Since we're about to drastically raise our PHP version requirements, we end up in the area where the old `mysql` extension used by DatabaseMysql is deprecated in favor of `mysqli`. After that, it is completely removed in PHP7 and HHVM. I therefore propose to first deprecate then remove the support for it.
[[https://secure.php.net/manual/en/book.mysql.php|Official documentation for PHP extension 'mysql']]
Deprecated in MW 1.30 - to be decided if removed in MW 1.31 or later.
Extensions using DatabaseMysql (see [[https://codesearch.wmflabs.org/search/?q=DatabaseMysql|CodeSearch]]):
[x] ContributionReporting (in code)
** Abandoned and unused, the old code haven't working even before that. No point in wasting time on this.
[ ] OdbcDatabase (in code) ([[https://gerrit.wikimedia.org/r/#/c/404543/1|I6c2c37b]])
[ ] Wikibase (in tests)
[ ] Echo (in tests) ([[https://gerrit.wikimedia.org/r/#/c/404522/|I3150bcd]])
[x] Flow (in tests) ([[https://gerrit.wikimedia.org/r/#/c/404541/1|Ib24561d]])
[ ] EducationProgram (in tests) ([[https://gerrit.wikimedia.org/r/#/c/404537/|I7228c3a]])
[x] SemanticExtraSpecialProperties (in tests) (5ce8bdc during refactoring for 2.0 (still in alpha))
[x] MathSearch (in comments for type hinting) (rEMAS9c316a4)