From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Dima Kogan <dima@secretsauce.net>
Cc: 19363@debbugs.gnu.org
Subject: bug#19363: Acknowledgement (24.4.1; Notifications can make ERC unusable)
Date: Sun, 04 Jan 2015 14:52:07 -0500 [thread overview]
Message-ID: <jwvppau9vp1.fsf-monnier+emacsbugs@gnu.org> (raw)
In-Reply-To: <878uhnn3ub.fsf@secretsauce.net> (Dima Kogan's message of "Wed, 31 Dec 2014 07:47:24 -0800")
> If we have some (eval-after-load 'erc ...) stuff then by the time this
> (defvar) is evaluated, the list may already have a value, so the defvar
> then does NOT add its value to the list. The patch explicitly changes
> the (defvar list default) idiom to
> (defvar list nil) (add-to-list 'list default) and thus the default value
> always appears in the list.
Thanks. That's a good change.
The general rule is that a hook's initial/default value should be nil
(that's fairly strong "should", with relatively few exceptions.
This bug-report is a good example of why it should be that way).
It's also generally better if the hook's "normal" value is nil, tho
I think in this case it'd be probably inconvenient.
But I do wonder: if the function *has* to be on that hook for ERC to
work correctly, then maybe that function's place is not in the hook but
right at those places where the hook is run (i.e. hard-coded).
Could you (or someone who understands the code better than I do) take
a look to see if such a change would be even better?
Stefan
>> From 28bc9430ce6342d210e986586af7b6f12e103043 Mon Sep 17 00:00:00 2001
> From: Dima Kogan <dima@secretsauce.net>
> Date: Wed, 31 Dec 2014 08:13:57 -0800
> Subject: [PATCH] ERC no longer gets confused by (eval-after-load 'erc ...)
> ERC was initializing one of its lists with (defvar list default). If
> the list already had a value due to (eval-after-load 'erc ...) for
> instance, then (defvar) would see an initialized variable, and would NOT
> add the default value to the list. This was breaking things. This
> patch changes the above defvar idiom to
> (defvar list nil)
> (add-to-list 'list default)
> This way the default value is added to the list unconditionally
> Closes: #19363
> ---
> lisp/erc/erc-backend.el | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
> diff --git a/lisp/erc/erc-backend.el b/lisp/erc/erc-backend.el
> index fa95d7e..43e56c0 100644
> --- a/lisp/erc/erc-backend.el
> +++ b/lisp/erc/erc-backend.el
> @@ -1179,8 +1179,11 @@ add things to `%s' instead."
> (cl-loop for alias in aliases
> collect (intern (format "erc-server-%s-functions" alias)))))
> `(prog2
> - ;; Normal hook variable.
> - (defvar ,hook-name ',fn-name ,(format hook-doc name))
> + ;; Normal hook variable. The variable may already have a
> + ;; value at this point, so I default to nil, and (add-hook)
> + ;; unconditionally
> + (defvar ,hook-name nil ,(format hook-doc name))
> + (add-to-list ',hook-name ',fn-name)
> ;; Handler function
> (defun ,fn-name (proc parsed)
> ,fn-doc
> --
> 2.1.3
next prev parent reply other threads:[~2015-01-04 19:52 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-13 6:32 bug#19363: 24.4.1; Notifications can make ERC unusable Dima Kogan
[not found] ` <handler.19363.B.141845239213530.ack@debbugs.gnu.org>
2014-12-31 8:34 ` bug#19363: Acknowledgement (24.4.1; Notifications can make ERC unusable) Dima Kogan
2014-12-31 8:59 ` Dima Kogan
2014-12-31 15:47 ` Dima Kogan
2015-01-04 19:52 ` Stefan Monnier [this message]
2015-01-04 21:26 ` Dima Kogan
2015-01-05 1:54 ` Stefan Monnier
2015-01-07 0:38 ` Dima Kogan
2014-12-31 17:46 ` Dima Kogan
2015-01-14 22:07 ` bug#19363: Close debbugs #19363 Kelvin White
2015-01-14 23:17 ` Kelvin White
2015-01-15 18:15 ` Glenn Morris
2015-01-15 23:41 ` Kelvin White
2015-01-16 13:27 ` bug#19363: Kelvin White
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