No Shutdown possible after external modification of file

[matthiasgeiger]

JabRef version at least 3.8 and master

Steps to reproduce:

1. Open a file
2. modify it externally
3. Accept changes
4. Try to close JabRef

java.lang.IllegalArgumentException: missing event subscriber for an annotated method. Is net.sf.jabref.logic.autosaveandbackup.BackupManager@5147902d registered?
	at com.google.common.eventbus.SubscriberRegistry.unregister(SubscriberRegistry.java:111) ~[guava-20.0.jar:?]
	at com.google.common.eventbus.EventBus.unregister(EventBus.java:201) ~[guava-20.0.jar:?]
	at net.sf.jabref.model.metadata.MetaData.unregisterListener(MetaData.java:257) ~[main/:?]
	at net.sf.jabref.logic.autosaveandbackup.BackupManager.shutdown(BackupManager.java:149) ~[main/:?]
	at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184) ~[?:1.8.0_60]
	at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:175) ~[?:1.8.0_60]
	at java.util.HashMap$KeySpliterator.forEachRemaining(HashMap.java:1540) ~[?:1.8.0_60]
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481) ~[?:1.8.0_60]
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[?:1.8.0_60]
	at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151) ~[?:1.8.0_60]
	at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174) ~[?:1.8.0_60]
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[?:1.8.0_60]
	at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418) ~[?:1.8.0_60]
	at net.sf.jabref.logic.autosaveandbackup.BackupManager.shutdown(BackupManager.java:85) ~[main/:?]
	at net.sf.jabref.gui.JabRefFrame.quit(JabRefFrame.java:859) ~[main/:?]
	at net.sf.jabref.gui.JabRefFrame$CloseAction.actionPerformed(JabRefFrame.java:1778) ~[main/:?]
	at net.sf.jabref.gui.JabRefFrame$2.windowClosing(JabRefFrame.java:604) ~[main/:?]
	at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:349) ~[?:1.8.0_60]`

....

[rfgiusti]

Additional info: this only happens if you review the changes (regardless of whether you keep them checked as accepted or uncheck). If you cancel the review or don't click "Review changes", nothing happens.

This bug can be work-arounded by closing the database before attempting to close JabRef (still raises an exception).

[matthiasgeiger]

also covered in #2486

as @lenhard is working on a fix I'll close this as a duplicate

[lenhard]

Blind me! Sorry for not discovering that this issue already existed!