Assign a user list to a multi user picker custom field (number of user undefined)

[Aymeric GOUJON]

I want to assign a user list to a multi user picker custom field
The size and content of the list is undefined
/!\ The problem is that the value of the custom field is overwritten and not added at each iteration
So I want the list of all my users in my custom field without knowing the content and the size of the list

customfield_10226 is my custom field multi user picker

listUser.each{ user ->
def update = put('/rest/api/2/issue/' + issue.key)
.header('Content-Type', 'application/json')
.body([
fields:[
customfield_10226:[[accountId : user]]
]
])
.asString()
}

[Sunny Ape · Accepted solution]

Hello @Aymeric Goujon 

This question gets asked regularly. It's not possible to insert / add one or more new values somewhere into a set of existing values in a user picker custom field. That's not how the REST API works.

You need to:

1. GET the current set of values from the field (usually into an array in your code)
2. In your code, add the new value(s) in the position(s) you want in the array
3. PUT / POST the new values into the field, in the order you have them in the array, to overwrite the old set of values.