bug#60024: 28.2; rgrep as part of function don't work

[Einar Largenius <jaadu@lysator.liu.se>]

Hello.

I have the following function:

(defun search-journal (regexp)
  "Searches journal for `regexp'."
  (interactive "sSök i journalen: ")
  (rgrep regexp "* .*" org-directory))

When I run it after startup. It gives me an error:

rgrep-default-command: Wrong type argument: stringp, nil

After I run M-x rgrep<RET>C-g. The above command works just fine. I tested with emacs -Q and the same thing happens.

In GNU Emacs 28.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.30, cairo version 1.16.0)
Windowing system distributor 'The X.Org Foundation', version 11.0.12014000
System Description: Fedora Linux 35 (Workstation Edition)

Configured using:
 'configure
 CONFIG_SHELL=/gnu/store/4y5m9lb8k3qkb1y9m02sw9w9a6hacd16-bash-minimal-5.1.8/bin/bash
 SHELL=/gnu/store/4y5m9lb8k3qkb1y9m02sw9w9a6hacd16-bash-minimal-5.1.8/bin/bash
 --prefix=/gnu/store/58yz6w0ggx5r6vf2p1inv9i9dpibp75h-emacs-28.2
 --enable-fast-install --with-modules --with-cairo
 --with-native-compilation --disable-build-details'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES
NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP SOUND THREADS TIFF
TOOLKIT_SCROLL_BARS X11 XDBE XIM XPM GTK3 ZLIB

-- 
Med vänliga hälsningar Einar