fix(rust-bridge): share provider resolution across route dispatch and execution

litellm/messages/dispatch.py

@@ -3,12 +3,10 @@ from collections.abc import AsyncIterator, Awaitable, Callable, Coroutine, Itera
 from types import MappingProxyType
 from typing import Final, TypeAlias, cast  # noqa: TID251  # native binding selects a sync result or an async awaitable
 
-from litellm.exceptions import BadRequestError
-from litellm.litellm_core_utils.get_llm_provider_logic import get_llm_provider
 from litellm.llms.anthropic.pass_through.messages import handler as main
 from litellm.llms.anthropic.pass_through.messages.interceptors import get_messages_interceptors
 from litellm.llms.anthropic.pass_through.safeguards import native_route_classifies
-from litellm.rust_bridge import detectors
+from litellm.rust_bridge import detectors, provider
 from litellm.rust_bridge.catalog import Feature, Route, RouteContext, Target
 from litellm.rust_bridge.dispatch import PublicDispatch
 from litellm.rust_bridge.messages.entrypoints import (
@@ -23,7 +21,6 @@ from litellm.rust_bridge.public_call import (
     native_call_hook,
     optional_mapping,
     optional_sequence,
-    optional_str,
     signature,
 )
 from litellm.types.llms.anthropic_messages.anthropic_response import AnthropicMessagesResponse
@@ -77,16 +74,6 @@ def _public_request(
     return native_call(legacy, args, _native_kwargs(fields, kwargs))
 
 
-def _resolved(request: NativeCall) -> tuple[str, str | None]:
-    model: Final = str(request.resolved["model"])
-    provider: Final = optional_str(request.resolved.get("custom_llm_provider"))
-    try:
-        resolved_model, resolved_provider, _, _ = get_llm_provider(model, provider)
-    except BadRequestError:
-        return model, provider
-    return resolved_model, resolved_provider
-
-
 def _target(request: NativeCall, model: str, provider: str | None) -> Target:
     requested_model: Final = str(request.resolved["model"])
     model_info: Final = request.resolved.get("model_info")
@@ -102,12 +89,11 @@ def _target(request: NativeCall, model: str, provider: str | None) -> Target:
     return Target.CHAT_COMPLETIONS
 
 
-def _intercepted(request: NativeCall) -> bool:
+def _intercepted(request: NativeCall, provider: str | None) -> bool:
     tools: Final = optional_sequence(request.resolved.get("tools"))
     if not tools:
         return False
     mappings: Final = tuple(mapping for mapping in map(optional_mapping, tools) if mapping is not None)
-    provider: Final = _resolved(request)[1]
     return any(interceptor.can_handle(mappings, provider) for interceptor in get_messages_interceptors())
 
 
@@ -131,33 +117,47 @@ _ASYNC_FEATURES: Final[detectors.Detectors] = MappingProxyType(
         **_FEATURES,
         Feature.PRE_REQUEST_HOOK: detectors.pre_request_hook,
         Feature.WEBSEARCH_INTERCEPTION: detectors.websearch_interception,
-        Feature.MESSAGES_INTERCEPTOR: _intercepted,
     }
 )
 
 
-def _context(request: NativeCall, features: detectors.Detectors) -> RouteContext:
+def _features(
+    request: NativeCall, provider: str | None, features: detectors.Detectors, intercepting: bool
+) -> frozenset[Feature]:
+    detected: Final = detectors.detected(features, request)
+    if not intercepting or not _intercepted(request, provider):
+        return detected
+    return detected | {Feature.MESSAGES_INTERCEPTOR}
+
+
+def _context(request: NativeCall, features: detectors.Detectors, intercepting: bool) -> RouteContext:
     requested_model: Final = str(request.resolved["model"])
-    model, provider = _resolved(request)
-    return RouteContext(
-        Route.MESSAGES,
-        provider=provider,
-        model=requested_model,
-        target=_target(request, model, provider),
-        features=detectors.detected(features, request),
-    )
+    resolution: Final = provider.resolve(request)
+    match resolution:
+        case provider.Resolved(model=resolved_model, provider=resolved_provider):
+            return RouteContext(
+                Route.MESSAGES,
+                provider=resolved_provider,
+                model=requested_model,
+                target=_target(request, resolved_model, resolved_provider),
+                features=_features(request, resolved_provider, features, intercepting),
+            )
+        case provider.Unresolved():
+            return RouteContext(
+                Route.MESSAGES, model=requested_model, features=_features(request, None, features, intercepting)
+            )
 
