[Patch] Load images from Wikimedia Commons can cause crash report

[GerdP]

What steps will reproduce the problem?

1. Start JOSM, note that Load images from Wikimedia Commons is disabled
2. Drag& drop an image to have one image layer, note that Load images from Wikimedia Commons is now enabled
3. delete the image layer
4. note that Load images from Wikimedia Commons is still enabled and causes a crash report when used

What is the expected result?

The action disabled again when there's no mapView.

What happens instead?

When the last layer is removed the updateEnabledState() checks MainApplication.isDisplayingMapView().
At this point this returns true, so the action remains enabled.

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

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2023-12-07 13:35:12 +0100 (Thu, 07 Dec 2023)
Revision:18907
Build-Date:2023-12-07 16:38:49
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (18907 en) Windows 10 64-Bit
OS Build number: Windows 10 Home 2009 (19045)
Memory Usage: 801 MB / 1972 MB (493 MB allocated, but free)
Java version: 17.0.8+7-LTS, Azul Systems, Inc., OpenJDK 64-Bit Server VM
Look and Feel: com.sun.java.swing.plaf.windows.WindowsLookAndFeel
Screen: \Display0 1920×1080 (scaling 1.00×1.00)
Maximum Screen Size: 1920×1080
Best cursor sizes: 16×16→32×32, 32×32→32×32
System property file.encoding: Cp1252
System property sun.jnu.encoding: Cp1252
Locale info: en_DE
Numbers with default locale: 1234567890 -> 1234567890
VM arguments: [-Djpackage.app-version=1.5.18789, --add-modules=java.scripting,java.sql,javafx.controls,javafx.media,javafx.swing,javafx.web, --add-exports=java.base/sun.security.action=ALL-UNNAMED, --add-exports=java.desktop/com.sun.imageio.plugins.jpeg=ALL-UNNAMED, --add-exports=java.desktop/com.sun.imageio.spi=ALL-UNNAMED, --add-opens=java.base/java.lang=ALL-UNNAMED, --add-opens=java.base/java.nio=ALL-UNNAMED, --add-opens=java.base/jdk.internal.loader=ALL-UNNAMED, --add-opens=java.base/jdk.internal.ref=ALL-UNNAMED, --add-opens=java.desktop/javax.imageio.spi=ALL-UNNAMED, --add-opens=java.desktop/javax.swing.text.html=ALL-UNNAMED, --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED, -DXss50k, -Djpackage.app-path=%UserProfile%\AppData\Local\JOSM\HWConsole.exe]

Plugins:
+ OpeningHoursEditor (36196)
+ RoadSigns (36196)
+ apache-commons (36176)
+ buildings_tools (36200)
+ comfort0 (36200)
+ o5m (36126)
+ pbf (36176)
+ poly (36126)
+ reltoolbox (36200)
+ reverter (36196)
+ undelete (36126)
+ utilsplugin2 (36200)

Validator rules:
+ c:\josm\core\resources\data\validator\combinations.mapcss
+ c:\josm\core\resources\data\validator\geometry.mapcss
+ c:\josm\core\resources\data\validator\relation.mapcss
+ c:\josm\core\resources\data\validator\unnecessary.mapcss
+ d:\java_tools\JOSM\mygeometry.mapcss
+ https://josm.openstreetmap.de/josmfile?page=Rules/GermanySpecific&zip=1

Last errors/warnings:
- 00000.653 W: extended font config - overriding 'filename.Myanmar_Text=mmrtext.ttf' with 'MMRTEXT.TTF'
- 00000.654 W: extended font config - overriding 'filename.Mongolian_Baiti=monbaiti.ttf' with 'MONBAITI.TTF'
- 00001.052 E: java.security.KeyStoreException: Windows-ROOT not found. Cause: java.security.NoSuchAlgorithmException: Windows-ROOT KeyStore not available
- 00042.499 E: Handled by bug report queue: java.lang.NullPointerException: Cannot read field "mapView" because the return value of "org.openstreetmap.josm.gui.MainApplication.getMap()" is null
- 00160.687 E: Handled by bug report queue: java.lang.NullPointerException: Cannot read field "mapView" because the return value of "org.openstreetmap.josm.gui.MainApplication.getMap()" is null



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

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: AWT-EventQueue-0 (22) of main
java.lang.NullPointerException: Cannot read field "mapView" because the return value of "org.openstreetmap.josm.gui.MainApplication.getMap()" is null
	at org.openstreetmap.josm.gui.layer.geoimage.WikimediaCommonsLoader$WikimediaCommonsLoadImagesAction.actionPerformed(WikimediaCommonsLoader.java:78)
	at java.desktop/javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton.doClick(Unknown Source)
	at java.desktop/javax.swing.plaf.basic.BasicMenuItemUI.doClick(Unknown Source)
	at java.desktop/javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(Unknown Source)
	at java.desktop/java.awt.Component.processMouseEvent(Unknown Source)
	at java.desktop/javax.swing.JComponent.processMouseEvent(Unknown Source)
	at java.desktop/java.awt.Component.processEvent(Unknown Source)
	at java.desktop/java.awt.Container.processEvent(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
	at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.Container.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Window.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.Component.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)

[GerdP]

Happens also with latest r18938.

[GerdP]

disable action when last layer was removed

[GerdP]

In 18943/josm:

fix #23417: Load images from Wikimedia Commons can cause crash report

• disable the action when last layer was closed

This requires special action in layerRemoving(), so default listeners in JosmAction are no longer needed