Merge branch 'ls/travis-submitting-patches' into HEAD
[git] / unpack-trees.c
1 #define NO_THE_INDEX_COMPATIBILITY_MACROS
2 #include "cache.h"
3 #include "dir.h"
4 #include "tree.h"
5 #include "tree-walk.h"
6 #include "cache-tree.h"
7 #include "unpack-trees.h"
8 #include "progress.h"
9 #include "refs.h"
10 #include "attr.h"
11 #include "split-index.h"
12 #include "dir.h"
13
14 /*
15  * Error messages expected by scripts out of plumbing commands such as
16  * read-tree.  Non-scripted Porcelain is not required to use these messages
17  * and in fact are encouraged to reword them to better suit their particular
18  * situation better.  See how "git checkout" and "git merge" replaces
19  * them using setup_unpack_trees_porcelain(), for example.
20  */
21 static const char *unpack_plumbing_errors[NB_UNPACK_TREES_ERROR_TYPES] = {
22         /* ERROR_WOULD_OVERWRITE */
23         "Entry '%s' would be overwritten by merge. Cannot merge.",
24
25         /* ERROR_NOT_UPTODATE_FILE */
26         "Entry '%s' not uptodate. Cannot merge.",
27
28         /* ERROR_NOT_UPTODATE_DIR */
29         "Updating '%s' would lose untracked files in it",
30
31         /* ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN */
32         "Untracked working tree file '%s' would be overwritten by merge.",
33
34         /* ERROR_WOULD_LOSE_UNTRACKED_REMOVED */
35         "Untracked working tree file '%s' would be removed by merge.",
36
37         /* ERROR_BIND_OVERLAP */
38         "Entry '%s' overlaps with '%s'.  Cannot bind.",
39
40         /* ERROR_SPARSE_NOT_UPTODATE_FILE */
41         "Entry '%s' not uptodate. Cannot update sparse checkout.",
42
43         /* ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN */
44         "Working tree file '%s' would be overwritten by sparse checkout update.",
45
46         /* ERROR_WOULD_LOSE_ORPHANED_REMOVED */
47         "Working tree file '%s' would be removed by sparse checkout update.",
48 };
49
50 #define ERRORMSG(o,type) \
51         ( ((o) && (o)->msgs[(type)]) \
52           ? ((o)->msgs[(type)])      \
53           : (unpack_plumbing_errors[(type)]) )
54
55 void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
56                                   const char *cmd)
57 {
58         int i;
59         const char **msgs = opts->msgs;
60         const char *msg;
61         const char *cmd2 = strcmp(cmd, "checkout") ? cmd : "switch branches";
62
63         if (advice_commit_before_merge)
64                 msg = "Your local changes to the following files would be overwritten by %s:\n%%s"
65                         "Please, commit your changes or stash them before you can %s.";
66         else
67                 msg = "Your local changes to the following files would be overwritten by %s:\n%%s";
68         msgs[ERROR_WOULD_OVERWRITE] = msgs[ERROR_NOT_UPTODATE_FILE] =
69                 xstrfmt(msg, cmd, cmd2);
70
71         msgs[ERROR_NOT_UPTODATE_DIR] =
72                 "Updating the following directories would lose untracked files in it:\n%s";
73
74         if (advice_commit_before_merge)
75                 msg = "The following untracked working tree files would be %s by %s:\n%%s"
76                         "Please move or remove them before you can %s.";
77         else
78                 msg = "The following untracked working tree files would be %s by %s:\n%%s";
79
80         msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = xstrfmt(msg, "removed", cmd, cmd2);
81         msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = xstrfmt(msg, "overwritten", cmd, cmd2);
82
83         /*
84          * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
85          * cannot easily display it as a list.
86          */
87         msgs[ERROR_BIND_OVERLAP] = "Entry '%s' overlaps with '%s'.  Cannot bind.";
88
89         msgs[ERROR_SPARSE_NOT_UPTODATE_FILE] =
90                 "Cannot update sparse checkout: the following entries are not up-to-date:\n%s";
91         msgs[ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN] =
92                 "The following Working tree files would be overwritten by sparse checkout update:\n%s";
93         msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
94                 "The following Working tree files would be removed by sparse checkout update:\n%s";
95
96         opts->show_all_errors = 1;
97         /* rejected paths may not have a static buffer */
98         for (i = 0; i < ARRAY_SIZE(opts->unpack_rejects); i++)
99                 opts->unpack_rejects[i].strdup_strings = 1;
100 }
101
102 static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
103                          unsigned int set, unsigned int clear)
104 {
105         clear |= CE_HASHED;
106
107         if (set & CE_REMOVE)
108                 set |= CE_WT_REMOVE;
109
110         ce->ce_flags = (ce->ce_flags & ~clear) | set;
111         return add_index_entry(&o->result, ce,
112                                ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
113 }
114
115 static struct cache_entry *dup_entry(const struct cache_entry *ce)
116 {
117         unsigned int size = ce_size(ce);
118         struct cache_entry *new = xmalloc(size);
119
120         memcpy(new, ce, size);
121         return new;
122 }
123
124 static void add_entry(struct unpack_trees_options *o,
125                       const struct cache_entry *ce,
126                       unsigned int set, unsigned int clear)
127 {
128         do_add_entry(o, dup_entry(ce), set, clear);
129 }
130
131 /*
132  * add error messages on path <path>
133  * corresponding to the type <e> with the message <msg>
134  * indicating if it should be display in porcelain or not
135  */
136 static int add_rejected_path(struct unpack_trees_options *o,
137                              enum unpack_trees_error_types e,
138                              const char *path)
139 {
140         if (!o->show_all_errors)
141                 return error(ERRORMSG(o, e), path);
142
143         /*
144          * Otherwise, insert in a list for future display by
145          * display_error_msgs()
146          */
147         string_list_append(&o->unpack_rejects[e], path);
148         return -1;
149 }
150
151 /*
152  * display all the error messages stored in a nice way
153  */
154 static void display_error_msgs(struct unpack_trees_options *o)
155 {
156         int e, i;
157         int something_displayed = 0;
158         for (e = 0; e < NB_UNPACK_TREES_ERROR_TYPES; e++) {
159                 struct string_list *rejects = &o->unpack_rejects[e];
160                 if (rejects->nr > 0) {
161                         struct strbuf path = STRBUF_INIT;
162                         something_displayed = 1;
163                         for (i = 0; i < rejects->nr; i++)
164                                 strbuf_addf(&path, "\t%s\n", rejects->items[i].string);
165                         error(ERRORMSG(o, e), path.buf);
166                         strbuf_release(&path);
167                 }
168                 string_list_clear(rejects, 0);
169         }
170         if (something_displayed)
171                 fprintf(stderr, "Aborting\n");
172 }
173
174 /*
175  * Unlink the last component and schedule the leading directories for
176  * removal, such that empty directories get removed.
