To add 'Copy value from field to field' post-function to a transition :
Click Edit for the workflow that has the transition you wish to add the post-function on.
In the Workflow Designer, select the transition.
Click on Post Functions in the properties panel.
Click on Addpost function.
Select Copy value from field to field from the list of post-functions.
Click on Add to add the post-function on the transition.
Select the field name from the From field drop-down.
Select the field name from the To field drop-down.
Click on Add to add the post-function to the transition.
See here for a use case for this post-function
Known issues common to all post-functions:
Known issues specific to this post-function:
Troubleshooting this post-function configuration: In case the post-function does not work as expected these are the things to look out for
JMWE shows an error message on the issue view if any error occurs during the execution of the post-function. This message is displayed only if the current user is a Jira administrator.
When you add this post-function to a transition and trigger the transition, the add-on copies the value(s) of the selected From field to the To field of the current issue.
Return "parent-child" for cascading custom fields: This option is applicable for the Select list (cascading) custom fields. If you select the Return "parent-child" for cascading custom fields option, values from both the parent and child lists are copied into the destination field. For example, a custom cascading field has the values A and 1 in the parent and its child lists respectively. When this field is copied into a text field
without the option, the value 1 is copied into the text field
with the option, the value A - 1 is copied into the text field.
Copy only if not set: Copies the value(s) of the From field to the To field of the current issue, only when the To field is empty on the current issue.
Create missing value(s): Allows creating any missing Component/s or Version/s while setting or copying a field that expects Versions or Components. Note this is applicable for version and component fields.
Ignore empty value: Will not set (clear) the destination field of the current issue, if the value of the source field is empty or null.
Add value(s) to the destination field: Appends the value(s) of the selected From field to the To field of the current issue. This is applicable only to multi-valued fields.
Send notifications: Jira sends notifications for the change in the selected To field value on the current issue. You can control the default value of the "Send notifications" option in the Configuration page under JMWE administration. Click here for more information.
Run as current user: The current user will be the author of the field change.
Run as add-on user: The add-on user will be the author of the field change.
Run as this user: Any user selected in this field will be the author of the field change.
Running this post-function as any user other than the "Add-on user" is discouraged
If you select any option other than "Run as add-on user", so that the change appears to be done by the current user or a specific user, the following must be true:
The destination field must be present on the Edit screen applicable to the issue being modified
The selected user must have the Edit issues permission on the issue being modified
A typical use case for this post-function is to copy a field to another field value of the same issue during a transition. Consider a use case where you want to set the components of an issue with a value selected from a cascading field that carries the Main and Sub-components in parent and child. To configure this:
Add the Copy value from field to field post-function to the Create transition of the issue workflow.
Select the Cascading field as the From field.
Select the Components field as the To field.
Select Return "parent - child" for cascading custom fields option.
Note: The Component name should be in Component - Subcomponent format.