Module agent_session_runtime 

AgentSessionRuntime — owns the current AgentSession and drives the new / switch / fork / import replacement pipeline.

Ports coding-agent/src/core/agent-session-runtime.ts. The runtime is single-owner: each replacement operation (under a serializing async mutex) creates the replacement session, tears down the current one, atomically swaps, and rebinds listeners on the new session.

Replacement order (matches TS regression 2860: withSession runs AFTER rebind on the NEW session):

1. emit_before_switch / emit_before_fork (cancellable).
2. Build the new session manager.
3. Call the factory → new session + services + diagnostics.
4. teardown_current: typed session_shutdown{reason, targetSessionFile} emit, then before_session_invalidate, then session.dispose().
5. apply(result): swap session + services + diagnostics.
6. finish_session_replacement: rebind_session(new_session) then optional with_session(ctx). The mode’s rebind calls bind_extensions on the new session, which emits the stored session_start{new|resume|fork} after the old host received its session_shutdown in step 4.

Re-exports

pub use crate::core::session_transfer::SessionImportFileNotFoundError as SessionImportFileNotFound;

Structs

AgentSessionRuntime

Owns the current AgentSession plus cwd-bound services, and drives the replacement pipeline for new / switch / fork / import.

AgentSessionRuntimeServices

Cwd-bound service handles the runtime needs to drive replacements.

CreateAgentSessionRuntimeOptions

Inputs to CreateAgentSessionRuntimeFactory::create.

CreateAgentSessionRuntimeResult

Result returned by CreateAgentSessionRuntimeFactory::create.

ForkOutcome

Outcome of fork.

NewSessionOptions

Options for AgentSessionRuntime::new_session.

SwitchOutcome

Outcome of new_session / switch_session / import_from_jsonl.

SwitchSessionOptions

Options for AgentSessionRuntime::switch_session.

Enums

AgentSessionRuntimeError

Errors from runtime operations.

ForkPosition

Options for AgentSessionRuntime::fork.

Traits

CreateAgentSessionRuntimeFactory

Factory that builds a fresh session + services from a session manager.

Functions

create_agent_session_runtime

Create the initial runtime from a factory and initial session manager.

Type Aliases

BeforeSessionInvalidateCallback

Synchronous callback invoked after session_shutdown handlers finish but before the old session is invalidated (host UI teardown that must not yield to the event loop).

RebindSessionCallback

Async callback invoked on the new session after teardown + apply, before with_session. Re-binds listeners / event subscriptions.