Fix preconf mapping optimizations

Author: Tinche

HISTORY.md

@@ -27,6 +27,8 @@ Our backwards-compatibility policy can be found [here](https://github.com/python
   ([#598](https://github.com/python-attrs/cattrs/pull/598))
 - Literals containing enums are now unstructured properly, and their unstructuring is greatly optimized in the _bson_, stdlib JSON, _cbor2_, _msgpack_, _msgspec_, _orjson_ and _ujson_ preconf converters.
   ([#598](https://github.com/python-attrs/cattrs/pull/598))
+- Preconf converters now handle dictionaries with literal keys properly.
+  ([#599](https://github.com/python-attrs/cattrs/pull/599))
 - Replace `cattrs.gen.MappingStructureFn` with `cattrs.SimpleStructureHook[In, T]`.
 - Python 3.13 is now supported.
   ([#543](https://github.com/python-attrs/cattrs/pull/543) [#547](https://github.com/python-attrs/cattrs/issues/547))

src/cattrs/_compat.py

@@ -252,7 +252,6 @@ def is_literal(_) -> bool:
 
 
 Set = AbcSet
-AbstractSet = AbcSet
 MutableSet = AbcMutableSet
 Sequence = AbcSequence
 MutableSequence = AbcMutableSequence

src/cattrs/preconf/bson.py

@@ -1,14 +1,14 @@
 """Preconfigured converters for bson."""
 
 from base64 import b85decode, b85encode
+from collections.abc import Set
 from datetime import date, datetime
 from typing import Any, TypeVar, Union
 
 from bson import DEFAULT_CODEC_OPTIONS, CodecOptions, Int64, ObjectId, decode, encode
 
-from cattrs._compat import AbstractSet, is_mapping
-from cattrs.gen import make_mapping_structure_fn
-
+from .._compat import is_mapping, is_subclass
+from ..cols import mapping_structure_factory
 from ..converters import BaseConverter, Converter
 from ..dispatch import StructureHook
 from ..fns import identity
@@ -69,9 +69,9 @@ def gen_unstructure_mapping(cl: Any, unstructure_to=None):
         key_handler = str
         args = getattr(cl, "__args__", None)
         if args:
-            if issubclass(args[0], str):
+            if is_subclass(args[0], str):
                 key_handler = None
-            elif issubclass(args[0], bytes):
+            elif is_subclass(args[0], bytes):
 
                 def key_handler(k):
                     return b85encode(k).decode("utf8")
@@ -82,10 +82,10 @@ def key_handler(k):
 
     def gen_structure_mapping(cl: Any) -> StructureHook:
         args = getattr(cl, "__args__", None)
-        if args and issubclass(args[0], bytes):
-            h = make_mapping_structure_fn(cl, converter, key_type=Base85Bytes)
+        if args and is_subclass(args[0], bytes):
+            h = mapping_structure_factory(cl, converter, key_type=Base85Bytes)
         else:
-            h = make_mapping_structure_fn(cl, converter)
+            h = mapping_structure_factory(cl, converter)
         return h
 
     converter.register_structure_hook(Base85Bytes, lambda v, _: b85decode(v))
@@ -112,7 +112,7 @@ def gen_structure_mapping(cl: Any) -> StructureHook:
 @wrap(BsonConverter)
 def make_converter(*args: Any, **kwargs: Any) -> BsonConverter:
     kwargs["unstruct_collection_overrides"] = {
-        AbstractSet: list,
+        Set: list,
         **kwargs.get("unstruct_collection_overrides", {}),
     }
     res = BsonConverter(*args, **kwargs)

src/cattrs/preconf/cbor2.py

@@ -1,12 +1,11 @@
 """Preconfigured converters for cbor2."""
 
+from collections.abc import Set
 from datetime import date, datetime, timezone
 from typing import Any, TypeVar, Union
 
 from cbor2 import dumps, loads
 
-from cattrs._compat import AbstractSet
-
 from ..converters import BaseConverter, Converter
 from ..fns import identity
 from ..literals import is_literal_containing_enums
@@ -48,7 +47,7 @@ def configure_converter(converter: BaseConverter):
 @wrap(Cbor2Converter)
 def make_converter(*args: Any, **kwargs: Any) -> Cbor2Converter:
     kwargs["unstruct_collection_overrides"] = {
-        AbstractSet: list,
+        Set: list,
         **kwargs.get("unstruct_collection_overrides", {}),
     }
     res = Cbor2Converter(*args, **kwargs)

src/cattrs/preconf/json.py

@@ -1,11 +1,12 @@
 """Preconfigured converters for the stdlib json."""
 
 from base64 import b85decode, b85encode
+from collections.abc import Set
 from datetime import date, datetime
 from json import dumps, loads
 from typing import Any, TypeVar, Union
 
-from .._compat import AbstractSet, Counter
+from .._compat import Counter
 from ..converters import BaseConverter, Converter
 from ..fns import identity
 from ..literals import is_literal_containing_enums
@@ -56,7 +57,7 @@ def configure_converter(converter: BaseConverter):
 @wrap(JsonConverter)
 def make_converter(*args: Any, **kwargs: Any) -> JsonConverter:
     kwargs["unstruct_collection_overrides"] = {
-        AbstractSet: list,
+        Set: list,
         Counter: dict,
         **kwargs.get("unstruct_collection_overrides", {}),
     }

src/cattrs/preconf/msgpack.py

@@ -1,12 +1,11 @@
 """Preconfigured converters for msgpack."""
 