177  */
178 static void unlink_entry(const struct cache_entry *ce)
179 {
180         if (!check_leading_path(ce->name, ce_namelen(ce)))
181                 return;
182         if (remove_or_warn(ce->ce_mode, ce->name))
183                 return;
184         schedule_dir_for_removal(ce->name, ce_namelen(ce));
185 }
186
187 static struct checkout state;
188 static int check_updates(struct unpack_trees_options *o)
189 {
190         unsigned cnt = 0, total = 0;
191         struct progress *progress = NULL;
192         struct index_state *index = &o->result;
193         int i;
194         int errs = 0;
195
196         if (o->update && o->verbose_update) {
197                 for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
198                         const struct cache_entry *ce = index->cache[cnt];
199                         if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))
200                                 total++;
201                 }
202
203                 progress = start_progress_delay(_("Checking out files"),
204                                                 total, 50, 1);
205                 cnt = 0;
206         }
207
208         if (o->update)
209                 git_attr_set_direction(GIT_ATTR_CHECKOUT, &o->result);
210         for (i = 0; i < index->cache_nr; i++) {
211                 const struct cache_entry *ce = index->cache[i];
212
213                 if (ce->ce_flags & CE_WT_REMOVE) {
214                         display_progress(progress, ++cnt);
215                         if (o->update && !o->dry_run)
216                                 unlink_entry(ce);
217                         continue;
218                 }
219         }
220         remove_marked_cache_entries(&o->result);
221         remove_scheduled_dirs();
222
223         for (i = 0; i < index->cache_nr; i++) {
224                 struct cache_entry *ce = index->cache[i];
225
226                 if (ce->ce_flags & CE_UPDATE) {
227                         if (ce->ce_flags & CE_WT_REMOVE)
228                                 die("BUG: both update and delete flags are set on %s",
229                                     ce->name);
230                         display_progress(progress, ++cnt);
231                         ce->ce_flags &= ~CE_UPDATE;
232                         if (o->update && !o->dry_run) {
233                                 errs |= checkout_entry(ce, &state, NULL);
234                         }
235                 }
236         }
237         stop_progress(&progress);
238         if (o->update)
239                 git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
240         return errs != 0;
241 }
242
243 static int verify_uptodate_sparse(const struct cache_entry *ce,
244                                   struct unpack_trees_options *o);
245 static int verify_absent_sparse(const struct cache_entry *ce,
246                                 enum unpack_trees_error_types,
247                                 struct unpack_trees_options *o);
248
249 static int apply_sparse_checkout(struct index_state *istate,
250                                  struct cache_entry *ce,
251                                  struct unpack_trees_options *o)
252 {
253         int was_skip_worktree = ce_skip_worktree(ce);
254
255         if (ce->ce_flags & CE_NEW_SKIP_WORKTREE)
256                 ce->ce_flags |= CE_SKIP_WORKTREE;
257         else
258                 ce->ce_flags &= ~CE_SKIP_WORKTREE;
259         if (was_skip_worktree != ce_skip_worktree(ce)) {
260                 ce->ce_flags |= CE_UPDATE_IN_BASE;
261                 istate->cache_changed |= CE_ENTRY_CHANGED;
262         }
263
264         /*
265          * if (!was_skip_worktree && !ce_skip_worktree()) {
266          *      This is perfectly normal. Move on;
267          * }
268          */
269
270         /*
271          * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
272          * area as a result of ce_skip_worktree() shortcuts in
273          * verify_absent() and verify_uptodate().
274          * Make sure they don't modify worktree if they are already
275          * outside checkout area
276          */
277         if (was_skip_worktree && ce_skip_worktree(ce)) {
278                 ce->ce_flags &= ~CE_UPDATE;
279
280                 /*
281                  * By default, when CE_REMOVE is on, CE_WT_REMOVE is also
282                  * on to get that file removed from both index and worktree.
283                  * If that file is already outside worktree area, don't
284                  * bother remove it.
285                  */
286                 if (ce->ce_flags & CE_REMOVE)
287                         ce->ce_flags &= ~CE_WT_REMOVE;
288         }
289
290         if (!was_skip_worktree && ce_skip_worktree(ce)) {
291                 /*
292                  * If CE_UPDATE is set, verify_uptodate() must be called already
293                  * also stat info may have lost after merged_entry() so calling
294                  * verify_uptodate() again may fail
295                  */
296                 if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
297                         return -1;
298                 ce->ce_flags |= CE_WT_REMOVE;
299                 ce->ce_flags &= ~CE_UPDATE;
300         }
301         if (was_skip_worktree && !ce_skip_worktree(ce)) {
302                 if (verify_absent_sparse(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o))
303                         return -1;
304                 ce->ce_flags |= CE_UPDATE;
305         }
306         return 0;
307 }
308
309 static inline int call_unpack_fn(const struct cache_entry * const *src,
310                                  struct unpack_trees_options *o)
311 {
312         int ret = o->fn(src, o);
313         if (ret > 0)
314                 ret = 0;
315         return ret;
316 }
317
318 static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
319 {
320         ce->ce_flags |= CE_UNPACKED;
321
322         if (o->cache_bottom < o->src_index->cache_nr &&
323             o->src_index->cache[o->cache_bottom] == ce) {
324                 int bottom = o->cache_bottom;
325                 while (bottom < o->src_index->cache_nr &&
326                        o->src_index->cache[bottom]->ce_flags & CE_UNPACKED)
327                         bottom++;
328                 o->cache_bottom = bottom;
329         }
330 }
331
332 static void mark_all_ce_unused(struct index_state *index)
333 {
334         int i;
335         for (i = 0; i < index->cache_nr; i++)
336                 index->cache[i]->ce_flags &= ~(CE_UNPACKED | CE_ADDED | CE_NEW_SKIP_WORKTREE);
337 }
338
339 static int locate_in_src_index(const struct cache_entry *ce,
340                                struct unpack_trees_options *o)
341 {
342         struct index_state *index = o->src_index;
343         int len = ce_namelen(ce);
344         int pos = index_name_pos(index, ce->name, len);
345         if (pos < 0)
346                 pos = -1 - pos;
347         return pos;
348 }
349
350 /*
351  * We call unpack_index_entry() with an unmerged cache entry
352  * only in diff-index, and it wants a single callback.  Skip
353  * the other unmerged entry with the same name.
354  */
355 static void mark_ce_used_same_name(struct cache_entry *ce,
356                                    struct unpack_trees_options *o)
357 {
358         struct index_state *index = o->src_index;
359         int len = ce_namelen(ce);
360         int pos;
361
362         for (pos = locate_in_src_index(ce, o); pos < index->cache_nr; pos++) {
363                 struct cache_entry *next = index->cache[pos];
364                 if (len != ce_namelen(next) ||
365                     memcmp(ce->name, next->name, len))
366                         break;
367                 mark_ce_used(next, o);
368         }
369 }
370
371 static struct cache_entry *next_cache_entry(struct unpack_trees_options *o)
372 {
373         const struct index_state *index = o->src_index;
374         int pos = o->cache_bottom;
375
376         while (pos < index->cache_nr) {
377                 struct cache_entry *ce = index->cache[pos];
378                 if (!(ce->ce_flags & CE_UNPACKED))
379                         return ce;
380                 pos++;
381         }
382         return NULL;
383 }
384
385 static void add_same_unmerged(const struct cache_entry *ce,
386                               struct unpack_trees_options *o)
387 {
388         struct index_state *index = o->src_index;
389         int len = ce_namelen(ce);
390         int pos = index_name_pos(index, ce->name, len);
391
392         if (0 <= pos)
393                 die("programming error in a caller of mark_ce_used_same_name");
394         for (pos = -pos - 1; pos < index->cache_nr; pos++) {
395                 struct cache_entry *next = index->cache[pos];
396                 if (len != ce_namelen(next) ||
397                     memcmp(ce->name, next->name, len))
398                         break;
399                 add_entry(o, next, 0, 0);
400                 mark_ce_used(next, o);
401         }
402 }
403
404 static int unpack_index_entry(struct cache_entry *ce,
405                               struct unpack_trees_options *o)
406 {
407         const struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
408         int ret;
409
410         src[0] = ce;
411
412         mark_ce_used(ce, o);
413         if (ce_stage(ce)) {
414                 if (o->skip_unmerged) {
415                         add_entry(o, ce, 0, 0);
416                         return 0;
417                 }
418         }
419         ret = call_unpack_fn(src, o);
420         if (ce_stage(ce))
421                 mark_ce_used_same_name(ce, o);
422         return ret;
423 }
424
425 static int find_cache_pos(struct traverse_info *, const struct name_entry *);
426
427 static void restore_cache_bottom(struct traverse_info *info, int bottom)
428 {
429         struct unpack_trees_options *o = info->data;
430
431         if (o->diff_index_cached)
432                 return;
433         o->cache_bottom = bottom;
434 }
435
436 static int switch_cache_bottom(struct traverse_info *info)
437 {
438         struct unpack_trees_options *o = info->data;
439         int ret, pos;
440
441         if (o->diff_index_cached)
442                 return 0;
443         ret = o->cache_bottom;
444         pos = find_cache_pos(info->prev, &info->name);
445
446         if (pos < -1)
447                 o->cache_bottom = -2 - pos;
448         else if (pos < 0)
449                 o->cache_bottom = o->src_index->cache_nr;
450         return ret;
451 }
452
453 static int traverse_trees_recursive(int n, unsigned long dirmask,
454                                     unsigned long df_conflicts,
455                                     struct name_entry *names,
456                                     struct traverse_info *info)
457 {
458         int i, ret, bottom;
459         struct tree_desc t[MAX_UNPACK_TREES];
460         void *buf[MAX_UNPACK_TREES];
461         struct traverse_info newinfo;
462         struct name_entry *p;
463
464         p = names;
465         while (!p->mode)
466                 p++;
467
468         newinfo = *info;
469         newinfo.prev = info;
470         newinfo.pathspec = info->pathspec;
471         newinfo.name = *p;
472         newinfo.pathlen += tree_entry_len(p) + 1;
473         newinfo.df_conflicts |= df_conflicts;
474
475         for (i = 0; i < n; i++, dirmask >>= 1) {
476                 const unsigned char *sha1 = NULL;
477                 if (dirmask & 1)
478                         sha1 = names[i].sha1;
479                 buf[i] = fill_tree_descriptor(t+i, sha1);
480         }
481
482         bottom = switch_cache_bottom(&newinfo);
483         ret = traverse_trees(n, t, &newinfo);
484         restore_cache_bottom(&newinfo, bottom);
485
486         for (i = 0; i < n; i++)
487                 free(buf[i]);
488
489         return ret;
490 }
491
492 /*
493  * Compare the traverse-path to the cache entry without actually
494  * having to generate the textual representation of the traverse
495  * path.
