As Brion points out in <https://bugzilla.wikimedia.org/show_bug.cgi?id=29747#c7>, the shared memory functions are very buggy. In fact, eAccelerator has disabled the shared memory functions by default for awhile now. I didn't touch APC, XCache or WinCache, but I imagine they suffer from the same problems.
Writing to cache is now handled in a new method. That makes recache() a bit
shorter and easier to read. Since there is no point in writing data to
/dev/null , return early in such a case (ie if store is LCStore_Null).
.... I've found another bug with the implementation - it also
relies on the presence of key '...:preload' and doesn't check it
when checking for the expired cache, which can lead to "Invalid or
missing localisation cache" exceptions.
* 'editfont' => 'sans-serif'; -> trivial (can be set in CSS)
* 'underline' => 0; by languages written in scripts that are hard to read with underlines -> now set in shared.css, which makes it work also when they are used as interface language (note that [lang="xx"] is not yet present on wikitext content by default but will be soon as part of my work on RTL improvements)
* 'quickbar' => 2; by RTL languages. For this, I introduced a new option (5) that sets left/right according to the directionality of your interface language (and automatic is better than setting it in MessagesXx files!). Note that the broken feature was in this case "corrected" by CSS flipping, causing preferences to say "left" while it was actually "right". This commit fixes that bug as well.
Third, it actually would have made more sense to have it them load for wgLang instead of wgContLang, but that's not possible because wgLang is itself dependent on preferences
* MW_MATH_* constants are now defined in Math extension
* Language::getMathNames() is removed
* mathNames section in message files is removed
* A hardcoded preference override in refreshLinks moved to MaintenanceRefreshLinksInit hook
* Allow any language code which consists entirely of valid title characters, and does not contain any path-traversal characters, to be customised via the uselang parameter. Language::isValidCode() represents this concept.
* Add some shortcuts preventing Language and LocalisationCache from looking for localisation files for a language code which does not follow the usual form of language codes in MediaWiki, i.e. /[a-z-]*/. This concept is represented by Language::isValidBuiltInCode().
* Do not allow colon characters in file names, per Platonides' suggestion on CR.
* In MagicWord::initRegex(), put the longest synonyms first in the alternation. This means that when one synonym is an initial substring of another, the longest one will match in precedence, which is generally in line with user expectations.
This patch automatically includes synonyms from the fallback localisation, and prevents the case flag from being overridden, thus making extensions resistant to translator error.
* MessageCache::singleton() calls wfGetMessageCacheStorage() directly instead of using $messageMemc, just in case this would be called before that variable is set
* Per TimStarling: also removed deprecated methods in MessageCache class: addMessages() and related, [get|set|enable|disable]Transform(), loadAllMessages(), loadMessageFile() and some others. Same for the legacyData stuff in LocalisationCache that was only used by MessageCache::addMessages() and related.
* Converted remaining extensions
* In SqlBagOStuff, ignore errors due to a read-only database, per my comments on CR r42796. Same for LocalisationCache.
* Merged SqlBagOStuff and MediaWikiBagOStuff, that proved to be an awkward and unnecessary generalisation. Use the standard quoting wrapper functions instead of $db->query().
* Implemented atomic incr() and decr() functions for SqlBagOStuff.
* Made incr() and decr() generally work roughly the same as it does in memcached, respecting negative steps instead of ignoring such operations. This allows decr() to be implemented in terms of incr().
* Per bug 11533, in MessageCache.php, don't retry 20 times on a cache failure, that's really memcached-specific and won't be useful for other cache types. It's not really very useful for memcached either.
* Moved MySQL-specific implementations of wasDeadlock() and wasErrorReissuable() to DatabaseMysql.
* Briefly tested page views with $wgReadOnly=read_only=1, fixed an error from Article::viewUpdates(). A CentralAuth fix will be in a subsequent commit.
