#88: coolant leaks LIVE -- the #64 damageZone shadow was the single break

in the leak chain

HeatSink::UpdateCoolant prices the damage-driven leak from the QUALIFIED
engine member (Subsystem::damageZone @0xE0): coolantDraw = zoneDamage *
heatLoad, with the coolantActive hysteresis (= the ReportLeak attribute
the 19 authored leak watchers ride).  But the MechSubsystem ctor only
ever filled its re-declared SHADOW member (gitea #64, gotcha #1), so the
engine member stayed NULL forever, zoneDamage pinned 0, and a coolant
leak was STRUCTURALLY IMPOSSIBLE no matter how much damage landed --
Oracle's night-7 report exactly.  The #80 crit fix and the #83 collision
rattle write real subsystem-zone damage, but into an object the leak
reader could never see.

Fix: alias the ENGINE base member to the same zone in both MechSubsystem
ctors.  Every shadow reader keeps working (same object); the engine base
Subsystem::TakeDamage latent null-AV (#64 consequence 2) is disarmed;
the full #64 de-shadow sweep remains the long-term cleanup.

Verified live (solo, BT_COOL_LOG/BT_CRIT_LOG): collision rattle drove a
damaged Myomers to [cool] draw = dmg*heatLoad with the level draining;
sustained weapon fire rolled real crits ([critroll]) and produced 588
leak-pricing lines.  Authored routing extracted from BTL4.RES: collision
rattle targets HeatSinkBank 0.3 / Gyro 0.35 / Torso 0.25 / Myomers 0.35
(Condenser+Reservoir authored 0 for collisions); weapon crits select via
the zone's crit-entry list.  Known-remaining fidelity item (documented):
HeatSink::DrawCoolant (slot 14, central top-up) is still a return-0 TODO.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019Zh7PTkFy4KwTzVighLR9J

context/subsystems.md

@@ -167,6 +167,24 @@ its electrical state. The full chain, byte-verified [T1]:
 - **STILL DEAD:** factory loops 2-4 (heatable/weapon/damageable capability rosters) go through the
   `SubProxy` stub whose `IsDerivedFrom` returns 0 — they add NOTHING. See [[open-questions]].
 
+## Coolant LEAKS (Gitea #88 fix, 2026-07-31) — the #64 shadow was the single break [T2]
+`HeatSink::UpdateCoolant` (@004adbf8) prices the damage-driven leak: `coolantDraw =
+ownZone->damageLevel × heatLoad`, floor 0.0025, and the `coolantActive@0x138` hysteresis
+(ON >0.003) IS the `ReportLeak` attribute the 19 authored leak watchers (3-note warning) ride.
+The read is the **qualified ENGINE member** `Subsystem::damageZone@0xE0` — which the port's
+MechSubsystem ctor never assigned (it filled only its re-declared shadow, gitea #64 / gotcha #1),
+so `zoneDamage` pinned 0 and a leak was **structurally impossible** regardless of damage. Fixed by
+ALIASING the engine base member to the same zone in both MechSubsystem ctors (mechsub.cpp) — every
+shadow reader is untouched (same object), the engine base `Subsystem::TakeDamage` null-AV is
+disarmed, and the #64 full de-shadow sweep remains the long-term cleanup.  Verified live: collision
+rattle and weapon crits (`[critroll]`) both drive `[cool]` leak lines (draw ≈ dmg×heatLoad, level
+draining, hysteresis arming).  **Authored damage routing** (BTL4.RES): collision rattle targets
+HeatSinkBank 0.3 / Gyro 0.35 / Torso 0.25 / Myomers 0.35 — Condenser + Reservoir are authored 0
+for collisions; weapon crits select via the ZONE's crit-entry list.  Remaining fidelity item:
+`HeatSink::DrawCoolant` (vtable slot 14, the central-system top-up) is still a `return 0` TODO, so
+a leaking subsystem drains its own loop; the pull-through to the central Reservoir gauge rides the
+loop-flow machinery.
+
 ## The coolant FLUSH (Gitea #7, 2026-07-19) — Reservoir InjectCoolant end-to-end [T2 live-verified]
 The manual-p24 coolant button (coolant MFD top-right; punch or HOLD): message id **4 "InjectCoolant"**
 on the Reservoir (handler table @**0x50e680**, one entry → @4aee70 — same per-receiver id space as the