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Josh Creek
866efa0d9b
Closes task 5.10's three recording gaps, and the gap-closing found a real input-loss bug. Replay log: a failed write now ends the log permanently instead of desyncing every later record's framing; close() is called from _exit_tree with a summary, since the RefCounted destructor closes it implicitly but never says whether the log is complete; rejected packets are recorded with their reason in the kind byte (framing unchanged, FORMAT_VERSION 2 so "no rejects" differs from "this build never recorded them"). Recording is capped at 8 per peer per window - uncapped, the diagnostic is a remote disk-fill amplifier, since the attacker picks the packet rate. Uncapped totals live on MatchSim and survive the peer's disconnect. The bug: a 2s host stall has the client sending at 60Hz throughout, and ENet delivers that whole backlog in the first window after resume - 70 of an honest client's packets rejected as "rate limit exceeded". Redundancy does not cover it, because the dropped packets are contiguous: 0 of 70 rescued, and 82 of 923 sequences (8.88%, ~1.4s of input) never reached the server, against 0.00% with no stall. Every prediction gate passed. Fixed by granting each already-tracked peer a capped, two-window packet grace when the server detects its own wall-clock stall. Rate-limit rejects 70 -> 0, sequences missing 8.88% -> 0.00%, seq-guard rejects 9 -> 0. Controls on the unfixed build lost 4.34/7.52/7.86%. All three abuse roles still disconnect and no flood induced a stall, so the grace cannot be farmed. Also corrects an earlier wrong conclusion: the reviewer's free-flight p95 0.688 is real and reproduces on two processes with 0.0% snapshot loss. The plain --role=client drive fails the 0.5 free-flight bound in 3 of 8 runs because that drive is mostly a contact test - the harness comment already said so - leaving a cohort as small as 12 samples. Near-surface error is genuinely several times open-air error, so the calibrated bound now belongs to --exercise-free-flight alone and the plain role asserts the always-well-sampled all-cohort percentiles at 1.2/2.0, printing the free-flight numbers as reported-not-asserted. 6/6 plain runs pass where 3/7 failed; tightening to 0.3 still fails. tools/replay_dump.gd reads a log back: counts by kind, plus how much of the input sequence stream reached the server once redundancy is counted.