496  *
497  * NOTE! This *only* compares up to the size of the traverse path
498  * itself - the caller needs to do the final check for the cache
499  * entry having more data at the end!
500  */
501 static int do_compare_entry_piecewise(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
502 {
503         int len, pathlen, ce_len;
504         const char *ce_name;
505
506         if (info->prev) {
507                 int cmp = do_compare_entry_piecewise(ce, info->prev,
508                                                      &info->name);
509                 if (cmp)
510                         return cmp;
511         }
512         pathlen = info->pathlen;
513         ce_len = ce_namelen(ce);
514
515         /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
516         if (ce_len < pathlen)
517                 return -1;
518
519         ce_len -= pathlen;
520         ce_name = ce->name + pathlen;
521
522         len = tree_entry_len(n);
523         return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
524 }
525
526 static int do_compare_entry(const struct cache_entry *ce,
527                             const struct traverse_info *info,
528                             const struct name_entry *n)
529 {
530         int len, pathlen, ce_len;
531         const char *ce_name;
532         int cmp;
533
534         /*
535          * If we have not precomputed the traverse path, it is quicker
536          * to avoid doing so.  But if we have precomputed it,
537          * it is quicker to use the precomputed version.
538          */
539         if (!info->traverse_path)
540                 return do_compare_entry_piecewise(ce, info, n);
541
542         cmp = strncmp(ce->name, info->traverse_path, info->pathlen);
543         if (cmp)
544                 return cmp;
545
546         pathlen = info->pathlen;
547         ce_len = ce_namelen(ce);
548
549         if (ce_len < pathlen)
550                 return -1;
551
552         ce_len -= pathlen;
553         ce_name = ce->name + pathlen;
554
555         len = tree_entry_len(n);
556         return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
557 }
558
559 static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
560 {
561         int cmp = do_compare_entry(ce, info, n);
562         if (cmp)
563                 return cmp;
564
565         /*
566          * Even if the beginning compared identically, the ce should
567          * compare as bigger than a directory leading up to it!
568          */
569         return ce_namelen(ce) > traverse_path_len(info, n);
570 }
571
572 static int ce_in_traverse_path(const struct cache_entry *ce,
573                                const struct traverse_info *info)
574 {
575         if (!info->prev)
576                 return 1;
577         if (do_compare_entry(ce, info->prev, &info->name))
578                 return 0;
579         /*
580          * If ce (blob) is the same name as the path (which is a tree
581          * we will be descending into), it won't be inside it.
582          */
583         return (info->pathlen < ce_namelen(ce));
584 }
585
586 static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
587 {
588         int len = traverse_path_len(info, n);
589         struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
590
591         ce->ce_mode = create_ce_mode(n->mode);
592         ce->ce_flags = create_ce_flags(stage);
593         ce->ce_namelen = len;
594         hashcpy(ce->sha1, n->sha1);
595         make_traverse_path(ce->name, info, n);
596
597         return ce;
598 }
599
600 static int unpack_nondirectories(int n, unsigned long mask,
601                                  unsigned long dirmask,
602                                  struct cache_entry **src,
603                                  const struct name_entry *names,
604                                  const struct traverse_info *info)
605 {
606         int i;
607         struct unpack_trees_options *o = info->data;
608         unsigned long conflicts = info->df_conflicts | dirmask;
609
610         /* Do we have *only* directories? Nothing to do */
611         if (mask == dirmask && !src[0])
612                 return 0;
613
614         /*
615          * Ok, we've filled in up to any potential index entry in src[0],
616          * now do the rest.
617          */
618         for (i = 0; i < n; i++) {
619                 int stage;
620                 unsigned int bit = 1ul << i;
621                 if (conflicts & bit) {
622                         src[i + o->merge] = o->df_conflict_entry;
623                         continue;
624                 }
625                 if (!(mask & bit))
626                         continue;
627                 if (!o->merge)
628                         stage = 0;
629                 else if (i + 1 < o->head_idx)
630                         stage = 1;
631                 else if (i + 1 > o->head_idx)
632                         stage = 3;
633                 else
634                         stage = 2;
635                 src[i + o->merge] = create_ce_entry(info, names + i, stage);
636         }
637
638         if (o->merge) {
639                 int rc = call_unpack_fn((const struct cache_entry * const *)src,
640                                         o);
641                 for (i = 0; i < n; i++) {
642                         struct cache_entry *ce = src[i + o->merge];
643                         if (ce != o->df_conflict_entry)
644                                 free(ce);
645                 }
646                 return rc;
647         }
648
649         for (i = 0; i < n; i++)
650                 if (src[i] && src[i] != o->df_conflict_entry)
651                         if (do_add_entry(o, src[i], 0, 0))
652                                 return -1;
653
654         return 0;
655 }
656
657 static int unpack_failed(struct unpack_trees_options *o, const char *message)
658 {
659         discard_index(&o->result);
660         if (!o->gently && !o->exiting_early) {
661                 if (message)
662                         return error("%s", message);
663                 return -1;
664         }
665         return -1;
666 }
667
668 /*
669  * The tree traversal is looking at name p.  If we have a matching entry,
670  * return it.  If name p is a directory in the index, do not return
671  * anything, as we will want to match it when the traversal descends into
672  * the directory.
673  */
674 static int find_cache_pos(struct traverse_info *info,
675                           const struct name_entry *p)
676 {
677         int pos;
678         struct unpack_trees_options *o = info->data;
679         struct index_state *index = o->src_index;
680         int pfxlen = info->pathlen;
681         int p_len = tree_entry_len(p);
682
683         for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
684                 const struct cache_entry *ce = index->cache[pos];
685                 const char *ce_name, *ce_slash;
686                 int cmp, ce_len;
687
688                 if (ce->ce_flags & CE_UNPACKED) {
689                         /*
690                          * cache_bottom entry is already unpacked, so
691                          * we can never match it; don't check it
692                          * again.
693                          */
694                         if (pos == o->cache_bottom)
695                                 ++o->cache_bottom;
696                         continue;
697                 }
698                 if (!ce_in_traverse_path(ce, info)) {
699                         /*
700                          * Check if we can skip future cache checks
701                          * (because we're already past all possible
702                          * entries in the traverse path).
703                          */
704                         if (info->traverse_path) {
705                                 if (strncmp(ce->name, info->traverse_path,
706                                             info->pathlen) > 0)
707                                         break;
708                         }
709                         continue;
710                 }
711                 ce_name = ce->name + pfxlen;
712                 ce_slash = strchr(ce_name, '/');
713                 if (ce_slash)
714                         ce_len = ce_slash - ce_name;
715                 else
716                         ce_len = ce_namelen(ce) - pfxlen;
717                 cmp = name_compare(p->path, p_len, ce_name, ce_len);
718                 /*
719                  * Exact match; if we have a directory we need to
720                  * delay returning it.
