a) True for non-threaded messages, thread roots and non-thread relations to thread roots.
b) False for messages with thread relations to the thread root.
c) False for messages with any kind of relation to a message from case b.
Note: true for redactions of messages that are in threads. Redacted messages
are not really in threads (because their relations are gone), so if they look
like they are in threads, that is a sign of a bug elsewhere. (At time of
writing, this bug definitely exists - messages are not moved to another
thread when they are redacted.)
a) True for non-threaded messages, thread roots and non-thread relations to thread roots. b) False for messages with thread relations to the thread root. c) False for messages with any kind of relation to a message from case b.
Note: true for redactions of messages that are in threads. Redacted messages are not really in threads (because their relations are gone), so if they look like they are in threads, that is a sign of a bug elsewhere. (At time of writing, this bug definitely exists - messages are not moved to another thread when they are redacted.)