Crashreport when mouse is near split pane

[GerdP]

What steps will reproduce the problem?

1. Move mouse onto the right side of the edit window

What is the expected result?

cursor changes to resize the split pane window

What happens instead?

crash report

Please provide any additional information below. Attach a screenshot if possible.

Build-Date:2020-05-17 15:04:03
Revision:16439
Is-Local-Build:true

Identification: JOSM/1.5 (16439 SVN en) Windows 10 64-Bit
OS Build number: Windows 10 Home 1903 (18362)
Memory Usage: 740 MB / 1753 MB (368 MB allocated, but free)
Java version: 1.8.0_191-b12, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Screen: \Display0 1920x1080
Maximum Screen Size: 1920x1080
VM arguments: [-agentlib:jdwp=transport=dt_socket,suspend=y,address=localhost:53347, -ea, -Dfile.encoding=UTF-8]
Program arguments: [--debug]
Dataset consistency test: No problems found

Plugins:
+ OpeningHoursEditor (35414)
+ PolygonCutOut (v0.7)
+ apache-commons (35362)
+ buildings_tools (35405)
+ continuosDownload (91)
+ ejml (35313)
+ geotools (35169)
+ jaxb (35092)
+ jts (35122)
+ merge-overlap (35248)
+ o5m (35248)
+ opendata (35405)
+ pbf (35446)
+ poly (35248)
+ reverter (35409)
+ undelete (35405)
+ utilsplugin2 (35440)

Validator rules:
+ c:\josm\core\resources\data\validator\geometry.mapcss

Last errors/warnings:
- E: Handled by bug report queue: java.lang.NullPointerException


=== REPORTED CRASH DATA ===
BugReportExceptionHandler#handleException:
No data collected.

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: AWT-EventQueue-0 (20) of main
java.lang.NullPointerException
	at java.util.Objects.requireNonNull(Objects.java:203)
	at java.util.Optional.<init>(Optional.java:96)
	at java.util.Optional.of(Optional.java:108)
	at java.util.stream.FindOps$FindSink$OfRef.get(FindOps.java:193)
	at java.util.stream.FindOps$FindSink$OfRef.get(FindOps.java:190)
	at java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:152)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:464)
	at org.openstreetmap.josm.gui.widgets.MultiSplitLayout.dividerAt(MultiSplitLayout.java:782)
	at org.openstreetmap.josm.gui.widgets.MultiSplitLayout.dividerAt(MultiSplitLayout.java:796)
	at org.openstreetmap.josm.gui.widgets.MultiSplitPane.updateCursor(MultiSplitPane.java:336)
	at org.openstreetmap.josm.gui.widgets.MultiSplitPane.access$0(MultiSplitPane.java:330)
	at org.openstreetmap.josm.gui.widgets.MultiSplitPane$InputHandler.mouseEntered(MultiSplitPane.java:350)
	at java.awt.Component.processMouseEvent(Component.java:6548)
	at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
	at java.awt.Component.processEvent(Component.java:6304)
	at java.awt.Container.processEvent(Container.java:2239)
	at java.awt.Component.dispatchEventImpl(Component.java:4889)
	at java.awt.Container.dispatchEventImpl(Container.java:2297)
	at java.awt.Component.dispatchEvent(Component.java:4711)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4904)
	at java.awt.LightweightDispatcher.retargetMouseEnterExit(Container.java:4686)
	at java.awt.LightweightDispatcher.trackMouseEnterExit(Container.java:4664)
	at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4515)
	at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4476)
	at java.awt.Container.dispatchEventImpl(Container.java:2283)
	at java.awt.Window.dispatchEventImpl(Window.java:2746)
	at java.awt.Component.dispatchEvent(Component.java:4711)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760)
	at java.awt.EventQueue.access$500(EventQueue.java:97)
	at java.awt.EventQueue$3.run(EventQueue.java:709)
	at java.awt.EventQueue$3.run(EventQueue.java:703)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:84)
	at java.awt.EventQueue$4.run(EventQueue.java:733)
	at java.awt.EventQueue$4.run(EventQueue.java:731)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

[GerdP]

In 16440/josm:

fix #19252: Crashreport when mouse is near split pane
revert changes in MultiSplitLayout from r16438, makes JOSM unusable
Don't know why the new code doesn't work.

[simon04]

Thank you for fixing this issue!

[GerdP]

Any idea why your change didn't work? Is the stream api not yet stable in JDK8?

[simon04]

In 16450/josm:

see #19252 - Java 8: use Stream

Now including the previously missing filter(Objects::nonNull)

[GerdP]

But do you really get the same result? My understanding is that the old code stopped when child.getBounds().contains(x, y) is true, no matter what result we get from dividerAt(child, x, y).
My understanding of the new code is that it continous to loop in case that dividerAt(child, x, y) returns null.

[GerdP]

What do you think about this variant?

            return split.getChildren().stream()
                    .filter(child -> child.getBounds().contains(x, y))
                    .findFirst()
                    .map(child -> dividerAt(child, x, y))
                    .orElse(null);

[simon04]

Yes, that's it! I rechecked for similar cases and found a few glitches in the refactoring. I'll commit a fix shortly.

[simon04]

In 16453/josm:

see #19251, see #19252 - fix findFirst/map/orElse sequence