#757 Null pointer in Stratego outliner during editing (project SpoofaxLegacy on YellowGrass.org)

Sometimes when editing Stratego an NPE is issued. This seems to be some interaction with error recovery and origin tracking. The stack trace is:

	java.lang.NullPointerException
	  at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	  at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	  at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	  at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	  at org.strategoxt.imp.runtime.stratego.StrategoTermPath.getTermPathWithOrigin(StrategoTermPath.java:177)
	  at org.strategoxt.imp.runtime.services.views.outline.SpoofaxOutlinePage.textSelectionToOutlineSelection(SpoofaxOutlinePage.java:153)
	  at org.strategoxt.imp.runtime.services.views.outline.SpoofaxOutlinePage.selectionChanged(SpoofaxOutlinePage.java:119)
	  at org.eclipse.jface.viewers.Viewer$2.run(Viewer.java:164)
	  at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
	  at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:49)
	  at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:175)
	  at org.eclipse.jface.viewers.Viewer.fireSelectionChanged(Viewer.java:162)
	  at org.eclipse.jface.text.TextViewer.fireSelectionChanged(TextViewer.java:2738)
	  at org.eclipse.jface.text.TextViewer.selectionChanged(TextViewer.java:2717)
	  at org.eclipse.jface.text.TextViewer.setSelectedRange(TextViewer.java:2402)
	  at org.eclipse.jface.text.link.LinkedModeUI.select(LinkedModeUI.java:933)
	  at org.eclipse.jface.text.link.LinkedModeUI.switchPosition(LinkedModeUI.java:851)
	  at org.eclipse.jface.text.link.LinkedModeUI.next(LinkedModeUI.java:798)
	  at org.eclipse.jface.text.link.LinkedModeUI.enter(LinkedModeUI.java:717)
	  at org.strategoxt.imp.runtime.services.ContentProposal$1.runInUIThread(ContentProposal.java:209)
	  at org.eclipse.ui.progress.UIJob$1.run(UIJob.java:95)
	  at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
	  at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
	  at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3946)
	  at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3623)
	  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1053)
	  at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
	  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:942)
	  at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:86)
	  at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:588)
	  at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
	  at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:543)
	  at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
	  at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:124)
	  at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
	  at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
	  at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
	  at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:353)
	  at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:180)
	  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	  at java.lang.reflect.Method.invoke(Method.java:606)
	  at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:629)
	  at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
	  at org.eclipse.equinox.launcher.Main.run(Main.java:1438)

Unfortunately i do not have a reliable way of recreating the issue, yet.

Submitted by Vlad Vergu on 29 October 2013 at 16:08

error@oskarvanrest

On 29 October 2013 at 16:08 Vlad Vergu tagged @oskarvanrest

On 29 October 2013 at 19:13 Oskar van Rest commented:

It’s hard to tell where this error comes from, so it would be great if we can figure out how to reproduce it. The terms passed to StrategoTermPath.getTermPathWithOrigin(...) by the outline cannot be null, so either the passed selection term has no origin because of a bug in EditorState.getSelectionAst(...), or there is a bug in StrategoTermPath.getTermPathWithOrigin(...).

Both methods also produce IndexOutOfBoundsExceptions, which are currently caught and handled by the outline, a quick and dirty hack. This should also be fixed properly.

On 29 October 2013 at 20:46 Vlad Vergu commented:

I understand. I’ll keep an eye out for this happening again, and hopefully figure out a way to recreate.

On 27 December 2013 at 08:27 Oskar van Rest commented:

To avoid the NPE, I’m now catching it and showing it in the Error Log instead.
The error will also include the input on which strategy position-of-term fails, which may allow us to figure out what the real issue is.

