Revert "make memory serialization great again (#18621)"

This reverts commit 98aca7e.

Author: logan-markewich

llama-index-core/llama_index/core/agent/workflow/multi_agent_workflow.py

@@ -15,7 +15,6 @@
     AgentSetup,
     AgentOutput,
 )
-from llama_index.core.bridge.pydantic import model_serializer
 from llama_index.core.llms import ChatMessage, TextBlock
 from llama_index.core.llms.llm import LLM
 from llama_index.core.memory import BaseMemory, ChatMemoryBuffer
@@ -81,17 +80,6 @@ async def handoff(ctx: Context, to_agent: str, reason: str) -> str:
     return handoff_output_prompt.format(to_agent=to_agent, reason=reason)
 
 
-class AgentWorkflowStartEvent(StartEvent):
-
-    @model_serializer()
-    def serialize_start_event(self) -> dict:
-        """Serialize the start event and exclude the memory."""
-        return {
-            "user_msg": self.user_msg,
-            "chat_history": self.chat_history,
-        }
-
-
 class AgentWorkflowMeta(WorkflowMeta, ABCMeta):
     """Metaclass for AgentWorkflow that inherits from WorkflowMeta."""
 
@@ -304,7 +292,7 @@ async def _call_tool(
         return tool_output
 
     @step
-    async def init_run(self, ctx: Context, ev: AgentWorkflowStartEvent) -> AgentInput:
+    async def init_run(self, ctx: Context, ev: StartEvent) -> AgentInput:
         """Sets up the workflow and validates inputs."""
         await self._init_context(ctx, ev)
 
@@ -557,11 +545,9 @@ def run(
         **kwargs: Any,
     ) -> WorkflowHandler:
         return super().run(
-            start_event=AgentWorkflowStartEvent(
-                user_msg=user_msg,
-                chat_history=chat_history,
-                memory=memory,
-            ),
+            user_msg=user_msg,
+            chat_history=chat_history,
+            memory=memory,
             ctx=ctx,
             stepwise=stepwise,
             checkpoint_callback=checkpoint_callback,

llama-index-core/llama_index/core/workflow/context.py

@@ -39,12 +39,6 @@
 T = TypeVar("T", bound=Event)
 EventBuffer = Dict[str, List[Event]]
 
-# Only warn once about unserializable keys
-class UnserializableKeyWarning(Warning):
-    pass
-
-warnings.simplefilter("once", UnserializableKeyWarning)
-
 
 class Context:
     """
@@ -58,10 +52,6 @@ class Context:
     Both `set` and `get` operations on global data are governed by a lock, and considered coroutine-safe.
     """
 
-    # These keys are set by pre-built workflows and
-    # are known to be unserializable in some cases.
-    known_unserializable_keys = ("memory", )
-
     def __init__(
         self,
         workflow: "Workflow",
@@ -135,14 +125,6 @@ def _serialize_globals(self, serializer: BaseSerializer) -> Dict[str, Any]:
             try:
                 serialized_globals[key] = serializer.serialize(value)
             except Exception as e:
-                if key in self.known_unserializable_keys:
-                    # Skip serialization of known unserializable keys
-                    warnings.warn(
-                        f"Skipping serialization of known unserializable key: {key} -- "
-                        "This is expected but will require this item to be set manually after deserialization.",
-                        category=UnserializableKeyWarning,
-                    )
-                    continue
                 raise ValueError(f"Failed to serialize value for key {key}: {e}")
         return serialized_globals