refactor(host-python): collect host failures in a thiserror Error enum (#46361)

* refactor(host-python): collect host failures in a thiserror Error enum

missing_state() and the inline PyRuntimeError/PyTypeError messages become Error variants with one From<Error> for PyErr, and InvokeError derives thiserror so From<PyErr> comes from #[from]

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(host-python): note the canonical HostError import alias in AGENTS.md

Co-Authored-By: Yujong Lee <yujong@berri.ai>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm-rust/Cargo.lock

@@ -3929,6 +3929,7 @@ dependencies = [
  "rstest",
  "serde",
  "serde_json",
+ "thiserror 2.0.19",
  "tokio",
 ]
 

litellm-rust/crates/callbacks-legacy-python/src/adapter.rs

@@ -9,7 +9,7 @@ use litellm_host::{
     interceptors::{RawResponse, RequestContext, WireRequest},
     lifecycle::{FailureOrigin, Timing, epoch_seconds},
 };
-use litellm_host_python::{HookStep, from_py, missing_state, to_py};
+use litellm_host_python::{Error as HostError, HookStep, from_py, to_py};
 use pyo3::{
     exceptions::{PyBaseException, PyException},
     gc::{PyTraverseError, PyVisit},
@@ -160,7 +160,7 @@ impl LegacyLogging {
         self.response
             .as_ref()
             .map(|response| HookStep::Ready(response.clone_ref(py)))
-            .ok_or_else(missing_state)
+            .ok_or_else(|| HostError::MissingState.into())
     }
 
     fn dispatch_success(&self, py: Python<'_>) -> PyResult<()> {
@@ -209,7 +209,7 @@ impl LegacyLogging {
 
     fn stream_success(&self, py: Python<'_>, stream: &DeliveredStream) -> PyResult<()> {
         let logger = self.logger()?;
-        let billing = self.stream_billing().ok_or_else(missing_state)?;
+        let billing = self.stream_billing().ok_or(HostError::MissingState)?;
         let billed = Streaming::Success.call(
             py,
             (
@@ -525,7 +525,7 @@ impl LegacyLogging {
             return self.stream_failure(py);
         }
         if origin == FailureOrigin::Call && self.logger.is_some() && self.runs_deployment_hooks() {
-            let error = self.error.as_ref().ok_or_else(missing_state)?;
+            let error = self.error.as_ref().ok_or(HostError::MissingState)?;
             return Ok(HookStep::Await(
                 DeploymentHooks::after_failure(py, self.call.kwargs(), error, self.call_type())?,
                 Self::resume_deployment_failure,
@@ -536,7 +536,7 @@ impl LegacyLogging {
 
     pub(crate) fn stream_opened(&mut self, py: Python<'_>, head: &Py<PyAny>) -> PyResult<()> {
         if self.stream_billing().is_none() {
-            return Err(missing_state());
+            return Err(HostError::MissingState.into());
         }
         if let Some(key) = &self.cache_key {
             head.bind(py).set_item("cache_key", key)?;
@@ -551,7 +551,7 @@ impl LegacyLogging {
     }
 
     pub(crate) fn stream_chunk(&mut self, py: Python<'_>, chunk: &Py<PyAny>) -> PyResult<()> {
-        let stream = self.stream.as_mut().ok_or_else(missing_state)?;
+        let stream = self.stream.as_mut().ok_or(HostError::MissingState)?;
         if stream.first_chunk.is_none() {
             stream.first_chunk = Some(datetime(py, epoch_seconds())?);
         }

