This involves several changes at different places:
- syncfoldersto() takes statusfolder as an argument, and returns the
list of new folders and the list of folders that should be ingnored,
typically those that were deleted. Warns the user about folders that
are present only on one side and are not synced.
- syncfoldersto() is called both ways, and on folder creation
forgetfolders() is used to rebuild the list and take the new creation
into account. Probably not the most efficient, since it involves
talking to the IMAP server again, but it will rarely be used anyway.
- Locally created folders are treated separately in the synchronization,
namely the local messages are uploaded and then the normal sync still
occurs. If the same folder is created on both sides and contains
messages on both sides, a two-way sync occurs.