Issues to be resolved before the next point release (1.5.21)

• IMAP delimiter bug (#3242)
• Some progress on unified NewMailHandling (see #3271)

IMAP delimiter bug

1. Identify code that mangles URLs or inserts folder delimiters
2. Figure out which of that code runs before a delimiter is known.

Desired behaviors

• mailboxes +foo where $folder is an IMAP folder, e.g., imap://server/INBOX should use the correct delimiter between INBOX and foo. The trick is that this is expanded before a connection is opened to get the delimiter for INBOX. Possibly we could add a 'not normalized' bit to the buffy list, and do the glue after the connection has been opened.

In general, the problem is that mutt_expand_path may be called before a connection is open, and it returns a simple string, so it's hard to signal that we don't have a real delimiter yet.

Possible strategies

• For IMAP urls, keep a separate table for entries where the delimiter isn't yet known, that records the original, unexpanded path and the guessed expansion. When it sees a URL matching the guessed expansion, it can go back to the unexpanded form and reexpand it with the known delimiter. Complicated.
• Defer path expansion until just before the path is actually accessed. This provides robust expansion, but if the definition of $folder changes, how do we make sure the version that was in effect at the time of the definition was used?