Bug#1050685: elpa-debian-el: Error when using debian-bug on certain binary package: (wrong-type-argument processp nil)

[Xiyue Deng <manphiz@gmail.com>]

Package: elpa-debian-el
Version: 37.10
Severity: normal
X-Debbugs-Cc: none, Xiyue Deng <manphiz@gmail.com>

I've encountered an error when using "M-x debian-bug" on certain binary
package, such as linux-image-6.4.0-3-amd64.  The error backtrace look
like this:

,----
| Debugger entered--Lisp error: (wrong-type-argument processp nil)
|   set-process-sentinel(nil (lambda (process event) (debian-bug-script-sentinel process event "linux-image-6.1.0-11-amd64" "normal" "Test" nil "/tmp/debian-bug-016wM9" #<window-configuration>)))
|   debian-bug-run-bug-script("linux-image-6.1.0-11-amd64" "normal" "Test" nil)
|   debian-bug-package()
|   debian-bug()
|   funcall-interactively(debian-bug)
|   command-execute(debian-bug record)
|   execute-extended-command(nil "debian-bug" "debian-bug")
|   funcall-interactively(execute-extended-command nil "debian-bug" "debian-bug")
|   command-execute(execute-extended-command)
`----

This happens on both stable and testing, so it's not Emacs 29.1 related.

Due to my lacking in elisp I haven't figured out a fix, but
preliminarily I suspect that in the triggering case the error originates
from [1] where "term-exec" may have failed so that the next
"get-buffer-process" returns nil which in turn caused this error at [2].

[1] https://salsa.debian.org/emacsen-team/debian-el/-/blob/master/debian-bug.el#L892-895
[2] https://salsa.debian.org/emacsen-team/debian-el/-/blob/master/debian-bug.el#L906

-- System Information:
Debian Release: 12.1
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 6.1.0-11-amd64 (SMP w/16 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages elpa-debian-el depends on:
ii  bzip2           1.0.8-5+b1
ii  dh-elpa-helper  2.0.16
ii  dpkg            1.21.22
ii  emacsen-common  3.0.5
ii  reportbug       12.0.0
ii  xz-utils        5.4.1-0.2

Versions of packages elpa-debian-el recommends:
ii  emacs              1:28.2+1-15
ii  emacs-gtk [emacs]  1:28.2+1-15
ii  wget               1.21.3-1+b2

elpa-debian-el suggests no packages.

-- no debconf information