make error type and translate function dynamic

Author: airportyh

src/replit_river/codegen/client.py

@@ -93,7 +93,8 @@
 
 from pydantic import BaseModel, Field, TypeAdapter, WrapValidator
 from replit_river.error_schema import RiverError
-from replit_river.client import RiverUnknownError, translate_unknown_error
+from replit_river.client import RiverUnknownError, translate_unknown_error, \
+    RiverUnknownValue, translate_unknown_value
 
 import replit_river as river
 
@@ -168,6 +169,17 @@ def encode_type(
     in_module: list[ModuleName],
     permit_unknown_members: bool,
 ) -> Tuple[TypeExpression, list[ModuleName], list[FileContents], set[TypeName]]:
+    def _make_open_union_type_expr(one_of: list[TypeExpression]) -> OpenUnionTypeExpr:
+        return OpenUnionTypeExpr(
+            UnionTypeExpr(one_of),
+            fallback_type="RiverUnknownError"
+                if base_model == "RiverError"
+                else "RiverUnknownValue",
+            validator_function="translate_unknown_error"
+                if base_model == "RiverError"
+                else "translate_unknown_value",
+        )
+
     encoder_name: TypeName | None = None  # defining this up here to placate mypy
     chunks: List[FileContents] = []
     if isinstance(type, RiverNotType):
@@ -318,7 +330,7 @@ def flatten_union(tpe: RiverType) -> list[RiverType]:
                     )
                 union: TypeExpression
                 if permit_unknown_members:
-                    union = OpenUnionTypeExpr(UnionTypeExpr(one_of))
+                    union = _make_open_union_type_expr(one_of)
                 else:
                     union = UnionTypeExpr(one_of)
                 chunks.append(
@@ -392,7 +404,7 @@ def flatten_union(tpe: RiverType) -> list[RiverType]:
                             )
                             raise ValueError(f"What does it mean to have {_o2} here?")
         if permit_unknown_members:
-            union = OpenUnionTypeExpr(UnionTypeExpr(any_of))
+            union = _make_open_union_type_expr(any_of)
         else:
             union = UnionTypeExpr(any_of)
         if is_literal(type):

src/replit_river/codegen/typing.py

@@ -58,6 +58,8 @@ def __str__(self) -> str:
 @dataclass(frozen=True)
 class OpenUnionTypeExpr:
     union: UnionTypeExpr
+    fallback_type: str
+    validator_function: str
 
     def __str__(self) -> str:
         raise Exception("Complex type must be put through render_type_expr!")
@@ -87,8 +89,8 @@ def render_type_expr(value: TypeExpression) -> str:
         case OpenUnionTypeExpr(inner):
             return (
                 "Annotated["
-                f"{render_type_expr(inner)} | RiverUnknownError,"
-                "WrapValidator(translate_unknown_error)"
+                f"{render_type_expr(inner)} | {value.fallback_type},"
+                f"WrapValidator({value.validator_function})"
                 "]"
             )
         case TypeName(name):