[3/5] Use dataclass_transform to prevent type errors in service definition (#15)

Author: dandavison

src/nexusrpc/_service.py

@@ -19,6 +19,8 @@
     overload,
 )
 
+from typing_extensions import dataclass_transform
+
 from nexusrpc._common import InputT, OutputT, ServiceT
 from nexusrpc._util import (
     get_annotations,
@@ -69,10 +71,12 @@ def _validation_errors(self) -> list[str]:
 
 
 @overload
+@dataclass_transform(field_specifiers=(Operation,))
 def service(cls: type[ServiceT]) -> type[ServiceT]: ...
 
 
 @overload
+@dataclass_transform(field_specifiers=(Operation,))
 def service(
     *, name: Optional[str] = None
 ) -> Callable[[type[ServiceT]], type[ServiceT]]: ...

tests/handler/test_invalid_usage.py

@@ -34,7 +34,7 @@ class OperationHandlerOverridesNameInconsistentlyWithServiceDefinition(_TestCase
     def build():
         @nexusrpc.service
         class SD:
-            my_op: nexusrpc.Operation[None, None]  # type: ignore[reportUninitializedInstanceVariable]
+            my_op: nexusrpc.Operation[None, None]
 
         @service_handler(service=SD)
         class SH:
@@ -49,8 +49,8 @@ class ServiceDefinitionHasExtraOp(_TestCase):
     def build():
         @nexusrpc.service
         class SD:
-            my_op_1: nexusrpc.Operation[None, None]  # type: ignore[reportUninitializedInstanceVariable]
-            my_op_2: nexusrpc.Operation[None, None]  # type: ignore[reportUninitializedInstanceVariable]
+            my_op_1: nexusrpc.Operation[None, None]
+            my_op_2: nexusrpc.Operation[None, None]
 
         @service_handler(service=SD)
         class SH:
@@ -67,7 +67,7 @@ class ServiceHandlerHasExtraOp(_TestCase):
     def build():
         @nexusrpc.service
         class SD:
-            my_op_1: nexusrpc.Operation[None, None]  # type: ignore[reportUninitializedInstanceVariable]
+            my_op_1: nexusrpc.Operation[None, None]
 
         @service_handler(service=SD)
         class SH:

tests/handler/test_request_routing.py

@@ -42,7 +42,7 @@ async def _op_impl(self, ctx: StartOperationContext, input: None) -> bool:
 class NoOverrides(_TestCase):
     @nexusrpc.service
     class UserService:
-        op: nexusrpc.Operation[None, bool]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[None, bool]
 
     @service_handler(service=UserService)
     class UserServiceHandler(_TestCase.UserServiceHandler):
@@ -56,7 +56,7 @@ async def op(self, ctx: StartOperationContext, input: None) -> bool:
 class OverrideServiceName(_TestCase):
     @nexusrpc.service(name="UserService-renamed")
     class UserService:
-        op: nexusrpc.Operation[None, bool]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[None, bool]
 
     @service_handler(service=UserService)
     class UserServiceHandler(_TestCase.UserServiceHandler):
@@ -70,7 +70,7 @@ async def op(self, ctx: StartOperationContext, input: None) -> bool:
 class OverrideOperationName(_TestCase):
     @nexusrpc.service
     class UserService:
-        op: nexusrpc.Operation[None, bool] = nexusrpc.Operation(name="op-renamed")  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[None, bool] = nexusrpc.Operation(name="op-renamed")
 
     @service_handler(service=UserService)
     class UserServiceHandler(_TestCase.UserServiceHandler):
@@ -84,7 +84,7 @@ async def op(self, ctx: StartOperationContext, input: None) -> bool:
 class OverrideServiceAndOperationName(_TestCase):
     @nexusrpc.service(name="UserService-renamed")
     class UserService:
-        op: nexusrpc.Operation[None, bool] = nexusrpc.Operation(name="op-renamed")  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[None, bool] = nexusrpc.Operation(name="op-renamed")
 
     @service_handler(service=UserService)
     class UserServiceHandler(_TestCase.UserServiceHandler):

tests/handler/test_service_handler_decorator_collects_expected_operation_definitions.py

@@ -105,7 +105,7 @@ def sync_operation_handler(
 class ManualOperationWithContract(_TestCase):
     @nexusrpc.service
     class Contract:
-        operation: nexusrpc.Operation[Input, Output]  # type: ignore[reportUninitializedInstanceVariable]
+        operation: nexusrpc.Operation[Input, Output]
 
