Server Group GC Cap Warning And Zombie Reaper

Server Group GC, Group-Cap Warning, and Zombie Reaper

Source-verified 2026-06-21 against master 0139a346. Paths relative to Missions/[55-2hc]warfarev2_073v48co.chernarus/ unless noted. Arma 2 OA 1.64.

Arma 2 OA enforces a hard engine ceiling of roughly 144 groups per side, and the engine does not automatically reclaim a group once its last unit dies or is deleted. Empty groups therefore accumulate as a slow leak: once a side reaches 144, createGroup returns grpNull and every downstream AI spawn fails silently with no error in the RPT. Server\FSM\server_groupsGC.sqf is the always-on server loop that keeps that ceiling unreachable in normal play. On a 60-second cadence it runs four jobs in one pass: an empty-group garbage-collection sweep, an orphaned-team "zombie" reaper, a debounced per-side cap-warning, and a telemetry suite (GCSTAT, GUERCAP, plus a throttled per-source audit). It also publishes a per-side group-count cache that other loops read instead of re-scanning allGroups themselves.

This page documents the GC loop itself. It is distinct from the AI-Headless delegation prose, from the marker/garbage/empty-vehicle collectors (Marker-Cleanup-Restoration-Systems-Atlas), and from the dormant debug-only groupsMonitor.sqf noted in the dead-code register.

Launch and loop frame

The script is launched once, late in server init, after the garbage collector and empty-vehicle collector are defined.

Aspect	Detail	Source
Server guard	if (!isServer) exitWith {}; — runs server-only	Server/FSM/server_groupsGC.sqf:9
Loop condition	while {!WFBE_GameOver} do { sleep 60; ... } — exits when the game ends	Server/FSM/server_groupsGC.sqf:16-17
Warn debounce	_warnInterval = 300; — 5 minutes between repeated warnings, same side and threshold	Server/FSM/server_groupsGC.sqf:13
Audit window counter	_auditN = 0; — counts elapsed 5-min windows; the expensive audit fires only every WFBE_C_GROUPAUDIT_EVERY-th window	Server/FSM/server_groupsGC.sqf:14

The order within each 60s cycle is: empty-group sweep, zombie reaper, per-side count + cache publish, GCSTAT/GUERCAP, cap warnings, then the throttled source-attribution audit.

Empty-group GC sweep

The first job iterates allGroups, finds every group with zero units, and deletes the non-persistent ones. Two counters are reset each pass: _gcEmptyFound counts all zero-unit groups seen (including persistent ones that are kept), and _gcReaped counts the non-persistent empties actually deleted.

Step	Detail	Source
Empty test	if (!isNull _grp && {(count (units _grp)) == 0}) then {...}	Server/FSM/server_groupsGC.sqf:25
Persistence read	_isPers = _grp getVariable "wfbe_persistent"; then if (isNil "_isPers") then {_isPers = false};	Server/FSM/server_groupsGC.sqf:29-30
Reap	if (!_isPers) then { deleteGroup _grp; _gcReaped = _gcReaped + 1; };	Server/FSM/server_groupsGC.sqf:31-34

A group flagged wfbe_persistent is never reaped even when empty — this is the contract static-defense manning relies on so a temporarily-empty garrison slot is not collected (Static-Defense-Manning-Reference). The A2-OA trap is called out in the source itself: the two-argument [name, default] form of getVariable is unreliable on GROUP objects in this engine (it can yield nil instead of the supplied default), so the sweep uses the single-argument form plus an explicit isNil guard (server_groupsGC.sqf:27-30).

Orphaned-team zombie reaper

The second job reclaims AI teams whose human player disconnected under JIP-preserve but never returned. When WFBE_C_AI_TEAMS_JIP_PRESERVE == 1, a disconnecting player's AI subordinates are kept alive and the team is stamped with the disconnect time. If the player never reconnects within the timeout, those units become orphaned "zombies" that consume a group slot and units forever; this reaper cleans them up.

