Division by zero in inventory code from TTA workstation

[Cervator]

Noticed while testing another potential Alpha RC

Started TTA, made an axe, got two wooden trunks, placed them adjacent, "blessed" them via right click of the axe so they'd turn into a workstation, e clicked it to access crafting, and boom:

00:50:46.978 [Saving-0] INFO  o.t.p.internal.SaveTransaction - Save game finished
00:51:32.575 [main] INFO  o.t.w.b.internal.BlockManagerImpl - Registered BlockFamily[WoodAndStone:GrandMapleLog]
00:51:32.576 [main] INFO  o.t.w.b.internal.BlockManagerImpl - Registered Block WoodAndStone:GrandMapleLog with id 1082
00:51:43.540 [main] ERROR o.terasology.engine.TerasologyEngine - Uncaught exception, attempting clean game shutdown
java.lang.ArithmeticException: / by zero
    at org.terasology.rendering.nui.layers.ingame.inventory.InventoryGrid.getPreferredContentSize(InventoryGrid.java:95) ~[na:na]
    at org.terasology.rendering.nui.internal.CanvasImpl.calculateRestrictedSize(CanvasImpl.java:347) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.layouts.ScrollableArea.onDraw(ScrollableArea.java:76) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.internal.CanvasImpl.drawStyledWidget(CanvasImpl.java:406) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.internal.CanvasImpl.drawWidget(CanvasImpl.java:392) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.layouts.relative.RelativeLayout.onDraw(RelativeLayout.java:78) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.internal.CanvasImpl.drawStyledWidget(CanvasImpl.java:406) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.internal.CanvasImpl.drawWidget(CanvasImpl.java:392) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.layouts.relative.RelativeLayout.onDraw(RelativeLayout.java:78) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.internal.CanvasImpl.drawStyledWidget(CanvasImpl.java:406) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.internal.CanvasImpl.drawWidget(CanvasImpl.java:392) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.CoreScreenLayer.onDraw(CoreScreenLayer.java:107) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.internal.CanvasImpl.drawStyledWidget(CanvasImpl.java:406) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.internal.CanvasImpl.drawWidget(CanvasImpl.java:392) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.rendering.nui.internal.NUIManagerInternal.render(NUIManagerInternal.java:377) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.engine.modes.StateIngame.renderUserInterface(StateIngame.java:234) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.engine.modes.StateIngame.render(StateIngame.java:218) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.engine.subsystem.lwjgl.LwjglGraphics.postUpdate(LwjglGraphics.java:189) ~[engine-1.0.0-SNAPSHOT.jar:1644, develop, 1644, alpha]
    at org.terasology.engine.TerasologyEngine.mainLoop(TerasologyEngine.java:423) ~[engine-1.0.0-SNAPSHOT.jar:1644, origin/develop, 1644]
    at org.terasology.engine.TerasologyEngine.run(TerasologyEngine.java:369) ~[engine-1.0.0-SNAPSHOT.jar:1644, origin/develop, 1644]
    at org.terasology.engine.Terasology.main(Terasology.java:154) ~[Terasology.jar:1644, origin/develop, 1644]
00:51:43.540 [main] INFO  o.terasology.engine.TerasologyEngine - Shutting down Terasology...
00:51:43.595 [main] INFO  o.t.p.i.ReadWriteStorageManager - Saving - Creating game snapshot

Figuring it is probably a minor bug either resulting in an action working on a no-slot inventory or something not hardened well. Or both.

[ojsheikh]

This occurs because the CraftingStation skin does define a layout for ItemIcon. Perhaps this broke when the inventory code was moved from engine to core. An easy fix was to inherit from inventoryDefault, but perhaps a check should be added here for the case in which the preferred icon width is zero.

[Cervator]

Thanks! Tested out the fix and it works :-)

I submitted #2212 to get your mentioned zero check added, up for doing that sometime? I figure it might be needed in more places than one.

I also noticed #2213 while testing - I don't see the actual product listed in the g crafting menu