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Fix UpdateClass to preserve non-overridden existing members #112

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Merged
msullivan merged 1 commit into from
Mar 19, 2026
Merged

Fix UpdateClass to preserve non-overridden existing members #112

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19 changes: 3 additions & 16 deletions tests/test_dataclass_like.py
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Original file line number Diff line number Diff line change
Expand Up @@ -8,8 +8,6 @@

import typemap_extensions as typing

import pytest


class FieldArgs(TypedDict, total=False):
default: ReadOnly[object]
Expand Down Expand Up @@ -37,6 +35,9 @@ class Field[T: FieldArgs](typing.InitField[T]):
)


# TODO: what could we do to make dataclass_ish work at runtime?


# Begin PEP section: dataclass like __init__

"""
Expand Down Expand Up @@ -133,30 +134,16 @@ class Hero(Model):
from typemap.type_eval import format_helper


@pytest.mark.xfail(reason="UpateClass currently drops things")
def test_dataclass_like_1():
tgt = eval_typing(Hero)
fmt = format_helper.format_class(tgt)

assert fmt == textwrap.dedent("""\
class Hero:
@classmethod
def __init_subclass__[T](cls: type[T]) -> typemap.typing.UpdateClass[InitFnType[T]]: ...
id: int | None = None
name: str
age: int | None = Field(default=None)
secret_name: str
def __init__(self: Self, *, id: int | None = ..., name: str, age: int | None = ..., secret_name: str) -> None: ...
""")


# XXX: Delete this test once above passes
def test_dataclass_like_1_temp():
tgt = eval_typing(Hero)
fmt = format_helper.format_class(tgt)

assert fmt == textwrap.dedent("""\
class Hero:
@classmethod
def __init_subclass__[T](cls: type[T]) -> typemap.typing.UpdateClass[InitFnType[T]]: ...
def __init__(self: Self, *, id: int | None = ..., name: str, age: int | None = ..., secret_name: str) -> None: ...
Expand Down
84 changes: 70 additions & 14 deletions tests/test_type_eval.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1927,19 +1927,20 @@ def __init_subclass__(
def f(self) -> int: ...

class B(A):
b0: int # omitted
b0: int # kept
b1: int # overridden
# b2 added in UpdateClass

def g(self) -> int: ... # omitted
def g(self) -> int: ... # kept

# Attrs
# Attrs: UpdateClass members first (a2, b1, b2), then non-overridden (b0)
attrs = eval_typing(Attrs[B])
assert attrs.__args__ == (
Member[Literal["a1"], int, Never, Never, A],
Member[Literal["a2"], str, Never, Never, B],
Member[Literal["b1"], str, Never, Never, B],
Member[Literal["b2"], str, Never, Never, B],
Member[Literal["b0"], int, Never, Never, B],
)

# Members
Expand All @@ -1951,6 +1952,7 @@ def g(self) -> int: ... # omitted
Member[Literal["a2"], str, Never, Never, B],
Member[Literal["b1"], str, Never, Never, B],
Member[Literal["b2"], str, Never, Never, B],
Member[Literal["b0"], int, Never, Never, B],
Member[
Literal["__init_subclass__"],
classmethod[
Expand All @@ -1973,6 +1975,13 @@ def g(self) -> int: ... # omitted
object,
A,
],
Member[
Literal["g"],
Callable[Params[Param[Literal["self"], B]], int],
Literal["ClassVar"],
object,
B,
],
]
)

Expand All @@ -1983,12 +1992,12 @@ def g(self) -> int: ... # omitted
GetMember[B, Literal["a2"]],
GetMember[B, Literal["b1"]],
GetMember[B, Literal["b2"]],
GetMember[B, Literal["b0"]],
GetMember[B, Literal["__init_subclass__"]],
GetMember[B, Literal["f"]],
GetMember[B, Literal["g"]],
]
)
m = eval_typing(GetMember[B, Literal["g"]])
assert m == Never


type MembersExceptInitSubclass[T] = tuple[
Expand Down Expand Up @@ -2018,13 +2027,13 @@ def __init_subclass__[T](
def f(self) -> int: ...

class B(A):
b0: int # omitted
b0: int # kept
b1: int # overridden
# b2 added in UpdateClass

def g(self) -> int: ... # omitted
def g(self) -> int: ... # kept

# Attrs
# Attrs: UpdateClass members first (a2, b1, b2), then non-overridden (b0)
attrs = eval_typing(Attrs[B])
assert (
attrs
Expand All @@ -2033,6 +2042,7 @@ def g(self) -> int: ... # omitted
Member[Literal["a2"], str, Never, Never, B],
Member[Literal["b1"], str, Never, Never, B],
Member[Literal["b2"], str, Never, Never, B],
Member[Literal["b0"], int, Never, Never, B],
]
)

