Merge branch 'en/ort-rename-fixes' into seen

Various bugs about rename handling in "ort" merge strategy have
been fixed.

* en/ort-rename-fixes:
  merge-ort: fix directory rename on top of source of other rename/delete
  merge-ort: fix incorrect file handling
  t6423: fix missed staging of file in testcases 12i,12j,12k
  t6423: document two bugs with rename-to-self testcases
  merge-ort: drop unnecessary temporary in check_for_directory_rename()
  merge-ort: update comments to modern testfile location

Author: gitster

merge-ort.c

@@ -2163,7 +2163,7 @@ static int handle_content_merge(struct merge_options *opt,
 		/*
 		 * FIXME: If opt->priv->call_depth && !clean, then we really
 		 * should not make result->mode match either a->mode or
-		 * b->mode; that causes t6036 "check conflicting mode for
+		 * b->mode; that causes t6416 "check conflicting mode for
 		 * regular file" to fail.  It would be best to use some other
 		 * mode, but we'll confuse all kinds of stuff if we use one
 		 * where S_ISREG(result->mode) isn't true, and if we use
@@ -2313,14 +2313,20 @@ static char *apply_dir_rename(struct strmap_entry *rename_info,
 	return strbuf_detach(&new_path, NULL);
 }
 
-static int path_in_way(struct strmap *paths, const char *path, unsigned side_mask)
+static int path_in_way(struct strmap *paths,
+		       const char *path,
+		       unsigned side_mask,
+		       struct diff_filepair *p)
 {
 	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));
+	return mi->clean || (side_mask & (ci->filemask | ci->dirmask))
+	  // See testcases 12n, 12p, 12q for more details on this next condition
+			 || ((ci->filemask & 0x01) &&
+			     strcmp(p->one->path, path));
 }
 
 /*
@@ -2332,6 +2338,7 @@ static int path_in_way(struct strmap *paths, const char *path, unsigned side_mas
 static char *handle_path_level_conflicts(struct merge_options *opt,
 					 const char *path,
 					 unsigned side_index,
+					 struct diff_filepair *p,
 					 struct strmap_entry *rename_info,
 					 struct strmap *collisions)
 {
@@ -2366,7 +2373,7 @@ static char *handle_path_level_conflicts(struct merge_options *opt,
 	 */
 	if (c_info->reported_already) {
 		clean = 0;
-	} else if (path_in_way(&opt->priv->paths, new_path, 1 << side_index)) {
+	} else if (path_in_way(&opt->priv->paths, new_path, 1 << side_index, p)) {
 		c_info->reported_already = 1;
 		strbuf_add_separated_string_list(&collision_paths, ", ",
 						 &c_info->source_files);
@@ -2520,7 +2527,7 @@ static void compute_collisions(struct strmap *collisions,
 	 * 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.
+	 * See testcases 9e and all of section 5 from t6423 for examples.
 	 */
 	for (i = 0; i < pairs->nr; ++i) {
 		struct strmap_entry *rename_info;
@@ -2573,14 +2580,14 @@ static void free_collisions(struct strmap *collisions)
 static char *check_for_directory_rename(struct merge_options *opt,
 					const char *path,
 					unsigned side_index,
+					struct diff_filepair *p,
 					struct strmap *dir_renames,
 					struct strmap *dir_rename_exclusions,
 					struct strmap *collisions,
 					int *clean_merge)
 {
 	char *new_path;
 	struct strmap_entry *rename_info;
-	struct strmap_entry *otherinfo;
 	const char *new_dir;
 	int other_side = 3 - side_index;
 
@@ -2615,14 +2622,13 @@ static char *check_for_directory_rename(struct merge_options *opt,
 	 * to not let Side1 do the rename to dumbdir, since we know that is
 	 * the source of one of our directory renames.
 	 *
-	 * That's why otherinfo and dir_rename_exclusions is here.
+	 * That's why dir_rename_exclusions is here.
 	 *
 	 * As it turns out, this also prevents N-way transient rename
-	 * confusion; See testcases 9c and 9d of t6043.
+	 * confusion; See testcases 9c and 9d of t6423.
 	 */
 	new_dir = rename_info->value; /* old_dir = rename_info->key; */
-	otherinfo = strmap_get_entry(dir_rename_exclusions, new_dir);
-	if (otherinfo) {
+	if (strmap_contains(dir_rename_exclusions, new_dir)) {
 		path_msg(opt, INFO_DIR_RENAME_SKIPPED_DUE_TO_RERENAME, 1,
 			 rename_info->key, path, new_dir, NULL,
 			 _("WARNING: Avoiding applying %s -> %s rename "
@@ -2631,7 +2637,7 @@ static char *check_for_directory_rename(struct merge_options *opt,
 		return NULL;
 	}
 
-	new_path = handle_path_level_conflicts(opt, path, side_index,
+	new_path = handle_path_level_conflicts(opt, path, side_index, p,
 					       rename_info,
 					       &collisions[side_index]);
 	*clean_merge &= (new_path != NULL);
@@ -2875,6 +2881,17 @@ static int process_renames(struct merge_options *opt,
 			newinfo = new_ent->value;
 		}
 
+		/*
+		 * Directory renames can result in rename-to-self, which we
+		 * want to skip so we don't mark oldpath for deletion.
+		 *
+		 * Note that we can avoid strcmp here because of prior
+		 * diligence in apply_directory_rename_modifications() to
+		 * ensure we reused existing paths from opt->priv->paths.
+		 */
+		if (oldpath == newpath)
+			continue;
+
 		/*
 		 * If pair->one->path isn't in opt->priv->paths, that means
 		 * that either directory rename detection removed that
@@ -3419,7 +3436,7 @@ static int collect_renames(struct merge_options *opt,
 		}
 
 		new_path = check_for_directory_rename(opt, p->two->path,
-						      side_index,
+						      side_index, p,
 						      dir_renames_for_side,
 						      rename_exclusions,
 						      collisions,