Content would not be returned anymore via solr when you save then discard a draft of that content.
As a workaround you can comment out following signal-slot
Other issues found while working on this:
- DeleteContent does not correctly update the tree, this is used by UI when deleting Users
- API calls by custom script against UserService will not update Solr on User/UserGroup deletion
- And some cleanup on how trashing info is passed to Search engine
Note for 5.4: These things are only relevant on API use, not via legacy admin.