NPE when failing to delete some document

 <throwable class="com.xpn.xwiki.XWikiException">
          <detailMessage>Exception while deleting document {0}</detailMessage>
          <cause class="java.lang.NullPointerException">
            <stackTrace>
              <trace>com.xpn.xwiki.store.XWikiHibernateStore.maybeMakeSpaceHidden(XWikiHibernateStore.java:734)</trace>
              <trace>com.xpn.xwiki.store.XWikiHibernateStore.maybeDeleteXWikiSpace(XWikiHibernateStore.java:1104)</trace>
              <trace>com.xpn.xwiki.store.XWikiHibernateStore.maybeDeleteXWikiSpace(XWikiHibernateStore.java:1086)</trace>
              <trace>com.xpn.xwiki.store.XWikiHibernateStore.deleteXWikiDoc(XWikiHibernateStore.java:1059)</trace>
              <trace>com.xpn.xwiki.store.XWikiCacheStore.deleteXWikiDoc(XWikiCacheStore.java:327)</trace>
              <trace>com.xpn.xwiki.XWiki.deleteDocument(XWiki.java:3792)</trace>
              <trace>com.xpn.xwiki.XWiki.deleteAllDocuments(XWiki.java:5647)</trace>
              <trace>com.xpn.xwiki.XWiki.deleteAllDocuments(XWiki.java:5635)</trace>
              <trace>org.xwiki.refactoring.internal.DefaultModelBridge.delete(DefaultModelBridge.java:166)</trace>
              <trace>org.xwiki.refactoring.internal.job.DeleteJob.maybeDelete(DeleteJob.java:100)</trace>
              <trace>org.xwiki.refactoring.internal.job.DeleteJob.process(DeleteJob.java:77)</trace>
              <trace>org.xwiki.refactoring.internal.job.DeleteJob.process(DeleteJob.java:62)</trace>
              <trace>org.xwiki.refactoring.internal.job.AbstractEntityJob.runInternal(AbstractEntityJob.java:141)</trace>
              <trace>org.xwiki.job.AbstractJob.runInContext(AbstractJob.java:205)</trace>
              <trace>org.xwiki.job.AbstractJob.run(AbstractJob.java:188)</trace>
              <trace>java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)</trace>
              <trace>java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)</trace>
              <trace>java.lang.Thread.run(Thread.java:745)</trace>
            </stackTrace>
            <suppressedExceptions class="java.util.Collections$UnmodifiableRandomAccessList" resolves-to="java.util.Collections$UnmodifiableList">
              <c class="list"/>
              <list reference="../c"/>
            </suppressedExceptions>
          </cause>
          <stackTrace>
            <trace>com.xpn.xwiki.store.XWikiHibernateStore.deleteXWikiDoc(XWikiHibernateStore.java:1066)</trace>
            <trace>com.xpn.xwiki.store.XWikiCacheStore.deleteXWikiDoc(XWikiCacheStore.java:327)</trace>
            <trace>com.xpn.xwiki.XWiki.deleteDocument(XWiki.java:3792)</trace>
            <trace>com.xpn.xwiki.XWiki.deleteAllDocuments(XWiki.java:5647)</trace>
            <trace>com.xpn.xwiki.XWiki.deleteAllDocuments(XWiki.java:5635)</trace>
            <trace>org.xwiki.refactoring.internal.DefaultModelBridge.delete(DefaultModelBridge.java:166)</trace>
            <trace>org.xwiki.refactoring.internal.job.DeleteJob.maybeDelete(DeleteJob.java:100)</trace>
            <trace>org.xwiki.refactoring.internal.job.DeleteJob.process(DeleteJob.java:77)</trace>
            <trace>org.xwiki.refactoring.internal.job.DeleteJob.process(DeleteJob.java:62)</trace>
            <trace>org.xwiki.refactoring.internal.job.AbstractEntityJob.runInternal(AbstractEntityJob.java:141)</trace>
            <trace>org.xwiki.job.AbstractJob.runInContext(AbstractJob.java:205)</trace>
            <trace>org.xwiki.job.AbstractJob.run(AbstractJob.java:188)</trace>
            <trace>java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)</trace>
            <trace>java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)</trace>
            <trace>java.lang.Thread.run(Thread.java:745)</trace>
          </stackTrace>
          <suppressedExceptions class="java.util.Collections$UnmodifiableRandomAccessList" reference="../cause/suppressedExceptions"/>