Python: [Bug]: Injected Redis context indexes cannot encode optional null message fields #9067

Description

RedisContextProvider.after_run() cannot write an ordinary message through an injected AsyncSearchIndex with RedisVL's default validate_on_load=False. The provider prepares optional fields such as message_id, author_name, and unset scope IDs as None; Redis HASH command encoding rejects these values before the message can be written.

The provider-created index enables validation and RedisVL already removes null fields on that path. The injected-index path should omit the same null fields, while preserving configured scopes, caller-supplied IDs, and non-null values.

I am taking on a small fix that omits null values from the prepared copies immediately before load(), after embedding generation, with SDK-chain regressions.

Code Sample

The following illustrates the public hook with an injected index; running it against a service requires Redis with Search support and a new index name.

import asyncio
from uuid import uuid4
from unittest.mock import MagicMock

import redis.asyncio as redis
from agent_framework import AgentSession, Message, SessionContext
from agent_framework_redis import RedisContextProvider
from redisvl.index import AsyncSearchIndex

async def main():
    name = f"context-null-repro-{uuid4().hex}"
    client = redis.Redis.from_url("redis://localhost:6379", decode_responses=False)
    template = RedisContextProvider(user_id="user-1", index_name=name, prefix=name)
    index = AsyncSearchIndex.from_dict(template.schema_dict, redis_client=client)
    provider = RedisContextProvider(
        redis_index=index, user_id="user-1", index_name=name, prefix=name
    )
    session = AgentSession(session_id="session-1")
    context = SessionContext(
        session_id=session.session_id,
        input_messages=[Message(role="user", contents=["Remember tea"])],
    )
    try:
        await provider.after_run(
            agent=MagicMock(), session=session, context=context, state={}
        )
    finally:
        await client.aclose()

asyncio.run(main())

Error Messages / Stack Traces

RedisVLError: Failed to load data: Invalid input of type: 'NoneType'.
Convert to a bytes, string, int or float first.

Package Versions

Official main 2df61296bb563a95552b18491ad29b1e1a509f81: agent-framework-core 1.20.0 and agent-framework-redis 1.0.0b261002 source; RedisVL 0.15.0 and redis-py 7.1.1.

Python Version

Python 3.14.3 on Windows.

Additional Context

The failure was verified offline through the actual RedisVL load() / HashStorage / redis-py pipeline and Encoder chain, with index existence/creation and network transport stubbed. No live Redis server, authentication, or model service was tested. The public hook also fails with all application/agent/user scopes configured, because a normal message can still have no message ID or author. Fully populated non-null records are successful controls.

This is separate from #9062/#9063: the reproduction uses a new index and never enters existing-index schema validation. The generic RedisCollection HASH null-rejection contract is also unaffected.