Subject: [PATCH v1] Fix errors generated when multiple IRC clients talk to a single IRC proxy.

From: David Edmondson <[email-masked]>
Date: Thu, 13 Nov 2014 06:19:07 +0000

If multiple IRC clients are connected to a single IRC proxy, an
instance of erc can receive the response to a NAMES request issued by
another client. Given that this instance of erc didn't initiate the
NAMES request, `erc-channel-begin-receiving-names' will not have been
called and `erc-channel-new-member-names' will be nil.

To avoid this causing problems, initialise
`erc-channel-new-member-names' by calling
`erc-channel-begin-receiving-names' if it is nil.
---

Michael Olson asked me to send this to emacs-devel after I had posted it
to erc-discuss. I'm not subscribed to the list - please include me
directly in any replies.

 erc.el | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/erc.el b/erc.el
index 6e37f36..320cc02 100644
--- a/erc.el
+++ b/erc.el
@@ -4539,11 +4539,12 @@ received.  Should be called with the current buffer set to the
 channel buffer.
 
 See also `erc-channel-begin-receiving-names'."
-  (maphash (lambda (nick user)
-	     (if (null (gethash nick erc-channel-new-member-names))
-		 (erc-remove-channel-user nick)))
-	   erc-channel-users)
-  (setq erc-channel-new-member-names nil))
+  (when erc-channel-new-member-names
+    (maphash (lambda (nick user)
+	       (if (null (gethash nick erc-channel-new-member-names))
+		   (erc-remove-channel-user nick)))
+	     erc-channel-users)
+    (setq erc-channel-new-member-names nil)))
 
 (defun erc-parse-prefix ()
   "Return an alist of valid prefix character types and their representations.
@@ -4600,6 +4601,11 @@ channel."
 		  op 'off
 		  voice 'off))
 	  (when updatep
+	    ;; If we didn't issue the NAMES request (consider two clients
+	    ;; talking to an IRC proxy), `erc-channel-begin-receiving-names'
+	    ;; will not have been called, so we have to do it here.
+	    (unless erc-channel-new-member-names
+	      (erc-channel-begin-receiving-names))
 	    (puthash (erc-downcase name) t
 		     erc-channel-new-member-names)
 	    (erc-update-current-channel-member
-- 
2.1.0