litellm-rust/crates/host-python/AGENTS.md

@@ -28,6 +28,7 @@ Terminal notifications share the selected response or exception. An ordinary not
   - `PythonBinding::decode_request` receives the keyword view returned by `prepare_arguments` and updated by `arguments_prepared`, not the caller's dict. A binding that decodes from it inherits all composed argument rewrites
   - A native failure, including one a host op returns as `InvokeError::Native`, is classified exactly once through the binding's `map_error`. A Python exception raised inside the call, and a failure in `prepare_arguments` or `transform_response`, is raised as is
   - A failing `map_error` is raised with the native error's text as its `__context__`, never swallowed
+- Consumers import this crate's error as `use litellm_host_python::Error as HostError`, so it never shadows their own `Error`
 - Use standard PyO3 ownership and conversion APIs
   - Prefer `Bound<'py, T>` for attached operations/results, `Py<T>` for retention. Binding/unbinding does not copy payloads
   - Use `pythonize` for selected Serde data, never a JSON-text round trip. Share conversion with `Pythonized<T>`

litellm-rust/crates/host-python/Cargo.toml

@@ -11,6 +11,7 @@ litellm-host.workspace = true
 bytes.workspace = true
 futures-util.workspace = true
 serde.workspace = true
+thiserror.workspace = true
 tokio = { workspace = true, features = ["rt", "sync"] }
 
 pyo3.workspace = true

litellm-rust/crates/host-python/src/driver.rs

@@ -18,7 +18,7 @@ use crate::PythonHostCalls;
 use crate::handle::{Execution, ExecutionBody, ExecutionStep, PythonLifecycle};
 use crate::hooks::{HookResume, HookStep, PythonCallEvent, PythonCallHooks};
 use crate::native::{NativeMachine, NativePoll};
-use crate::{InvokeError, PythonBinding, missing_state};
+use crate::{Error, InvokeError, PythonBinding};
 
 type ProtocolOf<H> = <H as PythonBinding>::Protocol;
 type ErrorOf<H> = <ProtocolOf<H> as Protocol>::Error;
@@ -158,9 +158,7 @@ where
         ExecutionStep::Open(head) => Execution::suspended(driver, options.lifecycle)
             .into_sync_stream(py, head)
             .map(Bound::unbind),
-        ExecutionStep::Await(_) | ExecutionStep::Yield(_) => {
-            Err(PyRuntimeError::new_err("sync call suspended"))
-        }
+        ExecutionStep::Await(_) | ExecutionStep::Yield(_) => Err(Error::SyncCallSuspended.into()),
     }
 }
 
@@ -254,7 +252,7 @@ where
                     Err(error) => self.hook_failed(py, error),
                 }
             }
-            _ => Err(missing_state()),
+            _ => Err(Error::MissingState.into()),
         }
     }
 
@@ -281,8 +279,8 @@ where
                         return self.failure(py, error, FailureOrigin::Call);
                     }
                 };
-                let start = self.start.take().ok_or_else(missing_state)?;
-                let arguments = self.arguments.as_ref().ok_or_else(missing_state)?;
+                let start = self.start.take().ok_or(Error::MissingState)?;
+                let arguments = self.arguments.as_ref().ok_or(Error::MissingState)?;
                 let machine = match start(py, arguments.bind(py), request) {
                     Ok(machine) => machine,
                     Err(error) => return self.failure(py, error, FailureOrigin::Host),
@@ -357,7 +355,7 @@ where
                         Stage::Failed(error) => {
                             Err(PyErr::from_value(error.bind(py).clone().into_any()))
                         }
-                        _ => Err(missing_state()),
+                        _ => Err(Error::MissingState.into()),
                     }
                 }
             },
@@ -365,7 +363,7 @@ where
     }
 
     fn begin(&mut self, py: Python<'_>) -> PyResult<ExecutionStep> {
-        let arguments = self.arguments.take().ok_or_else(missing_state)?;
+        let arguments = self.arguments.take().ok_or(Error::MissingState)?;
         match self.hooks.prepare_arguments(py, arguments, self.started_at) {
             Ok(step) => self.on_arguments(py, step),
             Err(error) => self.hook_failed(py, error),

