1 files changed, 31 insertions, 0 deletions

diff --git a/lisp/eshell/em-basic.el b/lisp/eshell/em-basic.el
index 016afe811b2..554ee83b015 100644
--- a/lisp/eshell/em-basic.el
+++ b/lisp/eshell/em-basic.el
@@ -188,6 +188,37 @@ or `eshell-printn' for display."
 
 (put 'eshell/umask 'eshell-no-numeric-conversions t)
 
+(defun eshell/eshell-debug (&rest args)
+  "A command for toggling certain debug variables."
+  (eshell-eval-using-options
+   "eshell-debug" args
+   '((?h "help" nil nil "display this usage message")
+     :usage "[KIND]...
+This command is used to aid in debugging problems related to Eshell
+itself.  It is not useful for anything else.  The recognized `kinds'
+are:
+
+   error       stops Eshell from trapping errors
+   form        shows command form manipulation in `*eshell last cmd*'")
+   (if args
+       (dolist (kind args)
+         (if (equal kind "error")
+             (setq eshell-handle-errors (not eshell-handle-errors))
+           (let ((kind-sym (intern kind)))
+             (if (memq kind-sym eshell-debug-command)
+                 (setq eshell-debug-command
+                       (delq kind-sym eshell-debug-command))
+               (push kind-sym eshell-debug-command)))))
+     ;; Output the currently-enabled debug kinds.
+     (unless eshell-handle-errors
+       (eshell-print "errors\n"))
+     (dolist (kind eshell-debug-command)
+       (eshell-printn (symbol-name kind))))))
+
+(defun pcomplete/eshell-mode/eshell-debug ()
+  "Completion for the `debug' command."
+  (while (pcomplete-here '("error" "form"))))
+
 (provide 'em-basic)
 
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