721                  */
722                 if (!cmp)
723                         return ce_slash ? -2 - pos : pos;
724                 if (0 < cmp)
725                         continue; /* keep looking */
726                 /*
727                  * ce_name sorts after p->path; could it be that we
728                  * have files under p->path directory in the index?
729                  * E.g.  ce_name == "t-i", and p->path == "t"; we may
730                  * have "t/a" in the index.
731                  */
732                 if (p_len < ce_len && !memcmp(ce_name, p->path, p_len) &&
733                     ce_name[p_len] < '/')
734                         continue; /* keep looking */
735                 break;
736         }
737         return -1;
738 }
739
740 static struct cache_entry *find_cache_entry(struct traverse_info *info,
741                                             const struct name_entry *p)
742 {
743         int pos = find_cache_pos(info, p);
744         struct unpack_trees_options *o = info->data;
745
746         if (0 <= pos)
747                 return o->src_index->cache[pos];
748         else
749                 return NULL;
750 }
751
752 static void debug_path(struct traverse_info *info)
753 {
754         if (info->prev) {
755                 debug_path(info->prev);
756                 if (*info->prev->name.path)
757                         putchar('/');
758         }
759         printf("%s", info->name.path);
760 }
761
762 static void debug_name_entry(int i, struct name_entry *n)
763 {
764         printf("ent#%d %06o %s\n", i,
765                n->path ? n->mode : 0,
766                n->path ? n->path : "(missing)");
767 }
768
769 static void debug_unpack_callback(int n,
770                                   unsigned long mask,
771                                   unsigned long dirmask,
772                                   struct name_entry *names,
773                                   struct traverse_info *info)
774 {
775         int i;
776         printf("* unpack mask %lu, dirmask %lu, cnt %d ",
777                mask, dirmask, n);
778         debug_path(info);
779         putchar('\n');
780         for (i = 0; i < n; i++)
781                 debug_name_entry(i, names + i);
782 }
783
784 static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
785 {
786         struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
787         struct unpack_trees_options *o = info->data;
788         const struct name_entry *p = names;
789
790         /* Find first entry with a real name (we could use "mask" too) */
791         while (!p->mode)
792                 p++;
793
794         if (o->debug_unpack)
795                 debug_unpack_callback(n, mask, dirmask, names, info);
796
797         /* Are we supposed to look at the index too? */
798         if (o->merge) {
799                 while (1) {
800                         int cmp;
801                         struct cache_entry *ce;
802
803                         if (o->diff_index_cached)
804                                 ce = next_cache_entry(o);
805                         else
806                                 ce = find_cache_entry(info, p);
807
808                         if (!ce)
809                                 break;
810                         cmp = compare_entry(ce, info, p);
811                         if (cmp < 0) {
812                                 if (unpack_index_entry(ce, o) < 0)
813                                         return unpack_failed(o, NULL);
814                                 continue;
815                         }
816                         if (!cmp) {
817                                 if (ce_stage(ce)) {
818                                         /*
819                                          * If we skip unmerged index
820                                          * entries, we'll skip this
821                                          * entry *and* the tree
822                                          * entries associated with it!
823                                          */
824                                         if (o->skip_unmerged) {
825                                                 add_same_unmerged(ce, o);
826                                                 return mask;
827                                         }
828                                 }
829                                 src[0] = ce;
830                         }
831                         break;
832                 }
833         }
834
835         if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
836                 return -1;
837
838         if (o->merge && src[0]) {
839                 if (ce_stage(src[0]))
840                         mark_ce_used_same_name(src[0], o);
841                 else
842                         mark_ce_used(src[0], o);
843         }
844
845         /* Now handle any directories.. */
846         if (dirmask) {
847                 /* special case: "diff-index --cached" looking at a tree */
848                 if (o->diff_index_cached &&
849                     n == 1 && dirmask == 1 && S_ISDIR(names->mode)) {
850                         int matches;
851                         matches = cache_tree_matches_traversal(o->src_index->cache_tree,
852                                                                names, info);
853                         /*
854                          * Everything under the name matches; skip the
855                          * entire hierarchy.  diff_index_cached codepath
856                          * special cases D/F conflicts in such a way that
857                          * it does not do any look-ahead, so this is safe.
858                          */
859                         if (matches) {
860                                 o->cache_bottom += matches;
861                                 return mask;
862                         }
863                 }
864
865                 if (traverse_trees_recursive(n, dirmask, mask & ~dirmask,
866                                              names, info) < 0)
867                         return -1;
868                 return mask;
869         }
870
871         return mask;
872 }
873
874 static int clear_ce_flags_1(struct cache_entry **cache, int nr,
875                             struct strbuf *prefix,
876                             int select_mask, int clear_mask,
877                             struct exclude_list *el, int defval);
878
879 /* Whole directory matching */
880 static int clear_ce_flags_dir(struct cache_entry **cache, int nr,
881                               struct strbuf *prefix,
882                               char *basename,
883                               int select_mask, int clear_mask,
884                               struct exclude_list *el, int defval)
885 {
886         struct cache_entry **cache_end;
887         int dtype = DT_DIR;
888         int ret = is_excluded_from_list(prefix->buf, prefix->len,
889                                         basename, &dtype, el);
890         int rc;
891
892         strbuf_addch(prefix, '/');
893
894         /* If undecided, use matching result of parent dir in defval */
895         if (ret < 0)
896                 ret = defval;
897
898         for (cache_end = cache; cache_end != cache + nr; cache_end++) {
899                 struct cache_entry *ce = *cache_end;
900                 if (strncmp(ce->name, prefix->buf, prefix->len))
901                         break;
902         }
903
904         /*
905          * TODO: check el, if there are no patterns that may conflict
906          * with ret (iow, we know in advance the incl/excl
907          * decision for the entire directory), clear flag here without
908          * calling clear_ce_flags_1(). That function will call
909          * the expensive is_excluded_from_list() on every entry.
910          */
911         rc = clear_ce_flags_1(cache, cache_end - cache,
912                               prefix,
913                               select_mask, clear_mask,
914                               el, ret);
915         strbuf_setlen(prefix, prefix->len - 1);
916         return rc;
917 }
918
919 /*
920  * Traverse the index, find every entry that matches according to
921  * o->el. Do "ce_flags &= ~clear_mask" on those entries. Return the
922  * number of traversed entries.
923  *
924  * If select_mask is non-zero, only entries whose ce_flags has on of
925  * those bits enabled are traversed.
926  *
927  * cache        : pointer to an index entry
928  * prefix_len   : an offset to its path
929  *
930  * The current path ("prefix") including the trailing '/' is
931  *   cache[0]->name[0..(prefix_len-1)]
932  * Top level path has prefix_len zero.
