bug#34987: 27.0.50; Error after toggling duplicate suppression

[Basil L. Contovounesios]

[CCing Yamaoka-san due to recent work in this area.]

"Basil L. Contovounesios" <contovob@tcd.ie> writes:

> "Basil L. Contovounesios" <contovob@tcd.ie> writes:
>
>> Patch to follow.
>
> Here it is:
>
> From 162c8d12a4614776e0104b6701d27f5b30bf607b Mon Sep 17 00:00:00 2001
> From: "Basil L. Contovounesios" <contovob@tcd.ie>
> Date: Mon, 25 Mar 2019 02:15:10 +0000
> Subject: [PATCH] Fix Gnus duplicate suppression guards (bug#34987)
>
> * lisp/gnus/gnus-dup.el (gnus-dup-enter-articles)
> (gnus-dup-suppress-articles): Use gnus-dup-hashtb as an indicator of
> initialization instead of gnus-dup-list, which may happen to be nil.
> (gnus-dup-unsuppress-article): Do nothing if gnus-dup-hashtb is
> uninitialized.
> ---
>  lisp/gnus/gnus-dup.el | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/lisp/gnus/gnus-dup.el b/lisp/gnus/gnus-dup.el
> index 8b876489e1..86dbf1a574 100644
> --- a/lisp/gnus/gnus-dup.el
> +++ b/lisp/gnus/gnus-dup.el
> @@ -105,7 +105,7 @@ gnus-dup-save
>  
>  (defun gnus-dup-enter-articles ()
>    "Enter articles from the current group for future duplicate suppression."
> -  (unless gnus-dup-list
> +  (unless gnus-dup-hashtb
>      (gnus-dup-open))
>    (setq gnus-dup-list-dirty t)               ; mark list for saving
>    (let (msgid)
> @@ -129,7 +129,7 @@ gnus-dup-enter-articles
>  
>  (defun gnus-dup-suppress-articles ()
>    "Mark duplicate articles as read."
> -  (unless gnus-dup-list
> +  (unless gnus-dup-hashtb
>      (gnus-dup-open))
>    (gnus-message 8 "Suppressing duplicates...")
>    (let ((auto (and gnus-newsgroup-auto-expire
> @@ -149,9 +149,10 @@ gnus-dup-suppress-articles
>  
>  (defun gnus-dup-unsuppress-article (article)
>    "Stop suppression of ARTICLE."
> -  (let* ((header (gnus-data-header (gnus-data-find article)))
> -      (id     (when header (mail-header-id header))))
> -    (when id
> +  (let (header id)
> +    (when (and gnus-dup-hashtb
> +               (setq header (gnus-data-header (gnus-data-find article)))
> +               (setq id (mail-header-id header)))
>        (setq gnus-dup-list-dirty t)
>        (setq gnus-dup-list (delete id gnus-dup-list))
>        (remhash id gnus-dup-hashtb))))
> -- 
> 2.20.1

Sorry to nag, but I think this is a straightforward enough fix that I
would like to push soon.  WDYT?

Thanks,

-- 
Basil