The MediaWiki restriction on whitespace, as far as I can tell, has to do with Special:UserRights. (This is a guess.) This page creates a checkbox for each user group, with name="wgGroup-$groupname". In other words, if the group name contains whitespace, you get invalid HTML4 by putting whitespace into the "name" attribute of the tag. If MediaWiki would sanitize the name, would this MediaWiki restriction on group names go away?

Suggested fix:

• Supply a function, perhaps named LdapAuthentication::transformLDAPGroupName($name), that converts a space to an underscore. Make it public and static so other extensions can call it too.

public static function transformLDAPGroupName($name) {
  return str_replace(' ', '_', $name);
}

• At the end of function getGroups(), for each member of $this->userLDAPGroups["short"] and $this->allLDAPGroups["short"], replace space characters with underscores. Supply a global variable $wgLDAPGroupsFixWhitespace (boolean) to turn this behavior on and off.

if ($this->getConf(LDAPGroupsFixWhitespace) {
  if (isset($this->userLDAPGroups) && isset($this->userLDAPGroups["short"])) {
    foreach ($this->userLDAPGroups["short"] as $key => $value) {
      $this->userLDAPGroups["short"][$key] = self::transformLDAPGroupName($value);
    }
  }
  if (isset($this->allLDAPGroups) && isset($this->allLDAPGroups["short"])) {
    foreach ($this->allLDAPGroups["short"] as $key => $value) {
      $this->allLDAPGroups["short"][$key] = self::transformLDAPGroupName($value);
    }
  }
}

Uploading a patch against LdapAuthentication 2.0d (latest).

Thanks for taking a look at the code!

You are very welcome to use developer access to submit this as a Git branch directly into Gerrit.

Putting your branch in Git makes it easier to review it quickly. If you don't want to set up Git/Gerrit, you can also use the Gerrit Patch Uploader. Thanks again!

Change 187917 had a related patch set uploaded (by Gerrit Patch Uploader):
Phabricator T87376: Don't create invalid MediaWiki group names containing whitespace: change spaces to underscores.

https://gerrit.wikimedia.org/r/187917

Patch-For-Review

Patch submitted:
https://gerrit.wikimedia.org/r/#/c/187917/

Change 187917 had a related patch set uploaded (by Luke081515):
Don't create invalid MediaWiki group names containing whitespace: change spaces to underscores.

https://gerrit.wikimedia.org/r/187917