On 28 March 2014 at 17:42 Gabriël Konat commented:

I got this NPE today while trying to reproduce https://yellowgrass.org/issue/Spoofax/840. I had 6 instances of this, here’s the data from the error log:

Spoofax/757: position-of-term failed for input: (Form("Problems"{Def(URI(Language("QL"),[ID(NablNsForm,"Problems",Unique("/Users/gohla/Spoofax/Repositories/bitbucket.org/lwc2013/QL-examples/vehicle-checkin/problems.ql/0"))]))},[Question("probs"{Def(URI(Language("QL"),[ID(NablNsQuestion,"probs",NonUnique),ID(NablNsForm,"Problems",Unique("/Users/gohla/Spoofax/Repositories/bitbucket.org/lwc2013/QL-examples/vehicle-checkin/problems.ql/0"))]))},Label("\"Problems?\""),BoolTy),Conditional(Ref("probs"{Use(Result(40))}){(Type,Result(323))},[Question("sinceP"{Def(URI(Language("QL"),[ID(NablNsQuestion,"sinceP",NonUnique),ID(NablNsForm,"Problems",Unique("/Users/gohla/Spoofax/Repositories/bitbucket.org/lwc2013/QL-examples/vehicle-checkin/problems.ql/0"))]))},Label("\"Since?\""),DateTy),Question("engineP"{Def(URI(Language("QL"),[ID(NablNsQuestion,"engineP",NonUnique),ID(NablNsForm,"Problems",Unique("/Users/gohla/Spoofax/Repositories/bitbucket.org/lwc2013/QL-examples/vehicle-checkin/problems.ql/0"))]))},Label("\"Engine?\""),BoolTy),Question("drivetP"{Def(URI(Language("QL"),[ID(NablNsQuestion,"drivetP",NonUnique),ID(NablNsForm,"Problems",Unique("/Users/gohla/Spoofax/Repositories/bitbucket.org/lwc2013/QL-examples/vehicle-checkin/problems.ql/0"))]))},Label("\"Drivetrain?\""),BoolTy),Question("bodyP"{Def(URI(Language("QL"),[ID(NablNsQuestion,"bodyP",NonUnique),ID(NablNsForm,"Problems",Unique("/Users/gohla/Spoofax/Repositories/bitbucket.org/lwc2013/QL-examples/vehicle-checkin/problems.ql/0"))]))},Label("\"Body?\""),BoolTy)]),Conditional(Ref("probs"{Use(Result(40))}){(Type,Result(323))},[Question("since"{Def(URI(Language("QL"),[ID(NablNsQuestion,"since",NonUnique),ID(NablNsForm,"Problems",Unique("/Users/gohla/Spoofax/Repositories/bitbucket.org/lwc2013/QL-examples/vehicle-checkin/problems.ql/0"))]))},Label("\"Since\""),DateTy)]),Conditional(Ref("engineP"{Use(Result(44))}){(Type,Result(330))},[Question("desEngP"{Def(URI(Language("QL"),[ID(NablNsQuestion,"desEngP",NonUnique),ID(NablNsForm,"Problems",Unique("/Users/gohla/Spoofax/Repositories/bitbucket.org/lwc2013/QL-examples/vehicle-checkin/problems.ql/0"))]))},Label("\"Describe\""),StringTy)]),Conditional(Ref("drivetP"{Use(Result(47))}){(Type,Result(336))},[Question("desDrvP"{Def(URI(Language("QL"),[ID(NablNsQuestion,"desDrvP",NonUnique),ID(NablNsForm,"Problems",Unique("/Users/gohla/Spoofax/Repositories/bitbucket.org/lwc2013/QL-examples/vehicle-checkin/problems.ql/0"))]))},Label("\"Describe\""),StringTy)]),Conditional(Ref("bodyP"{Use(Result(49))}){(Type,Result(342))},[Question("desBdyP"{Def(URI(Language("QL"),[ID(NablNsQuestion,"desBdyP",NonUnique),ID(NablNsForm,"Problems",Unique("/Users/gohla/Spoofax/Repositories/bitbucket.org/lwc2013/QL-examples/vehicle-checkin/problems.ql/0"))]))},Label("\"Describe\""),StringTy)])]), TestOrigin)

