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Merged
Udzu merged 3 commits into from
Oct 8, 2025
Merged

Support TypeAliases #21

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6d4724f
Support TypeAliases
Oct 8, 2025
079b593
Fix ForwardRef evaluation
Oct 8, 2025
707daf4
Bump version
Oct 8, 2025
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1 change: 0 additions & 1 deletion .python-version
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This file was deleted.

2 changes: 1 addition & 1 deletion pyproject.toml
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
[project]
name = "dataglasses"
version = "0.7.0"
version = "0.8.0"
dependencies = []
requires-python = ">=3.10"
authors = [{ name = "Uri Granta", email = "uri.granta+python@gmail.com" }]
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28 changes: 26 additions & 2 deletions src/dataglasses/core.py
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
import collections
import dataclasses
import inspect
import sys
from enum import Enum
from types import NoneType, UnionType
from typing import (
Expand All @@ -20,6 +21,11 @@
get_origin,
)

try:
from typing import TypeAliasType # type: ignore
except ImportError: # pragma: no cover
TypeAliasType = type("TypeAliasTypeNotImplemented", (), {}) # type: ignore

T = TypeVar("T")

TransformRules: TypeAlias = Mapping[type | tuple[type, str], tuple[type, Callable]]
Expand All @@ -31,6 +37,18 @@
"""


def evaluate_forward_ref(
ref: ForwardRef, globals: Mapping[str, Any], locals: Mapping[str, Any]
) -> type:
"""
Evaluate a ForwardRef, something that's not currently exposed publicly.
"""
if sys.version_info < (3, 12, 4):
return ref._evaluate(globals, locals, frozenset()) # type: ignore # pragma: no cover

return ref._evaluate(globals, locals, frozenset(), recursive_guard=set()) # type: ignore # pragma: no cover


def from_dict(
cls: type[T],
value: Any,
Expand Down Expand Up @@ -100,11 +118,14 @@ def _from_dict(
if local_refs is not None:
_locals = _locals | {c.__name__: c for c in local_refs}
return _from_dict(
ref._evaluate(_globals, _locals, frozenset()),
evaluate_forward_ref(ref, _globals, _locals),
value,
datacls,
)

elif isinstance(cls, TypeAliasType): # pragma: no cover
return _from_dict(cls.__value__, value, datacls)

origin = cast(type, get_origin(cls))

if origin in transform and not transformed:
Expand Down Expand Up @@ -275,9 +296,12 @@ def _json_schema(
_locals = datacls.__dict__
if local_refs is not None:
_locals = _locals | {c.__name__: c for c in local_refs}
evaluated_type = cast(type, ref._evaluate(_globals, _locals, frozenset()))
evaluated_type = evaluate_forward_ref(ref, _globals, _locals)
return _json_schema(evaluated_type, datacls)

if isinstance(cls, TypeAliasType): # pragma: no cover
return _json_schema(cls.__value__, datacls)

origin = cast(type, get_origin(cls))

if origin in transform and not transformed:
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23 changes: 23 additions & 0 deletions tests/test_dataklasses.py
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
import json
import sys
from dataclasses import asdict, dataclass
from enum import Enum, IntEnum
from types import MappingProxyType
Expand Down Expand Up @@ -465,6 +466,28 @@ def test_transform_generic() -> None:
validate(value, schema)


# ============
# TYPE ALIASES
# ============

if sys.version_info >= (3, 12): # pragma: no cover
exec("type TypeAliasList = list[int]")
exec("type TypeAliasSet = set[int]")

@dataclass
class DataclassTypeAlias:
a: TypeAliasList # type: ignore # noqa: F821
b: TypeAliasSet # type: ignore # noqa: F821

def test_transform_type_alias() -> None:
value = {"a": [1, 2], "b": [3, 4]}
transform: TransformRules = {set: (list[int], set)}
data = from_dict(DataclassTypeAlias, value, transform=transform)
assert data == DataclassTypeAlias([1, 2], {3, 4})
schema = to_json_schema(DataclassTypeAlias, transform=transform)
validate(value, schema)


# =================
# UNSUPPORTED TYPES
# =================
Expand Down
7 changes: 4 additions & 3 deletions uv.lock
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