litellm-rust/crates/host-python/src/error.rs

@@ -1,20 +1,57 @@
-use pyo3::prelude::*;
+use pyo3::{
+    PyErr,
+    exceptions::{PyRuntimeError, PyTypeError},
+};
+
+/// A failure host-python raises itself, surfacing in Python as the exception `PyErr::from` picks.
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    #[error("missing native call state")]
+    MissingState,
+    #[error("execution is already running")]
+    ExecutionRunning,
+    #[error("execution is closed")]
+    ExecutionClosed,
+    #[error("execution requires start before resume and can only start once")]
+    ExecutionOutOfOrder,
+    #[error("execution was closed while running")]
+    ExecutionClosedWhileRunning,
+    #[error("native execution closed")]
+    NativeExecutionClosed,
+    #[error("sync call suspended")]
+    SyncCallSuspended,
+    #[error("synchronous native routes cannot run from a Tokio context; use the async route")]
+    SyncInsideTokio,
+    #[error("the context body produced no value")]
+    ContextBodyProducedNothing,
+    #[error("file read must return bytes or str, got {got}")]
+    FileContentType { got: String },
+}
+
+impl From<Error> for PyErr {
+    fn from(error: Error) -> Self {
+        match error {
+            Error::FileContentType { .. } => PyTypeError::new_err(error.to_string()),
+            Error::MissingState
+            | Error::ExecutionRunning
+            | Error::ExecutionClosed
+            | Error::ExecutionOutOfOrder
+            | Error::ExecutionClosedWhileRunning
+            | Error::NativeExecutionClosed
+            | Error::SyncCallSuspended
+            | Error::SyncInsideTokio
+            | Error::ContextBodyProducedNothing => PyRuntimeError::new_err(error.to_string()),
+        }
+    }
+}
 
 /// Why a custom operation the host answered did not produce a result: the route's own code
 /// rejected it, which the route classifies like any other native failure, or Python code
 /// raised, which reaches the caller as it was raised.
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum InvokeError<E> {
+    #[error("{0}")]
     Native(E),
-    Python(PyErr),
-}
-
-impl<E> From<PyErr> for InvokeError<E> {
-    fn from(error: PyErr) -> Self {
-        Self::Python(error)
-    }
-}
-
-pub fn missing_state() -> PyErr {
-    pyo3::exceptions::PyRuntimeError::new_err("missing native call state")
+    #[error(transparent)]
+    Python(#[from] PyErr),
 }

litellm-rust/crates/host-python/src/file_reader.rs

@@ -3,13 +3,14 @@
 
 use bytes::Bytes;
 use pyo3::{
-    exceptions::PyTypeError,
     gc::{PyTraverseError, PyVisit},
     prelude::*,
     pybacked::PyBackedBytes,
     types::{PyBytes, PyString},
 };
 
+use crate::Error;
+
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct FileContent {
     pub bytes: Bytes,
@@ -50,10 +51,10 @@ impl PythonFileReader {
         } else if value.is_instance_of::<PyBytes>() {
             py_bytes(&value)?
         } else {
-            return Err(PyTypeError::new_err(format!(
-                "file read must return bytes or str, got {}",
-                value.get_type(),
-            )));
+            return Err(Error::FileContentType {
+                got: value.get_type().to_string(),
+            }
+            .into());
         };
         Ok(FileContent {
             bytes,

litellm-rust/crates/host-python/src/gil.rs

@@ -3,7 +3,9 @@ use std::sync::{
     atomic::{AtomicU64, Ordering},
 };
 
-use pyo3::{exceptions::PyRuntimeError, prelude::*};
+use pyo3::prelude::*;
+
+use crate::Error;
 