933  */
934 static int clear_ce_flags_1(struct cache_entry **cache, int nr,
935                             struct strbuf *prefix,
936                             int select_mask, int clear_mask,
937                             struct exclude_list *el, int defval)
938 {
939         struct cache_entry **cache_end = cache + nr;
940
941         /*
942          * Process all entries that have the given prefix and meet
943          * select_mask condition
944          */
945         while(cache != cache_end) {
946                 struct cache_entry *ce = *cache;
947                 const char *name, *slash;
948                 int len, dtype, ret;
949
950                 if (select_mask && !(ce->ce_flags & select_mask)) {
951                         cache++;
952                         continue;
953                 }
954
955                 if (prefix->len && strncmp(ce->name, prefix->buf, prefix->len))
956                         break;
957
958                 name = ce->name + prefix->len;
959                 slash = strchr(name, '/');
960
961                 /* If it's a directory, try whole directory match first */
962                 if (slash) {
963                         int processed;
964
965                         len = slash - name;
966                         strbuf_add(prefix, name, len);
967
968                         processed = clear_ce_flags_dir(cache, cache_end - cache,
969                                                        prefix,
970                                                        prefix->buf + prefix->len - len,
971                                                        select_mask, clear_mask,
972                                                        el, defval);
973
974                         /* clear_c_f_dir eats a whole dir already? */
975                         if (processed) {
976                                 cache += processed;
977                                 strbuf_setlen(prefix, prefix->len - len);
978                                 continue;
979                         }
980
981                         strbuf_addch(prefix, '/');
982                         cache += clear_ce_flags_1(cache, cache_end - cache,
983                                                   prefix,
984                                                   select_mask, clear_mask, el, defval);
985                         strbuf_setlen(prefix, prefix->len - len - 1);
986                         continue;
987                 }
988
989                 /* Non-directory */
990                 dtype = ce_to_dtype(ce);
991                 ret = is_excluded_from_list(ce->name, ce_namelen(ce),
992                                             name, &dtype, el);
993                 if (ret < 0)
994                         ret = defval;
995                 if (ret > 0)
996                         ce->ce_flags &= ~clear_mask;
997                 cache++;
998         }
999         return nr - (cache_end - cache);
1000 }
1001
1002 static int clear_ce_flags(struct cache_entry **cache, int nr,
1003                             int select_mask, int clear_mask,
1004                             struct exclude_list *el)
1005 {
1006         static struct strbuf prefix = STRBUF_INIT;
1007
1008         strbuf_reset(&prefix);
1009
1010         return clear_ce_flags_1(cache, nr,
1011                                 &prefix,
1012                                 select_mask, clear_mask,
1013                                 el, 0);
1014 }
1015
1016 /*
1017  * Set/Clear CE_NEW_SKIP_WORKTREE according to $GIT_DIR/info/sparse-checkout
1018  */
1019 static void mark_new_skip_worktree(struct exclude_list *el,
1020                                    struct index_state *the_index,
1021                                    int select_flag, int skip_wt_flag)
1022 {
1023         int i;
1024
1025         /*
1026          * 1. Pretend the narrowest worktree: only unmerged entries
1027          * are checked out
1028          */
1029         for (i = 0; i < the_index->cache_nr; i++) {
1030                 struct cache_entry *ce = the_index->cache[i];
1031
1032                 if (select_flag && !(ce->ce_flags & select_flag))
1033                         continue;
1034
1035                 if (!ce_stage(ce))
1036                         ce->ce_flags |= skip_wt_flag;
1037                 else
1038                         ce->ce_flags &= ~skip_wt_flag;
1039         }
1040
1041         /*
1042          * 2. Widen worktree according to sparse-checkout file.
1043          * Matched entries will have skip_wt_flag cleared (i.e. "in")
1044          */
1045         clear_ce_flags(the_index->cache, the_index->cache_nr,
1046                        select_flag, skip_wt_flag, el);
1047 }
1048
1049 static int verify_absent(const struct cache_entry *,
1050                          enum unpack_trees_error_types,
1051                          struct unpack_trees_options *);
1052 /*
1053  * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
1054  * resulting index, -2 on failure to reflect the changes to the work tree.
1055  *
1056  * CE_ADDED, CE_UNPACKED and CE_NEW_SKIP_WORKTREE are used internally
1057  */
1058 int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
1059 {
1060         int i, ret;
1061         static struct cache_entry *dfc;
1062         struct exclude_list el;
1063
1064         if (len > MAX_UNPACK_TREES)
1065                 die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
1066         memset(&state, 0, sizeof(state));
1067         state.base_dir = "";
1068         state.force = 1;
1069         state.quiet = 1;
1070         state.refresh_cache = 1;
1071         state.istate = &o->result;
1072
1073         memset(&el, 0, sizeof(el));
1074         if (!core_apply_sparse_checkout || !o->update)
1075                 o->skip_sparse_checkout = 1;
1076         if (!o->skip_sparse_checkout) {
1077                 char *sparse = git_pathdup("info/sparse-checkout");
1078                 if (add_excludes_from_file_to_list(sparse, "", 0, &el, 0) < 0)
1079                         o->skip_sparse_checkout = 1;
1080                 else
1081                         o->el = &el;
1082                 free(sparse);
1083         }
1084
1085         memset(&o->result, 0, sizeof(o->result));
1086         o->result.initialized = 1;
1087         o->result.timestamp.sec = o->src_index->timestamp.sec;
1088         o->result.timestamp.nsec = o->src_index->timestamp.nsec;
1089         o->result.version = o->src_index->version;
1090         o->result.split_index = o->src_index->split_index;
1091         if (o->result.split_index)
1092                 o->result.split_index->refcount++;
1093         hashcpy(o->result.sha1, o->src_index->sha1);
1094         o->merge_size = len;
1095         mark_all_ce_unused(o->src_index);
1096
1097         /*
1098          * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries
1099          */
1100         if (!o->skip_sparse_checkout)
1101                 mark_new_skip_worktree(o->el, o->src_index, 0, CE_NEW_SKIP_WORKTREE);
1102
1103         if (!dfc)
1104                 dfc = xcalloc(1, cache_entry_size(0));
1105         o->df_conflict_entry = dfc;
1106
1107         if (len) {
1108                 const char *prefix = o->prefix ? o->prefix : "";
1109                 struct traverse_info info;
1110
1111                 setup_traverse_info(&info, prefix);
1112                 info.fn = unpack_callback;
1113                 info.data = o;
1114                 info.show_all_errors = o->show_all_errors;
1115                 info.pathspec = o->pathspec;
1116
1117                 if (o->prefix) {
1118                         /*
1119                          * Unpack existing index entries that sort before the
1120                          * prefix the tree is spliced into.  Note that o->merge
1121                          * is always true in this case.
1122                          */
1123                         while (1) {
1124                                 struct cache_entry *ce = next_cache_entry(o);
1125                                 if (!ce)
1126                                         break;
1127                                 if (ce_in_traverse_path(ce, &info))
1128                                         break;
1129                                 if (unpack_index_entry(ce, o) < 0)
1130                                         goto return_failed;
1131                         }
1132                 }
1133
1134                 if (traverse_trees(len, t, &info) < 0)
1135                         goto return_failed;
1136         }
1137
1138         /* Any left-over entries in the index? */
1139         if (o->merge) {
1140                 while (1) {
1141                         struct cache_entry *ce = next_cache_entry(o);
1142                         if (!ce)
1143                                 break;
1144                         if (unpack_index_entry(ce, o) < 0)
1145                                 goto return_failed;
1146                 }
1147         }
1148         mark_all_ce_unused(o->src_index);
1149
1150         if (o->trivial_merges_only && o->nontrivial_merge) {
1151                 ret = unpack_failed(o, "Merge requires file-level merging");
1152                 goto done;
1153         }
1154
1155         if (!o->skip_sparse_checkout) {
1156                 int empty_worktree = 1;
1157
1158                 /*
1159                  * Sparse checkout loop #2: set NEW_SKIP_WORKTREE on entries not in loop #1
1160                  * If the will have NEW_SKIP_WORKTREE, also set CE_SKIP_WORKTREE
1161                  * so apply_sparse_checkout() won't attempt to remove it from worktree
1162                  */
1163                 mark_new_skip_worktree(o->el, &o->result, CE_ADDED, CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1164
1165                 ret = 0;
1166                 for (i = 0; i < o->result.cache_nr; i++) {
1167                         struct cache_entry *ce = o->result.cache[i];
1168
1169                         /*
1170                          * Entries marked with CE_ADDED in merged_entry() do not have
1171                          * verify_absent() check (the check is effectively disabled
1172                          * because CE_NEW_SKIP_WORKTREE is set unconditionally).
1173                          *
1174                          * Do the real check now because we have had
1175                          * correct CE_NEW_SKIP_WORKTREE
1176                          */
1177                         if (ce->ce_flags & CE_ADDED &&
1178                             verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1179                                 if (!o->show_all_errors)
1180                                         goto return_failed;
1181                                 ret = -1;
1182                         }
1183
1184                         if (apply_sparse_checkout(&o->result, ce, o)) {
1185                                 if (!o->show_all_errors)
1186                                         goto return_failed;
1187                                 ret = -1;
1188                         }
1189                         if (!ce_skip_worktree(ce))
1190                                 empty_worktree = 0;
1191
1192                 }
1193                 if (ret < 0)
1194                         goto return_failed;
1195                 /*
1196                  * Sparse checkout is meant to narrow down checkout area
1197                  * but it does not make sense to narrow down to empty working
1198                  * tree. This is usually a mistake in sparse checkout rules.
1199                  * Do not allow users to do that.
