Merge from trunk.

[gnu-emacs] / lisp / emacs-lisp / debug.el

diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index 88633eaaa4648eea379aa5615eeb77b45a7b2b97..157749500e7f90ec6faef5d79bf9c5ac78f9f030 100644 (file)
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -102,7 +102,7 @@ and `debugger-reenable' to temporarily disable debug-on-entry.")
 (setq debugger 'debug)
 ;;;###autoload
 (defun debug (&rest debugger-args)
 (setq debugger 'debug)
 ;;;###autoload
 (defun debug (&rest debugger-args)

-  "Enter debugger.  To return, type \\<debugger-mode-map>`\\[debugger-continue]'.
+  "Enter debugger.  \\<debugger-mode-map>`\\[debugger-continue]' returns from the debugger.

 Arguments are mainly for use when this is called from the internals
 of the evaluator.
 
 Arguments are mainly for use when this is called from the internals
 of the evaluator.
 


@@ -118,6 +118,10 @@ first will be printed into the backtrace buffer."
     (let (debugger-value
          (debug-on-error nil)
          (debug-on-quit nil)
     (let (debugger-value
          (debug-on-error nil)
          (debug-on-quit nil)

+         (debugger-previous-state
+           (if (get-buffer "*Backtrace*")
+               (with-current-buffer (get-buffer "*Backtrace*")
+                 (list major-mode (buffer-string)))))

          (debugger-buffer (get-buffer-create "*Backtrace*"))
          (debugger-old-buffer (current-buffer))
          (debugger-step-after-exit nil)
          (debugger-buffer (get-buffer-create "*Backtrace*"))
          (debugger-old-buffer (current-buffer))
          (debugger-step-after-exit nil)


@@ -214,8 +218,6 @@ first will be printed into the backtrace buffer."
              ;; recreate it every time the debugger stops, so instead we'll
              ;; erase it (and maybe hide it) but keep it alive.
              (with-current-buffer debugger-buffer
              ;; recreate it every time the debugger stops, so instead we'll
              ;; erase it (and maybe hide it) but keep it alive.
              (with-current-buffer debugger-buffer

-               (erase-buffer)
-               (fundamental-mode)

                (with-selected-window (get-buffer-window debugger-buffer 0)
                   (when (and (window-dedicated-p (selected-window))
                              (not debugger-will-be-back))
                (with-selected-window (get-buffer-window debugger-buffer 0)
                   (when (and (window-dedicated-p (selected-window))
                              (not debugger-will-be-back))


@@ -232,7 +234,18 @@ first will be printed into the backtrace buffer."
                     ;; to be left at the top-level, still working on how
                     ;; best to do that.
                     (bury-buffer))))
                     ;; to be left at the top-level, still working on how
                     ;; best to do that.
                     (bury-buffer))))

-           (kill-buffer debugger-buffer))
+            (unless debugger-previous-state
+              (kill-buffer debugger-buffer)))
+          ;; Restore the previous state of the debugger-buffer, in case we were
+          ;; in a recursive invocation of the debugger.
+          (when (buffer-live-p debugger-buffer)
+            (with-current-buffer debugger-buffer
+              (let ((inhibit-read-only t))
+                (erase-buffer)
+                (if (null debugger-previous-state)
+                    (fundamental-mode)
+                  (insert (nth 1 debugger-previous-state))
+                  (funcall (nth 0 debugger-previous-state))))))

          (with-timeout-unsuspend debugger-with-timeout-suspend)
          (set-match-data debugger-outer-match-data)))
       ;; Put into effect the modified values of these variables
          (with-timeout-unsuspend debugger-with-timeout-suspend)
          (set-match-data debugger-outer-match-data)))
       ;; Put into effect the modified values of these variables