MWX/Invite/notes/take 2

What seems like it should work, but hasn't, is to intercept the userCan hook, ignore anything that isn't the SpecialCreateAccount, and authorize everything as long as a valid invite code is passed.

The problem is that authorizing access doesn't seem to authorize access; I still get this same message:

You do not have permission to do that, for the following reason:
You are not allowed to execute the action you have requested.

So now it's a matter of tracing back through the code to find out why it thinks this.

The second line corresponds to the error message badaccess-group0. I searched the code for that message and found several possible places where it could be occurring. The one which was actually being tripped was this:

Original exception: [e851e4d8ff408613bd96ef03] /w/Special:CreateAccount Exception from line 587 of /home/psycrit/site/mediawiki-1.34.2/includes/Permissions/PermissionManager.php: 2020-09-10 What is triggering this error? action=deletedhistory
Backtrace:

• #0 /home/psycrit/site/mediawiki-1.34.2/includes/Permissions/PermissionManager.php(789): MediaWiki\Permissions\PermissionManager->missingPermissionError(string, boolean)
  
• #1 /home/psycrit/site/mediawiki-1.34.2/includes/Permissions/PermissionManager.php(395): MediaWiki\Permissions\PermissionManager->checkQuickPermissions(string, User, array, string, boolean, Title)
  
• #2 /home/psycrit/site/mediawiki-1.34.2/includes/Permissions/PermissionManager.php(229): MediaWiki\Permissions\PermissionManager->getPermissionErrorsInternal(string, User, Title, string, boolean)
  
• #3 /home/psycrit/site/mediawiki-1.34.2/includes/Permissions/PermissionManager.php(248): MediaWiki\Permissions\PermissionManager->userCan(string, User, Title, string)
  
• #4 /home/psycrit/site/mediawiki-1.34.2/includes/skins/Skin.php(733): MediaWiki\Permissions\PermissionManager->quickUserCan(string, User, Title)
  
• #5 /home/psycrit/site/mediawiki-1.34.2/includes/skins/SkinTemplate.php(284): Skin->getUndeleteLink()
  
• #6 /home/psycrit/site/mediawiki-1.34.2/includes/skins/SkinTemplate.php(215): SkinTemplate->prepareQuickTemplate()
  
• #7 /home/psycrit/site/mediawiki-1.34.2/includes/OutputPage.php(2574): SkinTemplate->outputPage()
  
• #8 /home/psycrit/site/mediawiki-1.34.2/includes/MediaWiki.php(537): OutputPage->output()
  
• #9 /home/psycrit/site/mediawiki-1.34.2/index.php(44): MediaWiki->run()
  
• #10 {main}

Unfortunately, this turns out not to be the place where the exception is actually being thrown. From what I can tell, the above is the result of a UI check in the SkinTemplate class to see if various action-links should be displayed. If they shouldn't, then it just doesn't display them; the decision not to display the CreateAccount form is taking place somewhere else.

I should probably look at the CreateAccount code...

(Note: I also took a look at the source code for Extension:InviteSignup, especially InviteSignupHooks.php, and copied some of its techniques -- but that doesn't seem to have fixed the problem.)