I noticed that agentd and agent2 works inconsistent in some cases when configuration parameter(s) are passed without value.

Steps to reproduce:

• Open zabbix_agent2.conf file
• Uncomment for e.g. HeartbeatFrequency= and save the configuration.
• Start the agent2
• Do the same steps for agentd
• Compare results

Result: Agent2 started successfully, but agentd returns an error ->

zabbix_agentd [229522]: wrong value of "HeartbeatFrequency" in config file "/home/zabbix/workspace/7.0/etc/zabbix_agentd.conf", line 276

Expected: I guess in this case agent2 should work the same as agentd and it should return an error about wrong or empty value.

Note: the same behavior (agent2 can be started with empty param value) is for parameters:

• EnablePersistentBuffer (7.0, master)
• UnsafeUserParameters (7.0, master)
• TLSConnect (6.0, 7.0, master)
• TLSAccept (6.0, 7.0, master)
• TLSCAFile (6.0, 7.0, master)
• TLSCRLFile (6.0, 7.0, master)
• TLSServerCertIssuer (6.0, 7.0, master)
• TLSServerCertSubject (6.0, 7.0, master)
• TLSCertFile (6.0, 7.0, master)
• TLSKeyFile (6.0, 7.0, master)
• TLSPSKIdentity (6.0, 7.0, master)
• TLSPSKFile (6.0, 7.0, master)
• ForceActiveChecksOnStart (only agent2 param, actual for 7.0, master)
  Maybe more.

IMHO it would be nice to validate empty parameters because it is useful for troubleshooting.