))
2266                 o->renormalize = 1;
2267         else if (!strcmp(s, "no-renormalize"))
2268                 o->renormalize = 0;
2269         else if (!strcmp(s, "no-renames"))
2270                 o->detect_rename = 0;
2271         else if (!strcmp(s, "find-renames")) {
2272                 o->detect_rename = 1;
2273                 o->rename_score = 0;
2274         }
2275         else if (skip_prefix(s, "find-renames=", &arg) ||
2276                  skip_prefix(s, "rename-threshold=", &arg)) {
2277                 if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
2278                         return -1;
2279                 o->detect_rename = 1;
2280         }
2281         else
2282                 return -1;
2283         return 0;
2284 }