A workflow validator which ensures that a multi-valued field does not contain more than one value during a transition. This validator can be customized such that field value(s) copied from the issue's sub-tasks can be excluded.

To add 'Field has single value Validator' to a transition:

Click Edit for the workflow that has the transition you wish to configure the validator on.
In the Workflow Designer, select the transition.
Click on Validators in the properties panel.
Click on Add validator.
Select Field has single value Validator from the list of validators.
Click on Add to add the validator on the transition.
Select the multi-value field name from the Field drop-down.
Click on Add to add the validator to the transition.

Related links :

Refer to the Use cases for validators page for use cases for this validator.

When you add this validator to a transition and trigger the transition, the add-on checks the number of values in the selected field. If there is more than one value, then a validation failure message is displayed. Customize this condition using the additional option provided as a part of the condition. The option is

Options

Excluding values copied from sub-tasks

Excludes the common values in parent and sub-task, while checking for the values in the selected field.

For example: When the parent has Affects Version/s: V1 and V2, its child has Affects Version/s V1. The validator considers the Affects Version/s has a single value, excluding the common value.

Validator Scope

To execute this validator based on the result of a groovy expression see Conditional execution using Groovy expression