Aspect	Detail	Source
Timeout param	_zombieTimeout = missionNamespace getVariable ["WFBE_C_DISCONNECT_ZOMBIE_TIMEOUT", 600]; — default 600s; set 0 to disable the whole block	Server/FSM/server_groupsGC.sqf:42-43
Orphan stamp read	_orphanedAt = _grp getVariable "wfbe_orphaned_at"; then if (isNil "_orphanedAt") then {_orphanedAt = -1};	Server/FSM/server_groupsGC.sqf:50-51
Age gate	if (_orphanedAt >= 0 && {(time - _orphanedAt) >= _zombieTimeout}) then {...}	Server/FSM/server_groupsGC.sqf:52
Unclaimed check	_uidVal = _grp getVariable "wfbe_uid"; if (isNil "_uidVal") then {...} — only reaps if no player has re-claimed the team	Server/FSM/server_groupsGC.sqf:54-55
HQ exclusion	_zombieHQ = (side _grp) Call WFBE_CO_FNC_GetSideHQ; then subtracted from the kill list	Server/FSM/server_groupsGC.sqf:58-61
Vehicle gather	_zombieVehicles = [_grp, false] Call GetTeamVehicles;	Server/FSM/server_groupsGC.sqf:60
Kill loop	{ if (!isPlayer _x && !(_x in playableUnits)) then { deleteVehicle _x; ... } } forEach _zombieUnits;	Server/FSM/server_groupsGC.sqf:63-68
Clear stamp	_grp setVariable ["wfbe_orphaned_at", nil]; — prevents re-reaping the now-empty husk	Server/FSM/server_groupsGC.sqf:69
Log	INFORMATION ... reaped %1 zombie unit(s) from orphaned team %2 (disconnected %3s ago) via WFBE_CO_FNC_AICOMLog	Server/FSM/server_groupsGC.sqf:70

The reaper mirrors the preserve==0 deletion pattern from the disconnect handler (the same isPlayer/playableUnits guard and HQ exclusion, so a teammate crewing the MHQ is never deleted). After the units are removed, the now-empty group is left for the empty-group sweep above to delete on a later pass.

Feeder and claim contract

The reaper is fed by the player-disconnect handler, and the unclaimed test relies on wfbe_uid being cleared.

Event	Action	Source
Connect	_team setVariable ["wfbe_uid", _uid]; — team is claimed	Server/Functions/Server_OnPlayerConnected.sqf:65
Disconnect, preserve==1	_team setVariable ["wfbe_orphaned_at", time]; — stamps the orphan clock	Server/Functions/Server_OnPlayerDisconnected.sqf:110-113
Disconnect, preserve==0	Deletes the units immediately (same guard pattern) instead of stamping	Server/Functions/Server_OnPlayerDisconnected.sqf:105-109
Disconnect, both paths	_team setVariable ["wfbe_uid", nil]; — marks the team unclaimed	Server/Functions/Server_OnPlayerDisconnected.sqf:132

Because wfbe_uid is cleared on disconnect and re-set on connect, a player who reconnects before the timeout re-claims the team (wfbe_uid is non-nil), and the reaper's isNil "_uidVal" check at server_groupsGC.sqf:55 skips it. Player-Join-Disconnect-And-AntiStack-Lifecycle documents the disconnect feeder; this loop is the GC consumer of the wfbe_orphaned_at stamp.

Per-side count and group-count cache

After the reaper, the loop does one allGroups pass to count groups per side and to count untagged groups (those with no wfbe_group_src, i.e. created outside the WFBE_CO_FNC_CreateGroup wrapper). The per-side counts are published to missionNamespace so other loops do not re-scan allGroups.

Variable	Meaning	Source
wfbe_grpcnt_west / _east / _guer	Per-side group count from this sweep	Server/FSM/server_groupsGC.sqf:96-98
wfbe_grpcnt_t	time of the last publish (cache freshness)	Server/FSM/server_groupsGC.sqf:99
_untW / _untE / _untG	Untagged-group count per side (wrapper-bypass leak signal)	Server/FSM/server_groupsGC.sqf:86-91

server_town_ai.sqf reads wfbe_grpcnt_guer from this cache, falling back to a live allGroups scan only until the first GC sweep warms it (server_town_ai.sqf:62). The B7 efficiency note in the source explains this is precisely why the cache exists (server_groupsGC.sqf:94-95).

