RE: Merging Finder into package mechanism

["Drew Adams" <drew.adams@oracle.com>]

> Which package is this?

It doesn't matter.  It's not my library, if that's what you're worried about.
It uses `finder-package-info' only in this way:

(cadr (assoc (format "%s.el" (symbol-name feature))
             finder-package-info))

That's all.  So please say how to do the equivalent using package.el or
whatever.  That should be simple since you say the same info is still available
(somewhere).

> > If you truly "merged" those two variables, why couldn't you provide
> > compatibility - via defalias or something?
> 
> Preferably not.  If almost no one is using the old data, it's 
> better to make a clean break than to lug around two copies of
> the same data.

Since when does `def(var)alias' make a copy?  I didn't say anything about
creating copies.

In any case, where is the remaining copy of the data that you still lug around?
What guidance do you provide to update code that uses `finder-package-info' so
that it can DTRT after Emacs 23?

If the data is still available then it should be simple to update the code above
for Emacs 24+.  Please indicate how.

And how do you know that "almost no one is using the old data"?  Did you
survey/poll/search or just divine this?  You incorrectly assumed/claimed that
"third-party code is unlikely to make use of it."  Now you suppose that _almost_
no one is using it.  Based on what?

I came across one library that uses it, just by accident.

Googling indicates others, including `ee-finder.el' by Juri, which does this:

(mapcar
 (lambda (package)
   (mapcar
    (lambda (field-name)
      (cond ((eq field-name 'file)     (nth 0 package))
            ((eq field-name 'synopsis) (nth 1 package))
            ((eq field-name 'keywords) (nth 2 package))))
    field-names))
 finder-package-info)

And a post from Tim Cross entitled "Warning regarding current emacs 24" says
that Emacsspeak needs `finder-package-info' and that your change "breaks
emacspeak-finder.el, which in turn breaks the emacspeak config step."
 
http://www.cs.vassar.edu/~priestdo/emacspeak/2010/msg00149.html

No doubt all such 3rd-party coders can eventually make adjustments for your
"clean break".  But please document what's involved so they know what to do and
can begin to do it.

> > Also, I do not, in any case, see any `package--builtins-base'
> > in Emacs 24.
> 
> The system has been tweaked a couple of times since I posted 
> that.

Surely some person(s) did the tweaking, and so should update NEWS accordingly.
So far, we have user-visible changes with no explanation in the user-visible
NEWS.

> I'll add a placeholder NEWS entry as a reminder, but
> there will likely be more changes before Emacs 24 is released.

Please keep NEWS updated correctly wrt this breakage.  NEWS is for users.  If
you can update change logs for developers then you can also update NEWS for
users.  You don't use "placeholders" in change logs, do you?