NPE in Eclipse TextMate Grammar preference page

[bvo42]

Describe the bug

Spring Boot Language Server Feature breaks Eclipse preferences page Windows > Preferences > TextMate > Grammar.

When selecting an arbitrary grammar in the Create, edit or remove TextMate grammars the NPE below is thrown. With the NPW the whole preference page is no longer functional.

java.lang.NullPointerException: Cannot invoke "org.eclipse.swt.widgets.Button.setEnabled(boolean)" because the return value of "org.eclipse.tm4e.ui.internal.widgets.ThemeAssociationsWidget.getNewButton()" is null
	at org.eclipse.tm4e.ui.internal.preferences.GrammarPreferencePage$1.selectionChanged(GrammarPreferencePage.java:244)
	at org.eclipse.jface.viewers.Viewer$1.run(Viewer.java:151)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:174)
	at org.eclipse.jface.viewers.Viewer.fireSelectionChanged(Viewer.java:148)
	at org.eclipse.jface.viewers.StructuredViewer.updateSelection(StructuredViewer.java:2128)
	at org.eclipse.jface.viewers.StructuredViewer.handleSelect(StructuredViewer.java:1176)
	at org.eclipse.jface.viewers.StructuredViewer$4.widgetSelected(StructuredViewer.java:1205)
	at org.eclipse.jface.util.OpenStrategy.fireSelectionEvent(OpenStrategy.java:263)
	at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:421)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5796)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1529)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:5025)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:4477)
	at org.eclipse.jface.window.Window.runEventLoop(Window.java:823)
	at org.eclipse.jface.window.Window.open(Window.java:799)
	at org.eclipse.ui.internal.OpenPreferencesAction.run(OpenPreferencesAction.java:66)
	at org.eclipse.jface.action.Action.runWithEvent(Action.java:474)
	at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:580)
	at org.eclipse.jface.action.ActionContributionItem.lambda$4(ActionContributionItem.java:414)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5796)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1529)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:5025)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:4477)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1155)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1046)
	at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155)
	at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:643)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:550)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:171)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:152)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:136)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:402)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:659)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:596)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1467)
	at org.eclipse.equinox.launcher.Main.main(Main.java:1440)

To Reproduce

1. Download an unzip eclipse-java-2022-09-R-linux-gtk-x86_64.tar.gz
2. Add STS update site https://download.springsource.com/release/TOOLS/sts4/update/e4.25/
3. Install Spring Boot Language Server Feature
4. Restart Eclipse
5. Go to Windows > Preferences > TextMate > Grammar and select arbitrary grammar in table Create, edit or remove TextMate grammars

[martinlippert]

Thanks @bvo42 for reporting this.

• I can reproduce this with the STS 4.16.1.RELEASE build using a fresh install.
• I cannot reproduce this anymore with the latest 4.17.0 CI builds, so looks like this doesn't happen anymore with the next upcoming release.

Nevertheless, need to investigate why this happens on 4.16.1

[martinlippert]

You can fix this by installing the latest TM4E version from here:
https://download.eclipse.org/tm4e/releases/0.6.2/

Go to Install New Software, paste in the mentioned URL, and install the feature called TextMate Core. After that upgrade, the preference page works again.

This new version of TM4E will be included by default in the upcoming 4.17.0.RELEASE.

[bvo42]

Upgrading TextMate Core from 0.5.1 to 0.5.2 helped. Thank you for your help.