feat: (WIP) Let developers more easily override SQL column type to JS…

…ON schema mapping

singer_sdk/typing.py

@@ -52,6 +52,7 @@
 
 from __future__ import annotations
 
+import functools
 import json
 import typing as t
 
@@ -1086,6 +1087,49 @@ def __iter__(self) -> t.Iterator[Property]:
         return self.wrapped.values().__iter__()
 
 
+@functools.singledispatch
+def _sa_type_to_jsonschema(sa_type: sa.types.TypeEngine) -> dict:  # noqa: ARG001
+    return StringType.type_dict  # type: ignore[no-any-return]
+
+
+@_sa_type_to_jsonschema.register
+def _sa_type_to_jsonschema_datetime(sa_type: sa.types.DateTime) -> dict:  # noqa: ARG001
+    return DateTimeType.type_dict  # type: ignore[no-any-return]
+
+
+@_sa_type_to_jsonschema.register
+def _sa_type_to_jsonschema_date(sa_type: sa.types.Date) -> dict:  # noqa: ARG001
+    return DateType.type_dict  # type: ignore[no-any-return]
+
+
+@_sa_type_to_jsonschema.register
+def _sa_type_to_jsonschema_integer(sa_type: sa.types.Integer) -> dict:  # noqa: ARG001
+    return IntegerType.type_dict  # type: ignore[no-any-return]
+
+
+@_sa_type_to_jsonschema.register
+def _sa_type_to_jsonschema_float(sa_type: sa.types.Numeric) -> dict:  # noqa: ARG001
+    return NumberType.type_dict  # type: ignore[no-any-return]
+
+
+@_sa_type_to_jsonschema.register
+def _sa_type_to_jsonschema_string(sa_type: sa.types.String) -> dict:  # noqa: ARG001
+    # TODO: Enable support for maxLength.
+    # if sa_type.length:
+    #     return StringType(max_length=sa_type.length).type_dict  # noqa: ERA001
+    return StringType.type_dict  # type: ignore[no-any-return]
+
+
+@_sa_type_to_jsonschema.register
+def _sa_type_to_jsonschema_boolean(sa_type: sa.types.Boolean) -> dict:  # noqa: ARG001
+    return BooleanType.type_dict  # type: ignore[no-any-return]
+
+
+@_sa_type_to_jsonschema.register
+def _sa_type_to_jsonschema_time(sa_type: sa.types.Variant) -> dict:  # noqa: ARG001
+    return TimeType.type_dict  # type: ignore[no-any-return]
+
+
 def to_jsonschema_type(
     from_type: str | sa.types.TypeEngine | type[sa.types.TypeEngine],
 ) -> dict:
@@ -1122,7 +1166,7 @@ def to_jsonschema_type(
     if isinstance(from_type, str):
         type_name = from_type
     elif isinstance(from_type, sa.types.TypeEngine):
-        type_name = type(from_type).__name__
+        return _sa_type_to_jsonschema(from_type)
     elif isinstance(from_type, type) and issubclass(
         from_type,
         sa.types.TypeEngine,