config: Opening a nonexistent file returns ENOTFOUND

include/git2/config.h

@@ -189,7 +189,8 @@ GIT_EXTERN(int) git_config_add_file(
  * @param force if a config file already exists for the given
  *  priority level, replace it
  * @return 0 on success, GIT_EEXISTS when adding more than one file
- *  for a given priority level (and force_replace set to 0), or error code
+ *  for a given priority level (and force_replace set to 0),
+ *  GIT_ENOTFOUND when the file doesn't exist or error code
  */
 GIT_EXTERN(int) git_config_add_file_ondisk(
 	git_config *cfg,
@@ -197,7 +198,6 @@ GIT_EXTERN(int) git_config_add_file_ondisk(
 	unsigned int level,
 	int force);
 
-
 /**
  * Create a new config instance containing a single on-disk file
  *
@@ -206,11 +206,12 @@ GIT_EXTERN(int) git_config_add_file_ondisk(
  *	- git_config_new
  *	- git_config_add_file_ondisk
  *
- * @param cfg The configuration instance to create
+ * @param out The configuration instance to create
  * @param path Path to the on-disk file to open
- * @return 0 or an error code
+ * @return 0 on success, GIT_ENOTFOUND when the file doesn't exist
+ * or an error code
  */
-GIT_EXTERN(int) git_config_open_ondisk(git_config **cfg, const char *path);
+GIT_EXTERN(int) git_config_open_ondisk(git_config **out, const char *path);
 
 /**
  * Build a single-level focused config object from a multi-level one.

src/config.c

@@ -90,6 +90,13 @@ int git_config_add_file_ondisk(
 	git_config_file *file = NULL;
 	int res;
 
+	assert(cfg && path);
+
+	if (!git_path_isfile(path)) {
+		giterr_set(GITERR_CONFIG, "File '%s' doesn't exists.", path);
+		return GIT_ENOTFOUND;
+	}
+
 	if (git_config_file__ondisk(&file, path) < 0)
 		return -1;
 
@@ -105,17 +112,22 @@ int git_config_add_file_ondisk(
 	return 0;
 }
 
-int git_config_open_ondisk(git_config **cfg, const char *path)
+int git_config_open_ondisk(git_config **out, const char *path)
 {
-	if (git_config_new(cfg) < 0)
+	int error;
+	git_config *config;
+
+	*out = NULL;
+
+	if (git_config_new(&config) < 0)
 		return -1;
 
-	if (git_config_add_file_ondisk(*cfg, path, GIT_CONFIG_LEVEL_LOCAL, 0) < 0) {
-		git_config_free(*cfg);
-		return -1;
-	}
+	if ((error = git_config_add_file_ondisk(config, path, GIT_CONFIG_LEVEL_LOCAL, 0)) < 0)
+		git_config_free(config);
+	else
+		*out = config;
 
-	return 0;
+	return error;
 }
 
 static int find_internal_file_by_level(

src/repository.c

@@ -750,6 +750,23 @@ static bool are_symlinks_supported(const char *wd_path)
 	return _symlinks_supported;
 }
 
+static int create_empty_file(const char *path, mode_t mode)
+{
+	int fd;
+
+	if ((fd = p_creat(path, mode)) < 0) {
+		giterr_set(GITERR_OS, "Error while creating '%s'", path);
+		return -1;
+	}
+
+	if (p_close(fd) < 0) {
+		giterr_set(GITERR_OS, "Error while closing '%s'", path);
+		return -1;
+	}
+
+	return 0;
+}
+
 static int repo_init_config(
 	const char *repo_dir,
 	const char *work_dir,
@@ -766,6 +783,12 @@ static int repo_init_config(
 	if (git_buf_joinpath(&cfg_path, repo_dir, GIT_CONFIG_FILENAME_INREPO) < 0)
 		return -1;
 
+	if (!git_path_isfile(git_buf_cstr(&cfg_path)) &&
+		create_empty_file(git_buf_cstr(&cfg_path), GIT_CONFIG_FILE_MODE) < 0) {
+			git_buf_free(&cfg_path);
+			return -1;
+	}
+
 	if (git_config_open_ondisk(&config, git_buf_cstr(&cfg_path)) < 0) {
 		git_buf_free(&cfg_path);
 		return -1;

tests-clar/config/new.c

@@ -11,6 +11,7 @@ void test_config_new__write_new_config(void)
 	const char *out;
 	git_config *config;
 
+	cl_git_mkfile(TEST_CONFIG, "");
 	cl_git_pass(git_config_open_ondisk(&config, TEST_CONFIG));
 
 	cl_git_pass(git_config_set_string(config, "color.ui", "auto"));

tests-clar/config/read.c

@@ -430,3 +430,23 @@ void test_config_read__simple_read_from_specific_level(void)
 	git_config_free(cfg_specific);
 	git_config_free(cfg);
 }
+
+void test_config_read__can_load_and_parse_an_empty_config_file(void)
+{
+	git_config *cfg;
+	int i;
+
+	cl_git_mkfile("./empty", "");
+	cl_git_pass(git_config_open_ondisk(&cfg, "./empty"));
+	cl_assert_equal_i(GIT_ENOTFOUND, git_config_get_int32(&i, cfg, "nope.neither"));
+
+	git_config_free(cfg);
+}
+
+void test_config_read__cannot_load_a_non_existing_config_file(void)
+{
+	git_config *cfg;
+	int i;
+
+	cl_assert_equal_i(GIT_ENOTFOUND, git_config_open_ondisk(&cfg, "./no.config"));
+}