Diagnostics¶

The SDK emits warnings through the standard log::warn! macro whenever something in the plugin lifecycle goes wrong silently. Every message is prefixed with [rust-samp] so it can be grepped quickly in the server log:

[rust-samp] null ICore* in on_load — samp::plugin::omp_core() will return None

The prefix is a single constant in samp/src/macros.rs (SDK_LOG_PREFIX) — do not hardcode the literal in your own logs.

Where they fire¶

These warnings cover the native Open Multiplayer lifecycle; on SA-MP the SDK does not emit any of them (the corresponding failure modes do not exist in that environment).

Trigger	Message	Consequence
`ICore*` was null in `comp_on_load`	`null ICore* in on_load — samp::plugin::omp_core() will return None`	Plugin keeps running; `omp_core()` returns `None`.
`IPawnComponent` missing in `comp_on_init`	`IPawnComponent not found in on_init — Pawn natives unavailable`	Native registration is skipped; Pawn cannot call your natives.
`IEventDispatcher<PawnEventHandler>` null in `comp_on_init`	`null IEventDispatcher<PawnEventHandler> in on_init — on_amx_load/on_amx_unload will not be called`	Loaded Pawn scripts do not trigger the AMX hooks.
`getAmxFunctions()` returned `0` even at `on_ready`	`getAmxFunctions() returned 0 in on_ready — Pawn natives unavailable`	Pawn natives are not registered, even after the deferred retry.
`on_ready`: `IPawnComponent` could not be queried again	`on_ready: IPawnComponent not found`	Same as the previous row — natives are not registered.
`ITimersComponent` missing while `enable_tick()` is on	`ITimersComponent not found — on_tick will not be called`	Tick callback never fires on Open Multiplayer (SA-MP unaffected).
`ITimersComponent::create()` returned null	`failed to create timer on ITimersComponent — on_tick will not be called`	Same as above; the heap handler is freed before the warning is emitted.

Panic safety¶

Beyond the warnings, the SDK wraps every callback that crosses the FFI boundary in std::panic::catch_unwind. If a panic escapes the plugin code:

Inside a native — the #[native] wrapper catches the panic, logs [<NativeName>] panic in native: <payload> through samp::log::error!, and returns 0 to the AMX VM.
Inside an Open Multiplayer vtable callback (comp_on_load, comp_on_init, comp_on_ready, comp_on_free, comp_free, pawn_on_amx_load, pawn_on_amx_unload, tick_handler_timeout, tick_handler_free) — the SDK catches the panic so the server process is not aborted.

Without those guards a panic crossing extern "C" aborts the entire server (Rust 1.71+ guarantee).

Native-call error logging¶

When a native is declared with a Result/AmxResult return, the generated wrapper logs Err automatically:

[<NativeName>] <Display of the error value>

For argument parsing failures the wrapper logs a more detailed message that includes the positional index and the expected type:

[<NativeName>] failed to parse argument #1 'key' (expected type: AmxString)

This kicks in only in the standard #[native] mode. In raw mode the macro hands the Args over verbatim and parsing is the plugin's responsibility.

Reading the warnings¶

All messages flow through whatever log implementation the plugin installed. With the default routing they end up wherever the server sends logprintf (SA-MP) or ICore::logLnU8 (Open Multiplayer). With a custom fern::Dispatch they follow the dispatch chain described in Logging.

A practical filter in the server console:

grep -E '^\[rust-samp\]|^\[<YourNativeName>\]' server_log.txt

Where to look next when something is wrong¶

omp_core() returns None despite running on Open Multiplayer → check the first warning above. The server may have passed a null ICore*, or the plugin is in legacy mode (no ComponentEntryPoint).
A Pawn native MyNative(...) is reported as unresolved by the script compiler at runtime → check the IPawnComponent / getAmxFunctions warnings. The dispatcher might not have fired on_amx_load for this script either.
on_amx_load is never called → look for the IEventDispatcher<PawnEventHandler> warning.
on_tick is never called on Open Multiplayer → look for the ITimersComponent warnings. Make sure samp::plugin::enable_tick() is called inside the constructor block.