rerere: plug conflict ID leaks

The merge_rr string list stores the conflict ID (a hexadecimal
string that is used to index into $GIT_DIR/rr-cache) in the .util
field of its elements, and when do_plain_rerere() resolves a
conflict, the field is cleared.  Also, when rerere_forget()
recomputes the conflict ID to updates the preimage file, the
conflict ID for the path is updated.

We forgot to free the existing conflict ID when we did these two
operations.

Signed-off-by: Junio C Hamano <[email protected]>

Author: gitster

rerere.c

@@ -559,6 +559,7 @@ static int do_plain_rerere(struct string_list *rr, int fd)
 		fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 		copy_file(rerere_path(name, "postimage"), path, 0666);
 	mark_resolved:
+		free(rr->items[i].util);
 		rr->items[i].util = NULL;
 	}
 
@@ -627,6 +628,7 @@ static int rerere_forget_one_path(const char *path, struct string_list *rr)
 	char *hex;
 	unsigned char sha1[20];
 	int ret;
+	struct string_list_item *item;
 
 	ret = handle_cache(path, sha1, NULL);
 	if (ret < 1)
@@ -641,8 +643,9 @@ static int rerere_forget_one_path(const char *path, struct string_list *rr)
 	handle_cache(path, sha1, rerere_path(hex, "preimage"));
 	fprintf(stderr, "Updated preimage for '%s'\n", path);
 
-
-	string_list_insert(rr, path)->util = hex;
+	item = string_list_insert(rr, path);
+	free(item->util);
+	item->util = hex;
 	fprintf(stderr, "Forgot resolution for %s\n", path);
 	return 0;
 }