With one-byte fragments and a reliable queue of 16, even an empty snapshot
can never be queued: every reply vanished while rudp_send_failures
counted, and the peer timed out. Rust refuses such a configuration at
startup in validate_options; Python's __post_init__ accepted it.
__post_init__ now applies Rust's rules to every option the two servers
share, in Rust's order: max_snapshot_bytes, max_snapshot_documents,
rudp_resend_delay_ms, rudp_max_pending_reliable_packets and
rudp_max_fragment_bytes must be greater than zero (the first two when
set; zero was accepted before), max_snapshot_bytes must hold an empty
snapshot response, and an empty snapshot response in fragments of
rudp_max_fragment_bytes, counted rounding up, must fit the lesser of
65535 and the reliable queue. Rust's session, lifetime and payload-budget
rules have no Python option to apply to.
The test measures the empty snapshot the server actually sends, pins each
rule at its boundary, and shows the configuration at the bound does
answer.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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