chore: improve typing for select_streaming_callback (#2008)

Author: anakin87

integrations/amazon_bedrock/src/haystack_integrations/components/generators/amazon_bedrock/chat/chat_generator.py

@@ -371,7 +371,9 @@ def _prepare_request_params(
         if additional_fields:
             params["additionalModelRequestFields"] = additional_fields
 
-        callback = select_streaming_callback(
+        # overloads that exhaust finite Literals(bool) not treated as exhaustive
+        # see https://github.com/python/mypy/issues/14764
+        callback = select_streaming_callback(  # type: ignore[call-overload]
             init_callback=self.streaming_callback,
             runtime_callback=streaming_callback,
             requires_async=requires_async,

integrations/anthropic/src/haystack_integrations/components/generators/anthropic/chat/chat_generator.py

@@ -633,8 +633,7 @@ def run(
             **generation_kwargs,
         )
 
-        # select_streaming_callback returns a StreamingCallbackT, but we know it's SyncStreamingCallbackT
-        return self._process_response(response=response, streaming_callback=streaming_callback)  # type: ignore[arg-type]
+        return self._process_response(response=response, streaming_callback=streaming_callback)
 
     @component.output_types(replies=List[ChatMessage])
     async def run_async(
@@ -675,5 +674,4 @@ async def run_async(
             **generation_kwargs,
         )
 
-        # select_streaming_callback returns a StreamingCallbackT, but we know it's AsyncStreamingCallbackT
-        return await self._process_response_async(response, streaming_callback)  # type: ignore[arg-type]
+        return await self._process_response_async(response, streaming_callback)

integrations/cohere/src/haystack_integrations/components/generators/cohere/chat/chat_generator.py

@@ -528,11 +528,10 @@ def run(
                 messages=formatted_messages,
                 **generation_kwargs,
             )
-            # we know that streaming_callback is sync but mypy doesn't
             chat_message = _parse_streaming_response(
                 response=streamed_response,
                 model=self.model,
-                streaming_callback=streaming_callback,  # type: ignore[arg-type]
+                streaming_callback=streaming_callback,
             )
         else:
             response = self.client.chat(
@@ -590,11 +589,10 @@ async def run_async(
                 messages=formatted_messages,
                 **generation_kwargs,
             )
-            # we know that streaming_callback is async but mypy doesn't
             chat_message = await _parse_async_streaming_response(
                 response=streamed_response,
                 model=self.model,
-                streaming_callback=streaming_callback,  # type: ignore[arg-type]
+                streaming_callback=streaming_callback,
             )
         else:
             response = await self.async_client.chat(