There was a conditional that was documented to make the method bail out
if the current revision was unsaved, but it was missing the actual return
statement.
Note that preview code in EditPage does not use
DifferenceEngine::renderNewRevision.
Change-Id: I86a25e9464435ac17c72f78f7ce1f354adf3d055
// New revision is unsaved; bail out.
// TODO in theory rendering the new revision is a meaningful thing to do
// even if it's unsaved, but a lot of untangling is required to do it safely.
+ return;
}
$out->setRevisionId( $this->mNewid );