fix fallbacks dont recurse on the same fallback

litellm/tests/test_router_fallbacks.py

@@ -1185,3 +1185,49 @@ async def test_router_content_policy_fallbacks(
         )
 
     assert response.model == "my-fake-model"
+
+
+@pytest.mark.parametrize("sync_mode", [False])
+@pytest.mark.asyncio
+async def test_using_default_fallback(sync_mode):
+    """
+    Tests Client Side Fallbacks
+
+    User can pass "fallbacks": ["gpt-3.5-turbo"] and this should work
+
+    """
+    litellm.set_verbose = True
+
+    import logging
+
+    from litellm._logging import verbose_logger, verbose_router_logger
+
+    verbose_logger.setLevel(logging.DEBUG)
+    verbose_router_logger.setLevel(logging.DEBUG)
+    litellm.default_fallbacks = ["very-bad-model"]
+    router = Router(
+        model_list=[
+            {
+                "model_name": "openai/*",
+                "litellm_params": {
+                    "model": "openai/*",
+                    "api_key": os.getenv("OPENAI_API_KEY"),
+                },
+            },
+        ],
+    )
+    try:
+        if sync_mode:
+            response = router.completion(
+                model="openai/foo",
+                messages=[{"role": "user", "content": "Hey, how's it going?"}],
+            )
+        else:
+            response = await router.acompletion(
+                model="openai/foo",
+                messages=[{"role": "user", "content": "Hey, how's it going?"}],
+            )
+        print("got response=", response)
+        pytest.fail(f"Expected call to fail we passed model=openai/foo")
+    except Exception as e:
+        print("got exception = ", e)