+from collections.abc import Set
 from datetime import date, datetime, time, timezone
 from typing import Any, TypeVar, Union
 
 from msgpack import dumps, loads
 
-from cattrs._compat import AbstractSet
-
 from ..converters import BaseConverter, Converter
 from ..fns import identity
 from ..literals import is_literal_containing_enums
@@ -55,7 +54,7 @@ def configure_converter(converter: BaseConverter):
 @wrap(MsgpackConverter)
 def make_converter(*args: Any, **kwargs: Any) -> MsgpackConverter:
     kwargs["unstruct_collection_overrides"] = {
-        AbstractSet: list,
+        Set: list,
         **kwargs.get("unstruct_collection_overrides", {}),
     }
     res = MsgpackConverter(*args, **kwargs)

src/cattrs/preconf/orjson.py

@@ -1,15 +1,16 @@
 """Preconfigured converters for orjson."""
 
 from base64 import b85decode, b85encode
+from collections.abc import Set
 from datetime import date, datetime
 from enum import Enum
 from functools import partial
 from typing import Any, TypeVar, Union
 
 from orjson import dumps, loads
 
-from .._compat import AbstractSet, is_mapping
-from ..cols import is_namedtuple, namedtuple_unstructure_factory
+from .._compat import is_subclass
+from ..cols import is_mapping, is_namedtuple, namedtuple_unstructure_factory
 from ..converters import BaseConverter, Converter
 from ..fns import identity
 from ..literals import is_literal_containing_enums
@@ -56,7 +57,7 @@ def gen_unstructure_mapping(cl: Any, unstructure_to=None):
         key_handler = str
         args = getattr(cl, "__args__", None)
         if args:
-            if issubclass(args[0], str) and issubclass(args[0], Enum):
+            if is_subclass(args[0], str) and is_subclass(args[0], Enum):
 
                 def key_handler(v):
                     return v.value
@@ -96,7 +97,7 @@ def key_handler(v):
 @wrap(OrjsonConverter)
 def make_converter(*args: Any, **kwargs: Any) -> OrjsonConverter:
     kwargs["unstruct_collection_overrides"] = {
-        AbstractSet: list,
+        Set: list,
         **kwargs.get("unstruct_collection_overrides", {}),
     }
     res = OrjsonConverter(*args, **kwargs)

src/cattrs/preconf/tomlkit.py

@@ -1,6 +1,7 @@
 """Preconfigured converters for tomlkit."""
 
 from base64 import b85decode, b85encode
+from collections.abc import Set
 from datetime import date, datetime
 from enum import Enum
 from operator import attrgetter
@@ -9,8 +10,7 @@
 from tomlkit import dumps, loads
 from tomlkit.items import Float, Integer, String
 
-from cattrs._compat import AbstractSet, is_mapping
-
+from .._compat import is_mapping, is_subclass
 from ..converters import BaseConverter, Converter
 from ..strategies import configure_union_passthrough
 from . import validate_datetime, wrap
@@ -48,9 +48,9 @@ def gen_unstructure_mapping(cl: Any, unstructure_to=None):
             # Currently, tomlkit has inconsistent behavior on 3.11
             # so we paper over it here.
             # https://github.com/sdispater/tomlkit/issues/237
-            if issubclass(args[0], str):
-                key_handler = _enum_value_getter if issubclass(args[0], Enum) else None
-            elif issubclass(args[0], bytes):
+            if is_subclass(args[0], str):
+                key_handler = _enum_value_getter if is_subclass(args[0], Enum) else None
+            elif is_subclass(args[0], bytes):
 
                 def key_handler(k: bytes):
                     return b85encode(k).decode("utf8")
@@ -77,7 +77,7 @@ def key_handler(k: bytes):
 @wrap(TomlkitConverter)
 def make_converter(*args: Any, **kwargs: Any) -> TomlkitConverter:
     kwargs["unstruct_collection_overrides"] = {
-        AbstractSet: list,
+        Set: list,
         tuple: list,
         **kwargs.get("unstruct_collection_overrides", {}),
     }

src/cattrs/preconf/ujson.py

@@ -1,12 +1,12 @@
 """Preconfigured converters for ujson."""
 
 from base64 import b85decode, b85encode
+from collections.abc import Set
 from datetime import date, datetime
 from typing import Any, AnyStr, TypeVar, Union
 
 from ujson import dumps, loads
 
-from .._compat import AbstractSet
 from ..converters import BaseConverter, Converter
 from ..fns import identity
 from ..literals import is_literal_containing_enums
@@ -55,7 +55,7 @@ def configure_converter(converter: BaseConverter):
 @wrap(UjsonConverter)
 def make_converter(*args: Any, **kwargs: Any) -> UjsonConverter:
     kwargs["unstruct_collection_overrides"] = {
-        AbstractSet: list,
+        Set: list,
         **kwargs.get("unstruct_collection_overrides", {}),
     }
     res = UjsonConverter(*args, **kwargs)

tests/test_cols.py

@@ -1,11 +1,12 @@
 """Tests for the `cattrs.cols` module."""
 
+from collections.abc import Set
 from typing import Dict
 
 from immutables import Map
 
 from cattrs import BaseConverter, Converter
-from cattrs._compat import AbstractSet, FrozenSet
+from cattrs._compat import FrozenSet
 from cattrs.cols import (
     is_any_set,
     iterable_unstructure_factory,
@@ -23,7 +24,7 @@ def test_set_overriding(converter: BaseConverter):
         lambda t, c: iterable_unstructure_factory(t, c, unstructure_to=sorted),
     )
 
-    assert converter.unstructure({"c", "b", "a"}, AbstractSet[str]) == ["a", "b", "c"]
+    assert converter.unstructure({"c", "b", "a"}, Set[str]) == ["a", "b", "c"]
     assert converter.unstructure(frozenset(["c", "b", "a"]), FrozenSet[str]) == [
         "a",
         "b",