config: Refactor `git_config_backend_from_string` to take a length

src/config_backend.h

@@ -30,8 +30,9 @@ extern int git_config_backend_from_file(git_config_backend **out, const char *pa
  *
  * @param out the new backend
  * @param cfg the configuration that is to be parsed
+ * @param len the length of the string pointed to by `cfg`
  */
-extern int git_config_backend_from_string(git_config_backend **out, const char *cfg);
+extern int git_config_backend_from_string(git_config_backend **out, const char *cfg, size_t len);
 
 GIT_INLINE(int) git_config_backend_open(git_config_backend *cfg, unsigned int level, const git_repository *repo)
 {

src/config_mem.c

@@ -186,7 +186,7 @@ static void config_memory_free(git_config_backend *_backend)
 	git__free(backend);
 }
 
-int git_config_backend_from_string(git_config_backend **out, const char *cfg)
+int git_config_backend_from_string(git_config_backend **out, const char *cfg, size_t len)
 {
 	config_memory_backend *backend;
 
@@ -198,7 +198,7 @@ int git_config_backend_from_string(git_config_backend **out, const char *cfg)
 		return -1;
 	}
 
-	if (git_buf_sets(&backend->cfg, cfg) < 0) {
+	if (git_buf_put(&backend->cfg, cfg, len) < 0) {
 		git_config_entries_free(backend->entries);
 		git__free(backend);
 		return -1;

tests/config/memory.c

@@ -61,7 +61,7 @@ static void assert_config_contains_all(git_config_backend *backend,
 
 static void setup_backend(const char *cfg)
 {
-	cl_git_pass(git_config_backend_from_string(&backend, cfg));
+	cl_git_pass(git_config_backend_from_string(&backend, cfg, strlen(cfg)));
 	cl_git_pass(git_config_backend_open(backend, 0, NULL));
 }
 
@@ -85,9 +85,10 @@ void test_config_memory__simple(void)
 
 void test_config_memory__malformed_fails_to_open(void)
 {
-	cl_git_pass(git_config_backend_from_string(&backend,
+	const char *cfg =
 		"[general\n"
-		"foo=bar\n"));
+		"foo=bar\n";
+	cl_git_pass(git_config_backend_from_string(&backend, cfg, strlen(cfg)));
 	cl_git_fail(git_config_backend_open(backend, 0, NULL));
 }