Can't add an user in UserGroupsControlpanelView to a Group with pas.plugin.ldap with plone.many_users=True

[1letter]

What I did:

• add plone group testgroup1 via /@@usergroup-groupprefs
• set registry entries for plone.many_users and plone.many_groups to True
• add a Folder
• go to the folder and call the sharing view /myfolder/@@sharing
• add the group testgroup1 with reader, editor roles
• click on the group to add some users /@@usergroup-groupmembership?groupname=testgroup1
• search a user
• select a user (should be a LDAP User) and save

What I expect to happen:

• the user is added to the group

What actually happened:

• endless waiting for response after click on "Add" Button

What version of Plone/ Addons I am using:

• Plone 6.0.4
• pas.plugin.ldap 1.8.2
• node.ext.ldap 1.2
• node 1.2.1
• LDAP Backend user objects > 10000

Some investigations

• in the ZMI acl_users -> source_groups the action is possible without errors
• with loglevel DEBUG i see thousands of queries to the LDAP Backend
• the task run many minutes
• its a limitation of pas.plugin.ldap

the GroupMembershipControlPanel clean the searchstring in the request and pass it to the membership search in UsersGroupsControlPanelView.

An empty searchstring is like a intention "list all users" and a violation against the option many_users = True. The search with empty searchstring should not be performed.

With the following patch, all is fine ;-)

if searchGroups:
  if not self.many_groups or bool(searchString):
    groupResults = searchView.merge(chain(*[searchView.searchGroups(**{field: searchString}) for field in ['id', 'title']]), 'groupid')
    groupResults = [gtool.getGroupById(g['id']) for g in groupResults if g['id'] not in ignore]
    groupResults.sort(key=lambda x: x is not None and normalizeString(x.getGroupTitleOrName()))

  if searchUsers:
    if not self.many_users or bool(searchString):
      userResults = searchView.merge(chain(*[searchView.searchUsers(**{field: searchString}) for field in ['login', 'fullname', 'email']]), 'userid')
      userResults = [mtool.getMemberById(u['id']) for u in userResults if u['id'] not in ignore]
      userResults.sort(key=lambda x: x is not None and x.getProperty('fullname') is not None and normalizeString(x.getProperty('fullname')) or '')