1200                  */
1201                 if (o->result.cache_nr && empty_worktree) {
1202                         ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
1203                         goto done;
1204                 }
1205         }
1206
1207         o->src_index = NULL;
1208         ret = check_updates(o) ? (-2) : 0;
1209         if (o->dst_index) {
1210                 if (!ret) {
1211                         if (!o->result.cache_tree)
1212                                 o->result.cache_tree = cache_tree();
1213                         if (!cache_tree_fully_valid(o->result.cache_tree))
1214                                 cache_tree_update(&o->result,
1215                                                   WRITE_TREE_SILENT |
1216                                                   WRITE_TREE_REPAIR);
1217                 }
1218                 discard_index(o->dst_index);
1219                 *o->dst_index = o->result;
1220         } else {
1221                 discard_index(&o->result);
1222         }
1223
1224 done:
1225         clear_exclude_list(&el);
1226         return ret;
1227
1228 return_failed:
1229         if (o->show_all_errors)
1230                 display_error_msgs(o);
1231         mark_all_ce_unused(o->src_index);
1232         ret = unpack_failed(o, NULL);
1233         if (o->exiting_early)
1234                 ret = 0;
1235         goto done;
1236 }
1237
1238 /* Here come the merge functions */
1239
1240 static int reject_merge(const struct cache_entry *ce,
1241                         struct unpack_trees_options *o)
1242 {
1243         return o->gently ? -1 :
1244                 add_rejected_path(o, ERROR_WOULD_OVERWRITE, ce->name);
1245 }
1246
1247 static int same(const struct cache_entry *a, const struct cache_entry *b)
1248 {
1249         if (!!a != !!b)
1250                 return 0;
1251         if (!a && !b)
1252                 return 1;
1253         if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
1254                 return 0;
1255         return a->ce_mode == b->ce_mode &&
1256                !hashcmp(a->sha1, b->sha1);
1257 }
1258
1259
1260 /*
1261  * When a CE gets turned into an unmerged entry, we
1262  * want it to be up-to-date
1263  */
1264 static int verify_uptodate_1(const struct cache_entry *ce,
1265                              struct unpack_trees_options *o,
1266                              enum unpack_trees_error_types error_type)
1267 {
1268         struct stat st;
1269
1270         if (o->index_only)
1271                 return 0;
1272
1273         /*
1274          * CE_VALID and CE_SKIP_WORKTREE cheat, we better check again
1275          * if this entry is truly up-to-date because this file may be
1276          * overwritten.
1277          */
1278         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
1279                 ; /* keep checking */
1280         else if (o->reset || ce_uptodate(ce))
1281                 return 0;
1282
1283         if (!lstat(ce->name, &st)) {
1284                 int flags = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE;
1285                 unsigned changed = ie_match_stat(o->src_index, ce, &st, flags);
1286                 if (!changed)
1287                         return 0;
1288                 /*
1289                  * NEEDSWORK: the current default policy is to allow
1290                  * submodule to be out of sync wrt the superproject
1291                  * index.  This needs to be tightened later for
1292                  * submodules that are marked to be automatically
1293                  * checked out.
1294                  */
1295                 if (S_ISGITLINK(ce->ce_mode))
1296                         return 0;
1297                 errno = 0;
1298         }
1299         if (errno == ENOENT)
1300                 return 0;
1301         return o->gently ? -1 :
1302                 add_rejected_path(o, error_type, ce->name);
1303 }
1304
1305 static int verify_uptodate(const struct cache_entry *ce,
1306                            struct unpack_trees_options *o)
1307 {
1308         if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1309                 return 0;
1310         return verify_uptodate_1(ce, o, ERROR_NOT_UPTODATE_FILE);
1311 }
1312
1313 static int verify_uptodate_sparse(const struct cache_entry *ce,
1314                                   struct unpack_trees_options *o)
1315 {
1316         return verify_uptodate_1(ce, o, ERROR_SPARSE_NOT_UPTODATE_FILE);
1317 }
1318
1319 static void invalidate_ce_path(const struct cache_entry *ce,
1320                                struct unpack_trees_options *o)
1321 {
1322         if (!ce)
1323                 return;
1324         cache_tree_invalidate_path(o->src_index, ce->name);
1325         untracked_cache_invalidate_path(o->src_index, ce->name);
1326 }
1327
1328 /*
1329  * Check that checking out ce->sha1 in subdir ce->name is not
1330  * going to overwrite any working files.
1331  *
1332  * Currently, git does not checkout subprojects during a superproject
1333  * checkout, so it is not going to overwrite anything.
1334  */
1335 static int verify_clean_submodule(const struct cache_entry *ce,
1336                                   enum unpack_trees_error_types error_type,
1337                                   struct unpack_trees_options *o)
1338 {
1339         return 0;
1340 }
1341
1342 static int verify_clean_subdirectory(const struct cache_entry *ce,
1343                                      enum unpack_trees_error_types error_type,
1344                                      struct unpack_trees_options *o)
1345 {
1346         /*
1347          * we are about to extract "ce->name"; we would not want to lose
1348          * anything in the existing directory there.
1349          */
1350         int namelen;
1351         int i;
1352         struct dir_struct d;
1353         char *pathbuf;
1354         int cnt = 0;
1355         unsigned char sha1[20];
1356
1357         if (S_ISGITLINK(ce->ce_mode) &&
1358             resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
1359                 /* If we are not going to update the submodule, then
1360                  * we don't care.
1361                  */
1362                 if (!hashcmp(sha1, ce->sha1))
1363                         return 0;
1364                 return verify_clean_submodule(ce, error_type, o);
1365         }
1366
1367         /*
1368          * First let's make sure we do not have a local modification
1369          * in that directory.
1370          */
1371         namelen = ce_namelen(ce);
1372         for (i = locate_in_src_index(ce, o);
1373              i < o->src_index->cache_nr;
1374              i++) {
1375                 struct cache_entry *ce2 = o->src_index->cache[i];
1376                 int len = ce_namelen(ce2);
1377                 if (len < namelen ||
1378                     strncmp(ce->name, ce2->name, namelen) ||
1379                     ce2->name[namelen] != '/')
1380                         break;
1381                 /*
1382                  * ce2->name is an entry in the subdirectory to be
1383                  * removed.
1384                  */
1385                 if (!ce_stage(ce2)) {
1386                         if (verify_uptodate(ce2, o))
1387                                 return -1;
1388                         add_entry(o, ce2, CE_REMOVE, 0);
1389                         mark_ce_used(ce2, o);
1390                 }
1391                 cnt++;
1392         }
1393
1394         /*
1395          * Then we need to make sure that we do not lose a locally
1396          * present file that is not ignored.
1397          */
1398         pathbuf = xstrfmt("%.*s/", namelen, ce->name);
1399
1400         memset(&d, 0, sizeof(d));
1401         if (o->dir)
1402                 d.exclude_per_dir = o->dir->exclude_per_dir;
1403         i = read_directory(&d, pathbuf, namelen+1, NULL);
1404         if (i)
1405                 return o->gently ? -1 :
1406                         add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
1407         free(pathbuf);
1408         return cnt;
1409 }
1410
1411 /*
1412  * This gets called when there was no index entry for the tree entry 'dst',
1413  * but we found a file in the working tree that 'lstat()' said was fine,
1414  * and we're on a case-insensitive filesystem.
1415  *
1416  * See if we can find a case-insensitive match in the index that also
1417  * matches the stat information, and assume it's that other file!
1418  */
1419 static int icase_exists(struct unpack_trees_options *o, const char *name, int len, struct stat *st)
1420 {
1421         const struct cache_entry *src;
1422
1423         src = index_file_exists(o->src_index, name, len, 1);
1424         return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
1425 }
1426
1427 static int check_ok_to_remove(const char *name, int len, int dtype,
1428                               const struct cache_entry *ce, struct stat *st,
1429                               enum unpack_trees_error_types error_type,
1430                               struct unpack_trees_options *o)
1431 {
1432         const struct cache_entry *result;
1433
1434         /*
1435          * It may be that the 'lstat()' succeeded even though
1436          * target 'ce' was absent, because there is an old
1437          * entry that is different only in case..
1438          *
1439          * Ignore that lstat() if it matches.
