fix(policy_engine): resolve policies once and apply fallback semantics in get_matching_policies

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm/proxy/policy_engine/policy_matcher.py

@@ -114,7 +114,7 @@ class PolicyMatcher:
             verbose_proxy_logger.debug("AttachmentRegistry not initialized, returning empty list")
             return []
 
-        return registry.get_attached_policies(context)
+        return registry.get_attached_policies(context, PolicyMatcher.policy_applies(context))
 
     @staticmethod
     def get_matching_policies_from_registry(
@@ -137,14 +137,22 @@ class PolicyMatcher:
         policies: dict[str, Policy] | None = None,
     ) -> Callable[[str], bool]:
         """Predicate telling whether a policy exists and its condition matches the context."""
+        resolved: Final = policies if policies is not None else PolicyMatcher._registry_policies()
         return lambda policy_name: bool(
             PolicyMatcher.get_policies_with_matching_conditions(
                 policy_names=(policy_name,),
                 context=context,
-                policies=policies,
+                policies=resolved,
             )
         )
 
+    @staticmethod
+    def _registry_policies() -> dict[str, Policy]:
+        from litellm.proxy.policy_engine.policy_registry import get_policy_registry
+
+        registry: Final = get_policy_registry()
+        return registry.get_all_policies() if registry.is_initialized() else {}
+
     @staticmethod
     def get_policies_with_matching_conditions(
         policy_names: Sequence[str],
@@ -167,17 +175,12 @@ class PolicyMatcher:
             List of policy names whose conditions match the context
         """
         from litellm.proxy.policy_engine.condition_evaluator import ConditionEvaluator
-        from litellm.proxy.policy_engine.policy_registry import get_policy_registry
 
-        if policies is None:
-            registry: Final = get_policy_registry()
-            if not registry.is_initialized():
-                return []
-            policies = registry.get_all_policies()
+        resolved: Final = policies if policies is not None else PolicyMatcher._registry_policies()
 
         matching_policies: Final = []
         for policy_name in policy_names:
-            policy = policies.get(policy_name)
+            policy = resolved.get(policy_name)
             if policy is None:
                 continue
             # Policy matches if it has no condition OR condition evaluates to True

tests/test_litellm/proxy/policy_engine/test_policy_matcher.py

@@ -8,8 +8,11 @@ Tests:
 
 import pytest
 
+import litellm.proxy.policy_engine.attachment_registry as attachment_registry_module
+import litellm.proxy.policy_engine.policy_registry as policy_registry_module
 from litellm.proxy.policy_engine.attachment_registry import AttachmentRegistry
 from litellm.proxy.policy_engine.policy_matcher import PolicyMatcher
+from litellm.proxy.policy_engine.policy_registry import PolicyRegistry
 from litellm.types.proxy.policy_engine import (
     PolicyMatchContext,
     PolicyScope,
@@ -196,3 +199,48 @@ class TestPolicyMatcherWithAttachments:
         attached = registry.get_attached_policies(context)
 
         assert "healthcare-policy" not in attached
+
+
+def _global_registries(monkeypatch):
+    policies = PolicyRegistry()
+    policies.load_policies(
+        {
+            "guardrail-y": {"guardrails": {"add": ["y"]}},
+            "guardrail-x": {"guardrails": {"add": ["x"]}, "condition": {"model": "claude.*"}},
+        }
+    )
+    attachments = AttachmentRegistry()
+    attachments.load_attachments(
+        [
+            {"policy": "guardrail-x", "tags": ["opt-in"]},
+            {"policy": "guardrail-y", "scope": "*", "default": True},
+        ]
+    )
+    monkeypatch.setattr(policy_registry_module, "get_policy_registry", lambda: policies)
+    monkeypatch.setattr(attachment_registry_module, "get_attachment_registry", lambda: attachments)
+    return policies
+
+
+class TestGetMatchingPoliciesFallback:
+    def test_condition_failing_opt_in_falls_back_to_default(self, monkeypatch):
+        _global_registries(monkeypatch)
+        context = PolicyMatchContext(team_alias="t", key_alias="k", model="gpt-5.5", tags=["opt-in"])
+
+        assert PolicyMatcher.get_matching_policies(context=context) == ["guardrail-y"]
+
+    def test_condition_passing_opt_in_suppresses_default(self, monkeypatch):
+        _global_registries(monkeypatch)
+        context = PolicyMatchContext(team_alias="t", key_alias="k", model="claude-haiku", tags=["opt-in"])
+
+        assert PolicyMatcher.get_matching_policies(context=context) == ["guardrail-x"]
+
+    def test_policy_applies_reads_registry_once(self, monkeypatch):
+        policies = _global_registries(monkeypatch)
+        calls = []
+        original = policies.get_all_policies
+        monkeypatch.setattr(policies, "get_all_policies", lambda: calls.append(1) or original())
+        context = PolicyMatchContext(team_alias="t", key_alias="k", model="gpt-5.5", tags=["opt-in"])
+
+        PolicyMatcher.get_matching_policies(context=context)
+
+        assert len(calls) == 1