[Orgmode] Behavior Change/Bug: Agenda sorting of deadline items v > 4.73

[Eric J Haywiser]

I've noticed a change in the way org displays deadlines in the agenda starting
sometime after v4.73.  Before that time deadlines were displayed in 
chronological order.  This is the behavior I expect.  In the current org-5.16a 
and a number of versions before that the agenda items are in somewhat random 
order.  Order seems to depend on both the date and the order of the deadlines in 
the org file.

Apologies if this was an intended design change and I missed the announcement.
It has been difficult to keep up with all the wonderful advancements in org.
Perhaps I need to configure some variable to get back to the original behavior?

Behavior in 5.16a

Thursday  31 January 2008
  deadline-order-bug:In -730 d.:  Jan One DEADLINE: <2006-01-31 Thu>
  deadline-order-bug:In -365 d.:  Jan Two DEADLINE: <2007-01-31 Thu>
  deadline-order-bug:Deadline:   Jan Three DEADLINE: <2008-01-31 Thu>
  deadline-order-bug:In -715 d.:  Feb One DEADLINE: <2006-02-15 Thu>
  deadline-order-bug:In -350 d.:  Feb Two DEADLINE: <2007-02-15 Thu>
  deadline-order-bug:In  15 d.:  Feb Three DEADLINE: <2008-02-15 Thu>
  deadline-order-bug:In 366 d.:  Jan Four DEADLINE: <2009-01-31 Thu>
  deadline-order-bug:In 381 d.:  Feb Four DEADLINE: <2009-02-15 Thu>

Behavior in 4.67c

Thursday  31 January 2008
  deadline-order-bug:In -730 d.:  Jan One DEADLINE: <2006-01-31 Thu>
  deadline-order-bug:In -715 d.:  Feb One DEADLINE: <2006-02-15 Thu>
  deadline-order-bug:In -365 d.:  Jan Two DEADLINE: <2007-01-31 Thu>
  deadline-order-bug:In -350 d.:  Feb Two DEADLINE: <2007-02-15 Thu>
  deadline-order-bug:Deadline:   Jan Three DEADLINE: <2008-01-31 Thu>
  deadline-order-bug:In  15 d.:  Feb Three DEADLINE: <2008-02-15 Thu>
  deadline-order-bug:In 366 d.:  Jan Four DEADLINE: <2009-01-31 Thu>
  deadline-order-bug:In 381 d.:  Feb Four DEADLINE: <2009-02-15 Thu>

Also note that something like the <= v4.73 behavior can be achieved by inserting
the older org-agenda-get-deadlines function into 5.16a, but it seems to have 
some side effects.  Note the missing Deadline item for TODAY aka "Jan Three"
below.  Regardless I believe the bug, if present, may lie in that 
function.  I don't yet understand the internals.

Behavior in 5.16a with o-a-g-d from 4.67c overlayed

Thursday  31 January 2008
  deadline-order-bug:In -730 d.:  Jan One DEADLINE: <2006-01-31 Thu>
  deadline-order-bug:In -715 d.:  Feb One DEADLINE: <2006-02-15 Thu>
  deadline-order-bug:In -365 d.:  Jan Two DEADLINE: <2007-01-31 Thu>
  deadline-order-bug:In -350 d.:  Feb Two DEADLINE: <2007-02-15 Thu>
  deadline-order-bug:In  15 d.:  Feb Three DEADLINE: <2008-02-15 Thu>
  deadline-order-bug:In 366 d.:  Jan Four DEADLINE: <2009-01-31 Thu>
  deadline-order-bug:In 381 d.:  Feb Four DEADLINE: <2009-02-15 Thu>

The following is the example org file to generate this behavior.
Also, You will need to (set-variable org-deadline-warning-days 1000)
to test this.

* Jan One DEADLINE: <2006-01-31 Thu>
* Jan Two DEADLINE: <2007-01-31 Thu>
* Jan Three DEADLINE: <2008-01-31 Thu>
* Jan Four DEADLINE: <2009-01-31 Thu>

* Feb Three DEADLINE: <2008-02-15 Thu>
* Feb One DEADLINE: <2006-02-15 Thu>
* Feb Two DEADLINE: <2007-02-15 Thu>
* Feb Four DEADLINE: <2009-02-15 Thu>

Thanks.

P.S. Examples from emacs22, but similar problems in e21.