Features used to implement the example

• Copy parsed text to a field

Example: Add or remove request participants

To manage Jira Service desk issue visibility in customer portal, it would be great to have a post function to add or remove users from Request Participants custom field

The logic would be the same than add or remove watchers.

With existing post functions I'm able to:

• Clear this field
• add user(s) with overwriting
• add user(s) with appending
• add users from group (groovy)

What's missing is removing user from custom fields or group. Maybe a good idea would be to have a "add or remove from user picker custom field" where you can select the destination custom field to update.

You can currently do it. To do it you should use Copy a parsed text to a field post-function with the following configuration:

Target field: "Request Participants" Parsing mode: basic** Text to be parsed: depends on the operation

1. Clear the field: leave "Text to be parsed" parameter empty.
   
   
2. Add user(s) with overwriting: "Text to be parsed" parameter should contain a comma separated list of usernames (don't confuse with user's full name).
   Example: john.williams, david.russell, julian.bream


3. Add user(s) with appending: use prefix + before the comma separated list of user names.
   Example: + john.williams, david.russell, julian.bream
If you use prefix - you will remove the separated users instead of appending.
   
   If you want to set the field with users in a User Picker or Multi User Picker custom field, simply write the field code, since those kind of fields are rendered as a comma separated list of usernames.
   Example: %{10021} or + %{10021}


4. Add users from group: simply write + group_name . Example: use the following value in "Text to be parsed" parameter for adding all the users in group jira-users to field "Request Participants":
   + jira-users

Versions earlier than 2.2.9 have a bug making it fail when you try to add users to field "Request participants" using prefix + when the field is empty.