(reveal-post-command): Better error handling and debugging.

1 files changed, 11 insertions, 3 deletions

diff --git a/lisp/reveal.el b/lisp/reveal.el
index 245c7a3c4a0..c30686e4e27 100644
--- a/lisp/reveal.el
+++ b/lisp/reveal.el
@@ -61,6 +61,8 @@
 
 ;; Actual code
 
+(defvar reveal-backtrace nil)
+
 (defun reveal-post-command ()
   ;; Refresh the spots that might have changed.
   ;; `Refreshing' here means to try and re-hide the corresponding text.
@@ -107,7 +109,11 @@
                (setq repeat t)
                (condition-case err
                    (funcall open ol nil)
-                 (error (message "!!Reveal-show: %s !!" err))))))))
+                 (error (setq reveal-backtrace (backtrace))
+                        (message "!!Reveal-show: %s !!" err)
+                        ;; Let's default to a meaningful behavior to avoid
+                        ;; getting stuck in an infinite loop.
+                        (overlay-put ol 'invisible nil))))))))
      ;; Close old overlays.
      (dolist (ol old-ols)
        (when (and (eq (current-buffer) (overlay-buffer ol))
@@ -128,9 +134,11 @@
                                          (get ol 'isearch-open-invisible-temporary)))))
                  (condition-case err
                      (funcall open ol t)
-                   (error (message "!!Reveal-hide: %s !!" err)))
+                   (error (setq reveal-backtrace (backtrace))
+                          (message "!!Reveal-hide: %s !!" err)))
                (overlay-put ol 'invisible inv)))))))
-   (error (message "Reveal: %s" err)))))
+   (error (setq reveal-backtrace (backtrace))
+          (message "Reveal: %s" err)))))
 
 ;;;###autoload
 (define-minor-mode reveal-mode