Extract shared nextActiveAfter() advance core. Both nextTurn and
computeTurnOrderAfterRemoval delegate to it — single source of truth,
eliminates drift risk where one path changes and the other doesn't.
Previously two separate advance implementations computed the same
target, but any future edit to one would silently desync deact-current
advance from normal nextTurn advance.
Replay (scripts/replay-combat.js):
- Move turn-line print before mutations (event order = reality)
- Emit [pointer X→Y] lines when a mutation advances currentTurnParticipantId
- Emit [pointer X→Y wrap] when round bumps (removal-wrap case)
- Skip pointer emission for nextTurn (label=null) — already logged via turn line
Parser (scripts/analyze-turns.js):
- Parse [pointer X→Y wrap] events
- Credit pointer-target as acted (deact-current advance = turn pointer)
- Wrap pointer credits NEXT round (not current) — fixes cross-round false skip
- Drop currentRemoved special-case — pointer lines make skip check precise
Tests:
- shared/tests/turn.dry.test.js: 3 tests lock deact-current advance ==
nextTurn advance (mid-round, inactive-skipper, wrap+round-bump). RED
catches future drift.
Results: 500-round replay now 0 real skips, 0 double-acts (was 5+3).
Shared suite: 79 green + 1 RED (BUG-6 reorder, intentional).
Removal of current participant when no active after → advance to order[0]
+ bump round. Without bump, nextTurn replays whole round (BUG-5 pattern).
Parser 500-40b: 24 skips/1 double (was 46/64). Down not zero. Remaining
skips = replay async stale read (getDoc between turns), not turn.js.
Root cause: addParticipant appended participant to participants[] without
checking id uniqueness. Two participants with same id in array. On
togglePause resume, turnOrderIds rebuilt via sort → dup id appears twice.
nextTurn then stuck repeating that id (rotation breaks).
This was the enabling step for BUG-1's full corruption (audit chain):
pause blocks advance → totalTurns frozen → addParticipant re-adds
same r${totalTurns} id → resume dup → nextTurn stuck.
Fix: throw on duplicate id in addParticipant. Caller must use fresh id
(crypto.randomUUID in App, replay already does).
Evidence:
- Test: 'addParticipant rejects duplicate id' (was test.skip, now live).
- Pre-fix: 1 RED (Received function did not throw).
- Post-fix: 50 green (shared), 23 green (server), 62 green (FE).
- Reachability in normal app: low (App uses crypto.randomUUID) but no
guard existed before. Defensive + unblocks BUG-1 isolation.
No other behavior changed.
david raistrick