LLD stopped working with agent 3.4.x

[nobodysu]

I have custom script with discovery rule that works under zabbix server 3.4.1 and agents 2.4, 3.0, 3.2, but is not working with agent 3.4.0 or 3.4.1 returning absolutely no errors. Regular discovery rules such as Network and Filesystem Discovery are working fine.

Was something changed in LLD behavior? Could this be a bug? Anyone have working LLD with 3.4.x agent?

[Atsushi]

Please check the exit code of the discovery script.
Is the script ended with a non-zero exit code?

[nobodysu]

It actually is!
Thank you so much for pointing it out - I can't comprehend how one would track it down without any error reporting.
I don't know reasons for this change but it discourages from using proper error codes.
Again, thanks.