Avoid NPE when loading complex property with unknown key (mongodb)

setProperties: Terminate computation due to previous failure

javax.security.auth.login.LoginException: java.lang.NullPointerException
	at org.nuxeo.ecm.core.api.model.impl.ComplexProperty.init(ComplexProperty.java:203)
	at org.nuxeo.ecm.core.api.impl.DataModelImpl.<init>(DataModelImpl.java:73)
	at org.nuxeo.ecm.directory.BaseSession.createEntryModel(BaseSession.java:272)
	at org.nuxeo.ecm.directory.BaseSession.createEntryModel(BaseSession.java:286)
	at org.nuxeo.directory.mongodb.MongoDBSession.fieldMapToDocumentModel(MongoDBSession.java:648)
	at org.nuxeo.directory.mongodb.MongoDBSession.doQuery(MongoDBSession.java:337)
	at org.nuxeo.directory.mongodb.MongoDBSession.getEntryFromSource(MongoDBSession.java:98)
	at org.nuxeo.ecm.directory.DirectoryCache.getEntry(DirectoryCache.java:121)
	at org.nuxeo.ecm.directory.BaseSession.getEntry(BaseSession.java:344)
	at org.nuxeo.ecm.platform.usermanager.UserManagerImpl.getUserModel(UserManagerImpl.java:1266)
	at org.nuxeo.ecm.platform.usermanager.UserManagerImpl.getPrincipal(UserManagerImpl.java:1309)
	at org.nuxeo.ecm.platform.usermanager.UserManagerImpl.getPrincipal(UserManagerImpl.java:1292)
	at org.nuxeo.ecm.platform.usermanager.UserManagerImpl.getPrincipalUsingCache(UserManagerImpl.java:624)
	at org.nuxeo.ecm.platform.usermanager.UserManagerImpl.getPrincipal(UserManagerImpl.java:616)
	at org.nuxeo.ecm.platform.usermanager.UserManagerImpl.getPrincipal(UserManagerImpl.java:608)
	at org.nuxeo.ecm.platform.login.NuxeoLoginModule.lambda$createIdentity$0(NuxeoLoginModule.java:272)
	at org.nuxeo.runtime.api.Framework.doPrivileged(Framework.java:293)
	at org.nuxeo.ecm.platform.login.NuxeoLoginModule.createIdentity(NuxeoLoginModule.java:272)
	at org.nuxeo.ecm.platform.login.NuxeoLoginModule.validateUserIdentity(NuxeoLoginModule.java:333)
	at org.nuxeo.ecm.platform.login.NuxeoLoginModule.getPrincipal(NuxeoLoginModule.java:194)
	at org.nuxeo.ecm.platform.login.NuxeoLoginModule.login(NuxeoLoginModule.java:236)
	at org.nuxeo.runtime.api.LoginModuleWrapper.login(LoginModuleWrapper.java:80)
	at sun.reflect.GeneratedMethodAccessor85.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at javax.security.auth.login.LoginContext.invoke(LoginContext.java:755)
	at javax.security.auth.login.LoginContext.access$000(LoginContext.java:195)
	at javax.security.auth.login.LoginContext$4.run(LoginContext.java:682)
	at javax.security.auth.login.LoginContext$4.run(LoginContext.java:680)
	at java.security.AccessController.doPrivileged(Native Method)
	at javax.security.auth.login.LoginContext.invokePriv(LoginContext.java:680)
	at javax.security.auth.login.LoginContext.login(LoginContext.java:587)
	at org.nuxeo.ecm.platform.ui.web.auth.NuxeoAuthenticationFilter.loginAs(NuxeoAuthenticationFilter.java:1243)
	at org.nuxeo.ecm.platform.ui.web.auth.service.LoginAsImpl.loginAs(LoginAsImpl.java:34)
	at org.nuxeo.runtime.api.Framework.loginAsUser(Framework.java:345)
	at org.nuxeo.ecm.core.bulk.action.computation.AbstractBulkComputation.lambda$processBatchOfDocuments$1(AbstractBulkComputation.java:144)
	at org.nuxeo.runtime.transaction.TransactionHelper.lambda$runInTransaction$5(TransactionHelper.java:634)
	at org.nuxeo.runtime.transaction.TransactionHelper.runInTransaction(TransactionHelper.java:667)
	at org.nuxeo.runtime.transaction.TransactionHelper.runInTransaction(TransactionHelper.java:634)
	at org.nuxeo.runtime.transaction.TransactionHelper.runInTransaction(TransactionHelper.java:622)
	at org.nuxeo.ecm.core.bulk.action.computation.AbstractBulkComputation.processBatchOfDocuments(AbstractBulkComputation.java:140)
	at org.nuxeo.ecm.core.bulk.action.computation.AbstractBulkComputation.processRecord(AbstractBulkComputation.java:104)
	at org.nuxeo.lib.stream.computation.log.ComputationRunner.lambda$processRecordWithRetry$10(ComputationRunner.java:417)
	at net.jodah.failsafe.Functions$10.call(Functions.java:252)
	at net.jodah.failsafe.SyncFailsafe.call(SyncFailsafe.java:145)
	at net.jodah.failsafe.SyncFailsafe.run(SyncFailsafe.java:81)
	at org.nuxeo.lib.stream.computation.log.ComputationRunner.processRecordWithRetry(ComputationRunner.java:417)