Quote and escape ConfigFile keys when necessary

[timothyqiu]

Unexpected things happen when keys of ConfigFile contain special characters. For example:

• When the key is a=b, saving works fine. But it complains about invalid identifier when loading.

  ERROR: ConfigFile parse error at user://test.cfg:2: Unexpected identifier: 'b'..
     at: _parse (core/io/config_file.cpp:280)
  

• When the key contains non-Ascii characters like Chinese, saving works fine. But it might be decoded incorrectly when loaded again. (静音 will become ��.)

This PR encodes the keys with String::property_name_encode(). This is also how ResourceFormatSaverText encodes property names.

Test Script

extends SceneTree

const CONFIG_PATH := "user://test.cfg"

func _init():
	var config := ConfigFile.new()

	config.set_value("音频", "静音", 42)
	config.set_value("Audio", "a=b", 7)

	var err := config.save(CONFIG_PATH)
	assert(err == OK)

	config.clear()
	err = config.load(CONFIG_PATH)
	assert(err == OK)

	for section in config.get_sections():
		print(section)
		for key in config.get_section_keys(section):
			printt("", key, config.get_value(section, key))

	quit()

[Calinou]

Could you modify tests/test_config_file.h to add test cases for this in the same commit? Thanks in advance 🙂

[timothyqiu]

Done. Didn't notice that ConfigFile has a unit test file ;-)

[Calinou]

Thanks!

[akien-mga]

Cherry-picked for 3.4.

[akien-mga]

Cherry-picked for 3.3.4.