merge-recursive: combine error handling

In handle_rename_rename_1to2(), we have duplicated error handling
around colliding paths. Specifically, when we want to write out
the file and there is a directory or untracked file in the way,
we need to create a temporary file to hold the contents. This has
some special output to alert the user, and this output is
duplicated for each side of the conflict.

Simplify the call by generating this new path in a helper
function.

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

merge-recursive.c

@@ -1709,6 +1709,27 @@ static int handle_rename_add(struct merge_options *o,
 				     ci->dst_entry1->stages[other_stage].mode);
 }
 
+static char *find_path_for_conflict(struct merge_options *o,
+				    const char *path,
+				    const char *branch1,
+				    const char *branch2)
+{
+	char *new_path = NULL;
+	if (dir_in_way(path, !o->call_depth, 0)) {
+		new_path = unique_path(o, path, branch1);
+		output(o, 1, _("%s is a directory in %s adding "
+			       "as %s instead"),
+		       path, branch2, new_path);
+	} else if (would_lose_untracked(path)) {
+		new_path = unique_path(o, path, branch1);
+		output(o, 1, _("Refusing to lose untracked file"
+			       " at %s; adding as %s instead"),
+		       path, new_path);
+	}
+
+	return new_path;
+}
+
 static int handle_rename_rename_1to2(struct merge_options *o,
 				     struct rename_conflict_info *ci)
 {
@@ -1783,19 +1804,9 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 						  &add->oid, add->mode) < 0)
 				return -1;
 		} else {
-			char *new_path = NULL;
-			if (dir_in_way(a->path, !o->call_depth, 0)) {
-				new_path = unique_path(o, a->path, ci->branch1);
-				output(o, 1, _("%s is a directory in %s adding "
-					       "as %s instead"),
-				       a->path, ci->branch2, new_path);
-			} else if (would_lose_untracked(a->path)) {
-				new_path = unique_path(o, a->path, ci->branch1);
-				output(o, 1, _("Refusing to lose untracked file"
-					       " at %s; adding as %s instead"),
-				       a->path, new_path);
-			}
-
+			char *new_path = find_path_for_conflict(o, a->path,
+								ci->branch1,
+								ci->branch2);
 			if (update_file(o, 0, &mfi.oid, mfi.mode, new_path ? new_path : a->path))
 				return -1;
 			free(new_path);
@@ -1812,19 +1823,9 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 						  &mfi.oid, mfi.mode) < 0)
 				return -1;
 		} else {
-			char *new_path = NULL;
-			if (dir_in_way(b->path, !o->call_depth, 0)) {
-				new_path = unique_path(o, b->path, ci->branch2);
-				output(o, 1, _("%s is a directory in %s adding "
-					       "as %s instead"),
-				       b->path, ci->branch1, new_path);
-			} else if (would_lose_untracked(b->path)) {
-				new_path = unique_path(o, b->path, ci->branch2);
-				output(o, 1, _("Refusing to lose untracked file"
-					       " at %s; adding as %s instead"),
-				       b->path, new_path);
-			}
-
+			char *new_path = find_path_for_conflict(o, b->path,
+								ci->branch2,
+								ci->branch1);
 			if (update_file(o, 0, &mfi.oid, mfi.mode, new_path ? new_path : b->path))
 				return -1;
 			free(new_path);