[chore] Remove type:ignore for field renames (#150)

Why
===

We had one overly-broad `# type: ignore` due to using the old-style of
pydantic field renaming. Switching to PEP593-`Annotated` types, we can
communicate the alias as well as the default value correctly.

What changed
============

Simplified codegen
Added tests

Test plan
=========

CI

Author: blast-hardcheese

src/replit_river/codegen/client.py

@@ -646,42 +646,24 @@ def extract_props(tpe: RiverType) -> list[dict[str, RiverType]]:
                         case LiteralTypeExpr(literal_value):
                             field_value = repr(literal_value)
                     if name not in type.required:
+                        type_name = UnionTypeExpr(
+                            [
+                                type_name,
+                                NoneTypeExpr(),
+                            ]
+                        )
                         value = ""
                         if base_model != "TypedDict":
-                            value = dedent(
-                                f"""\
-                                = Field(
-                                  default=None,
-                                  alias={repr(name)}, # type: ignore
-                                )
-                                """
-                            )
-                        current_chunks.append(
-                            f"  kind: {
-                                render_type_expr(
-                                    UnionTypeExpr(
-                                        [
-                                            type_name,
-                                            NoneTypeExpr(),
-                                        ]
-                                    )
-                                )
-                            }{value}"
-                        )
+                            value = f"= {repr(None)}"
                     else:
                         value = ""
                         if base_model != "TypedDict":
-                            value = dedent(
-                                f"""\
-                                = Field(
-                                    {field_value},
-                                    alias={repr(name)}, # type: ignore
-                                )
-                                """
-                            )
-                        current_chunks.append(
-                            f"  kind: {render_type_expr(type_name)}{value}"
-                        )
+                            value = f"= {field_value}"
+                    current_chunks.append(
+                        f"  kind: Annotated[{render_type_expr(type_name)}, Field(alias={
+                            repr(name)
+                        })]{value}"
+                    )
                 else:
                     if name not in type.required:
                         if base_model == "TypedDict":

tests/codegen/snapshot/snapshots/test_unknown_enum/enumService/needsEnumObject.py

@@ -38,7 +38,7 @@ def encode_NeedsenumobjectInputOneOf_in_first(
 
 
 class NeedsenumobjectInputOneOf_in_first(TypedDict):
-    kind: Literal["in_first"]
+    kind: Annotated[Literal["in_first"], Field(alias="$kind")]
     value: str
 
 
@@ -58,7 +58,7 @@ def encode_NeedsenumobjectInputOneOf_in_second(
 
 
 class NeedsenumobjectInputOneOf_in_second(TypedDict):
-    kind: Literal["in_second"]
+    kind: Annotated[Literal["in_second"], Field(alias="$kind")]
     bleep: int
 
 
@@ -83,20 +83,12 @@ def encode_NeedsenumobjectInput(
 
 
 class NeedsenumobjectOutputFooOneOf_out_first(BaseModel):
-    kind: Literal["out_first"] = Field(
-        "out_first",
-        alias="$kind",  # type: ignore
-    )
-
+    kind: Annotated[Literal["out_first"], Field(alias="$kind")] = "out_first"
     foo: int
 
 
 class NeedsenumobjectOutputFooOneOf_out_second(BaseModel):
-    kind: Literal["out_second"] = Field(
-        "out_second",
-        alias="$kind",  # type: ignore
-    )
-
+    kind: Annotated[Literal["out_second"], Field(alias="$kind")] = "out_second"
     bar: int
 
 

tests/codegen/snapshot/test_enum.py

@@ -1,4 +1,5 @@
 import importlib
+import json
 from io import StringIO
 
 from pytest_snapshot.plugin import Snapshot
@@ -203,3 +204,46 @@ def test_unknown_enum(snapshot: Snapshot) -> None:
         x = NeedsenumErrorsTypeAdapter.validate_python(error)
         assert x.code == error["code"]
         assert x.message == error["message"]
+
+
+def test_unknown_enum_field_aliases(snapshot: Snapshot) -> None:
+    validate_codegen(
+        snapshot=snapshot,
+        read_schema=lambda: StringIO(test_unknown_enum_schema),
+        target_path="test_unknown_enum",
+        client_name="foo",
+    )
+
+    import tests.codegen.snapshot.snapshots.test_unknown_enum
+
+    importlib.reload(tests.codegen.snapshot.snapshots.test_unknown_enum)
+    from tests.codegen.snapshot.snapshots.test_unknown_enum.enumService.needsEnumObject import (  # noqa
+        NeedsenumobjectOutputTypeAdapter,
+        NeedsenumobjectOutput,
+        NeedsenumobjectOutputFooOneOf_out_first,
+    )
+
+    initial = NeedsenumobjectOutput(foo=NeedsenumobjectOutputFooOneOf_out_first(foo=5))
+    result = NeedsenumobjectOutputTypeAdapter.dump_json(
+        initial,
+        by_alias=True,
+    )
+
+    obj = json.loads(result)
+
+    # Make sure we are testing what we think we are testing
+    assert "foo" in obj
+
+    # We must not include the un-aliased field name
+    assert "kind" not in obj["foo"]
+
+    # We must include the aliased field name
+    assert "$kind" in obj["foo"]
+
+    # ... and finally that the values are what we think they should be
+    assert obj["foo"]["$kind"] == "out_first"
+    assert obj["foo"]["foo"] == 5
+
+    # And one more sanity check for the decoder
+    decoded = NeedsenumobjectOutputTypeAdapter.validate_json(result)
+    assert decoded == initial