Merge pull request #3813 from tybug/json-defaultdict

Vendor `dataclasses.asdict`

hypothesis-python/RELEASE.rst

@@ -0,0 +1,3 @@
+RELEASE_TYPE: patch
+
+This patch fixes a bug introduced in :ref:`version 6.92.0 <v6.92.0>`, where using :func:`~python:dataclasses.dataclass` with a :class:`~python:collections.defaultdict` field as a strategy argument would error.

hypothesis-python/src/hypothesis/internal/compat.py

@@ -9,6 +9,8 @@
 # obtain one at https://mozilla.org/MPL/2.0/.
 
 import codecs
+import copy
+import dataclasses
 import inspect
 import platform
 import sys
@@ -188,3 +190,46 @@ def bad_django_TestCase(runner):
         from hypothesis.extra.django._impl import HypothesisTestCase
 
         return not isinstance(runner, HypothesisTestCase)
+
+
+# see issue #3812
+if sys.version_info[:2] < (3, 12):
+
+    def dataclass_asdict(obj, *, dict_factory=dict):
+        """
+        A vendored variant of dataclasses.asdict. Includes the bugfix for
+        defaultdicts (cpython/32056) for all versions. See also issues/3812.
+
+        This should be removed whenever we drop support for 3.11. We can use the
+        standard dataclasses.asdict after that point.
+        """
+        if not dataclasses._is_dataclass_instance(obj):  # pragma: no cover
+            raise TypeError("asdict() should be called on dataclass instances")
+        return _asdict_inner(obj, dict_factory)
+
+else:  # pragma: no cover
+    dataclass_asdict = dataclasses.asdict
+
+
+def _asdict_inner(obj, dict_factory):
+    if dataclasses._is_dataclass_instance(obj):
+        return dict_factory(
+            (f.name, _asdict_inner(getattr(obj, f.name), dict_factory))
+            for f in dataclasses.fields(obj)
+        )
+    elif isinstance(obj, tuple) and hasattr(obj, "_fields"):
+        return type(obj)(*[_asdict_inner(v, dict_factory) for v in obj])
+    elif isinstance(obj, (list, tuple)):
+        return type(obj)(_asdict_inner(v, dict_factory) for v in obj)
+    elif isinstance(obj, dict):
+        if hasattr(type(obj), "default_factory"):
+            result = type(obj)(obj.default_factory)
+            for k, v in obj.items():
+                result[_asdict_inner(k, dict_factory)] = _asdict_inner(v, dict_factory)
+            return result
+        return type(obj)(
+            (_asdict_inner(k, dict_factory), _asdict_inner(v, dict_factory))
+            for k, v in obj.items()
+        )
+    else:
+        return copy.deepcopy(obj)

hypothesis-python/src/hypothesis/strategies/_internal/core.py

@@ -77,6 +77,7 @@
 from hypothesis.internal.conjecture.utils import calc_label_from_cls, check_sample
 from hypothesis.internal.entropy import get_seeder_and_restorer
 from hypothesis.internal.floats import float_of
+from hypothesis.internal.observability import TESTCASE_CALLBACKS
 from hypothesis.internal.reflection import (
     define_function_signature,
     get_pretty_function_description,
@@ -2103,7 +2104,9 @@ def draw(self, strategy: SearchStrategy[Ex], label: Any = None) -> Ex:
         self.count += 1
         printer = RepresentationPrinter(context=current_build_context())
         desc = f"Draw {self.count}{'' if label is None else f' ({label})'}: "
-        self.conjecture_data._observability_args[desc] = to_jsonable(result)
+        if TESTCASE_CALLBACKS:
+            self.conjecture_data._observability_args[desc] = to_jsonable(result)
+
         printer.text(desc)
         printer.pretty(result)
         note(printer.getvalue())

hypothesis-python/src/hypothesis/strategies/_internal/utils.py

@@ -16,6 +16,7 @@
 import attr
 
 from hypothesis.internal.cache import LRUReusedCache
+from hypothesis.internal.compat import dataclass_asdict
 from hypothesis.internal.floats import float_to_int
 from hypothesis.internal.reflection import proxies
 from hypothesis.vendor.pretty import pretty
@@ -177,7 +178,7 @@ def to_jsonable(obj: object) -> object:
         and dcs.is_dataclass(obj)
         and not isinstance(obj, type)
     ):
-        return to_jsonable(dcs.asdict(obj))
+        return to_jsonable(dataclass_asdict(obj))
     if attr.has(type(obj)):
         return to_jsonable(attr.asdict(obj, recurse=False))  # type: ignore
     if (pyd := sys.modules.get("pydantic")) and isinstance(obj, pyd.BaseModel):

hypothesis-python/tests/cover/test_compat.py

@@ -9,14 +9,15 @@
 # obtain one at https://mozilla.org/MPL/2.0/.
 
 import math
+from collections import defaultdict, namedtuple
 from dataclasses import dataclass
 from functools import partial
 from inspect import Parameter, Signature, signature
 from typing import ForwardRef, Optional, Union
 
 import pytest
 
-from hypothesis.internal.compat import ceil, floor, get_type_hints
+from hypothesis.internal.compat import ceil, dataclass_asdict, floor, get_type_hints
 
 floor_ceil_values = [
     -10.7,
@@ -106,3 +107,24 @@ def func(a, b: int, *c: str, d: Optional[int] = None):
 )
 def test_get_hints_through_partial(pf, names):
     assert set(get_type_hints(pf)) == set(names.split())
+
+
+@dataclass
+class FilledWithStuff:
+    a: list
+    b: tuple
+    c: namedtuple
+    d: dict
+    e: defaultdict
+
+
+def test_dataclass_asdict():
+    ANamedTuple = namedtuple("ANamedTuple", ("with_some_field"))
+    obj = FilledWithStuff(a=[1], b=(2), c=ANamedTuple(3), d={4: 5}, e=defaultdict(list))
+    assert dataclass_asdict(obj) == {
+        "a": [1],
+        "b": (2),
+        "c": ANamedTuple(3),
+        "d": {4: 5},
+        "e": {},
+    }

hypothesis-python/tests/cover/test_searchstrategy.py

@@ -8,9 +8,11 @@
 # v. 2.0. If a copy of the MPL was not distributed with this file, You can
 # obtain one at https://mozilla.org/MPL/2.0/.
 
+import dataclasses
 import functools
-from collections import namedtuple
+from collections import defaultdict, namedtuple
 
+import attr
 import pytest
 
 from hypothesis.errors import InvalidArgument
@@ -90,3 +92,30 @@ def test_flatmap_with_invalid_expand():
 
 def test_jsonable():
     assert isinstance(to_jsonable(object()), str)
+
+
+@dataclasses.dataclass()
+class HasDefaultDict:
+    x: defaultdict
+
+
+@attr.s
+class AttrsClass:
+    n = attr.ib()
+
+
+def test_jsonable_defaultdict():
+    obj = HasDefaultDict(defaultdict(list))
+    obj.x["a"] = [42]
+    assert to_jsonable(obj) == {"x": {"a": [42]}}
+
+
+def test_jsonable_attrs():
+    obj = AttrsClass(n=10)
+    assert to_jsonable(obj) == {"n": 10}
+
+
+def test_jsonable_namedtuple():
+    Obj = namedtuple("Obj", ("x"))
+    obj = Obj(10)
+    assert to_jsonable(obj) == {"x": 10}