> I don't count that as a bug, it's merely a situation where one has to choose disadvantages.
There's no line in the IMAP spec. that very explicitly states "each mail MUST exist in exactly one folder", so you can certainly argue that Gmail technically follows the spec. but the only reason that line doesn't exist is because doing otherwise is so non-sensical as to not have been considered as a possibility. It does for example contain the following line, which Gmail does not follow: "permits manipulation of mailboxes (remote message folders) in a way that is functionally equivalent to local folders", but the fact that line is simply in the abstract and contains no MUST means one can argue it's not prescriptive.
There may be disadvantages to using flags instead of mailboxes, but equating their disadvantages is reverse hyperbole. If there was any equivalence, you wouldn't have every major client containing a rake of Gmail-specific code to work around the issue.
I don't see the phrase "MUST exist" anywhere in 3501? I see the word "exactly" in two sentences, neither of which appears to be the one you mean. Can you provide a reference?
I don't want to argue about the disadvantages of flags vs. mailboxes. It's a valid subject but I don't want a subject change.
There's no line in the IMAP spec. that very explicitly states "each mail MUST exist in exactly one folder", so you can certainly argue that Gmail technically follows the spec. but the only reason that line doesn't exist is because doing otherwise is so non-sensical as to not have been considered as a possibility. It does for example contain the following line, which Gmail does not follow: "permits manipulation of mailboxes (remote message folders) in a way that is functionally equivalent to local folders", but the fact that line is simply in the abstract and contains no MUST means one can argue it's not prescriptive.
There may be disadvantages to using flags instead of mailboxes, but equating their disadvantages is reverse hyperbole. If there was any equivalence, you wouldn't have every major client containing a rake of Gmail-specific code to work around the issue.