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HUD energy-time stat dereferencing a missing resource distributor

Category: Client only Patch: ClientPlugin/Patches/HudEnergyTimeRemainingStatPatch.cs Pull request: #3

The bug

MyStatControlledEntityEnergyEstimatedTimeRemaining.Update walks MySession.Static.ControlledGrid.GridSystems.ResourceDistributor with only ControlledGrid null-checked. The NullReferenceException lands on the update thread and takes the client down.

ResourceDistributor belongs to a logical group, not to the grid. MyCubeGridSystems' constructor never assigns it; OnAddedToGroup takes it from the group and OnRemovedFromGroup nulls it again, while GridSystems itself is assigned once and never nulled. "GridSystems non-null, ResourceDistributor null" is therefore the designed shape of a grid outside a logical group, not a startup artifact. The window opens at OnRemovedFromScene → RemoveNode(Logical) → OnRemovedFromGroup and closes at OnAddedToScene → AddNode → AcquireGroup → OnAddedToGroup. MySession.ControlledGrid is computed live from ControlledEntity.CubeGrid with no caching, so it keeps returning the grid across that window.

The driver, MyHud.UpdateBeforeSimulation → m_Stats.Update, is gated only on !Sync.IsDedicated. It is a simulation-phase update, not a draw call, with no platform branch in MyHud.cs, so a rendering Windows client runs it on the same schedule as a headless Linux one. Vanilla guards this same null in three other places, one of them MyStatControlledEntityPowerUsage, which reads the same field off the same controlled entity in the same stats sweep. This stat is the only one that omits the check, which makes it a vanilla inconsistency rather than a platform or loader artifact. Settled against decompiled 1.210.014.

How often a player hits the window is another question: taking control programmatically, right after replication, reaches it far more often than walking to a cockpit does. Closing the controlled grid does not: the game clears the controller before the systems lose their distributor, checked by instrumenting the prefix and closing a grid from under a seated character.

The fix

A prefix skips the stat for that frame when the distributor is missing, so the previous value stands until it appears; the game recomputes it on the next update.

The patch lives in ClientPlugin, not Shared: the type name is present in the dedicated server build so a patch would resolve, but a dedicated server has no HUD and never runs that update.

The fix was first written in the Remote plugin (SE1-0010) and ported here, where a vanilla game bug belongs. Remote has dropped its copy, so the two never patch the same method in one process.

Testing

Run in game under Pulsar (headless Linux client, Earth Rover Test):

  • The Harmony IL dump shows the prefix installed on MyStatControlledEntityEnergyEstimatedTimeRemaining::Update(), exactly once, and the plugin loads with no patch failure.
  • With the prefix temporarily instrumented, it runs on every frame, including with a real controlled grid while seated in a cockpit, and never skipped the stat in normal play, so the guard costs nothing there.
  • Behaviour is identical with the fix enabled and disabled in normal play.