Expand All @@ -2045,13 +2055,21 @@ def g(self) -> int: ... # omitted
Member[Literal["a2"], str, Never, Never, B],
Member[Literal["b1"], str, Never, Never, B],
Member[Literal["b2"], str, Never, Never, B],
Member[Literal["b0"], int, Never, Never, B],
Member[
Literal["f"],
Callable[Params[Param[Literal["self"], A]], int],
Literal["ClassVar"],
object,
A,
],
Member[
Literal["g"],
Callable[Params[Param[Literal["self"], B]], int],
Literal["ClassVar"],
object,
B,
],
]
)

Expand All @@ -2062,11 +2080,11 @@ def g(self) -> int: ... # omitted
GetMember[B, Literal["a2"]],
GetMember[B, Literal["b1"]],
GetMember[B, Literal["b2"]],
GetMember[B, Literal["b0"]],
GetMember[B, Literal["f"]],
GetMember[B, Literal["g"]],
]
)
m = eval_typing(GetMember[B, Literal["g"]])
assert m == Never


type AttrsAsSets[T] = UpdateClass[
Expand All @@ -2089,7 +2107,7 @@ def f(self) -> int: ...
class B(A):
b: str

def g(self) -> int: ... # omitted
def g(self) -> int: ... # kept

# Attrs
attrs = eval_typing(Attrs[B])
Expand All @@ -2115,6 +2133,13 @@ def g(self) -> int: ... # omitted
object,
A,
],
Member[
Literal["g"],
Callable[Params[Param[Literal["self"], B]], int],
Literal["ClassVar"],
object,
B,
],
]
)

Expand All @@ -2124,10 +2149,9 @@ def g(self) -> int: ... # omitted
GetMember[B, Literal["a"]],
GetMember[B, Literal["b"]],
GetMember[B, Literal["f"]],
GetMember[B, Literal["g"]],
]
)
m = eval_typing(GetMember[B, Literal["g"]])
assert m == Never


def test_update_class_members_04():
Expand Down Expand Up @@ -2581,7 +2605,39 @@ class B(A):
b: int

attrs = eval_typing(Attrs[B])
assert attrs == tuple[Member[Literal["a"], int, Never, Never, A]]
assert (
attrs
== tuple[
Member[Literal["a"], int, Never, Never, A],
Member[Literal["b"], int, Never, Never, B],
]
)


def test_update_class_never_removes():
# A member with type Never in UpdateClass removes it
class A:
a: int
b: str
c: float

def __init_subclass__[T](
cls: type[T],
) -> UpdateClass[Member[Literal["b"], Never],]:
super().__init_subclass__()

class B(A):
d: bool

attrs = eval_typing(Attrs[B])
assert (
attrs
== tuple[
Member[Literal["a"], int, Never, Never, A],
Member[Literal["c"], float, Never, Never, A],
Member[Literal["d"], bool, Never, Never, B],
]
)


##############
Expand Down
24 changes: 22 additions & 2 deletions typemap/type_eval/_eval_operators.py
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Original file line number Diff line number Diff line change
Expand Up @@ -170,7 +170,8 @@ def get_annotated_type_hints(cls, *, ctx, attrs_only=False, **kwargs):

hints[k] = ty, tuple(sorted(quals)), init, acls

return hints
# A type of Never in UpdateClass removes the member
return {k: v for k, v in hints.items() if v[0] is not typing.Never}


def get_annotated_method_hints(cls, *, ctx):
Expand Down Expand Up @@ -311,14 +312,18 @@ def _create_updated_class(
# Copy the module
dct["__module__"] = t.__module__

# Process the new members from UpdateClass
# Process UpdateClass members first to establish their ordering,
# then append non-overridden existing members.
dct["__annotations__"] = annos = {}
update_names: set[str] = set()

for m in ms:
tname, typ, quals, init, _ = typing.get_args(m)
member_name = _eval_literal(tname, ctx)
typ = _eval_types(typ, ctx)
tquals = _eval_types(quals, ctx)

update_names.add(member_name)
if (
type_eval.issubtype(typing.Literal["ClassVar"], tquals)
and _is_method_like(typ)
Expand All @@ -330,6 +335,21 @@ def _create_updated_class(
annos[member_name] = _add_quals(typ, tquals)
_unpack_init(dct, member_name, init)

# Append non-overridden existing annotations (preserving their order)
for name, typ in getattr(t, '__annotations__', {}).items():
if name not in update_names:
annos[name] = typ

# Append non-overridden existing methods and annotation defaults
existing_annos = getattr(t, '__annotations__', {})
for name, value in t.__dict__.items():
if name in update_names or name in _apply_generic.EXCLUDED_ATTRIBUTES:
continue
if isinstance(inspect.unwrap(value), types.FunctionType):
dct[name] = value
elif name in existing_annos:
dct[name] = value

# Create the updated class

# If typing.Generic is a base, we need to use it with the type params
Expand Down
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