Group-cap pre-warning (130 / 144)

Each pass, for WEST, EAST, and RESISTANCE, the loop emits a debounced RPT WARNING when the side's count crosses two thresholds: >= 130 (approaching) and >= 144 (at cap). Each threshold per side has its own debounce key in missionNamespace so a sustained high count does not spam the RPT more than once per _warnInterval (300s).

Threshold	Debounce key	Message	Source
WEST >= 130	wfbe_groupcap_warn_west130	...approaching cap (>= 130); AI spawns will fail silently at 144.	server_groupsGC.sqf:126-132
WEST >= 144	wfbe_groupcap_warn_west144	...AT CAP; createGroup will return grpNull and AI spawns will silently fail.	server_groupsGC.sqf:134-140
EAST >= 130 / 144	wfbe_groupcap_warn_east130 / _east144	same approach / at-cap text	server_groupsGC.sqf:142-157
RESISTANCE >= 130 / 144	wfbe_groupcap_warn_guer130 / _guer144	same approach / at-cap text	server_groupsGC.sqf:159-174

All six warnings route through WFBE_CO_FNC_AICOMLog at level WARNING. The debounce default sentinel is -9999 so the first crossing always fires (server_groupsGC.sqf:127).

GUER soft-cap monitor

For RESISTANCE the 144 engine cap is rarely the real limit. The mission imposes a soft cap, WFBE_C_GUER_GROUPS_MAX (default 80), and town AI defers new resistance garrisons once it is reached — so GUER town defense degrades long before the 130/144 engine warning would ever fire. The GC loop emits a GUERCAP telemetry line every pass tracking the soft cap.

Aspect	Detail	Source
Soft cap read	_guerMax = missionNamespace getVariable ["WFBE_C_GUER_GROUPS_MAX", 80]; (clamped to >= 1)	server_groupsGC.sqf:115-116
Percent	_guerPct = round ((_cntGuer / _guerMax) * 100);	server_groupsGC.sqf:117
90% threshold	_guerSoftThreshold = round (_guerMax * 0.9);	server_groupsGC.sqf:118
GUERCAP line	`GUERCAP	v1
Enforcement (consumer)	if (_side == resistance && _guerGroupCount >= _guerGroupsMax) then {...defer garrison...}	server_town_ai.sqf:168-173

The cap is re-read each pass so a live lobby-param change is honoured. AI-Commander-Tunable-Constants-Reference lists the constant; this loop and server_town_ai.sqf are where it is observed and enforced.

Telemetry reference

The GC loop emits a structured set of diag_log lines. Two are cheap and fire every 60s pass; the rest live inside the 5-minute source-attribution audit, which is additionally throttled by WFBE_C_GROUPAUDIT_EVERY.

Tag	Cadence	Payload	Source
`GCSTAT	v1`	every 60s	reaped, emptyFound, per-side west/east/guer, untagged untW/untE/untG, t (round min)
`GUERCAP	v1`	every 60s	count, max, pct, t
`EMPTYGRP	v1`	audit window	empty-group counts west/east/guer plus persistent-empty persW/persE/persG
`DELEGSTAT	v1`	audit window	total, srvLocal, remote, remotePct (HC offload proof)
`TOWNSTAT	v1`	audit window	town ownership west/east/guer/total by sideID
`ORBATSTAT	v1`	audit window	per-side crewed-vehicle order of battle (armor/car/heli/jet) + personnel
server_groupsGC.sqf: group audit [side] N/144: ...	audit window	per-(side, wfbe_group_src) breakdown + srvFps, activeTowns, units, auditMs	server_groupsGC.sqf:283-340

The throttled source-attribution audit

The expensive audit (full allGroups classification by wfbe_group_src, plus an allUnits pass and the per-side dump) is gated twice. First a 5-minute debounce on wfbe_groupaudit_last (server_groupsGC.sqf:178-181); then a modulo gate so the classification fires only on every WFBE_C_GROUPAUDIT_EVERY-th window (default 5, clamped to >= 1):

_every = missionNamespace getVariable ["WFBE_C_GROUPAUDIT_EVERY", 5];
if (_every < 1) then { _every = 1 };
if ((_auditN mod _every) == 0) then { ...expensive dump... };