 /// The caller's `contextvars` context, captured at the Python entry point so blocking Python
 /// work started from Rust sees the same request-local values as the Python caller.
@@ -49,7 +51,7 @@ impl PythonContext {
             .lock()
             .expect("context value slot poisoned")
             .take()
-            .ok_or_else(|| PyRuntimeError::new_err("the context body produced no value"))
+            .ok_or_else(|| Error::ContextBodyProducedNothing.into())
     }
 }
 

litellm-rust/crates/host-python/src/handle.rs

@@ -1,7 +1,7 @@
 use std::panic::{AssertUnwindSafe, catch_unwind};
 
-use crate::panic_to_pyerr;
-use pyo3::exceptions::{PyBaseException, PyRuntimeError};
+use crate::{Error, panic_to_pyerr};
+use pyo3::exceptions::PyBaseException;
 use pyo3::gc::{PyTraverseError, PyVisit};
 use pyo3::prelude::*;
 
@@ -76,15 +76,13 @@ impl Execution {
             match (&execution.state, result.is_some()) {
                 (ExecutionState::Created(_), false) | (ExecutionState::Suspended(_), true) => {}
                 (ExecutionState::Running, _) => {
-                    return Err(PyRuntimeError::new_err("execution is already running"));
+                    return Err(Error::ExecutionRunning.into());
                 }
                 (ExecutionState::Closed, _) => {
-                    return Err(PyRuntimeError::new_err("execution is closed"));
+                    return Err(Error::ExecutionClosed.into());
                 }
                 _ => {
-                    return Err(PyRuntimeError::new_err(
-                        "execution requires start before resume and can only start once",
-                    ));
+                    return Err(Error::ExecutionOutOfOrder.into());
                 }
             }
             match std::mem::replace(&mut execution.state, ExecutionState::Running) {
@@ -116,9 +114,7 @@ impl Execution {
                 drop(body);
                 outcome.and_then(|(step, suspended)| {
                     if suspended {
-                        Err(PyRuntimeError::new_err(
-                            "execution was closed while running",
-                        ))
+                        Err(Error::ExecutionClosedWhileRunning.into())
                     } else {
                         Ok(step)
                     }

litellm-rust/crates/host-python/src/hooks/chain/adapter.rs

@@ -6,7 +6,7 @@ use pyo3::{
     types::PyDict,
 };
 
-use crate::{HookResume, HookStep, PythonCallEvent, PythonCallHooks, PythonOwned, missing_state};
+use crate::{Error, HookResume, HookStep, PythonCallEvent, PythonCallHooks, PythonOwned};
 
 pub(super) enum ChainStep<T> {
     Ready(T),
@@ -110,7 +110,7 @@ impl<H: PythonCallHooks> ChainHooks for HookAdapter<H> {
         result: PyResult<Py<PyAny>>,
     ) -> PyResult<ChainStep<Py<PyDict>>> {
         let Some(Continuation::Arguments(resume)) = self.continuation.take() else {
-            return Err(missing_state());
+            return Err(Error::MissingState.into());
         };
         let step = resume(&mut self.hooks, py, result)?;
         Ok(self.step(step, Continuation::Arguments))
@@ -132,7 +132,7 @@ impl<H: PythonCallHooks> ChainHooks for HookAdapter<H> {
         result: PyResult<Py<PyAny>>,
     ) -> PyResult<ChainStep<Box<WireRequest>>> {
         let Some(Continuation::Wire(resume)) = self.continuation.take() else {
-            return Err(missing_state());
+            return Err(Error::MissingState.into());
         };
         let step = resume(&mut self.hooks, py, result)?;
         Ok(self.step(step, Continuation::Wire))
@@ -154,7 +154,7 @@ impl<H: PythonCallHooks> ChainHooks for HookAdapter<H> {
         result: PyResult<Py<PyAny>>,
     ) -> PyResult<ChainStep<Py<PyAny>>> {
         let Some(Continuation::Response(resume)) = self.continuation.take() else {
-            return Err(missing_state());
+            return Err(Error::MissingState.into());
         };
         let step = resume(&mut self.hooks, py, result)?;
         Ok(self.step(step, Continuation::Response))
@@ -171,7 +171,7 @@ impl<H: PythonCallHooks> ChainHooks for HookAdapter<H> {
         result: PyResult<Py<PyAny>>,
     ) -> PyResult<ChainStep<()>> {
         let Some(Continuation::Event(resume)) = self.continuation.take() else {
-            return Err(missing_state());
+            return Err(Error::MissingState.into());
         };
         let step = resume(&mut self.hooks, py, result)?;
         Ok(self.step(step, Continuation::Event))

