From 5feb6008d89043cc555da9cb844e84497be83597 Mon Sep 17 00:00:00 2001
From: Sameer Kankute <sameer@berri.ai>
Date: Fri, 1 May 2026 17:56:37 +0530
Subject: [PATCH] Fix greptile review

---
 litellm/router.py                 |  6 ++-
 tests/test_litellm/test_router.py | 72 +++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/litellm/router.py b/litellm/router.py
index 7a2e4fc996b..0020f2fbe18 100644
--- a/litellm/router.py
+++ b/litellm/router.py
@@ -9400,6 +9400,7 @@ class Router:
         healthy_deployments = self._get_all_deployments(
             model_name=model, team_id=request_team_id
         )
+        _pre_model_access_group_filter_len = len(healthy_deployments)
         healthy_deployments = self._filter_deployments_by_model_access_groups(
             model=model,
             healthy_deployments=healthy_deployments,
@@ -9409,7 +9410,10 @@ class Router:
 
         if len(healthy_deployments) == 0:
             # check if the user sent in a deployment name instead
-            healthy_deployments = self._get_deployment_by_litellm_model(model=model)
+            # Do not fall back when access-group filtering removed every candidate;
+            # _get_deployment_by_litellm_model does not re-apply that filter.
+            if _pre_model_access_group_filter_len == 0:
+                healthy_deployments = self._get_deployment_by_litellm_model(model=model)
 
         if verbose_router_logger.isEnabledFor(logging.DEBUG):
             verbose_router_logger.debug(
diff --git a/tests/test_litellm/test_router.py b/tests/test_litellm/test_router.py
index af8633361ac..e62a650d999 100644
--- a/tests/test_litellm/test_router.py
+++ b/tests/test_litellm/test_router.py
@@ -3319,3 +3319,75 @@ def test_explicit_model_access_does_not_force_access_group_filtering():
     deployment_groups = [d.get("model_info", {}).get("access_groups") for d in deployments]
     assert ["AG1"] in deployment_groups
     assert ["AG2"] in deployment_groups
+
+
+def test_access_group_filter_empty_does_not_bypass_via_litellm_model_fallback(
+    monkeypatch: pytest.MonkeyPatch,
+):
+    """
+    When access-group filtering removes all candidates, _get_deployment_by_litellm_model
+    must not run: it does not re-apply access groups and could return blocked deployments
+    that share the same litellm_params.model as the request model string.
+
+    ``get_model_access_groups`` is patched to expose AG1 for the public model (so the
+    access-group filter runs with a non-empty allowed set) while every deployment
+    returned for that name is AG2-only — filtered to empty. Without the guard, the
+    litellm-model fallback would return both rows because ``litellm_params.model`` matches.
+    """
+    from litellm.proxy._types import UserAPIKeyAuth
+
+    router = litellm.Router(
+        model_list=[
+            {
+                "model_name": "gpt-5",
+                "litellm_params": {
+                    "model": "gpt-5",
+                    "api_key": "key1",
+                    "mock_response": "blocked-dep-1",
+                },
+                "model_info": {"access_groups": ["AG2"]},
+            },
+            {
+                "model_name": "gpt-5",
+                "litellm_params": {
+                    "model": "gpt-5",
+                    "api_key": "key2",
+                    "mock_response": "blocked-dep-2",
+                },
+                "model_info": {"access_groups": ["AG2"]},
+            },
+        ]
+    )
+
+    orig_groups = router.get_model_access_groups
+
+    def fake_get_model_access_groups(
+        model_name=None, model_access_group=None, team_id=None
+    ):
+        if model_name == "gpt-5" and model_access_group is None:
+            return {"AG1": ["gpt-5"], "AG2": ["gpt-5"]}
+        return orig_groups(
+            model_name=model_name,
+            model_access_group=model_access_group,
+            team_id=team_id,
+        )
+
+    monkeypatch.setattr(router, "get_model_access_groups", fake_get_model_access_groups)
+
+    scoped_key = UserAPIKeyAuth(
+        api_key="hashed-key",
+        team_id="team2",
+        models=["AG1"],
+        team_models=["AG1"],
+    )
+
+    with pytest.raises(litellm.BadRequestError):
+        router._common_checks_available_deployment(
+            model="gpt-5",
+            request_kwargs={
+                "metadata": {
+                    "user_api_key_team_id": "team2",
+                    "user_api_key_auth": scoped_key,
+                }
+            },
+        )