From 1db0e31652518358618ca289c3008ff7130a8f98 Mon Sep 17 00:00:00 2001
From: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
Date: Tue, 23 Jun 2026 15:24:53 +0000
Subject: [PATCH] fix(typing): bring reportReturnType back under the
 basedpyright budget

completion()'s async/batch dispatch paths return a coroutine (MCP, responses
bridge), a list (batch_completion_models), or the untyped fallback runner's
result, none of which match its declared Union[ModelResponse,
CustomStreamWrapper]. The #30813 dispatch refactor made basedpyright able to
analyze these paths and surfaced four reportReturnType errors, pushing the
codebase total to 143 against the committed ceiling of 139.

Suppress exactly those four sites with coded, reasoned pyright ignores (the
repo sets enableTypeIgnoreComments=false, so the pre-existing
type: ignore[return-value] on the MCP path was dead). Widening completion()'s
return type would ripple across thousands of call sites and is out of scope.
---
 litellm/main.py | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/litellm/main.py b/litellm/main.py
index 1d75766c7e6b..4fade2ac4b09 100644
--- a/litellm/main.py
+++ b/litellm/main.py
@@ -5044,9 +5044,7 @@ def completion(  # type: ignore
         if LiteLLM_Proxy_MCP_Handler._should_use_litellm_mcp_gateway(
             tools=tools_for_mcp
         ):
-            # Return coroutine - acompletion will await it
-            # completion() can return a coroutine when MCP tools are present, which acompletion() awaits
-            return acompletion_with_mcp(  # type: ignore[return-value]
+            return acompletion_with_mcp(  # pyright: ignore[reportReturnType]  # MCP path returns a coroutine that acompletion() awaits; completion()'s sync return type omits it
                 model=model,
                 messages=messages,
                 functions=functions,
@@ -5218,12 +5216,16 @@ def completion(  # type: ignore
         logging: LiteLLMLoggingObj = cast(LiteLLMLoggingObj, litellm_logging_obj)
         fallbacks = fallbacks or litellm.model_fallbacks
         if fallbacks is not None:
-            return completion_with_fallbacks(**args)
+            return completion_with_fallbacks(  # pyright: ignore[reportReturnType]  # fallback runner is untyped; resolves to ModelResponse|CustomStreamWrapper at runtime
+                **args
+            )
         if model_list is not None:
             deployments = [
                 m["litellm_params"] for m in model_list if m["model_name"] == model
             ]
-            return litellm.batch_completion_models(deployments=deployments, **args)
+            return litellm.batch_completion_models(  # pyright: ignore[reportReturnType]  # batch path returns a list of responses, outside completion()'s single-response return type
+                deployments=deployments, **args
+            )
         if litellm.model_alias_map and model in litellm.model_alias_map:
             model = litellm.model_alias_map[
                 model
@@ -5545,7 +5547,7 @@ def completion(  # type: ignore
                 else:
                     optional_params["reasoning_effort"] = {"summary": rs_val}
 
-            return responses_api_bridge.completion(
+            return responses_api_bridge.completion(  # pyright: ignore[reportReturnType]  # bridge returns a coroutine on the acompletion path; awaited by the async caller
                 model=model,
                 messages=messages,
                 headers=headers,