Username being cast to lowercase without an obvious way to opt out

[Adambean]

Hello,

Thanks for this plug-in. This resolves an infinite loop issue recently encountered with the other auth_remoteuser plug-in.

I noticed that this plug-in expects a callable string in $wgAuthRemoteUserUsernameNormalizer otherwise "strtolower" is assumed:

AuthRemoteUser/src/PluggableAuth.php

Line 114 in a55d748

: 'strtolower';

This occurs if setting the variable to null or an empty string too, which could be considered a reasonable way to do no normalisation.

This needs to be opt-out-able otherwise the case sensitivity of usernames is not being respected. E.g. "SomeUser" needs to be kept as "SomeUser", not "Someuser". This matters because:

• The external authentication backend may handle usernames in a case sensitive way.
• MediaWiki database tables use binary collation by default, which is case sensitive, therefore this problem causes user duplication for existing people. (Particularly when migrating from the "auth_remoteuser" plug-in.)

In my opinion I'd not make use of strtolower() unless specifically configured. If the variable is null or an empty string leave the username unmodified.

As a workaround setting this variable to "strval" leaves the user casing alone.