(debug): Bind a bunch of vars, like last-command, to

neutral values.  Save the outer values in debugger-last-command, etc.
Put those saved values back into effect when returning.
(debugger-eval-expression): Put the saved values into effect
while evaluating, and store modified values back into
debugger-outer-... after evaluating.

1 files changed, 126 insertions, 56 deletions

diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index 9a98e47766f..717b1aceb83 100644
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -30,6 +30,19 @@
 (defvar debug-function-list nil
   "List of functions currently set for debug on entry.")
 
+(defvar debugger-outer-track-mouse)
+(defvar debugger-outer-last-command)
+(defvar debugger-outer-this-command)
+(defvar debugger-outer-unread-command-char)
+(defvar debugger-outer-unread-command-events)
+(defvar debugger-outer-last-input-event)
+(defvar debugger-outer-last-command-event)
+(defvar debugger-outer-last-nonmenu-event)
+(defvar debugger-outer-last-event-frame)
+(defvar debugger-outer-standard-input)
+(defvar debugger-outer-standard-output)
+(defvar debugger-outer-cursor-in-echo-area)
+
 ;;;###autoload
 (setq debugger 'debug)
 ;;;###autoload
@@ -52,62 +65,95 @@ first will be printed into the backtrace buffer."
         (debugger-step-after-exit nil)
         ;; Don't keep reading from an executing kbd macro!
         (executing-macro nil)
-        last-command this command
-        (cursor-in-echo-area nil))
-    (unwind-protect
-        (save-excursion
-          (save-window-excursion
-            (pop-to-buffer debugger-buffer)
-            (erase-buffer)
-            (let ((standard-output (current-buffer))
-                  (print-escape-newlines t)
-                  (print-length 50))
-              (backtrace))
-            (goto-char (point-min))
-            (debugger-mode)
-            (delete-region (point)
-                           (progn
-                             (search-forward "\n  debug(")
-                             (forward-line 1)
-                             (point)))
-            (debugger-reenable)
-            (cond ((memq (car debugger-args) '(lambda debug))
-                   (insert "Entering:\n")
-                   (if (eq (car debugger-args) 'debug)
-                       (progn
-                         (backtrace-debug 4 t)
-                         (delete-char 1)
-                         (insert ?*)
-                         (beginning-of-line))))
-                  ((eq (car debugger-args) 'exit)
-                   (insert "Return value: ")
-                   (setq debugger-value (nth 1 debugger-args))
-                   (prin1 debugger-value (current-buffer))
-                   (insert ?\n)
-                   (delete-char 1)
-                   (insert ? )
-                   (beginning-of-line))
-                  ((eq (car debugger-args) 'error)
-                   (insert "Signalling: ")
-                   (prin1 (nth 1 debugger-args) (current-buffer))
-                   (insert ?\n))
-                  ((eq (car debugger-args) t)
-                   (insert "Beginning evaluation of function call form:\n"))
-                  (t
-                   (prin1 (if (eq (car debugger-args) 'nil)
-                              (cdr debugger-args) debugger-args)
-                          (current-buffer))
-                   (insert ?\n)))
-            (message "")
-            (let ((inhibit-trace t)
-                  (standard-output nil)
-                  (buffer-read-only t))
+        ;; Save the outer values of these vars for the `e' command
+        ;; before we replace the values.
+        (debugger-outer-track-mouse track-mouse)
+        (debugger-outer-last-command last-command)
+        (debugger-outer-this-command this-command)
+        (debugger-outer-unread-command-char unread-command-char)
+        (debugger-outer-unread-command-events unread-command-events)
+        (debugger-outer-last-input-event last-input-event)
+        (debugger-outer-last-command-event last-command-event)
+        (debugger-outer-last-nonmenu-event last-nonmenu-event)
+        (debugger-outer-last-event-frame last-event-frame)
+        (debugger-outer-standard-input standard-input)
+        (debugger-outer-standard-output standard-output)
+        (debugger-outer-cursor-in-echo-area cursor-in-echo-area))
+    ;; Don't let these magic variables affect the debugger itself.
+    (let ((last-command nil) this-command track-mouse
+          unread-command-char unread-command-events
+          last-input-event last-command-event last-nonmenu-event
+          last-event-frame
+          (standard-input t) (standard-output t)
+          (cursor-in-echo-area nil))
+      (unwind-protect
+          (save-excursion
+            (save-window-excursion
+              (pop-to-buffer debugger-buffer)
+              (erase-buffer)
+              (let ((standard-output (current-buffer))
+                    (print-escape-newlines t)
+                    (print-length 50))
+                (backtrace))
+              (goto-char (point-min))
+              (debugger-mode)
+              (delete-region (point)
+                             (progn
+                               (search-forward "\n  debug(")
+                               (forward-line 1)
+                               (point)))
+              (debugger-reenable)
+              (cond ((memq (car debugger-args) '(lambda debug))
+                     (insert "Entering:\n")
+                     (if (eq (car debugger-args) 'debug)
+                         (progn
+                           (backtrace-debug 4 t)
+                           (delete-char 1)
+                           (insert ?*)
+                           (beginning-of-line))))
+                    ((eq (car debugger-args) 'exit)
+                     (insert "Return value: ")
+                     (setq debugger-value (nth 1 debugger-args))
+                     (prin1 debugger-value (current-buffer))
+                     (insert ?\n)
+                     (delete-char 1)
+                     (insert ? )
+                     (beginning-of-line))
+                    ((eq (car debugger-args) 'error)
+                     (insert "Signalling: ")
+                     (prin1 (nth 1 debugger-args) (current-buffer))
+                     (insert ?\n))
+                    ((eq (car debugger-args) t)
+                     (insert "Beginning evaluation of function call form:\n"))
+                    (t
+                     (prin1 (if (eq (car debugger-args) 'nil)
+                                (cdr debugger-args) debugger-args)
+                            (current-buffer))
+                     (insert ?\n)))
               (message "")
-              (recursive-edit))))
-      ;; So that users do not try to execute debugger commands
-      ;;  in an invalid context
-      (kill-buffer debugger-buffer)
-      (store-match-data debugger-match-data))
+              (let ((inhibit-trace t)
+                    (standard-output nil)
+                    (buffer-read-only t))
+                (message "")
+                (recursive-edit))))
+        ;; So that users do not try to execute debugger commands
+        ;;  in an invalid context
+        (kill-buffer debugger-buffer)
+        (store-match-data debugger-match-data)))
+    ;; Put into effect the modified values of these variables
+    ;; in case the user set them with the `e' command.
+    (setq track-mouse debugger-outer-track-mouse)
+    (setq last-command debugger-outer-last-command)
+    (setq this-command debugger-outer-this-command)
+    (setq unread-command-char debugger-outer-unread-command-char)
+    (setq unread-command-events debugger-outer-unread-command-events)
+    (setq last-input-event debugger-outer-last-input-event)
+    (setq last-command-event debugger-outer-last-command-event)
+    (setq last-nonmenu-event debugger-outer-last-nonmenu-event)
+    (setq last-event-frame debugger-outer-last-event-frame)
+    (setq standard-input debugger-outer-standard-input)
+    (setq standard-output debugger-outer-standard-output)
+    (setq cursor-in-echo-area debugger-outer-cursor-in-echo-area))
     (setq debug-on-next-call debugger-step-after-exit)
     debugger-value))
 
