* Create task-specific methods with simple defaults that require no
mocking or stubbing of any kind, as used by the pure unit tests
where service container (and by extent, storage services) are
disabled.
* Remove all use of global variables, LBFactory, JobQueue,
StatsdFactory, and RequestContext.
Bug: T265749
Change-Id: If85c448d2d1b806e70f641f06263680d49c6eeec
Follow-up ba6490aa1e.
That patch worked around $executeContext iteration errors due to the
lack of recursion support in doUpdates()/handleUpdateQueue(). Errors
were triggered by MediaWiki::schedulePostSendJobs() enqueueing deferred
updates that invoke JobRunner::run(), which, in turn, invoke doUpdates()
for each job via JobRunner:: doExecuteJob(). The doUpdates() method was
changed to operate on the sub-queue for the in-progress DeferrableUpdate.
Further improve the recursion logic:
* Use classes for the scope stack and scope queues.
* Put *all* updates added during a DeferrableUpdate::doUpdate() call into
the subqueue, regardless of "defer until" stage or whether it implements
MergeableUpdate. Now, doUpdate() can run *everything* it enqueued instead
of a non-obvious subset. Note that the TransactionRoundDefiningUpdate
that invokes JobRunner was already a POSTSEND update before ba6490aa1eb;
the only effect of this change is that MergeableUpdate instances from jobs
will once again run in doExecuteJob().
* Make recursive DeferredUpdates::doUpdate() calls error out immediately
unless the DeferrableUpdate responsible is a TransactionRoundAwareUpdate
with the TRX_ROUND_ABSENT flag. This covers the schedulePostSendJobs()
scenario and only prohibits insane call patterns. Failing early avoids
the risk of handleUpdateQueue() dropping all the updates due to the same
DBTransactionError error in DeferredUpdates::attemptUpdate().
* Avoid recursion loop in tryOpportunisticExecute() when JobQueueDB is in
use and a large number of tasks are pending. This happened due to methods
like onTransactionPreCommitOrIdle() being used within JobQueueDB.
Mark DeferredUpdates::doUpdates()/tryOpportunisticExecute() as @internal
and create a Maintenance::shutdown() method to avoid a direct call in the
doMaintenance.php file.
Bug: T249069
Bug: T268840
Change-Id: Ib369f0e74243a48ababdb9cd83b155c9a0f5e741
