Optimize can't import date variables with null values

Problem description:

• given:
  • I have an engine deployt with a process instance running
  • the process instance has a date variable
  • the value of the date variable is set to null using Cockpit
• when:
  • I start Optimize and it's importing the data from the engine
• then:
  • Optimize is throwing an error

    
    
    14:18:30.529 [ElasticsearchImportJobExecutor-pool-0] ERROR o.c.o.s.e.j.i.VariableUpdateElasticsearchImportJob - Error while executing import to elasticsearch
    java.time.format.DateTimeParseException: Text 'null' could not be parsed at index 0
    	at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1949)
    	at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
    	at java.time.ZonedDateTime.parse(ZonedDateTime.java:597)
    	at org.camunda.optimize.service.util.mapper.CustomDeserializer.deserialize(CustomDeserializer.java:38)
    	at org.camunda.optimize.service.util.mapper.CustomDeserializer.deserialize(CustomDeserializer.java:21)
    	at com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:1611)
    	at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1219)
    	at org.camunda.optimize.service.es.writer.variable.VariableWriter.parseValueWithException(VariableWriter.java:305)
    	at org.camunda.optimize.service.es.writer.variable.VariableWriter.parseValue(VariableWriter.java:250)
    	at org.camunda.optimize.service.es.writer.variable.VariableWriter.mapTypeValues(VariableWriter.java:220)
    	at org.camunda.optimize.service.es.writer.variable.VariableWriter.buildParameters(VariableWriter.java:208)
    	at org.camunda.optimize.service.es.writer.variable.VariableWriter.addImportVariablesRequest(VariableWriter.java:181)
    	at org.camunda.optimize.service.es.writer.variable.VariableWriter.importVariables(VariableWriter.java:83)
    	at org.camunda.optimize.service.es.job.importing.VariableUpdateElasticsearchImportJob.persistEntities(VariableUpdateElasticsearchImportJob.java:25)
    	at org.camunda.optimize.service.es.job.ElasticsearchImportJob.executeImport(ElasticsearchImportJob.java:62)
    	at org.camunda.optimize.service.es.job.ElasticsearchImportJob.run(ElasticsearchImportJob.java:43)
    	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    	at java.lang.Thread.run(Thread.java:748)
    

  • the import does not continue
• expected:
  • the import is conducted without any problems

Hints:
The variable refactoring might have already solved this problem, but she should at least test it.