```name=Error
Fatal exception of type "TypeError": Argument 1 passed to MediaWiki\EditPage\SpamChecker::checkSummary() must be of the type string, null given, called in /includes/EditPage.php on line 2692
```
```name=trace,lines=12
#0 /srv/mediawiki/php-1.35.0-wmf.32/includes/EditPage.php(2692): MediaWiki\EditPage\SpamChecker->checkSummary(NULL)
#1 /srv/mediawiki/php-1.35.0-wmf.32/includes/specials/SpecialChangeContentModel.php(150): EditPage::matchSummarySpamRegex(NULL)
#2 /srv/mediawiki/php-1.35.0-wmf.32/includes/htmlform/HTMLFormField.php(315): SpecialChangeContentModel->{closure}(NULL, array, OOUIHTMLForm)
#3 /srv/mediawiki/php-1.35.0-wmf.32/includes/htmlform/HTMLFormField.php(897): HTMLFormField->validate(NULL, array)
#4 /srv/mediawiki/php-1.35.0-wmf.32/includes/htmlform/HTMLFormField.php(606): HTMLFormField->getErrorsRaw(NULL)
#5 /srv/mediawiki/php-1.35.0-wmf.32/includes/htmlform/HTMLForm.php(1696): HTMLFormField->getOOUI(NULL)
#6 /srv/mediawiki/php-1.35.0-wmf.32/includes/htmlform/HTMLForm.php(1292): HTMLForm->displaySection(array, string)
#7 /srv/mediawiki/php-1.35.0-wmf.32/includes/htmlform/OOUIHTMLForm.php(282): HTMLForm->getBody()
#8 /srv/mediawiki/php-1.35.0-wmf.32/includes/htmlform/HTMLForm.php(1076): OOUIHTMLForm->getBody()
#9 /srv/mediawiki/php-1.35.0-wmf.32/includes/htmlform/HTMLForm.php(1055): HTMLForm->getHTML(boolean)
#10 /srv/mediawiki/php-1.35.0-wmf.32/includes/htmlform/HTMLForm.php(606): HTMLForm->displayForm(boolean)
#11 /srv/mediawiki/php-1.35.0-wmf.32/includes/specialpage/FormSpecialPage.php(187): HTMLForm->show()
#12 /srv/mediawiki/php-1.35.0-wmf.32/includes/specialpage/SpecialPage.php(576): FormSpecialPage->execute(string)
#13 /srv/mediawiki/php-1.35.0-wmf.32/includes/specialpage/SpecialPageFactory.php(623): SpecialPage->run(string)
#14 /srv/mediawiki/php-1.35.0-wmf.32/includes/MediaWiki.php(299): MediaWiki\SpecialPage\SpecialPageFactory->executePath(Title, RequestContext)
#15 /srv/mediawiki/php-1.35.0-wmf.32/includes/MediaWiki.php(973): MediaWiki->performRequest()
#16 /srv/mediawiki/php-1.35.0-wmf.32/includes/MediaWiki.php(535): MediaWiki->main()
#17 /srv/mediawiki/php-1.35.0-wmf.32/index.php(47): MediaWiki->run()
#18 /srv/mediawiki/w/index.php(3): require(string)
#19 {main}
```
Attempting to change content model of page will currently yields the above fatal in production
===== Impact====
Content model cannot be changed