Error when current namespace is null in config

[ThomasCAI-mlv]

Describe the bug

When the current namespace defined in the config file is null:

kafkactl:
  current-namespace: null
  api: http://localhost:8080
  user-token: xxxx

any command line (even trying to switch context) will result in the following error message:

Exception in thread "main" picocli.CommandLine$InitializationException: Could not instantiate class com.michelin.kafkactl.util.VersionProvider: io.micronaut.context.exceptions.DependencyInjectionException: Failed to inject value for parameter [currentNamespace] of method [setCurrentNamespace] of class: com.michelin.kafkactl.property.KafkactlProperties

Message: Failed to inject value for parameter [currentNamespace] of method [setCurrentNamespace] of class: com.michelin.kafkactl.property.KafkactlProperties

Message: Error resolving property value [kafkactl.current-namespace]. Property doesn't exist
Path Taken:
new @j.i.Singleton c.m.k.u.VersionProvider()
\---> @j.i.Singleton c.m.k.u.VersionProvider#kafkactlProperties
      \---> @i.m.c.a.ConfigurationProperties("kafkactl") c.m.k.p.KafkactlProperties#setCurrentNamespace([String currentNamespace])

To Reproduce

Steps to reproduce the behavior:

1. Create ~HOME/.kafkactl/config.yml with a context without namespace like

  contexts:
  - name: test
    context:
      api: http://localhost:8080
      user-token: xxxx

2. Switch to that context with kafkactl config use-context test
3. Try any command line like kafkactl get to or kafkactl get to -n <myNamespace>
4. See error

Expected behavior

• kafkactl get to should result in an explicit error like "No namespace set"
• kafkactl get to -n <myNamespace> should result in the correct topics listing
• kafkactl config use-context goodContext should switch context

Environment

• Kafkactl distribution: N/A
• Ns4Kafka version: N/A

Steps taken to try and solve the problem

Without the field current-namespace in the config file

kafkactl:
  api: http://localhost:8080
  user-token: xxxx

kafkactl behaviour is normal.

2 fixes might be needed:

• The kafkactl config use-context on a context without namespace should not initialize a "current-namespace" field
• If the current-namespace is set to null, kafkactl should still work when setting a namespace in the command line

Additional context

N/A