diff --git a/merge-recursive.c b/merge-recursive.c index a67bb58da7..50eb6c70dd 100644 --- a/merge-recursive.c +++ b/merge-recursive.c @@ -87,6 +87,29 @@ static void dir_rename_entry_init(struct dir_rename_entry *entry, string_list_init(&entry->possible_new_dirs, 0); } +static struct collision_entry *collision_find_entry(struct hashmap *hashmap, + char *target_file) +{ + struct collision_entry key; + + hashmap_entry_init(&key, strhash(target_file)); + key.target_file = target_file; + return hashmap_get(hashmap, &key, NULL); +} + +static int collision_cmp(void *unused_cmp_data, + const struct collision_entry *e1, + const struct collision_entry *e2, + const void *unused_keydata) +{ + return strcmp(e1->target_file, e2->target_file); +} + +static void collision_init(struct hashmap *map) +{ + hashmap_init(map, (hashmap_cmp_fn) collision_cmp, NULL, 0); +} + static void flush_output(struct merge_options *o) { if (o->buffer_output < 2 && o->obuf.len) { @@ -1404,6 +1427,31 @@ static int tree_has_path(struct tree *tree, const char *path) &hashy, &mode_o); } +/* + * Return a new string that replaces the beginning portion (which matches + * entry->dir), with entry->new_dir. In perl-speak: + * new_path_name = (old_path =~ s/entry->dir/entry->new_dir/); + * NOTE: + * Caller must ensure that old_path starts with entry->dir + '/'. + */ +static char *apply_dir_rename(struct dir_rename_entry *entry, + const char *old_path) +{ + struct strbuf new_path = STRBUF_INIT; + int oldlen, newlen; + + if (entry->non_unique_new_dir) + return NULL; + + oldlen = strlen(entry->dir); + newlen = entry->new_dir.len + (strlen(old_path) - oldlen) + 1; + strbuf_grow(&new_path, newlen); + strbuf_addbuf(&new_path, &entry->new_dir); + strbuf_addstr(&new_path, &old_path[oldlen]); + + return strbuf_detach(&new_path, NULL); +} + static void get_renamed_dir_portion(const char *old_path, const char *new_path, char **old_dir, char **new_dir) { @@ -1673,6 +1721,84 @@ static struct hashmap *get_directory_renames(struct diff_queue_struct *pairs, return dir_renames; } +static struct dir_rename_entry *check_dir_renamed(const char *path, + struct hashmap *dir_renames) +{ + char temp[PATH_MAX]; + char *end; + struct dir_rename_entry *entry; + + strcpy(temp, path); + while ((end = strrchr(temp, '/'))) { + *end = '\0'; + entry = dir_rename_find_entry(dir_renames, temp); + if (entry) + return entry; + } + return NULL; +} + +static void compute_collisions(struct hashmap *collisions, + struct hashmap *dir_renames, + struct diff_queue_struct *pairs) +{ + int i; + + /* + * Multiple files can be mapped to the same path due to directory + * renames done by the other side of history. Since that other + * side of history could have merged multiple directories into one, + * if our side of history added the same file basename to each of + * those directories, then all N of them would get implicitly + * renamed by the directory rename detection into the same path, + * and we'd get an add/add/.../add conflict, and all those adds + * from *this* side of history. This is not representable in the + * index, and users aren't going to easily be able to make sense of + * it. So we need to provide a good warning about what's + * happening, and fall back to no-directory-rename detection + * behavior for those paths. + * + * See testcases 9e and all of section 5 from t6043 for examples. + */ + collision_init(collisions); + + for (i = 0; i < pairs->nr; ++i) { + struct dir_rename_entry *dir_rename_ent; + struct collision_entry *collision_ent; + char *new_path; + struct diff_filepair *pair = pairs->queue[i]; + + if (pair->status == 'D') + continue; + dir_rename_ent = check_dir_renamed(pair->two->path, + dir_renames); + if (!dir_rename_ent) + continue; + + new_path = apply_dir_rename(dir_rename_ent, pair->two->path); + if (!new_path) + /* + * dir_rename_ent->non_unique_new_path is true, which + * means there is no directory rename for us to use, + * which means it won't cause us any additional + * collisions. + */ + continue; + collision_ent = collision_find_entry(collisions, new_path); + if (!collision_ent) { + collision_ent = xcalloc(1, + sizeof(struct collision_entry)); + hashmap_entry_init(collision_ent, strhash(new_path)); + hashmap_put(collisions, collision_ent); + collision_ent->target_file = new_path; + } else { + free(new_path); + } + string_list_insert(&collision_ent->source_files, + pair->two->path); + } +} + /* * Get information of all renames which occurred in 'pairs', making use of * any implicit directory renames inferred from the other side of history. @@ -1682,6 +1808,7 @@ static struct hashmap *get_directory_renames(struct diff_queue_struct *pairs, */ static struct string_list *get_renames(struct merge_options *o, struct diff_queue_struct *pairs, + struct hashmap *dir_renames, struct tree *tree, struct tree *o_tree, struct tree *a_tree, @@ -1689,8 +1816,12 @@ static struct string_list *get_renames(struct merge_options *o, struct string_list *entries) { int i; + struct hashmap collisions; + struct hashmap_iter iter; + struct collision_entry *e; struct string_list *renames; + compute_collisions(&collisions, dir_renames, pairs); renames = xcalloc(1, sizeof(struct string_list)); for (i = 0; i < pairs->nr; ++i) { @@ -1721,6 +1852,13 @@ static struct string_list *get_renames(struct merge_options *o, item = string_list_insert(renames, pair->one->path); item->util = re; } + + hashmap_iter_init(&collisions, &iter); + while ((e = hashmap_iter_next(&iter))) { + free(e->target_file); + string_list_clear(&e->source_files, 0); + } + hashmap_free(&collisions, 1); return renames; } @@ -2030,9 +2168,11 @@ static int handle_renames(struct merge_options *o, dir_re_head, head, dir_re_merge, merge); - ri->head_renames = get_renames(o, head_pairs, head, - common, head, merge, entries); - ri->merge_renames = get_renames(o, merge_pairs, merge, + ri->head_renames = get_renames(o, head_pairs, + dir_re_merge, head, + common, head, merge, entries); + ri->merge_renames = get_renames(o, merge_pairs, + dir_re_head, merge, common, head, merge, entries); clean = process_renames(o, ri->head_renames, ri->merge_renames); diff --git a/merge-recursive.h b/merge-recursive.h index fe64c78de4..50a4e6af4e 100644 --- a/merge-recursive.h +++ b/merge-recursive.h @@ -47,6 +47,13 @@ struct dir_rename_entry { struct string_list possible_new_dirs; }; +struct collision_entry { + struct hashmap_entry ent; /* must be the first member! */ + char *target_file; + struct string_list source_files; + unsigned reported_already:1; +}; + /* merge_trees() but with recursive ancestor consolidation */ int merge_recursive(struct merge_options *o, struct commit *h1,