emacs23 pops up debugger way too frequently

Question

Since I've upgraded to Ubuntu lucid and emacs23, Emacs pops up the debugger in situations, where emacs22 does not.

For example, when hitting C-c C-c in org-mode, emacs22 simply states can do nothing useful at this location, whereas in emacs23 the debugger shows up.

 Debugger entered--Lisp error: (error "C-c C-c can do nothing useful at this location")
   signal(error ("C-c C-c can do nothing useful at this location"))
   error("C-c C-c can do nothing useful at this location")
   org-ctrl-c-ctrl-c(nil)
   call-interactively(org-ctrl-c-ctrl-c nil nil)

That only illustrates the pattern -- the behavior is not limited to org-mode. Occurring every 3 minutes, it really annoys me. How can I prevent it?

I've already tried to stop this using debug-on-error and stack-trace-on-error: it didn't work.

Answer 1

Chances are that something is setting debug-on-error after you've configured it.

Some ways to confirm:

Start Org Mode, press C-c C-c to enter the debugger, and q to exit again. Now M-x set-variable RET debug-on-error RET nil RET, and try it again.

Next, try starting emacs with the -q argument (to avoid executing your init file), and then entering org mode and hitting C-c C-c. This should not trigger the debugger.

You could use M-x rgrep RET debug-on-error RET (or maybe debug-on-error t) on your site-lisp and custom lisp directories, to help track down which library is responsible.

As I could replicate your issue, I've just done this for myself. For me, the culprit was: (load "nxhtml/autostart.el"). I'm upgrading nxhtml now, which I suspect will resolve things in my case.

Edit: or not.

The current version of nxhtml has moved the statement from autoload.el into nxhtml-base.el. If this is the same culprit for you, you could either edit that file, or make sure that your customisation of the variable happens after nxhtml's autostart file executes.