Copy Custom field value from one field to another

[Pushpkant Garg]

My requirement is to copy Text field data into USer picker field. Text Field data has single email address.

When I used script runner "Copy custom field" option it gave me type casting error. 

Can anyone please help me with groovy script which will help me to update the same. We have around 30k+ records which need to be updated.

[Nic Brough -Adaptavist- · Accepted solution]

Duplicate of https://answers.atlassian.com/questions/44618908