+static void apply_directory_rename_modifications(struct merge_options *o,
+ struct diff_filepair *pair,
+ char *new_path,
+ struct rename *re,
+ struct tree *tree,
+ struct tree *o_tree,
+ struct tree *a_tree,
+ struct tree *b_tree,
+ struct string_list *entries,
+ int *clean)
+{
+ struct string_list_item *item;
+ int stage = (tree == a_tree ? 2 : 3);
+
+ /*
+ * In all cases where we can do directory rename detection,
+ * unpack_trees() will have read pair->two->path into the
+ * index and the working copy. We need to remove it so that
+ * we can instead place it at new_path. It is guaranteed to
+ * not be untracked (unpack_trees() would have errored out
+ * saying the file would have been overwritten), but it might
+ * be dirty, though.
+ */
+ remove_file(o, 1, pair->two->path, 0 /* no_wd */);
+
+ /* Find or create a new re->dst_entry */
+ item = string_list_lookup(entries, new_path);
+ if (item) {
+ /*
+ * Since we're renaming on this side of history, and it's
+ * due to a directory rename on the other side of history
+ * (which we only allow when the directory in question no
+ * longer exists on the other side of history), the
+ * original entry for re->dst_entry is no longer
+ * necessary...
+ */
+ re->dst_entry->processed = 1;
+
+ /*
+ * ...because we'll be using this new one.
+ */
+ re->dst_entry = item->util;
+ } else {
+ /*
+ * re->dst_entry is for the before-dir-rename path, and we
+ * need it to hold information for the after-dir-rename
+ * path. Before creating a new entry, we need to mark the
+ * old one as unnecessary (...unless it is shared by
+ * src_entry, i.e. this didn't use to be a rename, in which
+ * case we can just allow the normal processing to happen
+ * for it).
+ */
+ if (pair->status == 'R')
+ re->dst_entry->processed = 1;
+
+ re->dst_entry = insert_stage_data(new_path,
+ o_tree, a_tree, b_tree,
+ entries);
+ item = string_list_insert(entries, new_path);
+ item->util = re->dst_entry;
+ }
+
+ /*
+ * Update the stage_data with the information about the path we are
+ * moving into place. That slot will be empty and available for us
+ * to write to because of the collision checks in
+ * handle_path_level_conflicts(). In other words,
+ * re->dst_entry->stages[stage].oid will be the null_oid, so it's
+ * open for us to write to.
+ *
+ * It may be tempting to actually update the index at this point as
+ * well, using update_stages_for_stage_data(), but as per the big
+ * "NOTE" in update_stages(), doing so will modify the current
+ * in-memory index which will break calls to would_lose_untracked()
+ * that we need to make. Instead, we need to just make sure that
+ * the various conflict_rename_*() functions update the index
+ * explicitly rather than relying on unpack_trees() to have done it.
+ */
+ get_tree_entry(&tree->object.oid,
+ pair->two->path,
+ &re->dst_entry->stages[stage].oid,
+ &re->dst_entry->stages[stage].mode);
+
+ /* Update pair status */
+ if (pair->status == 'A') {
+ /*
+ * Recording rename information for this add makes it look
+ * like a rename/delete conflict. Make sure we can
+ * correctly handle this as an add that was moved to a new
+ * directory instead of reporting a rename/delete conflict.
+ */
+ re->add_turned_into_rename = 1;
+ }
+ /*
+ * We don't actually look at pair->status again, but it seems
+ * pedagogically correct to adjust it.
+ */
+ pair->status = 'R';
+
+ /*
+ * Finally, record the new location.
+ */
+ pair->two->path = new_path;
+}
+