Recipes to confirm bug 50630
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=50630

These will show two buffers with a directory listing for the same directory, but with different available space depending on the default-directory when executing.

On Windows, I confirmed the bug using two different drive letters for pwd-a and pwd-b. But my main testing was doing all 3 of these on GNU/Linux. On Windows, ls-lisp will probably always be used unless it's disabled.

for lisp/files.el (already fixed):

emacs -Q --eval "\
(progn \
   (setq pwd-a \"/\") \
   (setq pwd-b \"/proc\")  \
   (setq list-dir \"~\") \
   (with-current-buffer-window \"a\" nil nil \
      (cd pwd-a) \
      (insert-directory list-dir \"-l\" nil t) \
      (insert (format \"listing of %s in cwd %s\" list-dir (pwd)))) \
   (with-current-buffer-window \"b\" nil nil \
      (cd pwd-b) \
      (insert-directory list-dir \"-l\" nil t) \
      (insert (format \"listing of %s in cwd %s\" list-dir (pwd)))) \
   (switch-to-buffer \"a\") \
   (switch-to-buffer-other-window \"b\"))"


for lisp/ls-lisp.el:

emacs -Q --eval "\
(progn \
   (setq pwd-a \"/\") \
   (setq pwd-b \"/proc\")  \
   (setq list-dir \"~\") \
   (require 'ls-lisp) \
   (setq ls-lisp-use-insert-directory-program nil) \
   (with-current-buffer-window \"a\" nil nil \
      (cd pwd-a) \
      (insert-directory list-dir \"-l\" nil t) \
      (insert (format \"listing of %s in cwd %s\" list-dir (pwd)))) \
   (with-current-buffer-window \"b\" nil nil \
      (cd pwd-b) \
      (insert-directory list-dir \"-l\" nil t) \
      (insert (format \"listing of %s in cwd %s\" list-dir (pwd)))) \
   (switch-to-buffer \"a\") \
   (switch-to-buffer-other-window \"b\"))"


for lisp/net/tramp-sh.el:

emacs -Q --eval "\
(progn \
   (setq pwd-a \"/\") \
   (setq pwd-b \"/proc\")  \
   (setq list-dir \"/ssh:emacsdev@localhost:~/\") \
   (require 'tramp) \
   (setq ls-lisp-use-insert-directory-program t) \
   (with-current-buffer-window \"a\" nil nil \
      (cd pwd-a) \
      (insert-directory list-dir \"-l\" nil t) \
      (insert (format \"listing of %s in cwd %s\" list-dir (pwd)))) \
   (with-current-buffer-window \"b\" nil nil \
      (cd pwd-b) \
      (insert-directory list-dir \"-l\" nil t) \
      (insert (format \"listing of %s in cwd %s\" list-dir (pwd)))) \
   (switch-to-buffer \"a\") \
   (switch-to-buffer-other-window \"b\"))"