Disambiguate generics with unknown parametric assignments

codegen/core/src/main/java/software/amazon/smithy/python/codegen/ClientGenerator.java

@@ -542,6 +542,7 @@ await sleep(retry_token.retry_delay)
                 """);
 
         writer.pushState(new SignRequestSection());
+        writer.addStdlibImport("typing", "cast");
         if (context.applicationProtocol().isHttpProtocol() && supportsAuth) {
             writer.addStdlibImport("re");
             writer.addStdlibImport("typing", "Any");
@@ -571,9 +572,12 @@ await sleep(retry_token.retry_delay)
                                 signature = re.split("Signature=", auth_value)[-1]  # type: ignore
                                 context.properties["signature"] = signature.encode('utf-8')
 
-                                identity_key: PropertyKey[Identity | None] = PropertyKey(
-                                    key="identity",
-                                    value_type=Identity | None  # type: ignore
+                                identity_key = cast(
+                                    PropertyKey[Identity | None],
+                                    PropertyKey(
+                                        key="identity",
+                                        value_type=Identity | None  # type: ignore
+                                    )
                                 )
                                 sp_key: PropertyKey[dict[str, Any]] = PropertyKey(
                                     key="signer_properties",
@@ -665,12 +669,15 @@ await sleep(retry_token.retry_delay)
                         # Step 7r: Invoke read_after_deserialization
                         interceptor.read_after_deserialization(output_context)
                     except Exception as e:
-                        output_context: OutputContext[Input, Output, $1T, $2T] = OutputContext(
-                            request=context.request,
-                            response=e,  # type: ignore
-                            transport_request=context.transport_request,
-                            transport_response=transport_response,
-                            properties=context.properties
+                        output_context = cast(
+                            OutputContext[Input, Output, $1T, $2T],
+                            OutputContext(
+                                request=context.request,
+                                response=e,  # type: ignore
+                                transport_request=context.transport_request,
+                                transport_response=transport_response,
+                                properties=context.properties
+                            )
                         )
 
                     return await self._finalize_attempt(interceptor, output_context)

codegen/core/src/main/java/software/amazon/smithy/python/codegen/generators/StructureGenerator.java

@@ -215,7 +215,7 @@ private void writeProperties() {
             if (member.hasTrait(DefaultTrait.class)) {
 
                 defaultValue = getDefaultValue(writer, member);
-                if (target.isDocumentShape() || Set.of("list", "dict").contains(defaultValue)) {
+                if (target.isDocumentShape() || defaultValue.startsWith("list[") || defaultValue.startsWith("dict[")) {
                     writer.addStdlibImport("dataclasses", "field");
                     defaultKey = "default_factory";
                     requiresField = true;
@@ -308,8 +308,7 @@ private String getDefaultValue(PythonWriter writer, MemberShape member) {
             case BOOLEAN -> defaultNode.expectBooleanNode().getValue() ? "True" : "False";
             // These will be given to a default_factory in field. They're inherently empty, so no need to
             // worry about any potential values.
-            case ARRAY -> "list";
-            case OBJECT -> "dict";
+            case ARRAY, OBJECT -> symbolProvider.toSymbol(target).getName();
             default -> Node.printJson(defaultNode);
         };
     }

packages/smithy-aws-event-stream/src/smithy_aws_event_stream/events.py

@@ -187,7 +187,7 @@ class EventMessage:
       message.
     """
 
-    headers: HEADERS_DICT = field(default_factory=dict)
+    headers: HEADERS_DICT = field(default_factory=dict[str, HEADER_VALUE])
     """The headers present in the event message.
 
     Sized integer values may be indicated for the purpose of serialization

packages/smithy-core/src/smithy_core/schemas.py

@@ -20,8 +20,10 @@ class Schema:
 
     id: ShapeID
     shape_type: ShapeType
-    traits: dict[ShapeID, "Trait | DynamicTrait"] = field(default_factory=dict)
-    members: dict[str, "Schema"] = field(default_factory=dict)
+    traits: dict[ShapeID, "Trait | DynamicTrait"] = field(
+        default_factory=dict[ShapeID, "Trait | DynamicTrait"]
+    )
+    members: dict[str, "Schema"] = field(default_factory=dict[str, "Schema"])
     member_target: "Schema | None" = None
     member_index: int | None = None
 

packages/smithy-core/tests/unit/test_types.py

@@ -3,7 +3,7 @@
 
 # pyright: reportPrivateUsage=false
 from datetime import UTC, datetime
-from typing import Any, assert_type
+from typing import Any, assert_type, cast
 
 import pytest
 from smithy_core.exceptions import ExpectationNotMetError
@@ -323,9 +323,12 @@ def test_properties_typed_pop() -> None:
 
 def test_union_property() -> None:
     properties = TypedProperties()
-    union: PropertyKey[str | int] = PropertyKey(
-        key="union",
-        value_type=str | int,  # type: ignore
+    union = cast(
+        PropertyKey[str | int],
+        PropertyKey(
+            key="union",
+            value_type=str | int,  # type: ignore
+        ),
     )
 
     properties[union] = "foo"

packages/smithy-http/src/smithy_http/aio/crt.py

@@ -10,7 +10,7 @@
 from copy import deepcopy
 from functools import partial
 from io import BufferedIOBase, BytesIO
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, cast
 
 if TYPE_CHECKING:
     # Both of these are types that essentially are "castable to bytes/memoryview"
@@ -119,7 +119,7 @@ def set_stream(self, stream: "crt_http.HttpClientStream") -> None:
         if self._stream is not None:
             raise SmithyHTTPError("Stream already set on AWSCRTHTTPResponse object")
         self._stream = stream
-        concurrent_future: ConcurrentFuture[int] = stream.completion_future
+        concurrent_future = cast(ConcurrentFuture[int], stream.completion_future)
         self._completion_future = asyncio.wrap_future(concurrent_future)
         self._completion_future.add_done_callback(self._on_complete)
         self._stream.activate()
@@ -305,14 +305,15 @@ def _build_new_connection(
         if url.port is not None:
             port = url.port
 
