Function prewarm_persistence_postcondition_failed 

pub(crate) fn prewarm_persistence_postcondition_failed(
    fresh_compiles: usize,
    engine_count_after: usize,
) -> bool

Decides whether a single worker’s prewarm postcondition is violated.

The postcondition: if at least one shape on this worker reported a fresh compile (succeeded && !cache_hit) but the on-disk .engine file count is still zero, the TRT EP almost certainly emitted Ok(_) from session.run() without actually persisting the engine plan. This is the silent-persistence failure mode where the TRT EP reports compile success but writes no engine files (many compile-success events / 0 engines on disk).

Returning true should produce an ERROR log so operators see the failure in CloudWatch immediately. Non-fresh-compile shards (cache hits only) and shards where at least one engine file exists are accepted.

The check is keyed on engine_count_after == 0 rather than engine_count_delta <= 0. ORT’s TRT EP rewrites its single profile-based engine file in-place as more shapes are compiled (delta == 0 at steady state), so a delta-based rule would produce false-positive ERRORs on every shape after the first compile.