[O] bug#13820: It was not fixed; it now is, though I don't understand the reason

[Sebastien Vauban]

I've finally found the cause of a long lasting problem between Org and the dev
version of Emacs 24.4. Though, I don't understand it... Anyone?

When opening Org from my Emacs 24.3.1, everything's OK.

Same .emacs file, same everything, but latest version of Emacs: bang!

--8<---------------cut here---------------start------------->8---
Debugger entered--Lisp error: (wrong-type-argument symbolp (autoload 
"org-agenda" "Activate appointments found in `org-agenda-files'.
With a \\[universal-argument] prefix, refresh the list of
appointments.

If FILTER is t, interactively prompt the user for a regular
expression, and filter out entries that don't match it.

If FILTER is a string, use this string as a regular expression
for filtering entries out.

If FILTER is a function, filter out entries against which
calling the function returns nil.  This function takes one
argument: an entry from `org-agenda-get-day-entries'.

FILTER can also be an alist with the car of each cell being
either 'headline or 'category.  For example:

  '((headline \"IMPORTANT\")
    (category \"Work\"))

will only add headlines containing IMPORTANT or headlines
belonging to the \"Work\" category.

ARGS are symbols indicating what kind of entries to consider.
By default `org-agenda-to-appt' will use :deadline*, :scheduled*
(i.e., deadlines and scheduled items with a hh:mm specification)
and :timestamp entries.  See the docstring of `org-diary' for
details and examples.

If an entry has a APPT_WARNTIME property, its value will be used
to override `appt-message-warning-time'.

(fn &optional REFRESH FILTER &rest ARGS)" t nil))
  interactive-form((autoload "org-agenda" "Activate appointments found in 
`org-agenda-files'.\nWith a \\[universal-argument] prefix, refresh the list 
of\nappointments.\n\nIf FILTER is t, interactively prompt the user for a 
regular\nexpression, and filter out entries that don't match it.\n\nIf FILTER 
is a string, use this string as a regular expression\nfor filtering entries 
out.\n\nIf FILTER is a function, filter out entries against which\ncalling the 
function returns nil.  This function takes one\nargument: an entry from 
`org-agenda-get-day-entries'.\n\nFILTER can also be an alist with the car of 
each cell being\neither 'headline or 'category.  For example:\n\n  '((headline 
\"IMPORTANT\")\n    (category \"Work\"))\n\nwill only add headlines containing 
IMPORTANT or headlines\nbelonging to the \"Work\" category.\n\nARGS are symbols 
indicating what kind of entries to consider.\nBy default `org-agenda-to-appt' 
will use :deadline*, :scheduled*\n(i.e., deadlines and scheduled items with a 
hh:mm specification)\nand :timestamp entries.  See the docstring of `org-diary' 
for\ndetails and examples.\n\nIf an entry has a APPT_WARNTIME property, its 
value will be used\nto override `appt-message-warning-time'.\n\n(fn &optional 
REFRESH FILTER &rest ARGS)" t nil))
  advice--make-interactive-form(ad-Advice-org-agenda-to-appt (autoload 
"org-agenda" "Activate appointments found in `org-agenda-files'.\nWith a 
\\[universal-argument] prefix, refresh the list of\nappointments.\n\nIf FILTER 
is t, interactively prompt the user for a regular\nexpression, and filter out 
entries that don't match it.\n\nIf FILTER is a string, use this string as a 
regular expression\nfor filtering entries out.\n\nIf FILTER is a function, 
filter out entries against which\ncalling the function returns nil.  This 
function takes one\nargument: an entry from 
`org-agenda-get-day-entries'.\n\nFILTER can also be an alist with the car of 
each cell being\neither 'headline or 'category.  For example:\n\n  '((headline 
\"IMPORTANT\")\n    (category \"Work\"))\n\nwill only add headlines containing 
IMPORTANT or headlines\nbelonging to the \"Work\" category.\n\nARGS are symbols 
indicating what kind of entries to consider.\nBy default `org-agenda-to-appt' 
will use :deadline*, :scheduled*\n(i.e., deadlines and scheduled items with a 
hh:mm specification)\nand :timestamp entries.  See the docstring of `org-diary' 
for\ndetails and examples.\n\nIf an entry has a APPT_WARNTIME property, its 
value will be used\nto override `appt-message-warning-time'.\n\n(fn &optional 
REFRESH FILTER &rest ARGS)" t nil))
  advice--tweak(#[128 "\300\301\302#\207" [apply ad-Advice-org-agenda-to-appt 
nil nil] 5 #("Advised function" 0 16 (dynamic-docstring-function 
advice--make-docstring))] ...
  advice--subst-main(...
  advice--defalias-fset(...
  
load-with-code-conversion("d:/Users/sva/Public/Repositories/org-mode/lisp/org-loaddefs.el"
 "d:/Users/sva/Public/Repositories/org-mode/lisp/org-loaddefs.el" t t)
  funcall(#<subr load> "org-loaddefs.el" t t t nil)
--8<---------------cut here---------------end--------------->8---

The culprit: the following chunk of code in my .emacs file...

#+begin_src emacs-lisp
  ;; keep your appointment list clean: if you delete an appointment from
  ;; your Org agenda file, delete the corresponding alert
  (defadvice org-agenda-to-appt (before wickedcool activate)
    "Clear the existing appt-time-msg-list."
    (setq appt-time-msg-list nil))
#+end_src

With it, Emacs 24.3 correctly loads Org, Emacs 24.4 DOES NOT.

Without it, both are loading Org correctly...

Though, I don't understand the impact of my advice on the loading process.
BTW, another weirdness:

  M-x load-library RET org-loaddefs RET

did work in Emacs 24.4 (with the advice enabled).

That's

  M-x load-file RET ~/Public/Repositories/org-mode/lisp/org-loaddefs.el RET

which did NOT. Mystery...?

Best regards,
  Seb

-- 
Sebastien Vauban