From c064e576ee31ed05b067462412c6c234d364c8fd Mon Sep 17 00:00:00 2001
From: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Date: Thu, 10 Sep 2026 17:29:20 +0000
Subject: [PATCH] fix(proxy): tolerate missing router_settings and non-list
 fallbacks in fallback resolution

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
---
 litellm/proxy/common_request_processing.py                 | 4 ++--
 tests/test_litellm/proxy/test_common_request_processing.py | 4 +++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/litellm/proxy/common_request_processing.py b/litellm/proxy/common_request_processing.py
index 255bf3ebda2..9927320d795 100644
--- a/litellm/proxy/common_request_processing.py
+++ b/litellm/proxy/common_request_processing.py
@@ -2121,14 +2121,14 @@ class ProxyBaseLLMRequestProcessing:
 
         fallbacks = None
 
-        key_router_settings: Final = user_api_key_dict.router_settings
+        key_router_settings: Final = getattr(user_api_key_dict, "router_settings", None)
         if isinstance(key_router_settings, dict) and "fallbacks" in key_router_settings:
             fallbacks = key_router_settings["fallbacks"]
 
         if fallbacks is None:
             fallbacks = llm_router.fallbacks
 
-        if not fallbacks:
+        if not isinstance(fallbacks, list) or not fallbacks:
             return None
 
         fallback_model_group, generic_fallback_idx = get_fallback_model_group(
diff --git a/tests/test_litellm/proxy/test_common_request_processing.py b/tests/test_litellm/proxy/test_common_request_processing.py
index 89e0799ba16..4beb73b3a81 100644
--- a/tests/test_litellm/proxy/test_common_request_processing.py
+++ b/tests/test_litellm/proxy/test_common_request_processing.py
@@ -6449,7 +6449,9 @@ class TestPreCallWithFallbacksOnLocalRateLimit:
         mock_router = MagicMock()
         mock_router.fallbacks = None
 
-        with patch("litellm.proxy.common_request_processing.independent_snapshot") as snapshot_mock:
+        with patch(  # test-quality-ok: spying the snapshot seam is the only observable check that the no-fallback path skips it
+            "litellm.proxy.common_request_processing.independent_snapshot"
+        ) as snapshot_mock:
             with patch.object(
                 processor,
                 "common_processing_pre_call_logic",