Add support for MappingProxyType

README.md

@@ -221,6 +221,7 @@ for special primitives from the [`typing`](https://docs.python.org/3/library/typ
 for standard interpreter types from [`types`](https://docs.python.org/3/library/types.html#standard-interpreter-types) module:
 * [`NoneType`](https://docs.python.org/3/library/types.html#types.NoneType)
 * [`UnionType`](https://docs.python.org/3/library/types.html#types.UnionType)
+* [`MappingProxyType`](https://docs.python.org/3/library/types.html#types.MappingProxyType)
 
 for enumerations based on classes from the standard [`enum`](https://docs.python.org/3/library/enum.html) module:
 * [`Enum`](https://docs.python.org/3/library/enum.html#enum.Enum)

mashumaro/core/meta/types/unpack.py

@@ -1230,6 +1230,12 @@ def inner_expr(
         )
     elif is_typed_dict(spec.origin_type):
         return unpack_typed_dict(spec)
+    elif issubclass(spec.origin_type, types.MappingProxyType):
+        spec.builder.ensure_module_imported(types)
+        return (
+            f'types.MappingProxyType({{{inner_expr(0, "key")}: {inner_expr(1)}'
+            f" for key, value in {spec.expression}.items()}})"
+        )
     elif ensure_generic_mapping(spec, args, typing.Mapping):
         return (
             f'{{{inner_expr(0, "key")}: {inner_expr(1)} '

tests/test_data_types.py

@@ -16,6 +16,7 @@
     WindowsPath,
 )
 from queue import Queue
+from types import MappingProxyType
 from typing import (
     Any,
     AnyStr,
@@ -123,6 +124,7 @@ class Fixture:
     DICT = {"a": 1, "b": 2}
     ORDERED_DICT = collections.OrderedDict(a=1, b=2)
     DEFAULT_DICT = collections.defaultdict(int, a=1, b=2)
+    MAPPING_PROXY = MappingProxyType(DICT)
     DEFAULT_NONE_DICT = collections.defaultdict(None, a=1, b=2)
     COUNTER: Counter[str] = collections.Counter(a=1, b=2)
     BYTES = b"123"
@@ -204,6 +206,8 @@ class Fixture:
     (OrderedDict, Fixture.ORDERED_DICT, Fixture.DICT),
     (DefaultDict[str, int], Fixture.DEFAULT_DICT, Fixture.DICT),
     (DefaultDict, Fixture.DEFAULT_NONE_DICT, Fixture.DICT),
+    (MappingProxyType[str, int], Fixture.MAPPING_PROXY, Fixture.DICT),
+    (MappingProxyType, Fixture.MAPPING_PROXY, Fixture.DICT),
     (Counter[str], Fixture.COUNTER, Fixture.DICT),
     (Counter, Fixture.COUNTER, Fixture.DICT),
     (MutableMapping[str, int], Fixture.DICT, Fixture.DICT),

tests/test_meta.py

@@ -1,5 +1,6 @@
 import collections
 import collections.abc
+import types
 import typing
 from dataclasses import InitVar, dataclass
 from datetime import datetime
@@ -216,6 +217,9 @@ def test_type_name():
         type_name(typing.DefaultDict[int, int])
         == "typing.DefaultDict[int, int]"
     )
+    assert (
+        type_name(types.MappingProxyType[int, int]) == "mappingproxy[int, int]"
+    )
     assert type_name(typing.Optional[int]) == "typing.Optional[int]"
     assert type_name(typing.Union[None, int]) == "typing.Optional[int]"
     assert type_name(typing.Union[int, None]) == "typing.Optional[int]"
@@ -308,6 +312,10 @@ def test_type_name_short():
         type_name(typing.MutableMapping[int, int], short=True)
         == "MutableMapping[int, int]"
     )
+    assert (
+        type_name(types.MappingProxyType[int, int], short=True)
+        == "mappingproxy[int, int]"
+    )
     assert type_name(typing.Counter[int], short=True) == "Counter[int]"
     assert (
         type_name(typing.ChainMap[int, int], short=True)