Docs and more preconf fixes

HISTORY.rst

@@ -13,6 +13,8 @@ History
 * PyPy support (and tests, using a minimal Hypothesis profile) restored.
   (`#253 <https://github.com/python-attrs/cattrs/issues/253>`_)
 * Fix propagating the `detailed_validation` flag to mapping and counter structuring generators.
+* Fix ``typing.Set`` applying too broadly when used with the ``GenConverter.unstruct_collection_overrides`` parameter on Python versions below 3.9. Switch to ``typing.AbstractSet`` on those versions to restore the old behavior.
+  (`#264 <https://github.com/python-attrs/cattrs/issues/264>`_)
 
 22.1.0 (2022-04-03)
 -------------------

src/cattrs/preconf/bson.py

@@ -5,7 +5,7 @@
 
 from bson import DEFAULT_CODEC_OPTIONS, CodecOptions, ObjectId, decode, encode
 
-from cattrs._compat import Set, is_mapping
+from cattrs._compat import AbstractSet, is_mapping
 from cattrs.gen import make_mapping_structure_fn
 
 from ..converters import BaseConverter, Converter
@@ -89,7 +89,7 @@ def gen_structure_mapping(cl: Any):
 def make_converter(*args, **kwargs) -> BsonConverter:
     kwargs["unstruct_collection_overrides"] = {
         **kwargs.get("unstruct_collection_overrides", {}),
-        Set: list,
+        AbstractSet: list,
     }
     res = BsonConverter(*args, **kwargs)
     configure_converter(res)

src/cattrs/preconf/msgpack.py

@@ -4,7 +4,7 @@
 
 from msgpack import dumps, loads
 
-from cattrs._compat import Set
+from cattrs._compat import AbstractSet
 
 from ..converters import BaseConverter, Converter
 
@@ -35,7 +35,7 @@ def configure_converter(converter: BaseConverter):
 def make_converter(*args, **kwargs) -> MsgpackConverter:
     kwargs["unstruct_collection_overrides"] = {
         **kwargs.get("unstruct_collection_overrides", {}),
-        Set: list,
+        AbstractSet: list,
     }
     res = MsgpackConverter(*args, **kwargs)
     configure_converter(res)

src/cattrs/preconf/orjson.py

@@ -6,7 +6,7 @@
 
 from orjson import dumps, loads
 
-from cattrs._compat import Set, is_mapping
+from cattrs._compat import AbstractSet, is_mapping
 
 from ..converters import BaseConverter, Converter
 
@@ -69,7 +69,7 @@ def key_handler(v):
 def make_converter(*args, **kwargs) -> OrjsonConverter:
     kwargs["unstruct_collection_overrides"] = {
         **kwargs.get("unstruct_collection_overrides", {}),
-        Set: list,
+        AbstractSet: list,
     }
     res = OrjsonConverter(*args, **kwargs)
     configure_converter(res)

src/cattrs/preconf/tomlkit.py

@@ -5,7 +5,7 @@
 
 from tomlkit import dumps, loads
 
-from cattrs._compat import Set, is_mapping
+from cattrs._compat import AbstractSet, is_mapping
 
 from ..converters import BaseConverter, Converter
 from . import validate_datetime
@@ -59,7 +59,7 @@ def key_handler(k: bytes):
 def make_converter(*args, **kwargs) -> TomlkitConverter:
     kwargs["unstruct_collection_overrides"] = {
         **kwargs.get("unstruct_collection_overrides", {}),
-        Set: list,
+        AbstractSet: list,
         tuple: list,
     }
     res = TomlkitConverter(*args, **kwargs)

src/cattrs/preconf/ujson.py

@@ -5,7 +5,7 @@
 
 from ujson import dumps, loads
 
-from cattrs._compat import Set
+from cattrs._compat import AbstractSet
 
 from ..converters import BaseConverter, Converter
 
@@ -40,7 +40,7 @@ def configure_converter(converter: BaseConverter):
 def make_converter(*args, **kwargs) -> UjsonConverter:
     kwargs["unstruct_collection_overrides"] = {
         **kwargs.get("unstruct_collection_overrides", {}),
-        Set: list,
+        AbstractSet: list,
     }
     res = UjsonConverter(*args, **kwargs)
     configure_converter(res)