#15 Supports for GMail labels using X-GM-LABELS extension

[Martin Kletzander]

Even though non-standard, it would be great to have support for syncing gmail labels over IMAP using X-GM-LABELS as documented in https://developers.google.com/gmail/imap/imap-extensions

It is possible to figure out whether the server supports this using capabilities.

[Oswald Buddenhagen]

yes, that's an extension of supporting regular imap keywords, which has been on the TODO forever.

[Mark Diekhans]

I am trying to use mbsync and dovecot to implement a local cache to work around how slow gmail IMAP is. Not being sync local label from emacs VM with gmail is a drawback. So I worked with Claude Code to determine what would be involved in implementing this feature. Here is a proposal and options:

https://github.com/diekhans/isync-isync/blob/gmail-labels/mbsync-gmail-design.org

Thoughts?

[Oswald Buddenhagen]

i'm not convinced that even the first sentence in that "AI" output is correct. source?

and i'm not convinced that it makes sense the link gm-labels with keywords/flags, as they serve somewhat different purposes.

regarding x-keywords, the issue is that it is slow, as it requires each file to be opened to read these extended flags. it's basically unusable without a header cache. hence the interoperability issue. a survey of the various approaches used by relevant muas would be interesting.