@@ -226,7 +272,31 @@ Applies to the frame whose line point is on in the backtrace."
         ;; old buffer deleted
         (setq debugger-old-buffer (current-buffer)))
     (set-buffer debugger-old-buffer)
-    (eval-expression exp)))
+    (let ((track-mouse debugger-outer-track-mouse)
+          (last-command debugger-outer-last-command)
+          (this-command debugger-outer-this-command)
+          (unread-command-char debugger-outer-unread-command-char)
+          (unread-command-events debugger-outer-unread-command-events)
+          (last-input-event debugger-outer-last-input-event)
+          (last-command-event debugger-outer-last-command-event)
+          (last-nonmenu-event debugger-outer-last-nonmenu-event)
+          (last-event-frame debugger-outer-last-event-frame)
+          (standard-input debugger-outer-standard-input)
+          (standard-output debugger-outer-standard-output)
+          (cursor-in-echo-area debugger-outer-cursor-in-echo-area))
+      (prog1 (eval-expression exp)
+        (setq debugger-outer-track-mouse track-mouse)
+        (setq debugger-outer-last-command last-command)
+        (setq debugger-outer-this-command this-command)
+        (setq debugger-outer-unread-command-char unread-command-char)
+        (setq debugger-outer-unread-command-events unread-command-events)
+        (setq debugger-outer-last-input-event last-input-event)
+        (setq debugger-outer-last-command-event last-command-event)
+        (setq debugger-outer-last-nonmenu-event last-nonmenu-event)
+        (setq debugger-outer-last-event-frame last-event-frame)
+        (setq debugger-outer-standard-input standard-input)
+        (setq debugger-outer-standard-output standard-output)
+        (setq debugger-outer-cursor-in-echo-area cursor-in-echo-area)))))
 
 (defvar debugger-mode-map nil)
 (if debugger-mode-map