Cannot assign Component Lead without Browse User global permission

Summary of Issue

If a user does not have Browse User global permission, they cannot set or update the Component Lead.

How to reproduce

1. Install a fresh instance of JIRA 7.3.6
2. Log in as admin
   • Create a non-admin user test1 which belongs to jira-software-users group which has Browse Users Global Permission
   • Create a non-admin user test2 which belongs to jira-software-users group which has Browse Users Global Permission
   • Created a Test Project and added test1 as Project Administrator Role
3. Log into JIRA as test1
   • Navigated to Project Settings » Components » Added a new Component User Interface
     • Typing in test2 showed the User name in the drop down and I was able to select test2 and make them the Component Lead
4. Log in as admin
   • Removed jira-software-users from Browse Users global permission
5. Log into JIRA as test1
   • Navigated to Project Settings » Components » Edited existing Component User Interface
     • Type in test1 as Component Lead and get No Matches as the drop down
     • Pressing Enter with test1 reverts the Component Lead to test2
     • Clicking the mouse away with test1 reverts the Component Lead to test2

Now, repeat the above with JIRA 7.1.x and it was possible to set the Component Lead without Browse User global permission. Under JIRA 7.1.x, the Component Lead appears to be a free text field (when Browse Users global permission was removed) and only validates the user when the Add/Update button was pressed.

Expected Result

As per Project Settings » Users and roles » Add users to a role functionality, if a known Username is entered, the User Picker will show that user name and can be selected.

Actual Result

No Matches is shown under the drop down and cannot set or update the Component Lead.

Workaround for JIRA 7.3.6

1. It is possible to update the Component Lead via the JIRA Rest API without Browse User global permission; or
2. Request Browse Users Global permission access from your JIRA Administrator for your user; or
3. Request the JIRA Administrator assistance to update the Component Lead