as per subject
PHP Fatal error: Cannot instantiate abstract class Installer in .../includes/installer/Installer.php on line 468, referer: http
I'm looking at this, and I believe I know what is causing this.
Steps to reproduce:
Related URL: https://gerrit.wikimedia.org/r/60369 (Gerrit Change Ic456899028c054a761d172df8ec32f6a26dc5b97)
Patch in Gerrit awaiting review, might be nice to get this in for 1.21.0.
Definitely need this in 1.21 -- I found it when a client was working on their 1.21 upgrade. I would prefer that Chad reviews it, but since he seems to be busy, I will.
Tested and confirmed the fix works. Merging into 1.21
Related URL: https://gerrit.wikimedia.org/r/61189 (Gerrit Change Ic456899028c054a761d172df8ec32f6a26dc5b97)