Error out when user doesn't have access permission to the repository

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>

builtin-fetch--tool.c

@@ -511,10 +511,14 @@ int cmd_fetch__tool(int argc, const char **argv, const char *prefix)
 	if (!strcmp("append-fetch-head", argv[1])) {
 		int result;
 		FILE *fp;
+		char *filename;
 
 		if (argc != 8)
 			return error("append-fetch-head takes 6 args");
-		fp = fopen(git_path("FETCH_HEAD"), "a");
+		filename = git_path("FETCH_HEAD");
+		fp = fopen(filename, "a");
+		if (!fp)
+			return error("cannot open %s: %s\n", filename, strerror(errno));
 		result = append_fetch_head(fp, argv[2], argv[3],
 					   argv[4], argv[5],
 					   argv[6], !!argv[7][0],
@@ -525,10 +529,14 @@ int cmd_fetch__tool(int argc, const char **argv, const char *prefix)
 	if (!strcmp("native-store", argv[1])) {
 		int result;
 		FILE *fp;
+		char *filename;
 
 		if (argc != 5)
 			return error("fetch-native-store takes 3 args");
-		fp = fopen(git_path("FETCH_HEAD"), "a");
+		filename = git_path("FETCH_HEAD");
+		fp = fopen(filename, "a");
+		if (!fp)
+			return error("cannot open %s: %s\n", filename, strerror(errno));
 		result = fetch_native_store(fp, argv[2], argv[3], argv[4],
 					    verbose, force);
 		fclose(fp);

builtin-fetch.c

@@ -255,7 +255,7 @@ static int update_local_ref(struct ref *ref,
 	}
 }
 
-static void store_updated_refs(const char *url, struct ref *ref_map)
+static int store_updated_refs(const char *url, struct ref *ref_map)
 {
 	FILE *fp;
 	struct commit *commit;
@@ -263,8 +263,11 @@ static void store_updated_refs(const char *url, struct ref *ref_map)
 	char note[1024];
 	const char *what, *kind;
 	struct ref *rm;
+	char *filename = git_path("FETCH_HEAD");
 
-	fp = fopen(git_path("FETCH_HEAD"), "a");
+	fp = fopen(filename, "a");
+	if (!fp)
+		return error("cannot open %s: %s\n", filename, strerror(errno));
 	for (rm = ref_map; rm; rm = rm->next) {
 		struct ref *ref = NULL;
 
@@ -335,6 +338,7 @@ static void store_updated_refs(const char *url, struct ref *ref_map)
 		}
 	}
 	fclose(fp);
+	return 0;
 }
 
 /*
@@ -404,7 +408,7 @@ static int fetch_refs(struct transport *transport, struct ref *ref_map)
 	if (ret)
 		ret = transport_fetch_refs(transport, ref_map);
 	if (!ret)
-		store_updated_refs(transport->url, ref_map);
+		ret |= store_updated_refs(transport->url, ref_map);
 	transport_unlock_pack(transport);
 	return ret;
 }
@@ -487,8 +491,13 @@ static int do_fetch(struct transport *transport,
 		die("Don't know how to fetch from %s", transport->url);
 
 	/* if not appending, truncate FETCH_HEAD */
-	if (!append)
-		fclose(fopen(git_path("FETCH_HEAD"), "w"));
+	if (!append) {
+		char *filename = git_path("FETCH_HEAD");
+		FILE *fp = fopen(filename, "w");
+		if (!fp)
+			return error("cannot open %s: %s\n", filename, strerror(errno));
+		fclose(fp);
+	}
 
 	ref_map = get_ref_map(transport, refs, ref_count, tags, &autotags);