Bug 1464 - GraphUI Scene: Resolve Data Race Modding Z Position activating a shape and Arrays.sort(..)
Summary: GraphUI Scene: Resolve Data Race Modding Z Position activating a shape and Ar...
Status: IN_PROGRESS
Alias: None
Product: GraphUI
Classification: JogAmp
Component: Core (show other bugs)
Version: 2.6.0
Hardware: All all
: P2 critical
Assignee: Sven Gothel
URL:
Depends on: 1454
Blocks:
  Show dependency tree / graph
 
Reported: 2023-09-26 14:15 CEST by Sven Gothel
Modified: 2023-09-30 01:37 CEST (History)
0 users

See Also:
Type: DEFECT
SCM Refs:
Workaround: ---

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Description Sven Gothel 2023-09-26 14:15:12 CEST 
Currently the shape's Z Position is modified within the mouse event dispatcher (Input EDT/thread) as well as read on same thread and on a renderer thread using Arrays.sort(..). 
The position might also been modified on another thread than the Input EDT/thread, e.g. the renderer thread -> Data race condition, inconsistency.

Arrays.sort(..) using TimSort detects the data race sometimes, i.e. throws an exception since the equals methods doesn't match anymore:

Exception in thread "main-Display-.x11_:0-1-EDT-1" java.lang.IllegalArgumentException: Comparison method violates its general contract!
        at java.base/java.util.TimSort.mergeHi(TimSort.java:903)
        at java.base/java.util.TimSort.mergeAt(TimSort.java:520)
        at java.base/java.util.TimSort.mergeForceCollapse(TimSort.java:461)
        at java.base/java.util.TimSort.sort(TimSort.java:254)
        at java.base/java.util.Arrays.sort(Arrays.java:1233)
        at jogamp.graph.ui.TreeTool.forSortedAll(TreeTool.java:132)
        at com.jogamp.graph.ui.Group.forSortedAll(Group.java:369)
        at jogamp.graph.ui.TreeTool.forSortedAll(TreeTool.java:141)
        at com.jogamp.graph.ui.Scene.forSortedAll(Scene.java:739)
        at com.jogamp.graph.ui.Scene.pickShape(Scene.java:563)
        at com.jogamp.graph.ui.Scene.dispatchMouseEventPickShape(Scene.java:996)
        at com.jogamp.graph.ui.Scene$SBCMouseListener.mouseMoved(Scene.java:1096)
        at jogamp.newt.WindowImpl.dispatchMouseEvent(WindowImpl.java:4498)
        at jogamp.newt.WindowImpl.consumePointerEvent(WindowImpl.java:4346)
        at jogamp.newt.WindowImpl.consumeEvent(WindowImpl.java:3744)
        at jogamp.newt.WindowImpl.doEvent(WindowImpl.java:3686)
        at jogamp.newt.WindowImpl.doPointerEvent(WindowImpl.java:4131)
        at jogamp.newt.WindowImpl.doMouseEvent(WindowImpl.java:3794)
        at jogamp.newt.driver.x11.WindowDriver.doMouseEvent(WindowDriver.java:489)
        at jogamp.newt.WindowImpl.sendMouseEvent(WindowImpl.java:3761)
        at jogamp.newt.driver.x11.DisplayDriver.DispatchMessages0(Native Method)
        at jogamp.newt.driver.x11.DisplayDriver.dispatchMessagesNative(DisplayDriver.java:112)
        at jogamp.newt.DisplayImpl.dispatchMessages(DisplayImpl.java:753)
        at jogamp.newt.DisplayImpl$7.run(DisplayImpl.java:672)
        at jogamp.newt.DefaultEDTUtil$NEDT.run(DefaultEDTUtil.java:347)
Exception in thread "main-Display-.x11_:0-1-EDT-1" java.lang.RuntimeException: X11Display.DispatchMessages0: MotionNotify: Exception occured at sendMouseEvent(..)
        at jogamp.newt.driver.x11.DisplayDriver.DispatchMessages0(Native Method)
        at jogamp.newt.driver.x11.DisplayDriver.dispatchMessagesNative(DisplayDriver.java:112)
        at jogamp.newt.DisplayImpl.dispatchMessages(DisplayImpl.java:753)
        at jogamp.newt.DisplayImpl$7.run(DisplayImpl.java:672)
Comment 1 Sven Gothel 2023-09-26 14:19:33 CEST 
This bug became more visible since adding feature of Bug 1454