bug#17531: 24.4.50; REGRESSION: `cancel-debug-on-error' no longer works

[Michael Heerdegen]

Drew Adams <drew.adams@oracle.com> writes:

> emacs -Q
>
> M-x load-library mouse.el
> M-x debug-on-entry mouse-drag-region
>
> Confirm that clicking mouse-1 opens the debugger for
> `mouse-drag-region'.
>
> M-: (cancel-debug-on-error)   ; (or `M-x cancel-debug-on-error')

Typo: you mean and used `cancel-debug-on-entry'.  But I can reproduce
it.

Here, `debug--function-list' returns nil after the `debug-on-entry' use,
so I guess it's related to nadvice (the according `advice--member-p'
test fails).

Michael.