merge-ort: implement handle_path_level_conflicts()

This is copied from merge-recursive.c, with minor tweaks due to:
  * using strmap API
  * merge-ort not using the non_unique_new_dir field, since it'll
    obviate its need entirely later with performance improvements
  * adding a new path_in_way() function that uses opt->priv->paths
    instead of doing an expensive tree_has_path() lookup to see if
    a tree has a given path.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/merge-ort.c b/merge-ort.c
index 86d2214006ef96f74a40992ee29ad8e3a44d91fb..ad8ecb7e448ae638d686fc97ca7ba34822f8e30e 100644 (file)
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -864,6 +864,16 @@ static void get_renamed_dir_portion(const char *old_path, const char *new_path,
        *new_dir = xstrndup(new_path, end_of_new - new_path);
 }
 
+static int path_in_way(struct strmap *paths, const char *path, unsigned side_mask)
+{
+       struct merged_info *mi = strmap_get(paths, path);
+       struct conflict_info *ci;
+       if (!mi)
+               return 0;
+       INITIALIZE_CI(ci, mi);
+       return mi->clean || (side_mask & (ci->filemask | ci->dirmask));
+}
+
 /*
  * See if there is a directory rename for path, and if there are any file
  * level conflicts on the given side for the renamed location.  If there is
@@ -876,7 +886,67 @@ static char *handle_path_level_conflicts(struct merge_options *opt,
                                         struct strmap_entry *rename_info,
                                         struct strmap *collisions)
 {
-       die("Not yet implemented");
+       char *new_path = NULL;
+       struct collision_info *c_info;
+       int clean = 1;
+       struct strbuf collision_paths = STRBUF_INIT;
+
+       /*
+        * entry has the mapping of old directory name to new directory name
+        * that we want to apply to path.
+        */
+       new_path = apply_dir_rename(rename_info, path);
+       if (!new_path)
+               BUG("Failed to apply directory rename!");
+
+       /*
+        * The caller needs to have ensured that it has pre-populated
+        * collisions with all paths that map to new_path.  Do a quick check
+        * to ensure that's the case.
+        */
+       c_info = strmap_get(collisions, new_path);
+       if (c_info == NULL)
+               BUG("c_info is NULL");
+
+       /*
+        * Check for one-sided add/add/.../add conflicts, i.e.
+        * where implicit renames from the other side doing
+        * directory rename(s) can affect this side of history
+        * to put multiple paths into the same location.  Warn
+        * and bail on directory renames for such paths.
+        */
+       if (c_info->reported_already) {
+               clean = 0;
+       } else if (path_in_way(&opt->priv->paths, new_path, 1 << side_index)) {
+               c_info->reported_already = 1;
+               strbuf_add_separated_string_list(&collision_paths, ", ",
+                                                &c_info->source_files);
+               path_msg(opt, new_path, 0,
+                        _("CONFLICT (implicit dir rename): Existing file/dir "
+                          "at %s in the way of implicit directory rename(s) "
+                          "putting the following path(s) there: %s."),
+                      new_path, collision_paths.buf);
+               clean = 0;
+       } else if (c_info->source_files.nr > 1) {
+               c_info->reported_already = 1;
+               strbuf_add_separated_string_list(&collision_paths, ", ",
+                                                &c_info->source_files);
+               path_msg(opt, new_path, 0,
+                        _("CONFLICT (implicit dir rename): Cannot map more "
+                          "than one path to %s; implicit directory renames "
+                          "tried to put these paths there: %s"),
+                      new_path, collision_paths.buf);
+               clean = 0;
+       }
+
+       /* Free memory we no longer need */
+       strbuf_release(&collision_paths);
+       if (!clean && new_path) {
+               free(new_path);
+               return NULL;
+       }
+
+       return new_path;
 }
 
 static void increment_count(struct strmap *dir_rename_count,