-        connect_future: ConcurrentFuture[crt_http.HttpClientConnection] = (
+        connect_future = cast(
+            ConcurrentFuture[crt_http.HttpClientConnection],
             crt_http.HttpClientConnection.new(
                 bootstrap=self._client_bootstrap,
                 host_name=url.host,
                 port=port,
                 socket_options=self._socket_options,
                 tls_connection_options=tls_connection_options,
-            )
+            ),
         )
         return connect_future
 

packages/smithy-http/src/smithy_http/user_agent.py

@@ -50,17 +50,35 @@ def __str__(self) -> str:
 
 @dataclass(kw_only=True, slots=True)
 class UserAgent:
-    sdk_metadata: list[UserAgentComponent] = field(default_factory=list)
-    internal_metadata: list[UserAgentComponent] = field(default_factory=list)
-    ua_metadata: list[UserAgentComponent] = field(default_factory=list)
-    api_metadata: list[UserAgentComponent] = field(default_factory=list)
-    os_metadata: list[UserAgentComponent] = field(default_factory=list)
-    language_metadata: list[UserAgentComponent] = field(default_factory=list)
-    env_metadata: list[UserAgentComponent] = field(default_factory=list)
-    config_metadata: list[UserAgentComponent] = field(default_factory=list)
-    feat_metadata: list[UserAgentComponent] = field(default_factory=list)
+    sdk_metadata: list[UserAgentComponent] = field(
+        default_factory=list[UserAgentComponent]
+    )
+    internal_metadata: list[UserAgentComponent] = field(
+        default_factory=list[UserAgentComponent]
+    )
+    ua_metadata: list[UserAgentComponent] = field(
+        default_factory=list[UserAgentComponent]
+    )
+    api_metadata: list[UserAgentComponent] = field(
+        default_factory=list[UserAgentComponent]
+    )
+    os_metadata: list[UserAgentComponent] = field(
+        default_factory=list[UserAgentComponent]
+    )
+    language_metadata: list[UserAgentComponent] = field(
+        default_factory=list[UserAgentComponent]
+    )
+    env_metadata: list[UserAgentComponent] = field(
+        default_factory=list[UserAgentComponent]
+    )
+    config_metadata: list[UserAgentComponent] = field(
+        default_factory=list[UserAgentComponent]
+    )
+    feat_metadata: list[UserAgentComponent] = field(
+        default_factory=list[UserAgentComponent]
+    )
     additional_metadata: list[UserAgentComponent | RawStringUserAgentComponent] = field(
-        default_factory=list
+        default_factory=list[UserAgentComponent | RawStringUserAgentComponent]
     )
 
     def __str__(self) -> str:

packages/smithy-http/tests/unit/test_serializers.py

@@ -124,27 +124,29 @@
 @dataclass
 class _HTTPMapping(Protocol):
     boolean_member: bool | None = None
-    boolean_list_member: list[bool] = field(default_factory=list)
+    boolean_list_member: list[bool] = field(default_factory=list[bool])
     integer_member: int | None = None
-    integer_list_member: list[int] = field(default_factory=list)
+    integer_list_member: list[int] = field(default_factory=list[int])
     float_member: float | None = None
-    float_list_member: list[float] = field(default_factory=list)
+    float_list_member: list[float] = field(default_factory=list[float])
     big_decimal_member: Decimal | None = None
-    big_decimal_list_member: list[Decimal] = field(default_factory=list)
+    big_decimal_list_member: list[Decimal] = field(default_factory=list[Decimal])
     string_member: str | None = None
-    string_list_member: list[str] = field(default_factory=list)
+    string_list_member: list[str] = field(default_factory=list[str])
     default_timestamp_member: datetime.datetime | None = None
     http_date_timestamp_member: datetime.datetime | None = None
     http_date_list_timestamp_member: list[datetime.datetime] = field(
-        default_factory=list
+        default_factory=list[datetime.datetime]
     )
     date_time_timestamp_member: datetime.datetime | None = None
     date_time_list_timestamp_member: list[datetime.datetime] = field(
-        default_factory=list
+        default_factory=list[datetime.datetime]
     )
     epoch_timestamp_member: datetime.datetime | None = None
-    epoch_list_timestamp_member: list[datetime.datetime] = field(default_factory=list)
-    string_map_member: dict[str, str] = field(default_factory=dict)
+    epoch_list_timestamp_member: list[datetime.datetime] = field(
+        default_factory=list[datetime.datetime]
+    )
+    string_map_member: dict[str, str] = field(default_factory=dict[str, str])
 
     ID: ClassVar[ShapeID]
     SCHEMA: ClassVar[Schema]

pyproject.toml

@@ -10,7 +10,7 @@ dependencies = []
 dev = [
     "black>=25.1.0",
     "docformatter>=1.7.5",
-    "pyright>=1.1.396",
+    "pyright>=1.1.400",
     "pytest>=8.3.4",
     "pytest-asyncio>=0.25.3",
     "pytest-cov>=6.0.0",