bug#858: Conflict between ERC mode tracking and ibuffer window shrinking

[martin rudalics]

CC-ing Keegan because Bug #466 describes another problem with ERC and
windows.

>> There is a bug when using conjointly these two features. Here are the
>> relevant portions of configuration :
>>
>> ;;make ibuffer resize itself to its buffer size
>> (setq ibuffer-use-other-window t)
>> (setq ibuffer-default-shrink-to-minimum-size t)
>>
>> No specific configuration for erc, just enabling tracker is enough.
>> Then, run erc, and, in any erc buffer, call ibuffer. The screen
>> briefly flashes as an ERC window opens then disappears, and the
>> ibuffer window is reduced to a much smaller size than what it would be
>> outside ERC. I think the issue is erc's hook to
>> window-configuration-change somehow messing with ibuffer, but I'm not
>> experienced enough to find where the bug is.

Can't offer much insight but processing window-configuration-change
hooks has changed with Emacs 23.  So this

(defun erc-track-modified-channels ()
  "Hook function for `erc-insert-post-hook' to check if the current
buffer should be added to the modeline as a hidden, modified
channel.  Assumes it will only be called when current-buffer
is in `erc-mode'."
  (let ((this-channel (or (erc-default-target)
                          (buffer-name (current-buffer)))))
    ...                 

might have been broken for some reason.  To verify, someone would have
to try with Emacs 22 and 23 inserting just before the `let' something
like

(unless (eq major-mode 'erc-mode)
  (message "Not in erc-mode ..."))

and look whether it triggers.

martin