I have a new TGE field, marked as a required field in the field configuration. It is displaying as a red asterisk (*) on the create Screen, but it doesn't work as expected. Whenever there is no row in the TGE field, there should be a failure message. The issue creates without a value for the TGE field.
Jira does not display empty custom fields on the issue view screens. Therefore, to make Table Grid visible on the issue view, we store the number of rows as its custom field values.
Accordingly, Jira could not control whether the Table Grid field has some data or not. For Jira, there is always a value.
Table Grid stores the number of rows as its custom field value. Therefore, all you need to do is to check that the value of your Table Grid custom field is equal to '0'.
Implement validator with the help of any plugin that allows validation of the custom field values.
Option 1: Java API and Script Runner
Option 2: Any free plugin
In case you want to check only if the grid is not empty and you don't have the possibility to purchase any additional plugins.
Use any free plugin that allows validation of the custom field values. For example AM Utils.
Note that this approach is not applicable for the 'Create' transitions as far as there is no issue created before the transition is executed and Grid cannot update the customfield (since it needs issuei for this operation).