     @service_handler(service=Contract)
     class Service:

tests/handler/test_service_handler_decorator_requirements.py

@@ -29,8 +29,8 @@ class _DecoratorValidationTestCase(_TestCase):
 class MissingOperationFromDefinition(_DecoratorValidationTestCase):
     @nexusrpc.service
     class UserService:
-        op_A: nexusrpc.Operation[int, str]  # type: ignore[reportUninitializedInstanceVariable]
-        op_B: nexusrpc.Operation[bool, float]  # type: ignore[reportUninitializedInstanceVariable]
+        op_A: nexusrpc.Operation[int, str]
+        op_B: nexusrpc.Operation[bool, float]
 
     class UserServiceHandler:
         @operation_handler
@@ -44,7 +44,7 @@ def op_A(self) -> OperationHandler[int, str]: ...
 class MethodNameDoesNotMatchDefinition(_DecoratorValidationTestCase):
     @nexusrpc.service
     class UserService:
-        op_A: nexusrpc.Operation[int, str] = nexusrpc.Operation(name="foo")  # type: ignore[reportUninitializedInstanceVariable]
+        op_A: nexusrpc.Operation[int, str] = nexusrpc.Operation(name="foo")
 
     class UserServiceHandler:
         @operation_handler
@@ -81,12 +81,12 @@ class ServiceHandlerInheritanceWithServiceDefinition(
 ):
     @nexusrpc.service
     class BaseUserService:
-        base_op: nexusrpc.Operation[int, str]  # type: ignore[reportUninitializedInstanceVariable]
+        base_op: nexusrpc.Operation[int, str]
 
     @nexusrpc.service
     class UserService:
-        base_op: nexusrpc.Operation[int, str]  # type: ignore[reportUninitializedInstanceVariable]
-        child_op: nexusrpc.Operation[bool, float]  # type: ignore[reportUninitializedInstanceVariable]
+        base_op: nexusrpc.Operation[int, str]
+        child_op: nexusrpc.Operation[bool, float]
 
     @service_handler(service=BaseUserService)
     class BaseUserServiceHandler:
@@ -139,11 +139,11 @@ class _ServiceDefinitionInheritanceTestCase(_TestCase):
 class ServiceDefinitionInheritance(_ServiceDefinitionInheritanceTestCase):
     @nexusrpc.service
     class BaseUserService:
-        op_from_base_definition: nexusrpc.Operation[int, str]  # type: ignore[reportUninitializedInstanceVariable]
+        op_from_base_definition: nexusrpc.Operation[int, str]
 
     @nexusrpc.service
     class UserService(BaseUserService):
-        op_from_child_definition: nexusrpc.Operation[bool, float]  # type: ignore[reportUninitializedInstanceVariable]
+        op_from_child_definition: nexusrpc.Operation[bool, float]
 
     expected_ops = {
         "op_from_base_definition",

tests/handler/test_service_handler_decorator_validates_against_service_contract.py

@@ -26,7 +26,7 @@ class _InterfaceImplementationTestCase(_BaseTestCase):
 class ValidImpl(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[None, None]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[None, None]
 
         def unrelated_method(self) -> None: ...
 
@@ -54,7 +54,7 @@ def unrelated_method(self) -> None: ...
 class ValidImplWithoutTypeAnnotations(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[int, str]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[int, str]
 
     with warnings.catch_warnings(record=True) as _warnings:
         warnings.simplefilter("always")
@@ -74,7 +74,7 @@ async def op(self, ctx, input): ...  # type: ignore[reportMissingParameterType]
 class MissingOperation(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[None, None]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[None, None]
 
     class Impl:
         pass
@@ -85,7 +85,7 @@ class Impl:
 class MissingInputAnnotation(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[None, None]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[None, None]
 
     with warnings.catch_warnings(record=True) as _warnings:
         warnings.simplefilter("always")
@@ -105,7 +105,7 @@ async def op(self, ctx: StartOperationContext, input) -> None: ...  # type: igno
 class MissingContextAnnotation(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[None, None]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[None, None]
 
     with warnings.catch_warnings(record=True) as _warnings:
         warnings.simplefilter("always")
@@ -125,7 +125,7 @@ async def op(self, ctx, input: None) -> None: ...  # type: ignore[reportMissingP
 class WrongOutputType(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[None, int]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[None, int]
 
