bug#70230: 30.0.50; [PATCH] * lisp/master.el (master-says): check nil parameter

bug#70230: 30.0.50; [PATCH] * lisp/master.el (master-says): check nil parameter

[Lin Sun]

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Hi,

The `(master-says)' will trigger an unexpected error message with follow code:

(require 'master)
(master-says)

> Wrong type argument: stringp, nil

The patch tries checking the nil parameter before calling `get-buffer'
to avoid the unexpected err message.

Please help check it. Thanks.

Best regards
Lin

[-- Attachment #2: 0001-lisp-master.el-master-says-check-nil-parameter.patch --]
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From 7a0dcde5fec2b7b7fdd1c74db1440183c11cfca6 Mon Sep 17 00:00:00 2001
From: Lin Sun <sunlin7@hotmail.com>
Date: Fri, 5 Apr 2024 06:58:07 +0000
Subject: [PATCH] * lisp/master.el (master-says): check nil parameter

---
 lisp/master.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lisp/master.el b/lisp/master.el
index 0caf4d7963..4bdf686111 100644
--- a/lisp/master.el
+++ b/lisp/master.el
@@ -136,7 +136,8 @@ master-says-recenter
 (defun master-says (&optional command arg)
   "Display slave buffer and execute COMMAND with ARG in its window."
   (interactive)
-  (if (null (buffer-live-p (get-buffer master-of)))
+  (if (not (and master-of
+                (buffer-live-p (get-buffer master-of))))
       (error "Slave buffer has disappeared")
     (let ((window  (selected-window)))
       (if (not (eq (window-buffer window) (get-buffer master-of)))
-- 
2.20.5

bug#70230: 30.0.50; [PATCH] * lisp/master.el (master-says): check nil parameter

[Eli Zaretskii]

> From: Lin Sun <sunlin7.mail@gmail.com>
> Date: Sat, 6 Apr 2024 00:05:29 +0000
> 
> The `(master-says)' will trigger an unexpected error message with follow code:
> 
> (require 'master)
> (master-says)
> 
> > Wrong type argument: stringp, nil
> 
> The patch tries checking the nil parameter before calling `get-buffer'
> to avoid the unexpected err message.

Thanks, but "Slave buffer has disappeared" doesn't sound like a good
error message when master-of is nil, does it?

bug#70230: 30.0.50; [PATCH] * lisp/master.el (master-says): check nil parameter

[Lin Sun]

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Hi Eli,

On Sat, Apr 6, 2024 at 8:06 AM Eli Zaretskii <eliz@gnu.org> wrote:
> Thanks, but "Slave buffer has disappeared" doesn't sound like a good
> error message when master-of is nil, does it?
Totally, the message will confuse the user. I modified the patch and
it checks the parameter `master-of' and gives a message "Slave buffer
does not exist" when it's nil.

Please help review again. Thanks.

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bug#70230: 30.0.50; [PATCH] * lisp/master.el (master-says): check nil parameter

[Eli Zaretskii]

> From: Lin Sun <sunlin7.mail@gmail.com>
> Date: Sat, 6 Apr 2024 15:25:35 +0000
> Cc: 70230@debbugs.gnu.org
> 
> On Sat, Apr 6, 2024 at 8:06 AM Eli Zaretskii <eliz@gnu.org> wrote:
> > Thanks, but "Slave buffer has disappeared" doesn't sound like a good
> > error message when master-of is nil, does it?
> Totally, the message will confuse the user. I modified the patch and
> it checks the parameter `master-of' and gives a message "Slave buffer
> does not exist" when it's nil.

I think "Slave buffer does not exist" is not the best message, since
the slave master is simply undefined in that case.  A better message
would be something like "Current buffer is not a master of any other
buffer".

bug#70230: 30.0.50; [PATCH] * lisp/master.el (master-says): check nil parameter

[Lin Sun]

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Hi Eli,

Yes, the "Current buffer is not a master of any other buffer" is more accurate.
The changed message path is attached.

Thank you so much!

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From 77a2e56374a7891bdd572f2ffa51f700c6fb809f Mon Sep 17 00:00:00 2001
From: Lin Sun <sunlin7@hotmail.com>
Date: Fri, 5 Apr 2024 06:58:07 +0000
Subject: [PATCH] * lisp/master.el (master-says): check nil parameter

---
 lisp/master.el | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lisp/master.el b/lisp/master.el
index 0caf4d7963..9151ca212d 100644
--- a/lisp/master.el
+++ b/lisp/master.el
@@ -136,6 +136,8 @@ master-says-recenter
 (defun master-says (&optional command arg)
   "Display slave buffer and execute COMMAND with ARG in its window."
   (interactive)
+  (unless master-of
+    (error "Current buffer is not a master of any other buffer"))
   (if (null (buffer-live-p (get-buffer master-of)))
       (error "Slave buffer has disappeared")
     (let ((window  (selected-window)))
-- 
2.20.5

bug#70230: 30.0.50; [PATCH] * lisp/master.el (master-says): check nil parameter

[Eli Zaretskii]

> From: Lin Sun <sunlin7.mail@gmail.com>
> Date: Sat, 6 Apr 2024 21:26:49 +0000
> Cc: 70230@debbugs.gnu.org
> 
> Yes, the "Current buffer is not a master of any other buffer" is more accurate.
> The changed message path is attached.

Thanks, installed on master, and closing the bug.

P.S. Please in the future format the commit log message according to
our conventions, and also mention the bug number when known.

bug#70230: 30.0.50; [PATCH] * lisp/master.el (master-says): check nil parameter

[Lin Sun]

Yes, will do that. Thank you!