While upgrading an existing database with a fresh checkout from SVN [1], I found a reproducible UI problem after the step "upgrade existing installation".
After the "upgrade complete" message, the box shows a link with the text
a) "You can now start using your wiki" ; and
b) button text "Regenerate LocalSettings.php"
When you follow the link a), you somehow break the installation in between and restart the installer index.php ("LocalSettings not found, complete the installation"). It is possible to continue the installation, but difficult.
Suggestion package:
Remove that link a) ; and
Change the text on the button b) to "Continue the installation. A new LocalSettings.php will be created."
[1] I mean: after a fresh checkout, when accessing the wiki, the installer starts. The former LocalSettings.php is in a backup place. There is no LocalSettings.php to be regenerated after a fresh checkout or download.
Version: 1.20.x
Severity: normal
Whiteboard: aklapper-moreinfo