Since r61072 it checks for the actual bug, not version. The error message might be a confusing for those other affected versions.

r61072 is from presumably where it's failing.

That would mean your 5.2.12 is also bugged, as it's not done by version.

http://www.mediawiki.org/wiki/Manual:Installation_requirements

For the latest version of MediaWiki, PHP version 5.0 or later is required (recommended at least 5.1, PHP versions 5.2.11, 5.2.12 and 5.3.1 are affected by PHP bug 50394 and are discouraged).

At least we output the correct version in r61155

I don't know if it makes much sense to block updating, since 1.15 is equally incompatible. It simply doesn't have the check as the bug was introduced into php after releasing MediaWiki 1.15 release.

But at least it could be helpful if updater warned about possible problems.

I completely agree. It should warn you.

Since there is not actually any reported bug in PHP 5.2.11 or PHP 5.2.12, I am reverting r61204, and the various documentation changes that people have been making on the wiki that implies PHP 5.2.11 doesn't work.

Fixed in r61480. The bug check is now specific to PHP 5.3.x and will not give confusing error messages for PHP 5.2.x.