bug#21043: [PATCH] nnimap.el: make capability parsing more robust.

[Nikolaus Rath]

Package: gnus
Tags: patch

Hello,

Currently Gnus relies on the server supplying the capabilities in its
response to the LOGIN command, e.g. like this:

* CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE
SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT
MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS
LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES
WITHIN CONTEXT=SEARCH LIST-STATUS SPECIAL-USE BINARY MOVE SEARCH=FUZZY
QUOTA\r\n
1 OK Logged in\r\n

However, this assumption breaks if the server doesn't return the
capabilities automatically, or if he returns them as part of the OK
response, e.g.:

160 OK [CAPABILITY IMAP4rev1 LITERAL+ ID ENABLE ACL RIGHTS=kxten
QUOTA MAILBOX-REFERRALS NAMESPACE UIDPLUS NO_ATOMIC_RENAME UNSELECT
CHILDREN MULTIAPPEND BINARY CATENATE CONDSTORE ESEARCH SEARCH=FUZZY
SORT SORT=MODSEQ SORT=DISPLAY SORT=UID THREAD=ORDEREDSUBJECT
THREAD=REFERENCES ANNOTATEMORE ANNOTATE-EXPERIMENT-1 METADATA
LIST-EXTENDED LIST-STATUS LIST-MYRIGHTS LIST-METADATA WITHIN QRESYNC
SCAN XLIST XMOVE MOVE SPECIAL-USE CREATE-SPECIAL-USE DIGEST=SHA1
X-REPLICATION LOGINDISABLED XCONVERSATIONS COMPRESS=DEFLATE
X-QUOTA=STORAGE X-QUOTA=MESSAGE X-QUOTA=X-ANNOTATION-STORAGE
X-QUOTA=X-NUM-FOLDERS IDLE] User logged in
SESSIONID=<sloti32d1t18-237747-1436749914-1-18339819756817078727>\r\n


Currently, in this situation Gnus just keeps re-using the pre-LOGIN
capabilities (and thus does not take advantage of any additional
features).

The attached patch fixes this issue by explicitly asking the server for
its capabilities after login.


Thanks for considering,
-Nikolaus

[Nikolaus Rath]

Post by Nikolaus Rath
Package: gnus
Tags: patch

There was no patch!

Oops. Here it is.

[Lars Magne Ingebrigtsen]

- (dolist (response (cddr login-result))
+ (dolist (response (cddr (nnimap-command "CAPABILITY")))

That'll be an extra round trip when logging in...

[Nikolaus Rath]

Post by Lars Magne Ingebrigtsen

- (dolist (response (cddr login-result))
+ (dolist (response (cddr (nnimap-command "CAPABILITY")))

That'll be an extra round trip when logging in...

Yes. But that's not exactly a critical path, is it?


Best,
-Nikolaus

[Lars Magne Ingebrigtsen]

Subject: [PATCH] nnimap.el: make capability parsing more robust.

[...]

- (dolist (response (cddr login-result))
+ (dolist (response (cddr (nnimap-command "CAPABILITY")))

And we've already issued the CAPABILITY command in the
`open-protocol-stream' call, so if the results of that isn't in
`login-results', there's a bug in `open-protocol-stream'.

[Nikolaus Rath]

Post by Lars Magne Ingebrigtsen

Subject: [PATCH] nnimap.el: make capability parsing more robust.

[...]

- (dolist (response (cddr login-result))
+ (dolist (response (cddr (nnimap-command "CAPABILITY")))

And we've already issued the CAPABILITY command in the
`open-protocol-stream' call, so if the results of that isn't in
`login-results', there's a bug in `open-protocol-stream'.

No. The results of the CAPABILITY command before login may be different
than after login.

Best,
-Nikolaus