 
 _DISPATCH: Final = PublicDispatch(
     route=Route.MESSAGES,
     request=lambda args, kwargs: _public_request(_MESSAGES, args, kwargs),
-    context=lambda request: _context(request, _FEATURES),
+    context=lambda request: _context(request, _FEATURES, intercepting=False),
 )
 
 _ADISPATCH: Final = PublicDispatch(
     route=Route.MESSAGES,
     request=lambda args, kwargs: _public_request(_AMESSAGES, args, kwargs),
-    context=lambda request: _context(request, _ASYNC_FEATURES),
+    context=lambda request: _context(request, _ASYNC_FEATURES, intercepting=True),
 )
 
 

litellm/responses/dispatch.py

@@ -3,11 +3,9 @@ from collections.abc import Awaitable, Callable, Coroutine, Mapping
 from types import MappingProxyType
 from typing import Final, TypeAlias, cast  # noqa: TID251  # native binding selects a sync result or an async awaitable
 
-from litellm.exceptions import BadRequestError
-from litellm.litellm_core_utils.get_llm_provider_logic import get_llm_provider
 from litellm.responses import main
 from litellm.responses.streaming_iterator import BaseResponsesAPIStreamingIterator
-from litellm.rust_bridge import detectors
+from litellm.rust_bridge import detectors, provider
 from litellm.rust_bridge.catalog import Feature, Route, RouteContext
 from litellm.rust_bridge.dispatch import PublicDispatch
 from litellm.rust_bridge.public_call import (
@@ -16,7 +14,6 @@ from litellm.rust_bridge.public_call import (
     bind,
     native_call,
     native_call_hook,
-    optional_str,
     signature,
 )
 from litellm.rust_bridge.responses.entrypoints import (
@@ -65,14 +62,6 @@ def _public_request(
     return native_call(legacy, args, kwargs)
 
 
-def _provider(request: NativeCall) -> str | None:
-    provider: Final = optional_str(request.resolved.get("custom_llm_provider"))
-    try:
-        return get_llm_provider(str(request.resolved["model"]), provider)[1]
-    except BadRequestError:
-        return provider
-
-
 _FEATURES: Final[detectors.Detectors] = MappingProxyType(
     {
         **detectors.COMMON,
@@ -105,9 +94,10 @@ _SYNC_FEATURES: Final[detectors.Detectors] = MappingProxyType(
 
 
 def _context(request: NativeCall, features: detectors.Detectors) -> RouteContext:
+    resolution: Final = provider.resolve(request)
     return RouteContext(
         Route.RESPONSES,
-        provider=_provider(request),
+        provider=resolution.provider if isinstance(resolution, provider.Resolved) else None,
         model=str(request.resolved["model"]),
         features=detectors.detected(features, request),
     )