litellm-rust/crates/host-python/src/hooks/chain/dispatch.rs

@@ -10,9 +10,7 @@ use pyo3::{
     types::PyDict,
 };
 
-use crate::{
-    HookStep, PythonCallEvent, PythonCallHooks, PythonOwned, PythonRuntime, missing_state,
-};
+use crate::{Error, HookStep, PythonCallEvent, PythonCallHooks, PythonOwned, PythonRuntime};
 
 use super::adapter::{ChainHooks, ChainStep, HookAdapter};
 
@@ -72,7 +70,7 @@ impl HookChain {
         py: Python<'_>,
         result: PyResult<Py<PyAny>>,
     ) -> PyResult<HookStep<Self, Py<PyDict>>> {
-        let (index, context) = self.arguments.take().ok_or_else(missing_state)?;
+        let (index, context) = self.arguments.take().ok_or(Error::MissingState)?;
         let result = resume_unless_cancelled(py, result)?;
         let step = self.hooks[index].resume_arguments(py, result)?;
         self.arguments_step(py, index, step, context)
@@ -113,7 +111,7 @@ impl HookChain {
         py: Python<'_>,
         result: PyResult<Py<PyAny>>,
     ) -> PyResult<HookStep<Self, Box<WireRequest>>> {
-        let (index, context) = self.wire.take().ok_or_else(missing_state)?;
+        let (index, context) = self.wire.take().ok_or(Error::MissingState)?;
         let result = resume_unless_cancelled(py, result)?;
         let step = self.hooks[index].resume_wire(py, result)?;
         self.wire_step(py, index, step, &context)
@@ -154,7 +152,7 @@ impl HookChain {
         py: Python<'_>,
         result: PyResult<Py<PyAny>>,
     ) -> PyResult<HookStep<Self, Py<PyAny>>> {
-        let (index, context) = self.response.take().ok_or_else(missing_state)?;
+        let (index, context) = self.response.take().ok_or(Error::MissingState)?;
         let result = resume_unless_cancelled(py, result)?;
         let step = self.hooks[index].resume_response(py, result)?;
         self.response_step(py, index, step, context)
@@ -195,7 +193,7 @@ impl HookChain {
         py: Python<'_>,
         result: PyResult<Py<PyAny>>,
     ) -> PyResult<HookStep<Self, ()>> {
-        let (index, event) = self.event.take().ok_or_else(missing_state)?;
+        let (index, event) = self.event.take().ok_or(Error::MissingState)?;
         let result = resume_unless_cancelled(py, result)?;
         let result = self.hooks[index].resume_event(py, result);
         let step = notification_result(py, is_terminal(&event), result)?;

litellm-rust/crates/host-python/src/lib.rs

@@ -23,7 +23,7 @@ pub use argument::{effective_py_args, lookup, present};
 pub use binding::PythonBinding;
 pub use conversion_cache::{FromPythonCache, ToPythonCache};
 pub use driver::{CallOptions, run_call};
-pub use error::{InvokeError, missing_state};
+pub use error::{Error, InvokeError};
 pub use file_reader::{FileContent, PythonFileReader, py_bytes};
 pub use fork_gate::RuntimeAlreadyStarted;
 pub use gil::{PythonContext, attach_blocking, release_count, release_gil};

litellm-rust/crates/host-python/src/native.rs

@@ -5,11 +5,10 @@ use futures_util::future::{AbortHandle, Abortable};
 use litellm_host::call::HostedCompletion;
 use litellm_host::machine::{HostFailure, Machine, MachineStep};
 use litellm_host::protocol::Protocol;
-use pyo3::exceptions::PyRuntimeError;
 use pyo3::prelude::*;
 use tokio::sync::Mutex;
 
