game/scripts/save_store.gd

@@ -14,9 +14,10 @@ const KEEP_RECORDINGS := 10
 const KEY_BYTES := 16
 
 var base_dir: String
-## The result of the last attempt to read the key or the save: OK, or why
-## the file could not be read. A file that exists but cannot be read right
-## now, for example because another program holds it, is never replaced.
+## The result of the last attempt to read the key, the save or the settings:
+## OK, or why the file could not be read. A file that exists but cannot be
+## read right now, for example because another program holds it, is never
+## replaced.
 var last_read_error: Error = OK
 
 
@@ -132,8 +133,8 @@ func player_name() -> String:
 	return _setting("player", "name")
 
 
-func set_player_name(player_name: String) -> void:
-	_set_setting("player", "name", player_name)
+func set_player_name(new_name: String) -> void:
+	_set_setting("player", "name", new_name)
 
 
 ## The address of the host the player joined last time, or an empty text.
@@ -146,21 +147,40 @@ func set_last_address(address: String) -> void:
 
 
 func _setting(section: String, key: String) -> String:
-	var settings := ConfigFile.new()
-	if settings.load(base_dir.path_join(SETTINGS_FILE)) != OK:
+	var settings := _read_settings(base_dir.path_join(SETTINGS_FILE))
+	if settings == null:
 		return ""
 	return str(settings.get_value(section, key, ""))
 
 
+## Changes one setting and keeps the others. Settings that cannot be read
+## right now stay as they are, because writing them would lose the others.
 func _set_setting(section: String, key: String, value: String) -> void:
 	var path := base_dir.path_join(SETTINGS_FILE)
-	var settings := ConfigFile.new()
-	settings.load(path)
+	var settings := _read_settings(path)
+	if settings == null:
+		push_warning("settings could not be read at %s and stay as they are: %s" % [path, error_string(last_read_error)])
+		return
 	settings.set_value(section, key, value)
 	if settings.save(path) != OK:
 		push_warning("settings could not be stored at %s" % path)
 
 
+## The settings on disk, or null if the file exists but cannot be read right
+## now; last_read_error then says why. A missing file gives empty settings.
+## Of a damaged file, Godot reports the error and keeps what it read before
+## it, and the next change of a setting writes the file anew.
+func _read_settings(path: String) -> ConfigFile:
+	var settings := ConfigFile.new()
+	if not FileAccess.file_exists(path):
+		return settings
+	var text := _read_file(path).get_string_from_utf8()
+	if last_read_error != OK:
+		return null
+	settings.parse(text)
+	return settings
+
+
 ## Moves the backup back to the save if there is no save, see write_save.
 func _restore_backup() -> void:
 	var path := base_dir.path_join(SAVE_FILE)

game/tests/test_save_store.gd

@@ -174,3 +174,18 @@ func test_the_settings_are_kept() -> void:
 	check_eq(later.player_name(), "Ada", "name")
 	check_eq(later.last_address(), "192.168.1.20", "address")
 	TestFiles.remove_dir(directory)
+
+
+func test_settings_that_cannot_be_read_right_now_are_not_overwritten() -> void:
+	var directory := TestFiles.temporary_dir("held-settings")
+	var store := SaveStore.new(directory)
+	store.set_player_name("Ada")
+	store.set_last_address("192.168.1.20")
+	var held := HeldFileStore.new(directory)
+	held.unreadable = SaveStore.SETTINGS_FILE
+	check_eq(held.player_name(), "", "nothing read for now")
+	held.set_player_name("Grace")
+	var later := SaveStore.new(directory)
+	check_eq(later.player_name(), "Ada", "the name on disk is the old one")
+	check_eq(later.last_address(), "192.168.1.20", "the address is kept")
+	TestFiles.remove_dir(directory)