Subject: bug#79403: 30.1; M-x gdb startup problem with (eq gdb-debuginfod-enable-setting 'ask)

From: Eli Zaretskii <[email-masked]>
Date: Sat, 13 Sep 2025 12:37:29 +0300

> From: Gustav Hållberg <[email-masked]>
> Date: Sun, 7 Sep 2025 17:16:41 +0200
> 
> If gdb-debuginfod-enable-setting is set to 'ask, gdb-init-1 may be called recursively, causing
> gdb-token-number (and other variables) to be reset in the middle of startup.
> 
> This causes an "gdb-handle-reply: Wrong type argument: gdb-handler, nil" error message and other
> "strange" behavior.
> 
> It triggers every time for me when attaching gdb to a running process: "emacs -nw -q" and M-x gdb, "gdb -
> i=mi -p <some-pid>". I only tested it with emacs 30.1 but the code seems to be the same at origin/master.
> 
> If you insert (when (> gdb-token-number 0) (edebug)) in the begining of (gdb-init-1) you'll see what
> happens. Partial call trace:
> 
>   gdb-init-1()
>    :
>   gdb-update()
>    :
>   gdb-stopped(...)
>    :
>   gud-filter(...)
>   read-from-minibuffer(...)
>   y-or-n-p("Enable querying debuginfod servers for this session?")
>    :
>   gdb-init-1()
>    :
>   gdb-update()
>   gdb("gdb -i=mi -p ...")
> 
> I don't know what the right fix is, but it doesn't seem right to wait for user input in the middle of gdb-init-1.

Thanks.  Does the patch below give good results?

diff --git a/lisp/progmodes/gdb-mi.el b/lisp/progmodes/gdb-mi.el
index 74dff32..ebaff4a2 100644
--- a/lisp/progmodes/gdb-mi.el
+++ b/lisp/progmodes/gdb-mi.el
@@ -1108,7 +1108,9 @@ gdb-init-1
   ;; trigger questions about debuginfod queries.
   (if (eq gdb-debuginfod-enable 'ask)
       (setq gdb-debuginfod-enable
-            (y-or-n-p "Enable querying debuginfod servers for this session?")))
+            (let ((gud-filter-defer-flag t))
+              (y-or-n-p
+               "Enable querying debuginfod servers for this session?"))))
   (gdb-input (format "-gdb-set debuginfod enabled %s"
                      (if gdb-debuginfod-enable "on" "off"))
              'gdb-debuginfod-message)