Add watchers from another field

Use case

Add watchers to an issue from any field, be it, for example, the Assignee or the Reporter fields.

Using this combination of functions in several transitions will enable you to add several watchers if the user of the field changes, but not to remove them.

Configuration

Set up the custom field and the transitions that you are going to use.

Create a default User Picker (multiple users) field, and name it All watchers

Create a global reflexive transition (a transition from any issue to itself).

Set up the Update fields post function.

Add a Update fields post function to any workflow transition but the global reflexive one. The Create issue transition can be a good choice here.

Target issue

Choose Current issue

Fields

Choose All watchers

Value

In the popup, choose the value Set field value manually (parser expression)

Expression

Enter the following expression:

%{union(union(toStringList(%{issue.cf10001}), toStringList(%{issue.assignee})), toStringList(%{issue.watcher}))

with parsing mode set to General and replace the field code %{issue.cf10001} with the field code for the field All watchers

As it is, the expression will take the value of the Assignee field. It could be changed for the Reporter field or for a custom User Picker field replacing the field code %{issue.assignee} with the one of your choice.

Run as

Choose Current user

Set up the Transition issue post function.

Add a Transition issue post function to the same transition as the previous post function.

Target issue*

Select Current issue

Mode*

Select Execute transition

Select the transition to be executed

Select the global reflexive transition previously created.

Delayed execution

Delay the execution of the post function 1000 milliseconds.

Set up a Copy Value From Other Field post function

Add a Copy Value From Other Field Jira post function.

Source Field

Select All watchers

Destination Field

Select Watchers

Related use cases

Use case	Workflow function	Parser functions
Add a sub-task's summary and key to the description of its parent	Update fields
Add three days skipping weekends automatically to a Date Picker	Update fields	dateTimeToString() dayOfTheWeek() addDays()
Add watchers from another field	Update fields Transition issue	union() toStringList()
Assign an issue to the project lead, if the issue is unassigned on creation	Update fields
Assign an issue to the user who last commented on it	Update fields
Assign important issues to the project lead	Update fields
Copy field values from epic to issues under it after creation	Update fields Transition issue	epic() issuesUnderEpic() filterByStatus()
Copy labels of a sub-task to the parent issue upon closing	Update fields
Keep parent's priority in sync	Update fields
Obtain the difference between two dates	Update fields
Set a date field to a future date	Update fields	dateTimeToString()
Set a date field to the current date	Update fields	dateTimeToString()
Set Fix version to Affects version when resolving an issue	Update fields
Set the priority to Highest if the 'Infrastructure' component is selected	Update fields