Summary: Ref T13590. By default, PHP kills execution after web scripts run for 30 seconds. If this occurs in the locked section of a repository write while we're holding the durable write lock, the lock will get stuck. Use "set_time_limit(0)" to prevent this mechanism from interrupting execution while the durable lock is held. Test Plan: - Added "set_time_limit(1)" before the lock and "while (1);" in the critical section of the lock. - Pushed, got the lock stuck. - Cleared the lock, applied this patch, pushed. - Got an infinite hang instead. (Normally, we expect the script to take more than 30 seconds to execute because there is a large push that executes in finite time, not because there's an infinte loop.) Maniphest Tasks: T13590 Differential Revision: https://secure.phabricator.com/D21526