merge-recursive: Save D/F conflict filenames instead of unlinking them

Rename make_room_for_directories_of_df_conflicts() to
record_df_conflict_files() to reflect the change in functionality.

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

merge-recursive.c

@@ -360,20 +360,24 @@ static int string_list_df_name_compare(const void *a, const void *b)
 	return onelen - twolen;
 }
 
-
-
-static void make_room_for_directories_of_df_conflicts(struct merge_options *o,
-						      struct string_list *entries)
+static void record_df_conflict_files(struct merge_options *o,
+				     struct string_list *entries)
 {
-	/* If there are D/F conflicts, and the paths currently exist
-	 * in the working copy as a file, we want to remove them to
-	 * make room for the corresponding directory.  Such paths will
-	 * later be processed in process_df_entry() at the end.  If
-	 * the corresponding directory ends up being removed by the
-	 * merge, then the file will be reinstated at that time;
-	 * otherwise, if the file is not supposed to be removed by the
-	 * merge, the contents of the file will be placed in another
-	 * unique filename.
+	/* If there is a D/F conflict and the file for such a conflict
+	 * currently exist in the working copy, we want to allow it to
+	 * be removed to make room for the corresponding directory if
+	 * needed.  The files underneath the directories of such D/F
+	 * conflicts will be handled in process_entry(), while the
+	 * files of such D/F conflicts will be processed later in
+	 * process_df_entry().  If the corresponding directory ends up
+	 * being removed by the merge, then no additional work needs
+	 * to be done by process_df_entry() for the conflicting file.
+	 * If the directory needs to be written to the working copy,
+	 * then the conflicting file will simply be removed (e.g. in
+	 * make_room_for_path).  If the directory is written to the
+	 * working copy but the file also has a conflict that needs to
+	 * be resolved, then process_df_entry() will reinstate the
+	 * file with a new unique name.
 	 */
 	const char *last_file = NULL;
 	int last_len = 0;
@@ -390,6 +394,7 @@ static void make_room_for_directories_of_df_conflicts(struct merge_options *o,
 	qsort(entries->items, entries->nr, sizeof(*entries->items),
 	      string_list_df_name_compare);
 
+	string_list_clear(&o->df_conflict_file_set, 1);
 	for (i = 0; i < entries->nr; i++) {
 		const char *path = entries->items[i].string;
 		int len = strlen(path);
@@ -398,14 +403,15 @@ static void make_room_for_directories_of_df_conflicts(struct merge_options *o,
 		/*
 		 * Check if last_file & path correspond to a D/F conflict;
 		 * i.e. whether path is last_file+'/'+<something>.
-		 * If so, remove last_file to make room for path and friends.
+		 * If so, record that it's okay to remove last_file to make
+		 * room for path and friends if needed.
 		 */
 		if (last_file &&
 		    len > last_len &&
 		    memcmp(path, last_file, last_len) == 0 &&
 		    path[last_len] == '/') {
 			output(o, 3, "Removing %s to make room for subdirectory; may re-add later.", last_file);
-			unlink(last_file);
+			string_list_insert(&o->df_conflict_file_set, last_file);
 		}
 
 		/*
@@ -1569,7 +1575,7 @@ int merge_trees(struct merge_options *o,
 		get_files_dirs(o, merge);
 
 		entries = get_unmerged();
-		make_room_for_directories_of_df_conflicts(o, entries);
+		record_df_conflict_files(o, entries);
 		re_head  = get_renames(o, head, common, head, merge, entries);
 		re_merge = get_renames(o, merge, common, head, merge, entries);
 		clean = process_renames(o, re_head, re_merge);
@@ -1795,6 +1801,8 @@ void init_merge_options(struct merge_options *o)
 	o->current_file_set.strdup_strings = 1;
 	memset(&o->current_directory_set, 0, sizeof(struct string_list));
 	o->current_directory_set.strdup_strings = 1;
+	memset(&o->df_conflict_file_set, 0, sizeof(struct string_list));
+	o->df_conflict_file_set.strdup_strings = 1;
 }
 
 int parse_merge_opt(struct merge_options *o, const char *s)

merge-recursive.h

@@ -26,6 +26,7 @@ struct merge_options {
 	struct strbuf obuf;
 	struct string_list current_file_set;
 	struct string_list current_directory_set;
+	struct string_list df_conflict_file_set;
 };
 
 /* merge_trees() but with recursive ancestor consolidation */