Module ffi_guard 

Unified FFI guard for catching panics at Rust-R boundaries.

Four modules independently catch panics at FFI boundaries: worker.rs, altrep_bridge.rs, unwind_protect.rs, and connection.rs. This module extracts the common pattern into a single guarded_ffi_call function.

Guard Modes

• GuardMode::CatchUnwind: Wraps the closure in catch_unwind. On panic, fires telemetry and raises an R error via Rf_error (diverges). Used by worker and connection trampolines.

• GuardMode::RUnwind: Uses R_UnwindProtect to catch both Rust panics and R longjmps. Used by ALTREP callbacks that call R APIs.

The ALTREP-specific Unsafe mode (no protection at all) stays in altrep_bridge.rs since it has no general applicability.

Enums

GuardMode

FFI guard mode controlling how panics are caught at Rust-R boundaries.

Functions

guarded_ffi_call

Execute f inside an FFI guard selected by mode.

guarded_ffi_call_with_fallback

Execute f inside a CatchUnwind guard, returning fallback on panic.