Fix user-defined model serialization

Signed-off-by: Jacob Hayes <[email protected]>

src/hera/shared/_pydantic.py

@@ -23,6 +23,7 @@
 __all__ = [
     "BaseModel",
     "Field",
+    "PydanticBaseModel",  # Export for serialization.py to cover user-defined models
     "root_validator",
     "validate_arguments",
     "validator",

src/hera/shared/serialization.py

@@ -3,13 +3,17 @@
 from json import JSONEncoder
 from typing import Any, Optional
 
-from hera.shared._pydantic import BaseModel
+# NOTE: Use the original BaseModel in order to support serializing user-defined models,
+# which won't use our hera.shared._pydantic import. This does still require that the
+# user-defined models are using v1 pydantic models for now (either from a pydantic v1
+# installation or `pydantic.v1` import from a pydantic v2 installation).
+from hera.shared._pydantic import PydanticBaseModel
 
 MISSING = object()
-"""`MISSING` is a placeholder that indicates field value nullity. 
+"""`MISSING` is a placeholder that indicates field value nullity.
 
 When the user of a Hera object sets the field of an object specifically to `None`, Hera needs to distinguish between
-default nullity/None and user-provided `None` on, say, something like the `source` of `Script`.  
+default nullity/None and user-provided `None` on, say, something like the `source` of `Script`.
 """
 
 
@@ -18,7 +22,7 @@ class PydanticEncoder(JSONEncoder):
 
     def default(self, o: Any):
         """Return the default representation of the given object."""
-        if isinstance(o, BaseModel):
+        if isinstance(o, PydanticBaseModel):
             return o.dict(by_alias=True)
         return super().default(o)