bugfix: Fix issue where builders could resume completed tasks after being disabled

[Stubbjax]

This change fixes an issue introduced by #1870 that allows builders to resume an already completed task after being disabled.

When assigning a new build task to a builder, if the target building is an already-completed building, then the new task is ignored.

Before

BEFORE.mp4

After

AFTER.mp4

[greptile-apps]

Greptile Summary

This PR fixes a bug from #1870 where a builder (Dozer/Worker) could resume a completed build task after recovering from EMP, underpowered, or hacked states. The fix moves the "save current task" responsibility out of internalCancelTask and into Object::setDisabledUntil, and adds a setPreviousTask API with a guard against DOZER_TASK_INVALID.

• Core fix is sound: removing m_previousTask = task from internalCancelTask prevents a completed-build's ID from ever being stored as the task to resume, which closes the reported regression.
• setPreviousTask guard is correct: the new method returns early on DOZER_TASK_INVALID, eliminating the previously-flagged out-of-bounds array access when a builder is idle at disable time.
• Build-resume condition is inverted: in all four resumePreviousTask implementations, !target->testStatus(OBJECT_STATUS_UNDER_CONSTRUCTION) evaluates true for a completed building (status cleared at 100%) and false while still under construction — meaning a builder EMP'd mid-build will stay idle after recovery instead of resuming.

Confidence Score: 3/5

The primary structural change correctly prevents the reported regression, but all four resumePreviousTask implementations carry an inverted boolean guard that will prevent builders from resuming an in-progress build after EMP recovery.

The root-cause fix is architecturally correct and closes the completed-build resume bug. However, the !testStatus(OBJECT_STATUS_UNDER_CONSTRUCTION) condition in every resumePreviousTask is backwards: it allows resuming a completed building and blocks resuming an incomplete one — a direct regression of the EMP-during-build scenario that the old code handled correctly. This needs a one-character fix (! removal) in all four implementation files before merging.

All four resumePreviousTask implementations: Generals/.../DozerAIUpdate.cpp, Generals/.../WorkerAIUpdate.cpp, GeneralsMD/.../DozerAIUpdate.cpp, GeneralsMD/.../WorkerAIUpdate.cpp.

Important Files Changed

Filename	Overview
Generals/Code/GameEngine/Source/GameLogic/Object/Update/AIUpdate/DozerAIUpdate.cpp	Adds setPreviousTask (correctly guards against INVALID) and refactors resumePreviousTask, but the build-resume guard !testStatus(OBJECT_STATUS_UNDER_CONSTRUCTION) is inverted — newTask fires for complete buildings and is skipped for incomplete ones.
Generals/Code/GameEngine/Source/GameLogic/Object/Update/AIUpdate/WorkerAIUpdate.cpp	Mirrors DozerAIUpdate changes; carries the same inverted !testStatus guard in resumePreviousTask.
GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Update/AIUpdate/DozerAIUpdate.cpp	Zero Hour mirror of the Generals Dozer fix; same inverted !testStatus condition present.
GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Update/AIUpdate/WorkerAIUpdate.cpp	Zero Hour mirror of the Generals Worker fix; same inverted !testStatus condition present.
Generals/Code/GameEngine/Source/GameLogic/Object/Object.cpp	Correctly captures the current task via setPreviousTask at the moment of first EMP/underpowered/hacked disable, guarded against double-fire by the existing !isDisabledByType check.
GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Object.cpp	Identical, correct change to Generals/Object.cpp for Zero Hour.
Generals/Code/GameEngine/Include/GameLogic/Module/DozerAIUpdate.h	Adds setPreviousTask pure virtual and override declarations; no issues.
Generals/Code/GameEngine/Include/GameLogic/Module/WorkerAIUpdate.h	Adds setPreviousTask override declaration; no issues.
GeneralsMD/Code/GameEngine/Include/GameLogic/Module/DozerAIUpdate.h	Zero Hour mirror of DozerAIUpdate.h changes; no issues.
GeneralsMD/Code/GameEngine/Include/GameLogic/Module/WorkerAIUpdate.h	Zero Hour mirror of WorkerAIUpdate.h changes; no issues.

Sequence Diagram

sequenceDiagram
    participant OBJ as Object::setDisabledUntil
    participant DAU as DozerAIUpdate
    participant ICT as internalCancelTask
    participant RPT as resumePreviousTask

    Note over OBJ: Builder hit by EMP/underpowered/hacked
    OBJ->>DAU: setPreviousTask(getCurrentTask())
    Note over DAU: Guards DOZER_TASK_INVALID,<br/>saves m_previousTask + m_task[task]

    Note over ICT: Task cancelled due to disable
    ICT->>ICT: internalTaskCompleteOrCancelled(task)
    Note over ICT: m_previousTask no longer set here<br/>(removed by this PR)

    Note over RPT: Builder re-enables
    RPT->>RPT: "m_previousTask == INVALID? return"
    RPT->>RPT: "m_previousTask == DOZER_TASK_BUILD?"
    RPT->>RPT: findObjectByID(target)
    Note over RPT: ⚠ Inverted guard: !testStatus(UNDER_CONSTRUCTION)<br/>true=complete → calls newTask (wrong)<br/>false=incomplete → skips newTask (wrong)
    RPT->>DAU: newTask(BUILD, target)
    RPT->>RPT: "Reset m_previousTask = INVALID"

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_{Reviews (6): Last reviewed commit: "fix: Reverse condition" | Re-trigger Greptile}

[xezon]

Should this perhaps go into DozerAIUpdate::resumePreviousTask and here it should be an assert?

[Stubbjax]

Good point. I suppose it could seeing as this is the only way it can happen. Having to resolve the target from the task info does make the code a bit more complex though.

[xezon]

Now m_previousTask is no longer cleared if not DOZER_TASK_BUILD or already completed.

[xezon]

It is still not cleared if task is not DOZER_TASK_BUILD

[xezon]

This looks a bit strange. Wasn't cancelTask supposed to take of this? For example from Object::onDisabledEdge.

[Stubbjax]

Yes, but there was no distinction on how the disabling happened here. A unit entering a transport causes it to become disabled, and thus it would attempt to resume the task after exiting the transport.

[xezon]

Why is !target a valid condition for new task?

[Stubbjax]

I should just go to bed. 😅