From e8a6259cebf5ac22a07f8b8fcc1d24e4f39a1f88 Mon Sep 17 00:00:00 2001
From: Reiner Steib <Reiner.Steib@gmx.de>
Date: Sat, 31 Jan 2009 15:27:39 +0000
Subject: [PATCH] (imap-fetch-safe): Bind debug-on-error. (imap-debug): Add
 imap-fetch-safe.

---
 lisp/ChangeLog |  5 +++++
 lisp/imap.el   | 44 +++++++++++++++++++++++++++++---------------
 2 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index c887068ea..af477f4bc 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2009-01-31  Dave Love  <fx@gnu.org>
+
+	* imap.el (imap-fetch-safe): Bind debug-on-error.
+	(imap-debug): Add imap-fetch-safe.
+
 2009-01-26  Teodor Zlatanov  <tzlatanov@jumptrading.com>
 
 	* auth-source.el (auth-source-forget-user-or-password): Clarify docs.
diff --git a/lisp/imap.el b/lisp/imap.el
index 6f2b2d11f..88e897fa3 100644
--- a/lisp/imap.el
+++ b/lisp/imap.el
@@ -1798,25 +1798,38 @@ However, UIDS here is a cons, where the car is the canonical form
 of the UIDS specification, and the cdr is the one which works with
 Exchange 2007 or, potentially, other buggy servers.
 See `imap-enable-exchange-bug-workaround'."
-  ;; We don't unconditionally use the alternative (valid) form, since
-  ;; this is said to be significantly inefficient.  The first time we
-  ;; get here for a given, we'll try the canonical form.  If we get
-  ;; the known error from the buggy server, set the flag
-  ;; buffer-locally (to account for connections to multiple servers),
-  ;; then re-try with the alternative UIDS spec.
+  ;; The first time we get here for a given, we'll try the canonical
+  ;; form.  If we get the known error from the buggy server, set the
+  ;; flag buffer-locally (to account for connections to multiple
+  ;; servers), then re-try with the alternative UIDS spec.  We don't
+  ;; unconditionally use the alternative form, since the
+  ;; currently-used alternatives are seriously inefficient with some
+  ;; servers (although they are valid).
+  ;;
+  ;; FIXME:  Maybe it would be cleaner to have a flag to not signal
+  ;; the error (which otherwise gives a message), and test
+  ;; `imap-failed-tags'.  Also, Other IMAP clients use other forms of
+  ;; request which work with Exchange, e.g. Claws does "UID FETCH 1:*
+  ;; (UID)" rather than "FETCH UID 1,*".  Is there a good reason not
+  ;; to do the same?
   (condition-case data
-      (imap-fetch (if imap-enable-exchange-bug-workaround
-		      (cdr uids)
-		    (car uids))
-		  props receive nouidfetch buffer)
+      ;; Binding `debug-on-error' allows us to get the error from
+      ;; `imap-parse-response' -- it's normally caught by Emacs around
+      ;; execution of a process filter.
+      (let ((debug-on-error t))
+	(imap-fetch (if imap-enable-exchange-bug-workaround
+			(cdr uids)
+		      (car uids))
+		    props receive nouidfetch buffer))
     (error
      (if (and (not imap-enable-exchange-bug-workaround)
-	      (string-match
-	       "The specified message set is invalid"
-	       (cadr data)))
+	      ;; This is the Exchange 2007 response.  It may be more
+	      ;; robust just to check for a BAD response to the
+	      ;; attempted fetch.
+	      (string-match "The specified message set is invalid"
+			    (cadr data)))
 	 (with-current-buffer (or buffer (current-buffer))
-	   (set (make-local-variable
-		 'imap-enable-exchange-bug-workaround)
+	   (set (make-local-variable 'imap-enable-exchange-bug-workaround)
 		t)
 	   (imap-fetch (cdr uids) props receive nouidfetch))
        (signal (car data) (cdr data))))))
@@ -3027,6 +3040,7 @@ Return nil if no complete line has arrived."
 	  imap-list-to-message-set
 	  imap-fetch-asynch
 	  imap-fetch
+	  imap-fetch-safe
 	  imap-message-put
 	  imap-message-get
 	  imap-message-map
-- 
2.11.4.GIT