The event queue's heap seq was the last GC'd block surviving across
rounds: each round runs on a freshly spawned bot thread, so the N+1
thread realloc'd a block grown by dead thread N's allocator mid-round
(at the next capacity doubling, ~turn 104) -> rawDealloc SIGSEGV in
addEvent (7 gdb-confirmed coredumps). Replace with a static
array[MAX_QUEUE_SIZE, BotEvent] + eventsLen: no heap block crosses
threads, realloc can never happen.
Also fix the harness aborting the final round mid-train: PPO_Bot's
onRoundEnded trains synchronously after the runner's RoundEndedEvent,
so the counter read right after awaitResults() is the stale pre-train
value and System.exit killed the bot inside ppoUpdate. Poll up to 60s
for the counter to catch up before declaring the battle incomplete.
Verified: 72 consecutive rounds vs Fire, 100% wins, all rounds trained
(counter advanced 1:1), zero coredumps since the fix.
Manual-backprop PPO with Adam: TrajectoryBuffer, computeGAE, ppoUpdate
(4 epochs, minibatch 64, clip 0.2, grad norm 0.5). Reward helpers
computeTickReward/computeRoundReward. Bot wired: tick transitions
collected in run loop, ppoUpdate called on onRoundEnded. Fix: add
arraymancer import to PPO_Bot.nim so Tensor resolves at top level.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
SirStone