lash/
error.rs

1use crate::support::*;
2
3#[derive(Debug, thiserror::Error)]
4pub enum EmbedError {
5    #[error(
6        "protocol plugin is required; call .protocol_plugin(...) or use LashCore::standard_builder()/LashCore::rlm_builder(...)"
7    )]
8    MissingProtocolPlugin,
9    #[error("model spec is required; hosts must supply explicit model metadata")]
10    MissingModelSpec,
11    #[error("effect host is required; provide an explicit effect host with .effect_host(...)")]
12    MissingEffectHost,
13    #[error(
14        "attachment store is required; provide an explicit attachment store with .attachment_store(...)"
15    )]
16    MissingAttachmentStore,
17    #[error(
18        "process execution environment store is required; provide an explicit process env store with .process_env_store(...)"
19    )]
20    MissingProcessEnvStore,
21    #[error("failed to create store for session `{session_id}`: {message}")]
22    StoreFactory { session_id: String, message: String },
23    #[error("store is bound to session `{loaded}` but builder requested `{requested}`")]
24    StoreSessionMismatch { loaded: String, requested: String },
25    #[error("durable process worker requires a LashCore store factory")]
26    MissingProcessWorkerStoreFactory,
27    #[error(
28        "durable session store requires a durable {facet}; an ephemeral {facet} cannot back a durable session store"
29    )]
30    DurableStorePeerRequired { facet: &'static str },
31    #[error(
32        "durable process registry requires a durable session store factory; call .store_factory(...) with a durable store"
33    )]
34    DurableProcessRegistryRequiresStoreFactory,
35    #[error(
36        "a process registry is configured for the default inline process work runner but no session store factory is wired; the runner rebuilds a session runtime per process and cannot do so without one. Wire .store_factory(...) - InMemorySessionStoreFactory::new() for ephemeral process execution, or a durable factory - or use .process_work_driver(...) for an externally driven durable runner."
37    )]
38    ProcessRegistryRequiresStoreFactory,
39    #[error("durable process worker config requires a LashCore process registry")]
40    MissingProcessRegistry,
41    #[error("session deletion requires a LashCore store factory")]
42    MissingSessionStoreFactory,
43    #[error("failed to delete process state for session `{session_id}`: {message}")]
44    SessionDeleteProcess { session_id: String, message: String },
45    #[error("missing required turn input for plugin `{plugin_id}`")]
46    MissingPluginTurnInput { plugin_id: &'static str },
47    #[error(
48        "session is still in use: park()/close() consume the session and require exclusive ownership; drop any cloned handles and finish or cancel in-flight turns first"
49    )]
50    SessionStillInUse,
51    #[error("failed to flush trace sink: {0}")]
52    TraceFlush(#[from] lash_trace::TraceSinkError),
53    #[error(
54        "configured effect host for {operation} is durable and requires a handler context; use .effects(&controller) and provide .turn_id(...) for replayable foreground requests"
55    )]
56    DurableEffectHostRequiresHandlerContext { operation: &'static str },
57    #[error(
58        "pull-style turn streams require an effect host that can create a static scoped controller; use stream_to(...) inside the handler context"
59    )]
60    StaticTurnStreamRequiresStaticEffectHost,
61    #[error("runtime session error: {0}")]
62    Session(#[from] SessionError),
63    #[error("runtime turn error: {0}")]
64    Runtime(#[from] lash_core::RuntimeError),
65    #[error("runtime plugin/control error: {0}")]
66    Plugin(#[from] lash_core::PluginError),
67    #[error("remote protocol error: {0}")]
68    RemoteProtocol(#[from] lash_remote_protocol::RemoteProtocolError),
69    #[error("failed to encode protocol turn options: {0}")]
70    ProtocolTurnOptions(#[from] serde_json::Error),
71    #[error("failed to decode protocol turn options: {0}")]
72    DecodeProtocolTurnOptions(#[from] lash_core::ProtocolTurnOptionsError),
73    #[error("runtime control unavailable: {0}")]
74    Control(#[from] lash_core::PluginOperationInvokeError),
75}
76
77impl EmbedError {
78    /// True only when a typed signal says the failed operation is safe to
79    /// retry as-is; `false` means "no typed retryable signal", not "known
80    /// permanent" (see [`is_terminal`](Self::is_terminal) for that).
81    ///
82    /// The retryable set is enumerated deliberately from
83    /// [`RuntimeErrorCode`](lash_core::RuntimeErrorCode):
84    ///
85    /// - [`SessionExecutionBusy`](lash_core::RuntimeErrorCode::SessionExecutionBusy):
86    ///   another executor currently holds the session-execution lease; the
87    ///   turn was rejected before any state changed, so retrying after a
88    ///   backoff is safe.
89    /// - [`SessionExecutionLeaseLost`](lash_core::RuntimeErrorCode::SessionExecutionLeaseLost):
90    ///   the lease was fenced away mid-turn. The final commit is fenced on
91    ///   the same lease, so the failed attempt committed nothing and its
92    ///   queued-work/turn-input claims were released; a fresh attempt can
93    ///   re-claim safely.
94    ///
95    /// Everything else is `false`. Notably
96    /// [`StoreCommitFailed`](lash_core::RuntimeErrorCode::StoreCommitFailed)
97    /// stays `false`: the code does not distinguish transient store I/O from
98    /// conflicts, so there is no typed signal that a retry is safe.
