Re: [VM] vm-mark-folder-modified-p

[Uday Reddy]

Julian Bradfield writes:

> Returning to the problem noted a while ago of VM marking a read-only
> folder modified when it upgrades attribute data:
> Is there *any* case in which vm-mark-folder-modified-p should work on
> a read-only folder?

Rethinking this issue, I think there has been a general misunderstanding of
what it means for a folder to be visited read-only.  As the doc string of
`vm-visit-folder' says, visiting a folder read-only just means that "no
attribute changes, messages additions or deletions will be allowed in the
visited folder."  It does NOT mean that the folder buffer will not be
modified or that the folder on disk will be preserved.

(There might also have been a traditional view that vm is just an Emacs mode
for viewing a mail folder on disk.  That view is not valid any more.  There
could be changes made to the cached data headers, messages might move in and
out of the IMAP cache folders etc.  VM is evolving into a mail-reading
front-end that can transparently handle a variety of message stores at the
back end.  A mail folder on disk is just one possible back end.)

If people want read-only folders to be preserved on disk, the best way to
achieve it is via `vm-quit'.  As I have mentioned earlier
`vm-quit-no-change' can be used to quit folders without saving to disk.  If
that is too much trouble to use, I can modify the standard `vm-quit' to
refrain from saving read-only folders.  That might in fact be the best
solution for the kind of things you want to do.

Cheers,
Uday