java.lang.NullPointerException
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.runtime.stratego.StrategoTermPath.getTermPathWithOrigin(StrategoTermPath.java:179)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:100)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:94)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTerm(InputTermBuilder.java:83)
	at org.strategoxt.imp.runtime.services.views.properties.PropertiesService.getProperties(PropertiesService.java:89)
	at org.strategoxt.imp.runtime.editor.StrategoTermSelection.getFirstElement(StrategoTermSelection.java:68)
	at org.strategoxt.imp.runtime.editor.SpoofaxEditor$3.run(SpoofaxEditor.java:109)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)

java.lang.NullPointerException
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.runtime.stratego.StrategoTermPath.getTermPathWithOrigin(StrategoTermPath.java:179)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:100)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:94)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTerm(InputTermBuilder.java:83)
	at org.strategoxt.imp.runtime.services.views.properties.PropertiesService.getProperties(PropertiesService.java:89)
	at org.strategoxt.imp.runtime.editor.StrategoTermSelection.getFirstElement(StrategoTermSelection.java:68)
	at org.strategoxt.imp.runtime.editor.SpoofaxEditor$3.run(SpoofaxEditor.java:109)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)

java.lang.NullPointerException
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.runtime.stratego.StrategoTermPath.getTermPathWithOrigin(StrategoTermPath.java:179)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:100)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:94)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTerm(InputTermBuilder.java:83)
	at org.strategoxt.imp.runtime.services.views.properties.PropertiesService.getProperties(PropertiesService.java:89)
	at org.strategoxt.imp.runtime.editor.StrategoTermSelection.getFirstElement(StrategoTermSelection.java:68)
	at org.strategoxt.imp.runtime.editor.SpoofaxEditor$3.run(SpoofaxEditor.java:109)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)

java.lang.NullPointerException
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.runtime.stratego.StrategoTermPath.getTermPathWithOrigin(StrategoTermPath.java:179)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:100)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:94)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTerm(InputTermBuilder.java:83)
	at org.strategoxt.imp.runtime.services.views.properties.PropertiesService.getProperties(PropertiesService.java:89)
	at org.strategoxt.imp.runtime.editor.StrategoTermSelection.getFirstElement(StrategoTermSelection.java:68)
	at org.strategoxt.imp.runtime.editor.SpoofaxEditor$3.run(SpoofaxEditor.java:109)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)

java.lang.NullPointerException
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.runtime.stratego.StrategoTermPath.getTermPathWithOrigin(StrategoTermPath.java:179)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:100)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:94)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTerm(InputTermBuilder.java:83)
	at org.strategoxt.imp.runtime.services.views.properties.PropertiesService.getProperties(PropertiesService.java:89)
	at org.strategoxt.imp.runtime.editor.StrategoTermSelection.getFirstElement(StrategoTermSelection.java:68)
	at org.strategoxt.imp.runtime.editor.SpoofaxEditor$3.run(SpoofaxEditor.java:109)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)

java.lang.NullPointerException
	at org.strategoxt.imp.generator.position_of_term_1_1.invoke(position_of_term_1_1.java)
	at org.strategoxt.imp.generator.position_of_term_1_0.invoke(position_of_term_1_0.java)
	at org.strategoxt.imp.runtime.stratego.StrategoTermPath.getTermPathWithOrigin(StrategoTermPath.java:179)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:100)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTermResultingAst(InputTermBuilder.java:94)
	at org.strategoxt.imp.runtime.services.InputTermBuilder.makeInputTerm(InputTermBuilder.java:83)
	at org.strategoxt.imp.runtime.services.views.properties.PropertiesService.getProperties(PropertiesService.java:89)
	at org.strategoxt.imp.runtime.editor.StrategoTermSelection.getFirstElement(StrategoTermSelection.java:68)
	at org.strategoxt.imp.runtime.editor.SpoofaxEditor$3.run(SpoofaxEditor.java:109)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)

On 2 April 2014 at 00:56 Oskar van Rest commented:

Fixed with https://yellowgrass.org/issue/Spoofax/840

On 2 April 2014 at 00:56 Oskar van Rest closed this issue.

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Null pointer in Stratego outliner during editing

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