find_disconnected_db_submissions() does not check for disconnected replies

[cfm]

Description

find_disconnected_fs_submissions() checks for submission and reply files missing from the database, since their filenames exist in the same space:

securedrop/securedrop/management/submissions.py

Lines 85 to 89 in f5ca29b

	submissions = Submission.query.order_by(Submission.id, Submission.filename).all()
	files_in_db = {s.filename: True for s in submissions}
	replies = Reply.query.order_by(Reply.id, Reply.filename).all()
	files_in_db.update({r.filename: True for r in replies})

find_disconnected_db_submissions() does not check for submission and reply records missing from the filesystem, since their IDs do not exist in the same space:

securedrop/securedrop/management/submissions.py

Line 20 in f5ca29b

submissions = db.session.query(Submission).order_by(Submission.id, Submission.filename).all()

As a result, manage.py delete-disconnected-db-submissions cannot remove a disconnected reply.

Steps to Reproduce

1. Register as a source and submit something.
2. Reply.
3. Delete that source's directory from /var/lib/securedrop/store.
4. manage.py delete-disconnected-db-submissions

Expected Behavior

The reply is deleted from the database.

Actual Behavior

The reply is not deleted from the database.

Comments

The fundamental issue here is the subtyping within:

securedrop/securedrop/models.py

Line 116 in f5ca29b

collection: List[Union[Submission, Reply]] = []

For now we'd probably just want to add a separate find_disconnected_db_replies() function and iterate over that separately in delete_disconnected_db_replies().