litellm/rust_bridge/provider.py

@@ -0,0 +1,60 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from types import MappingProxyType
+from typing import Final, TypeAlias
+
+from litellm.exceptions import BadRequestError
+from litellm.litellm_core_utils.get_llm_provider_logic import get_llm_provider
+from litellm.rust_bridge.public_call import NativeCall, optional_str
+from litellm.types.router import GenericLiteLLMParams
+
+__all__ = ("Resolution", "Resolved", "Unresolved", "resolve")
+
+_HANDLER_FIELDS: Final = frozenset({"api_base", "api_key", "custom_llm_provider"})
+
+
+@dataclass(frozen=True, slots=True)
+class Resolved:
+    model: str
+    provider: str
+
+
+@dataclass(frozen=True, slots=True)
+class Unresolved:
+    pass
+
+
+Resolution: TypeAlias = Resolved | Unresolved
+
+
+def resolve(request: NativeCall) -> Resolution:
+    resolved: Final = request.resolved
+    model: Final = str(resolved["model"])
+    custom_llm_provider: Final = optional_str(resolved.get("custom_llm_provider"))
+    api_base: Final = optional_str(resolved.get("api_base"))
+    api_key: Final = optional_str(resolved.get("api_key"))
+    extra: Final = MappingProxyType(
+        {
+            name: value
+            for name, value in request.kwargs.items()
+            if name not in request.base and name not in _HANDLER_FIELDS
+        }
+    )
+    litellm_params: Final = GenericLiteLLMParams(
+        **extra,
+        api_key=api_key,
+        api_base=api_base,
+        custom_llm_provider=custom_llm_provider,
+    )
+    try:
+        resolved_model, resolved_provider, _, _ = get_llm_provider(
+            model=model,
+            custom_llm_provider=custom_llm_provider,
+            api_base=api_base,
+            api_key=api_key,
+            litellm_params=litellm_params,
+        )
+    except BadRequestError:
+        return Unresolved()
+    return Resolved(resolved_model, resolved_provider)

tests/test_litellm_rust/messages/test_dispatch.py

@@ -601,3 +601,55 @@ async def test_interceptor_feature_follows_the_resolved_provider() -> None:
         rules=rules,
     )
     assert result is native_result
+
+
+@pytest.mark.parametrize(
+    "kwargs",
+    (
+        {"api_base": "https://api.groq.com/openai/v1"},
+        {"api_base": "https://api.deepseek.com/v1"},
+        {"use_litellm_proxy": True},
+    ),
+)
+def test_provider_rule_uses_legacy_handler_provider_inputs(kwargs: Mapping[str, object]) -> None:
+    python_result: Final = response()
+
+    def python(*call_args: object, **call_kwargs: object) -> AnthropicMessagesResponse:  # kwargs-ok: fallback
+        return python_result
+
+    def native(request: NativeCall) -> AnthropicMessagesResponse:
+        pytest.fail("An anthropic provider rule must not route providers resolved from other handler inputs")
+
+    result: Final = _DISPATCH.run(
+        (16, MESSAGES, "claude-sonnet-4-5"),
+        kwargs,
+        python=python,
+        binding=messages_binding(native),
+        native=lambda hook, request, call_args, call_kwargs: hook(request),
+        rules=(RouteRule(Route.MESSAGES, Rollout.RUST_REQUIRED, providers=frozenset({"anthropic"})),),
+    )
+    assert result is python_result
+
+
+@pytest.mark.parametrize(
+    "kwargs",
+    (
+        {},
+        {"custom_llm_provider": "anthropic"},
+    ),
+)
+def test_provider_rule_keeps_anthropic_requests_native(kwargs: Mapping[str, object]) -> None:
+    native_result: Final = response()
+
+    def python(*call_args: object, **call_kwargs: object) -> AnthropicMessagesResponse:  # kwargs-ok: fallback
+        return response()
+
+    result: Final = _DISPATCH.run(
+        (16, MESSAGES, "claude-sonnet-4-5"),
+        kwargs,
+        python=python,
+        binding=messages_binding(lambda request: native_result),
+        native=lambda hook, request, call_args, call_kwargs: hook(request),
+        rules=(RouteRule(Route.MESSAGES, Rollout.RUST_REQUIRED, providers=frozenset({"anthropic"})),),
+    )
+    assert result is native_result

tests/test_litellm_rust/responses/test_dispatch.py

@@ -388,6 +388,8 @@ async def test_deployment_hook_keeps_only_sync_calls_on_python(monkeypatch: pyte
         ({"model": "anthropic/claude-sonnet-4-5"}, False),
         ({"model": "claude-sonnet-4-5"}, False),
         ({"model": "gpt-5", "custom_llm_provider": "azure"}, False),
+        ({"model": "gpt-5", "api_base": "https://api.groq.com/openai/v1"}, False),
+        ({"model": "gpt-5", "use_litellm_proxy": True}, False),
     ),
 )
 def test_provider_rule_sees_the_resolved_provider(kwargs: Mapping[str, object], native: bool) -> None: