databendlabs / openraft / 22836653978

88%

Build Type

push

github

Committed by drmingdrmer

Commit Message

change: add SM type parameter to Raft<C, SM> for compile-time state machine type safety

Previously, Raft::with_state_machine() and external_state_machine_request()
erased the SM type via dyn Any and performed runtime downcasting. If the caller
specified the wrong SM type, it would fail at runtime with
InvalidStateMachineType. This change lifts the SM type into Raft<C, SM>
itself, making type mismatches a compile-time error.

The SM command channel (sm_cmd_tx) is now stored directly on Raft, bypassing
RaftCore message loop for external SM requests. This eliminates the
ExternalCommand::StateMachineCommand variant and reduces latency for
with_state_machine calls.

SM defaults to () so existing code that does not use with_state_machine
continues to compile unchanged.

Changes:
- Add SM = () type parameter to Raft, Leader, Command, Engine,
  EngineOutput, and all handler types throughout the engine layer
- Store sm_cmd_tx on Raft and send external SM commands directly to the
  worker, bypassing RaftCore
- Rename sm::Command::Func to ExternalFunc, using BoxAsyncOnceMut<SM>
  instead of BoxMaybeAsyncOnceMut<dyn Any>
- Simplify with_state_machine return type from
  Result<Result<V, InvalidStateMachineType>, Fatal<C>> to Result<V, Fatal<C>>
- Remove ExternalCommand::StateMachineCommand variant and its routing in RaftCore
- Each example now defines pub type Raft = openraft::Raft<TypeConfig, SM> with
  its concrete SM type; declare_types.rs re-exports from parent module

Upgrade tip:

Raft::new() return type is now Raft<C, SM> where SM is inferred from the
state machine argument. If you use with_state_machine(), the SM type is
checked at compile time - no changes needed beyond ensuring the Raft type
carries the correct SM parameter.

Before:
    let raft: Raft<MyConfig> = Raft::new(id, config, net, log, sm).await?;
    let val = raft.with_state_machine::<_, MySM, _>(|sm| { ... }).await?.unwrap();

After:
    let raft: Raft<MyConfig, MySM> = Raft::new(id, config... (continued)

Run Details

87 of 118 new or added lines in 18 files covered. (73.73%)

14 existing lines in 5 files now uncovered.

15840 of 18086 relevant lines covered (87.58%)

147144.73 hits per line