99    ///
100    /// Provider failures never surface as `EmbedError` — a failed LLM call
101    /// finishes the turn with `TurnOutcome::Stopped(ProviderError)` — so
102    /// their typed retryability is carried on
103    /// [`TurnIssue::retryable`](crate::turn::TurnIssue) instead.
104    pub fn is_retryable(&self) -> bool {
105        use lash_core::RuntimeErrorCode;
106        match self {
107            Self::Runtime(err) => matches!(
108                err.code,
109                RuntimeErrorCode::SessionExecutionBusy
110                    | RuntimeErrorCode::SessionExecutionLeaseLost
111            ),
112            _ => false,
113        }
114    }
115
116    /// True only when a typed signal says retrying can never succeed without
117    /// host-side changes (wiring, configuration, or invariant violations that
118    /// a retry cannot repair). Errors that are neither
119    /// [`is_retryable`](Self::is_retryable) nor terminal are simply unknown.
120    ///
121    /// The terminal set:
122    ///
123    /// - builder/wiring variants of this enum (missing protocol plugin,
124    ///   model spec, effect host, stores, registries, handler context, and
125    ///   store/session mismatches) — the same call fails identically until
126    ///   the host changes its wiring;
127    /// - [`RuntimeErrorCode`](lash_core::RuntimeErrorCode) wiring codes:
128    ///   `MissingExecutionScopeId`, `ExecutionScopeTurnIdMismatch`,
129    ///   `MissingProcessExecutionId`, `DurableStoreRequired`,
130    ///   `DurableEffectLiveProtocolExtension`,
131    ///   `DurableEffectLivePluginInput`;
132    /// - session provider-configuration errors (`ProviderMismatch`,
133    ///   `ProviderUnconfigured`, `ProviderUnavailable`,
134    ///   `CodeExecutionUnavailable`).
135    pub fn is_terminal(&self) -> bool {
136        use lash_core::RuntimeErrorCode;
137        match self {
138            Self::MissingProtocolPlugin
139            | Self::MissingModelSpec
140            | Self::MissingEffectHost
141            | Self::MissingAttachmentStore
142            | Self::MissingProcessEnvStore
143            | Self::StoreSessionMismatch { .. }
144            | Self::MissingProcessWorkerStoreFactory
145            | Self::DurableStorePeerRequired { .. }
146            | Self::DurableProcessRegistryRequiresStoreFactory
147            | Self::ProcessRegistryRequiresStoreFactory
148            | Self::MissingProcessRegistry
149            | Self::MissingSessionStoreFactory
150            | Self::MissingPluginTurnInput { .. }
151            | Self::DurableEffectHostRequiresHandlerContext { .. }
152            | Self::StaticTurnStreamRequiresStaticEffectHost => true,
153            Self::Runtime(err) => matches!(
154                err.code,
155                RuntimeErrorCode::MissingExecutionScopeId
156                    | RuntimeErrorCode::ExecutionScopeTurnIdMismatch
157                    | RuntimeErrorCode::MissingProcessExecutionId
158                    | RuntimeErrorCode::DurableStoreRequired { .. }
159                    | RuntimeErrorCode::DurableEffectLiveProtocolExtension
160                    | RuntimeErrorCode::DurableEffectLivePluginInput
161            ),
162            Self::Session(err) => matches!(
163                err,
164                SessionError::ProviderMismatch { .. }
165                    | SessionError::ProviderUnconfigured { .. }
166                    | SessionError::ProviderUnavailable { .. }
167                    | SessionError::CodeExecutionUnavailable
168            ),
169            _ => false,
170        }
171    }
172}
173
174pub type Result<T> = std::result::Result<T, EmbedError>;
175
176#[cfg(test)]
177mod tests {
178    use super::EmbedError;
179    use lash_core::{RuntimeError, RuntimeErrorCode};
180
181    fn runtime_error(code: RuntimeErrorCode) -> EmbedError {
182        EmbedError::Runtime(RuntimeError::new(code, "test"))
183    }
184
185    #[test]
186    fn lease_contention_codes_are_retryable_and_not_terminal() {
187        for code in [
188            RuntimeErrorCode::SessionExecutionBusy,
189            RuntimeErrorCode::SessionExecutionLeaseLost,
190        ] {
191            let err = runtime_error(code);
192            assert!(err.is_retryable(), "{err}");
193            assert!(!err.is_terminal(), "{err}");
194        }
195    }
196
197    #[test]
198    fn untyped_failures_are_neither_retryable_nor_terminal() {
199        for err in [
200            runtime_error(RuntimeErrorCode::StoreCommitFailed),
201            runtime_error(RuntimeErrorCode::Other("plugin_defined_abort".into())),
202        ] {
203            assert!(!err.is_retryable(), "{err}");
204            assert!(!err.is_terminal(), "{err}");
205        }
206    }
207
208    #[test]
209    fn wiring_errors_are_terminal_and_not_retryable() {
210        for err in [
211            EmbedError::MissingProtocolPlugin,
212            EmbedError::MissingEffectHost,
213            runtime_error(RuntimeErrorCode::DurableStoreRequired {
214                facet: lash_core::DurableStoreFacet::SessionStore,
215            }),
216            runtime_error(RuntimeErrorCode::MissingExecutionScopeId),
217        ] {
218            assert!(err.is_terminal(), "{err}");
219            assert!(!err.is_retryable(), "{err}");
220        }
221    }
222}
lash/error.rs

lash/
error.rs
