Tree still being maintained when entity_hierarchy_disable_writes=1
Problem/Motivation
A node complete migration was performing glacially even though I'd set entity_hierarchy_disable_writes to 1. It turns out entity_hierarchy_entity_update() was in play, trying to move children between revisions of a node.
Steps to reproduce
Run a revision-aware migration involving destination nodes with an entity hierarchy relationship. Observe entity_hierarchy_entity_update() being invoked, even if tree maintenance is disabled.
Proposed resolution
Add a check in entity_hierarchy_entity_update() to return immediately if `entity_hierarchy_disable_writes` is true.
Edited by drupalbot