Vehicle Cargo Equip Loop Bounds

Vehicle Cargo Equip Loop Bounds

This page documents a confirmed cargo-application loop-bound bug in vehicle and backpack gear helpers. It replaces the older vague scout note in Gear/loadout/EASA atlas.

All mission paths are relative to Missions/[55-2hc]warfarev2_073v48co.chernarus/.

Current Flow

flowchart TD
    BuyGear["Client/GUI/GUI_BuyGearMenu.sqf"] --> GetVehicle["Client_GetVehicleContent.sqf"]
    GetVehicle --> VehicleContent["_gear_sel_vehicle / _gear_vehicle_content"]
    BuyGear --> EquipVehicle["Common_EquipVehicle.sqf"]
    BuildUnit["Client_BuildUnit.sqf soldier gear path"] --> EquipBackpack["Common_EquipBackpack.sqf"]
    EquipUnit["Common_EquipUnit.sqf"] --> EquipBackpack

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Source Evidence

Source	Evidence
Common/Init/Init_Common.sqf:108,110	Compiles WFBE_CO_FNC_EquipBackpack and WFBE_CO_FNC_EquipVehicle when not running the A2 vanilla fallback.
Client/GUI/GUI_BuyGearMenu.sqf:94,102,108	Reads current vehicle cargo through Client_GetVehicleContent.sqf and stores selected cargo arrays.
Client/GUI/GUI_BuyGearMenu.sqf:439	Applies selected vehicle cargo with [vehicle _target, _gear_sel_vehicle] Call WFBE_CO_FNC_EquipVehicle.
Client/Functions/Client_GetVehicleContent.sqf:20-22	Reads cargo with safe for '_i' from 0 to count(_items)-1 loops. The collector is not the bug.
Common/Functions/Common_EquipVehicle.sqf:27,33,39	Applies weapon, magazine and backpack cargo with inclusive for '_i' from 0 to count(_items) loops.
Common/Functions/Common_EquipBackpack.sqf:35,41	Applies backpack weapon and magazine contents with the same inclusive for '_i' from 0 to count(_items) loops.
Client/Functions/Client_BuildUnit.sqf:229	Calls WFBE_CO_FNC_EquipBackpack for soldier purchases when a backpack is present.
Common/Functions/Common_EquipUnit.sqf:38	Calls WFBE_CO_FNC_EquipBackpack for unit loadout application.

Bug Shape

SQF arrays are zero-indexed. These equip helpers iterate one slot past the last valid item:

for '_i' from 0 to count(_items) do {_vehicle addWeaponCargoGlobal [_items select _i, _counts select _i]};

For an array with N entries, valid indexes are 0 through N - 1. Index N is out of range.

Confirmed current-source locations:

Helper	Loops
Common_EquipVehicle.sqf	weapon cargo :27, magazine cargo :33, backpack cargo :39
Common_EquipBackpack.sqf	backpack weapon cargo :35, backpack magazine cargo :41

Likely impact:

• Each non-empty cargo application can attempt one out-of-range _items select _i / _counts select _i at the end of the loop.
• Depending on Arma 2 OA runtime behavior and logging settings, this may create RPT noise, abort the loop tail or fail silently after applying valid entries.
• Empty arrays may also enter the loop at index 0 unless the surrounding content guard exits first; Common_EquipVehicle.sqf checks only the top-level vehicle-content array, not each sub-array.
• This is a correctness and reliability bug in local gear/cargo application, not a public-server authority fix.

Patch Shape

Recommended first patch:

for '_i' from 0 to count(_items)-1 do {
    _vehicle addWeaponCargoGlobal [_items select _i, _counts select _i];
};

Apply the count(_items)-1 bound to all five confirmed loops.

Optional guard if the code owner wants clearer empty-array behavior:

if (count _items > 0) then {
    for '_i' from 0 to count(_items)-1 do {
        _vehicle addWeaponCargoGlobal [_items select _i, _counts select _i];
    };
};

Keep the patch scoped:

• Do not redesign the buy-gear UI.
• Do not treat this as gear-purchase authority hardening.
• Do not combine with Gear template profile filter, even though both live in the gear UI area.

Validation Plan

Source checks:

1. Common_EquipVehicle.sqf has no for '_i' from 0 to count(_items) do loops.
2. Common_EquipBackpack.sqf has no for '_i' from 0 to count(_items) do loops.
3. Client_GetVehicleContent.sqf still uses count(_items)-1 and does not regress.
4. Source Chernarus is patched first; Vanilla Takistan is propagated by LoadoutManager from a correctly named a2waspwarfare checkout.

Arma smoke:

1. Add one weapon cargo item to a vehicle through Buy Gear and confirm exactly one appears.
2. Add one magazine cargo item to a vehicle and confirm exactly one appears.
3. Add one backpack cargo item to a vehicle and confirm exactly one appears.
4. Add backpack weapon/magazine contents to a unit backpack and confirm contents apply without RPT out-of-range errors.
5. Try empty cargo groups and confirm no RPT out-of-range errors.

Generated And Modded Missions

Missions_Vanilla/[61-2hc]warfarev2_073v48co.takistan currently carries the same inclusive loops in Common_EquipVehicle.sqf and Common_EquipBackpack.sqf.

Per project rules:

• Patch source Chernarus first.
• Use Tools/LoadoutManager for Vanilla propagation.
• Treat Napf/Eden/Lingor as divergent forks and other modded folders as stubs unless the owner chooses a maintenance model.

Agent Notes

• This is a small, patch-ready reliability bug.
• It should be safe to patch independently from the server-authority/economy redesign because it only fixes loop bounds in cargo-application helpers.
• Keep this page paired with Gear/loadout/EASA atlas, Client UI systems atlas and Feature status.

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