1440          */
1441         if (ignore_case && icase_exists(o, name, len, st))
1442                 return 0;
1443
1444         if (o->dir &&
1445             is_excluded(o->dir, name, &dtype))
1446                 /*
1447                  * ce->name is explicitly excluded, so it is Ok to
1448                  * overwrite it.
1449                  */
1450                 return 0;
1451         if (S_ISDIR(st->st_mode)) {
1452                 /*
1453                  * We are checking out path "foo" and
1454                  * found "foo/." in the working tree.
1455                  * This is tricky -- if we have modified
1456                  * files that are in "foo/" we would lose
1457                  * them.
1458                  */
1459                 if (verify_clean_subdirectory(ce, error_type, o) < 0)
1460                         return -1;
1461                 return 0;
1462         }
1463
1464         /*
1465          * The previous round may already have decided to
1466          * delete this path, which is in a subdirectory that
1467          * is being replaced with a blob.
1468          */
1469         result = index_file_exists(&o->result, name, len, 0);
1470         if (result) {
1471                 if (result->ce_flags & CE_REMOVE)
1472                         return 0;
1473         }
1474
1475         return o->gently ? -1 :
1476                 add_rejected_path(o, error_type, name);
1477 }
1478
1479 /*
1480  * We do not want to remove or overwrite a working tree file that
1481  * is not tracked, unless it is ignored.
1482  */
1483 static int verify_absent_1(const struct cache_entry *ce,
1484                            enum unpack_trees_error_types error_type,
1485                            struct unpack_trees_options *o)
1486 {
1487         int len;
1488         struct stat st;
1489
1490         if (o->index_only || o->reset || !o->update)
1491                 return 0;
1492
1493         len = check_leading_path(ce->name, ce_namelen(ce));
1494         if (!len)
1495                 return 0;
1496         else if (len > 0) {
1497                 char *path;
1498                 int ret;
1499
1500                 path = xmemdupz(ce->name, len);
1501                 if (lstat(path, &st))
1502                         ret = error("cannot stat '%s': %s", path,
1503                                         strerror(errno));
1504                 else
1505                         ret = check_ok_to_remove(path, len, DT_UNKNOWN, NULL,
1506                                                  &st, error_type, o);
1507                 free(path);
1508                 return ret;
1509         } else if (lstat(ce->name, &st)) {
1510                 if (errno != ENOENT)
1511                         return error("cannot stat '%s': %s", ce->name,
1512                                      strerror(errno));
1513                 return 0;
1514         } else {
1515                 return check_ok_to_remove(ce->name, ce_namelen(ce),
1516                                           ce_to_dtype(ce), ce, &st,
1517                                           error_type, o);
1518         }
1519 }
1520
1521 static int verify_absent(const struct cache_entry *ce,
1522                          enum unpack_trees_error_types error_type,
1523                          struct unpack_trees_options *o)
1524 {
1525         if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1526                 return 0;
1527         return verify_absent_1(ce, error_type, o);
1528 }
1529
1530 static int verify_absent_sparse(const struct cache_entry *ce,
1531                                 enum unpack_trees_error_types error_type,
1532                                 struct unpack_trees_options *o)
1533 {
1534         enum unpack_trees_error_types orphaned_error = error_type;
1535         if (orphaned_error == ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN)
1536                 orphaned_error = ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN;
1537
1538         return verify_absent_1(ce, orphaned_error, o);
1539 }
1540
1541 static int merged_entry(const struct cache_entry *ce,
1542                         const struct cache_entry *old,
1543                         struct unpack_trees_options *o)
1544 {
1545         int update = CE_UPDATE;
1546         struct cache_entry *merge = dup_entry(ce);
1547
1548         if (!old) {
1549                 /*
1550                  * New index entries. In sparse checkout, the following
1551                  * verify_absent() will be delayed until after
1552                  * traverse_trees() finishes in unpack_trees(), then:
1553                  *
1554                  *  - CE_NEW_SKIP_WORKTREE will be computed correctly
1555                  *  - verify_absent() be called again, this time with
1556                  *    correct CE_NEW_SKIP_WORKTREE
1557                  *
1558                  * verify_absent() call here does nothing in sparse
1559                  * checkout (i.e. o->skip_sparse_checkout == 0)
1560                  */
1561                 update |= CE_ADDED;
1562                 merge->ce_flags |= CE_NEW_SKIP_WORKTREE;
1563
1564                 if (verify_absent(merge,
1565                                   ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1566                         free(merge);
1567                         return -1;
1568                 }
1569                 invalidate_ce_path(merge, o);
1570         } else if (!(old->ce_flags & CE_CONFLICTED)) {
1571                 /*
1572                  * See if we can re-use the old CE directly?
1573                  * That way we get the uptodate stat info.
1574                  *
1575                  * This also removes the UPDATE flag on a match; otherwise
1576                  * we will end up overwriting local changes in the work tree.
1577                  */
1578                 if (same(old, merge)) {
1579                         copy_cache_entry(merge, old);
1580                         update = 0;
1581                 } else {
1582                         if (verify_uptodate(old, o)) {
1583                                 free(merge);
1584                                 return -1;
1585                         }
1586                         /* Migrate old flags over */
1587                         update |= old->ce_flags & (CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1588                         invalidate_ce_path(old, o);
1589                 }
1590         } else {
1591                 /*
1592                  * Previously unmerged entry left as an existence
1593                  * marker by read_index_unmerged();
1594                  */
1595                 invalidate_ce_path(old, o);
1596         }
1597
1598         do_add_entry(o, merge, update, CE_STAGEMASK);
1599         return 1;
1600 }
1601
1602 static int deleted_entry(const struct cache_entry *ce,
1603                          const struct cache_entry *old,
1604                          struct unpack_trees_options *o)
1605 {
1606         /* Did it exist in the index? */
1607         if (!old) {
1608                 if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1609                         return -1;
1610                 return 0;
1611         }
1612         if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
1613                 return -1;
1614         add_entry(o, ce, CE_REMOVE, 0);
1615         invalidate_ce_path(ce, o);
1616         return 1;
1617 }
1618
1619 static int keep_entry(const struct cache_entry *ce,
1620                       struct unpack_trees_options *o)
1621 {
1622         add_entry(o, ce, 0, 0);
1623         return 1;
1624 }
1625
1626 #if DBRT_DEBUG
1627 static void show_stage_entry(FILE *o,
1628                              const char *label, const struct cache_entry *ce)
1629 {
1630         if (!ce)
1631                 fprintf(o, "%s (missing)\n", label);
1632         else
1633                 fprintf(o, "%s%06o %s %d\t%s\n",
1634                         label,
1635                         ce->ce_mode,
1636                         sha1_to_hex(ce->sha1),
1637                         ce_stage(ce),
1638                         ce->name);
1639 }
1640 #endif
1641
1642 int threeway_merge(const struct cache_entry * const *stages,
1643                    struct unpack_trees_options *o)
1644 {
1645         const struct cache_entry *index;
1646         const struct cache_entry *head;
1647         const struct cache_entry *remote = stages[o->head_idx + 1];
1648         int count;
1649         int head_match = 0;
1650         int remote_match = 0;
1651
1652         int df_conflict_head = 0;
1653         int df_conflict_remote = 0;
1654
1655         int any_anc_missing = 0;
1656         int no_anc_exists = 1;
1657         int i;
1658
1659         for (i = 1; i < o->head_idx; i++) {
1660                 if (!stages[i] || stages[i] == o->df_conflict_entry)
1661                         any_anc_missing = 1;
1662                 else
1663                         no_anc_exists = 0;
1664         }
1665
1666         index = stages[0];
1667         head = stages[o->head_idx];
1668
1669         if (head == o->df_conflict_entry) {
1670                 df_conflict_head = 1;
1671                 head = NULL;
1672         }
1673
1674         if (remote == o->df_conflict_entry) {
1675                 df_conflict_remote = 1;
1676                 remote = NULL;
1677         }
1678
1679         /*
1680          * First, if there's a #16 situation, note that to prevent #13
1681          * and #14.
1682          */
1683         if (!same(remote, head)) {
1684                 for (i = 1; i < o->head_idx; i++) {
1685                         if (same(stages[i], head)) {
1686                                 head_match = i;
1687                         }
1688                         if (same(stages[i], remote)) {
1689                                 remote_match = i;
1690                         }
1691                 }
1692         }
1693
1694         /*
1695          * We start with cases where the index is allowed to match
1696          * something other than the head: #14(ALT) and #2ALT, where it
1697          * is permitted to match the result instead.
