Mercurial command 'topics' is not supported

This error is thrown when the MercurialEclipse decorator tries to determine the current topic on a repository in which the evolve and topics extensions are not enabled.

For this to happen, the extensions must be totally absent from the configuration of the repository. Given that the topics extension is an external extension, it may well be absent, in which case JavaHg should be resilient enough to not prevent clients from operating.

Example stacktrace of the error:

org.javahg.UnknownCommandException: Mercurial command 'topics' is not supported by Mercurial version: 6.1+hg7.3c9bf1787bfd
	at org.javahg.internals.AbstractCommand.handleReturnCode(AbstractCommand.java:420)
	at org.javahg.internals.OutputChannelInputStream.findNextOutputChannelBlock(OutputChannelInputStream.java:173)
	at org.javahg.internals.OutputChannelInputStream.<init>(OutputChannelInputStream.java:74)
	at org.javahg.internals.Server.runCommand(Server.java:410)
	at org.javahg.internals.AbstractCommand.launchStream(AbstractCommand.java:220)
	at org.javahg.internals.AbstractCommand.launchString(AbstractCommand.java:185)
	at org.javahg.ext.topics.TopicsCommand.execute(TopicsCommand.java:53)
	at com.vectrace.MercurialEclipse.commands.extensions.HgTopicsClient.getActiveTopic(HgTopicsClient.java:83)
	at com.vectrace.MercurialEclipse.team.MercurialTeamProvider$$Lambda$1345/0x000000001fec0880.apply(Unknown Source)
	at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1705)
	at com.vectrace.MercurialEclipse.team.MercurialTeamProvider.getActiveTopic(MercurialTeamProvider.java:442)
	at com.vectrace.MercurialEclipse.team.ResourceDecorator.getSuffixForContainer(ResourceDecorator.java:573)
	at com.vectrace.MercurialEclipse.team.ResourceDecorator.decorate(ResourceDecorator.java:281)
	at org.eclipse.ui.internal.decorators.LightweightDecoratorDefinition.decorate(LightweightDecoratorDefinition.java:247)
	at org.eclipse.ui.internal.decorators.LightweightDecoratorManager$LightweightRunnable.run(LightweightDecoratorManager.java:105)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.ui.internal.decorators.LightweightDecoratorManager.decorate(LightweightDecoratorManager.java:360)
	at org.eclipse.ui.internal.decorators.LightweightDecoratorManager.getDecorations(LightweightDecoratorManager.java:346)
	at org.eclipse.ui.internal.decorators.DecorationScheduler$1.ensureResultCached(DecorationScheduler.java:386)
	at org.eclipse.ui.internal.decorators.DecorationScheduler$1.run(DecorationScheduler.java:362)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)