(server_groupsGC.sqf:190-192). The source notes the dump costs ~2100ms on 276 groups, which is why it is throttled; critically, the husk-reap sweep, zombie reaper, and cap warnings all run earlier in the same 60s cycle, outside this branch, so the throttle never delays the actual GC work (server_groupsGC.sqf:183-188).

wfbe_group_src tagging

The audit classifies each group by its wfbe_group_src tag; untagged groups show as untagged. Editor-placed player-slot groups in mission.sqm are born by the engine with no createGroup call, so the wrapper never tags them. A one-shot init sweep tags every still-untagged WEST/EAST/RESISTANCE group as editor-player-slot (audit-only; they already carry wfbe_persistent=true, which the persistence-aware empty-group sweep honours, so the GC never reaps them):

Step	Detail	Source
Guard	if (isNil "WFBE_EDITOR_GROUPS_TAGGED") then {...} (one-shot)	Server/Init/Init_Server.sqf:838-839
Tag	_x setVariable ["wfbe_group_src", "editor-player-slot", true]; for untagged WEST/EAST/RESISTANCE groups	Server/Init/Init_Server.sqf:850 (sweep body :840-852)

A rising untagged count in GCSTAT/the audit is therefore a wrapper-bypass leak signal rather than expected editor slots. Commander-HQ-Lifecycle-Atlas describes the wfbe_group_src tagging from the producer side.

This sweep is audit-only — never deleteGroup a JIP-selectable slot (cmdcon30, 2026-06-30)

The sweep must only TAG, never reap. The mission.sqm editor block has ~27 WEST + 27 EAST player-slot groups; of those, ~13/side are "overflow" slots whose placeholder unit self-deletes at load (init="... deleteVehicle this"), leaving an empty group that a human can still JIP into. Empty does not mean dead.

PR#122 (the qol-polish-pack) briefly turned this audit-only sweep into a REAPER: it called deleteGroup on the empty WEST/EAST/RESISTANCE editor groups to reclaim group-cap headroom, with count (units _x) == 0 as its only discriminator. That deleted a JIP-selectable overflow slot's group. The failure chain on the live server:

• a player JIP-joins that overflow slot -> the engine drops them into an already-deleteGroup'd group that carries no wfbe_side;
• the enrollment self-heal in Server/Functions/Server_OnPlayerConnected.sqf (the B746 resolver, "re-arming enrollment ... attempt N/3", keyed on WFBE_CONNECT_RETRY_<uid>, Server_OnPlayerConnected.sqf:120-143) never resolves a side, bails, re-arms 3x, and exhausts;
• the player is left in DEADSPAWN — no team, no HUD, no markers. JIP / mid-match specific.

cmdcon30 (2026-06-30) REMOVED the reaper, reverting to the pre-PR122 audit-only tagging (the cmdcon30 note lives in-source at Server/Init/Init_Server.sqf:844-849). The empty overflow slots ran the entire pre-PR122 history with no group-cap problem, and the only safe reap would skip them anyway since they carry wfbe_persistent — which the empty-group sweep above honours and the PR#122 reaper did not. Rule: never deleteGroup a JIP-selectable editor-slot group at boot. A re-join with the same UID was also permanently stuck because WFBE_CONNECT_RETRY_<uid> was only cleared on enrollment SUCCESS; cmdcon30 also clears it on disconnect (Server/Functions/Server_OnPlayerDisconnected.sqf) so a re-join gets fresh re-arms.

Continue Reading

• Static-Defense-Manning-Reference — the wfbe_persistent flag that exempts empty garrison groups from this sweep.
• Player-Join-Disconnect-And-AntiStack-Lifecycle — the disconnect handler that stamps wfbe_orphaned_at and feeds the zombie reaper.
• Commander-HQ-Lifecycle-Atlas — wfbe_group_src tagging from the group-creation producer side.
• AI-Commander-Tunable-Constants-Reference — WFBE_C_GUER_GROUPS_MAX, WFBE_C_DISCONNECT_ZOMBIE_TIMEOUT, and WFBE_C_GROUPAUDIT_EVERY constants.
• Marker-Cleanup-Restoration-Systems-Atlas — the sibling garbage, empty-vehicle, and map cleanup loops (distinct from group GC).