-use crate::missing_state;
+use crate::Error;
 use crate::runtime::{poll_async_value, run_async_value, run_sync_value};
 
 type NativeResult<M> = Result<
@@ -65,7 +64,7 @@ where
         py: Python<'_>,
         interruption: Option<HostFailure<<M::Protocol as Protocol>::Error>>,
     ) -> PyResult<NativePoll<NativeResult<M>>> {
-        let state = Arc::clone(self.state.as_ref().ok_or_else(missing_state)?);
+        let state = Arc::clone(self.state.as_ref().ok_or(Error::MissingState)?);
         let future = async move {
             let mut state = state.lock().await;
             let result = match interruption {
@@ -90,7 +89,7 @@ where
                 run_async_value(py, async move {
                     Abortable::new(future, registration)
                         .await
-                        .map_err(|_| PyRuntimeError::new_err("native execution closed"))?
+                        .map_err(|_| Error::NativeExecutionClosed)?
                 })?
                 .unbind(),
             ))
@@ -103,12 +102,12 @@ where
     pub(super) fn take_result(&self) -> PyResult<NativeResult<M>> {
         self.state
             .as_ref()
-            .ok_or_else(missing_state)?
+            .ok_or(Error::MissingState)?
             .try_lock()
-            .map_err(|_| missing_state())?
+            .map_err(|_| Error::MissingState)?
             .result
             .take()
-            .ok_or_else(missing_state)
+            .ok_or_else(|| Error::MissingState.into())
             .map(|result| {
                 result.map(|step| match step {
                     MachineStep::Suspended(op) => MachineStep::Suspended(op),

litellm-rust/crates/host-python/src/runtime.rs

@@ -5,7 +5,7 @@ use std::task::{Context, Poll, Waker};
 use std::time::Duration;
 
 use crate::fork_gate::{ForkGate, Refused, RuntimeAlreadyStarted};
-use crate::{Pythonized, panic_to_pyerr, release_gil};
+use crate::{Error, Pythonized, panic_to_pyerr, release_gil};
 use futures_util::FutureExt;
 use pyo3::exceptions::PyRuntimeError;
 use pyo3::prelude::*;
@@ -112,9 +112,7 @@ where
     F: Future<Output = PyResult<T>> + Send + 'static,
 {
     if Handle::try_current().is_ok() {
-        return Err(PyRuntimeError::new_err(
-            "synchronous native routes cannot run from a Tokio context; use the async route",
-        ));
+        return Err(Error::SyncInsideTokio.into());
     }
     release_gil(py, move || runtime.block_on(wait_for_sync_result(future)))?
 }
@@ -131,9 +129,7 @@ where
     F: Future<Output = Result<T, E>> + Send + 'static,
 {
     if Handle::try_current().is_ok() {
-        return Err(PyRuntimeError::new_err(
-            "synchronous native routes cannot run from a Tokio context; use the async route",
-        ));
+        return Err(Error::SyncInsideTokio.into());
     }
 
     let result = release_gil(py, move || runtime.block_on(wait_for_sync_result(future)))?;

