OnError can't trigger execution on IDE Ant developer tools?

there is an error in the onLaunch code because an is not defined:

   

that is, onError cannot trigger execution in IDE? What should I do if I need to test onError on IDE?

the IDE I use is 0.20.1 of Mac

Mar.22,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1c0fc0e-32c8a.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1c0fc0e-32c8a.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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