1698          */
1699         /* #14, #14ALT, #2ALT */
1700         if (remote && !df_conflict_head && head_match && !remote_match) {
1701                 if (index && !same(index, remote) && !same(index, head))
1702                         return reject_merge(index, o);
1703                 return merged_entry(remote, index, o);
1704         }
1705         /*
1706          * If we have an entry in the index cache, then we want to
1707          * make sure that it matches head.
1708          */
1709         if (index && !same(index, head))
1710                 return reject_merge(index, o);
1711
1712         if (head) {
1713                 /* #5ALT, #15 */
1714                 if (same(head, remote))
1715                         return merged_entry(head, index, o);
1716                 /* #13, #3ALT */
1717                 if (!df_conflict_remote && remote_match && !head_match)
1718                         return merged_entry(head, index, o);
1719         }
1720
1721         /* #1 */
1722         if (!head && !remote && any_anc_missing)
1723                 return 0;
1724
1725         /*
1726          * Under the "aggressive" rule, we resolve mostly trivial
1727          * cases that we historically had git-merge-one-file resolve.
1728          */
1729         if (o->aggressive) {
1730                 int head_deleted = !head;
1731                 int remote_deleted = !remote;
1732                 const struct cache_entry *ce = NULL;
1733
1734                 if (index)
1735                         ce = index;
1736                 else if (head)
1737                         ce = head;
1738                 else if (remote)
1739                         ce = remote;
1740                 else {
1741                         for (i = 1; i < o->head_idx; i++) {
1742                                 if (stages[i] && stages[i] != o->df_conflict_entry) {
1743                                         ce = stages[i];
1744                                         break;
1745                                 }
1746                         }
1747                 }
1748
1749                 /*
1750                  * Deleted in both.
1751                  * Deleted in one and unchanged in the other.
1752                  */
1753                 if ((head_deleted && remote_deleted) ||
1754                     (head_deleted && remote && remote_match) ||
1755                     (remote_deleted && head && head_match)) {
1756                         if (index)
1757                                 return deleted_entry(index, index, o);
1758                         if (ce && !head_deleted) {
1759                                 if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1760                                         return -1;
1761                         }
1762                         return 0;
1763                 }
1764                 /*
1765                  * Added in both, identically.
1766                  */
1767                 if (no_anc_exists && head && remote && same(head, remote))
1768                         return merged_entry(head, index, o);
1769
1770         }
1771
1772         /* Below are "no merge" cases, which require that the index be
1773          * up-to-date to avoid the files getting overwritten with
1774          * conflict resolution files.
1775          */
1776         if (index) {
1777                 if (verify_uptodate(index, o))
1778                         return -1;
1779         }
1780
1781         o->nontrivial_merge = 1;
1782
1783         /* #2, #3, #4, #6, #7, #9, #10, #11. */
1784         count = 0;
1785         if (!head_match || !remote_match) {
1786                 for (i = 1; i < o->head_idx; i++) {
1787                         if (stages[i] && stages[i] != o->df_conflict_entry) {
1788                                 keep_entry(stages[i], o);
1789                                 count++;
1790                                 break;
1791                         }
1792                 }
1793         }
1794 #if DBRT_DEBUG
1795         else {
1796                 fprintf(stderr, "read-tree: warning #16 detected\n");
1797                 show_stage_entry(stderr, "head   ", stages[head_match]);
1798                 show_stage_entry(stderr, "remote ", stages[remote_match]);
1799         }
1800 #endif
1801         if (head) { count += keep_entry(head, o); }
1802         if (remote) { count += keep_entry(remote, o); }
1803         return count;
1804 }
1805
1806 /*
1807  * Two-way merge.
1808  *
1809  * The rule is to "carry forward" what is in the index without losing
1810  * information across a "fast-forward", favoring a successful merge
1811  * over a merge failure when it makes sense.  For details of the
1812  * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
1813  *
1814  */
1815 int twoway_merge(const struct cache_entry * const *src,
1816                  struct unpack_trees_options *o)
1817 {
1818         const struct cache_entry *current = src[0];
1819         const struct cache_entry *oldtree = src[1];
1820         const struct cache_entry *newtree = src[2];
1821
1822         if (o->merge_size != 2)
1823                 return error("Cannot do a twoway merge of %d trees",
1824                              o->merge_size);
1825
1826         if (oldtree == o->df_conflict_entry)
1827                 oldtree = NULL;
1828         if (newtree == o->df_conflict_entry)
1829                 newtree = NULL;
1830
1831         if (current) {
1832                 if (current->ce_flags & CE_CONFLICTED) {
1833                         if (same(oldtree, newtree) || o->reset) {
1834                                 if (!newtree)
1835                                         return deleted_entry(current, current, o);
1836                                 else
1837                                         return merged_entry(newtree, current, o);
1838                         }
1839                         return reject_merge(current, o);
1840                 } else if ((!oldtree && !newtree) || /* 4 and 5 */
1841                          (!oldtree && newtree &&
1842                           same(current, newtree)) || /* 6 and 7 */
1843                          (oldtree && newtree &&
1844                           same(oldtree, newtree)) || /* 14 and 15 */
1845                          (oldtree && newtree &&
1846                           !same(oldtree, newtree) && /* 18 and 19 */
1847                           same(current, newtree))) {
1848                         return keep_entry(current, o);
1849                 } else if (oldtree && !newtree && same(current, oldtree)) {
1850                         /* 10 or 11 */
1851                         return deleted_entry(oldtree, current, o);
1852                 } else if (oldtree && newtree &&
1853                          same(current, oldtree) && !same(current, newtree)) {
1854                         /* 20 or 21 */
1855                         return merged_entry(newtree, current, o);
1856                 } else
1857                         return reject_merge(current, o);
1858         }
1859         else if (newtree) {
1860                 if (oldtree && !o->initial_checkout) {
1861                         /*
1862                          * deletion of the path was staged;
1863                          */
1864                         if (same(oldtree, newtree))
1865                                 return 1;
1866                         return reject_merge(oldtree, o);
1867                 }
1868                 return merged_entry(newtree, current, o);
1869         }
1870         return deleted_entry(oldtree, current, o);
1871 }
1872
1873 /*
1874  * Bind merge.
1875  *
1876  * Keep the index entries at stage0, collapse stage1 but make sure
1877  * stage0 does not have anything there.
1878  */
1879 int bind_merge(const struct cache_entry * const *src,
1880                struct unpack_trees_options *o)
1881 {
1882         const struct cache_entry *old = src[0];
1883         const struct cache_entry *a = src[1];
1884
1885         if (o->merge_size != 1)
1886                 return error("Cannot do a bind merge of %d trees",
1887                              o->merge_size);
1888         if (a && old)
1889                 return o->gently ? -1 :
1890                         error(ERRORMSG(o, ERROR_BIND_OVERLAP), a->name, old->name);
1891         if (!a)
1892                 return keep_entry(old, o);
1893         else
1894                 return merged_entry(a, NULL, o);
1895 }
1896
1897 /*
1898  * One-way merge.
1899  *
1900  * The rule is:
1901  * - take the stat information from stage0, take the data from stage1
1902  */
1903 int oneway_merge(const struct cache_entry * const *src,
1904                  struct unpack_trees_options *o)
1905 {
1906         const struct cache_entry *old = src[0];
1907         const struct cache_entry *a = src[1];
1908
1909         if (o->merge_size != 1)
1910                 return error("Cannot do a oneway merge of %d trees",
1911                              o->merge_size);
1912
1913         if (!a || a == o->df_conflict_entry)
1914                 return deleted_entry(old, old, o);
1915
1916         if (old && same(old, a)) {
1917                 int update = 0;
1918                 if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old)) {
1919                         struct stat st;
1920                         if (lstat(old->name, &st) ||
1921                             ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
1922                                 update |= CE_UPDATE;
1923                 }
1924                 add_entry(o, old, update, 0);
1925                 return 0;
1926         }
1927         return merged_entry(a, old, o);
1928 }