     class Impl:
         @sync_operation
@@ -137,7 +137,7 @@ async def op(self, ctx: StartOperationContext, input: None) -> str: ...
 class WrongOutputTypeWithNone(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[str, None]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[str, None]
 
     class Impl:
         @sync_operation
@@ -149,7 +149,7 @@ async def op(self, ctx: StartOperationContext, input: str) -> str: ...
 class ValidImplWithNone(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[str, None]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[str, None]
 
     class Impl:
         @sync_operation
@@ -161,7 +161,7 @@ async def op(self, ctx: StartOperationContext, input: str) -> None: ...
 class MoreSpecificImplAllowed(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[Any, Any]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[Any, Any]
 
     class Impl:
         @sync_operation
@@ -185,7 +185,7 @@ class Subclass(SuperClass):
 class OutputCovarianceImplOutputCanBeSameType(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[X, X]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[X, X]
 
     class Impl:
         @sync_operation
@@ -197,7 +197,7 @@ async def op(self, ctx: StartOperationContext, input: X) -> X: ...
 class OutputCovarianceImplOutputCanBeSubclass(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[X, SuperClass]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[X, SuperClass]
 
     class Impl:
         @sync_operation
@@ -211,7 +211,7 @@ class OutputCovarianceImplOutputCannnotBeStrictSuperclass(
 ):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[X, Subclass]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[X, Subclass]
 
     class Impl:
         @sync_operation
@@ -223,7 +223,7 @@ async def op(self, ctx: StartOperationContext, input: X) -> SuperClass: ...
 class InputContravarianceImplInputCanBeSameType(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[X, X]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[X, X]
 
     class Impl:
         @sync_operation
@@ -235,7 +235,7 @@ async def op(self, ctx: StartOperationContext, input: X) -> X: ...
 class InputContravarianceImplInputCanBeSuperclass(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[Subclass, X]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[Subclass, X]
 
     class Impl:
         @sync_operation
@@ -247,7 +247,7 @@ async def op(self, ctx: StartOperationContext, input: SuperClass) -> X: ...
 class InputContravarianceImplInputCannotBeSubclass(_InterfaceImplementationTestCase):
     @nexusrpc.service
     class Interface:
-        op: nexusrpc.Operation[SuperClass, X]  # type: ignore[reportUninitializedInstanceVariable]
+        op: nexusrpc.Operation[SuperClass, X]
 
     class Impl:
         @sync_operation
@@ -297,7 +297,7 @@ def test_service_decorator_enforces_interface_implementation(
 def test_service_does_not_implement_operation_name():
     @nexusrpc.service
     class Contract:
-        operation_a: nexusrpc.Operation[None, None]  # type: ignore[reportUninitializedInstanceVariable]
+        operation_a: nexusrpc.Operation[None, None]
 
     class Service:
         @sync_operation

tests/service_definition/test_service_decorator_creates_expected_operation_declaration.py

@@ -24,8 +24,8 @@ class OperationDeclarationTestCase(_BaseTestCase):
 class OperationDeclarations(OperationDeclarationTestCase):
     @nexusrpc.service
     class Interface:
-        a: nexusrpc.Operation[None, Output]  # type: ignore[reportUninitializedInstanceVariable]
-        b: nexusrpc.Operation[int, str] = nexusrpc.Operation(name="b-name")  # type: ignore[reportUninitializedInstanceVariable]
+        a: nexusrpc.Operation[None, Output]
+        b: nexusrpc.Operation[int, str] = nexusrpc.Operation(name="b-name")
 
     expected_ops = {
         "a": (type(None), Output),

tests/service_definition/test_service_definition_inheritance.py

@@ -29,7 +29,7 @@ class _TestCase(_BaseTestCase):
 class TypeAnnotationsOnly(_TestCase):
     @nexusrpc.service
     class A1:
-        a: Operation[int, str]  # type: ignore[reportUninitializedInstanceVariable]
+        a: Operation[int, str]
 
     # TODO(preview) why is the decorator omitted here?
     class A2(A1):
@@ -100,7 +100,7 @@ class A1:
 class ChildClassSynthesizedWithTypeValues(_TestCase):
     @nexusrpc.service
     class A1:
-        a: Operation[int, str]  # type: ignore[reportUninitializedInstanceVariable]
+        a: Operation[int, str]
 
     A2 = type("A2", (A1,), {name: Operation[int, str] for name in ["b"]})