Reduce duplication between StreamedRunResult and AgentStream (pydantic#2275)

Author: DouweM

pydantic_ai_slim/pydantic_ai/agent.py

@@ -36,7 +36,7 @@
 from .models.instrumented import InstrumentationSettings, InstrumentedModel, instrument_model
 from .output import OutputDataT, OutputSpec
 from .profiles import ModelProfile
-from .result import FinalResult, StreamedRunResult
+from .result import AgentStream, FinalResult, StreamedRunResult
 from .settings import ModelSettings, merge_model_settings
 from .tools import (
     AgentDepsT,
@@ -1127,29 +1127,15 @@ async def main():
             while True:
                 if self.is_model_request_node(node):
                     graph_ctx = agent_run.ctx
-                    async with node._stream(graph_ctx) as streamed_response:  # pyright: ignore[reportPrivateUsage]
-
-                        async def stream_to_final(
-                            s: models.StreamedResponse,
-                        ) -> FinalResult[models.StreamedResponse] | None:
-                            output_schema = graph_ctx.deps.output_schema
-                            async for maybe_part_event in streamed_response:
-                                if isinstance(maybe_part_event, _messages.PartStartEvent):
-                                    new_part = maybe_part_event.part
-                                    if isinstance(new_part, _messages.TextPart) and isinstance(
-                                        output_schema, _output.TextOutputSchema
-                                    ):
-                                        return FinalResult(s, None, None)
-                                    elif isinstance(new_part, _messages.ToolCallPart) and (
-                                        tool_def := graph_ctx.deps.tool_manager.get_tool_def(new_part.tool_name)
-                                    ):
-                                        if tool_def.kind == 'output':
-                                            return FinalResult(s, new_part.tool_name, new_part.tool_call_id)
-                                        elif tool_def.kind == 'deferred':
-                                            return FinalResult(s, None, None)
+                    async with node.stream(graph_ctx) as stream:
+
+                        async def stream_to_final(s: AgentStream) -> FinalResult[AgentStream] | None:
+                            async for event in stream:
+                                if isinstance(event, _messages.FinalResultEvent):
+                                    return FinalResult(s, event.tool_name, event.tool_call_id)
                             return None
 
-                        final_result = await stream_to_final(streamed_response)
+                        final_result = await stream_to_final(stream)
                         if final_result is not None:
                             if yielded:
                                 raise exceptions.AgentRunError('Agent run produced final results')  # pragma: no cover
@@ -1184,14 +1170,8 @@ async def on_complete() -> None:
                             yield StreamedRunResult(
                                 messages,
                                 graph_ctx.deps.new_message_index,
-                                graph_ctx.deps.usage_limits,
-                                streamed_response,
-                                graph_ctx.deps.output_schema,
-                                _agent_graph.build_run_context(graph_ctx),
-                                graph_ctx.deps.output_validators,
-                                final_result.tool_name,
+                                stream,
                                 on_complete,
-                                graph_ctx.deps.tool_manager,
                             )
                             break
                 next_node = await agent_run.next(node)