Update DOMLex.php

[amanpatel]

Fixed two issues where property references that don't exist cause errors on PHP 8 (on docker setup by "tiredofit").

[ezyang]

By any chance do you know where in the libxml changelog DOM was modified in this way? That would help me assess this change.

[amanpatel]

Could this be a PHP 8 issue? Normally undefined properties are notice level.

But for some reason in my setup for freescount (running under Docker/PHP 8), the undefined properties are triggering a ErrorExceptions. Perhaps laravel framework sets up error reporting this way. I am a bit confused as well.

Would sharing the HTML string for messages that trigger this help you recreate this error?

[amanpatel]

@ezyang I am going to close this PR, it turns out this might be what I'm looking for:
https://stackoverflow.com/questions/18497788/laravel-breaks-entire-app-on-php-notices

[ezyang]

reopening because we ought to be notice clean

[amanpatel]

I tried to run the tests locally, but failed (Wanted to see if I could create a failing test case for you). Failing that though, I can recreate this under my envrionment. So I'm attaching the input that causes the error. Also the error log is as below:

[2021-05-22 19:43:55] production.ERROR: Undefined property: DOMAttr::$name 
(View: /www/html/resources/views/conversations/partials/thread.blade.php) 
(View: /www/html/resources/views/conversations/partials/thread.blade.php) 
(View: /www/html/resources/views/conversations/partials/thread.blade.php) 


{"userId":1,"email":"aman.patel@resonancehealth.org", "exception":"[object] (ErrorException(code: 0): Undefined property: DOMAttr::$name 
(View: /www/html/resources/views/conversations/partials/thread.blade.php) 
(View: /www/html/resources/views/conversations/partials/thread.blade.php) 
(View: /www/html/resources/views/conversations/partials/thread.blade.php) at /www/html/vendor/ezyang/htmlpurifier/library/HTMLPurifier/Lexer/DOMLex.php:267, 

ErrorException(code: 0): Undefined property: DOMAttr::$name 
(View: /www/html/resources/views/conversations/partials/thread.blade.php) 
(View: /www/html/resources/views/conversations/partials/thread.blade.php) at /www/html/vendor/ezyang/htmlpurifier/library/HTMLPurifier/Lexer/DOMLex.php:267, 

ErrorException(code: 0): Undefined property: DOMAttr::$name 
(View: /www/html/resources/views/conversations/partials/thread.blade.php) at /www/html/vendor/ezyang/htmlpurifier/library/HTMLPurifier/Lexer/DOMLex.php:267, 

ErrorException(code: 0): Undefined property: DOMAttr::$name at /www/html/vendor/ezyang/htmlpurifier/library/HTMLPurifier/Lexer/DOMLex.php:267)

Fair warning (don't click on any links in the attached file). From that rabbit hole of following the function calls, I was able to determine that most likely the purifier makes its entry over here:

https://github.com/freescout-helpdesk/freescout/blob/f3aa63aa13f0e7964aff0df9e77b72b02dd0d51c/vendor/mews/purifier/src/Purifier.php#L263

html-purifier-domlex-error.txt

[amanpatel]

@ezyang This seems to be very specific to my environment. When I checked out this repository and ran the purify function with the basic config & the input attached above, it did not display any notices or error exceptions.

I will try to reproduce in a clean php 8 docker container to see if I get the same issue. If that is true, I'll have a reproducible test case for you.

[xemlock]

Use of null coalesce operator should be reflected in min PHP version required in composer.json (e.g.: "php": ">=7.0"), otherwise the library will be broken on older installations.