litellm-rust/crates/host-python/tests/driver.rs

@@ -12,8 +12,8 @@ use litellm_host::{
     protocol::Reply,
 };
 use litellm_host_python::{
-    CallOptions, HookChain, InvokeError, PythonBinding, PythonHostCalls, PythonOwned,
-    PythonRuntime, missing_state, run_call,
+    CallOptions, Error as HostError, HookChain, InvokeError, PythonBinding, PythonHostCalls,
+    PythonOwned, PythonRuntime, run_call,
 };
 use pyo3::{
     exceptions::{
@@ -818,7 +818,7 @@ fn cancellation_ends_the_call_without_terminal_dispatch(#[from(interpreter)] _py
                 match chunk {}
             }
             fn encode_response(&mut self, _: Python<'_>, _: String) -> PyResult<Py<PyAny>> {
-                Err(missing_state())
+                Err(HostError::MissingState.into())
             }
             fn map_error(&self, _: Python<'_>, error: Error) -> PyResult<Classified> {
                 self.0.push("classify");
@@ -835,7 +835,7 @@ fn cancellation_ends_the_call_without_terminal_dispatch(#[from(interpreter)] _py
                 _: Python<'_>,
                 _: (&'static str, Reply<String>),
             ) -> Result<(), InvokeError<Error>> {
-                Err(missing_state().into())
+                Err(PyErr::from(HostError::MissingState).into())
             }
         }
 

litellm-rust/crates/python-bridge/src/routes/mod.rs

@@ -11,10 +11,10 @@ pub(crate) mod traces;
 
 use litellm_callbacks_legacy_python::{LegacyLogging, LoggingOperation, PublicCall};
 use litellm_host::{call::HostedCompletion, machine::Machine, protocol::Protocol};
+use litellm_host_python::{Error as HostError, present};
 use litellm_host_python::{
     HookChain, PythonBinding, PythonCallHooks, PythonHostCalls, effective_py_args,
 };
-use litellm_host_python::{missing_state, present};
 use pyo3::{
     gc::{PyTraverseError, PyVisit},
     prelude::*,
@@ -64,7 +64,9 @@ impl RequestView {
     }
 
     fn dicts(&self) -> PyResult<&RequestDicts> {
-        self.0.as_ref().ok_or_else(missing_state)
+        self.0
+            .as_ref()
+            .ok_or_else(|| HostError::MissingState.into())
     }
 
     pub(crate) fn resolve(
@@ -72,7 +74,7 @@ impl RequestView {
         py: Python<'_>,
         arguments: &Bound<'_, PyDict>,
     ) -> PyResult<()> {
-        let dicts = self.0.as_mut().ok_or_else(missing_state)?;
+        let dicts = self.0.as_mut().ok_or(HostError::MissingState)?;
         dicts.request = effective_py_args(dicts.base.bind(py), arguments)?.unbind();
         Ok(())
     }

litellm-rust/crates/python-bridge/src/routes/ocr/host.rs

@@ -1,5 +1,5 @@
 use litellm_auth::ResolvedCredential;
-use litellm_host_python::{InvokeError, PythonBinding, missing_state};
+use litellm_host_python::{Error as HostError, InvokeError, PythonBinding};
 use litellm_host_python::{PythonHostCalls, PythonOwned};
 use litellm_inference_ocr::route::{Ocr, OcrCall, OcrOp};
 use litellm_llms::base_llm::ocr::error::Error;
@@ -42,7 +42,7 @@ impl OcrPythonHost {
     fn handles(&self) -> PyResult<&OcrHostHandles> {
         match &self.data {
             OcrHostData::Projected(handles) => Ok(handles),
-            _ => Err(missing_state()),
+            _ => Err(HostError::MissingState.into()),
         }
     }
 
@@ -50,13 +50,13 @@ impl OcrPythonHost {
         self.handles()?
             .azure_ad_token_provider
             .as_ref()
-            .ok_or_else(missing_state)?
+            .ok_or(HostError::MissingState)?
             .acquire(py)
     }
 
     fn projection(&mut self, py: Python<'_>, arguments: &Bound<'_, PyDict>) -> PyResult<OcrCall> {
         let OcrHostData::Unprojected = self.data else {
-            return Err(missing_state());
+            return Err(HostError::MissingState.into());
         };
         self.view.resolve(py, arguments)?;
         let (request, handles) = project_request(self.view.request(py)?, arguments)?;