Adding literal support

dataconf/utils.py

@@ -7,7 +7,7 @@
 from enum import IntEnum
 from inspect import isclass
 
-from typing import Any
+from typing import Any, Literal
 from typing import Dict
 from typing import get_args
 from typing import get_origin
@@ -200,6 +200,13 @@ def __parse(value: any, clazz: Type, path: str, strict: bool, ignore_unexpected:
 
  raise TypeConfigException(f"expected str or int at {path}, got {type(value)}")
 
+ if get_origin(clazz) is (Literal):
+ if value in args:
+ return value
+ raise TypeConfigException(
+ f"expected one of {', '.join(map(str, args))} at {path}, got {value}"
+ )
+
  if clazz is datetime:
  dt = __parse_type(value, clazz, path, isinstance(value, str))
  try:

tests/test_parse.py

@@ -5,7 +5,7 @@
 from enum import Enum
 from enum import IntEnum
 import os
-from typing import Any
+from typing import Any, Literal
 from typing import Dict
 from typing import List
 from typing import Optional
@@ -712,3 +712,38 @@ class TopLevel:
  top_b="some other value",
  top_c=Nested(nested_a=False, nested_b="some default value"),
  )
+
+ def test_literals(self):
+ @dataclass
+ class Something:
+ literal: Literal["a", "b", 3] = field(default="a")
+
+ config_string = """
+ literal: "a"
+ """
+
+ assert loads(config_string, Something, loader=dataconf.YAML) == Something(
+ literal="a"
+ )
+
+ config_string = """
+ literal: "b"
+ """
+
+ assert loads(config_string, Something, loader=dataconf.YAML) == Something(
+ literal="b"
+ )
+
+ config_string = """
+ literal: 3
+ """
+
+ assert loads(config_string, Something, loader=dataconf.YAML) == Something(
+ literal=3
+ )
+
+ with pytest.raises(TypeConfigException):
+ config_string = """
+ literal: "d"
+ """
+ loads(config_string, Something, loader=dataconf.YAML)