Problem with building Emacs diagnosed. Help please!

[Alan Mackenzie]

Hi, all!

As I've said once or twice recently, whilst 'make bootstrap'ping, I've
been getting the error message

    Loading loaddefs.el (source)...
    Symbol's function definition is void: eshell-defgroup
    make[1]: *** [emacs] Error 255
    make[1]: Leaving directory `/home/acm/emacs/emacs/src'
    make: *** [src] Error 2

.  I've diagnosed now what is going on.  The pertinent lines of
loaddefs.el look like this:

########################################################################
;;;### (autoloads nil "em-alias" "eshell/em-alias.el" (18494 62417))
;;; Generated autoloads from eshell/em-alias.el

(eshell-defgroup eshell-alias nil "Command aliases allow for easy definition of 
alternate commands." :tag "Command aliases" :gr\oup 'eshell-module)   ;  
<======================================================================

;;;***

<plus several more of the like>
.....
.....

;;;### (autoloads (eshell-command-result eshell-command eshell) "eshell"
;;;;;;  "eshell/eshell.el" (18578 7465))
;;; Generated autoloads from eshell/eshell.el

(defalias 'eshell-defgroup 'defgroup)     ; 
<========================================================================
########################################################################

, i.e. the problem is that `eshell-defgroup' is defined after it is used.

As far as I can make out (in .../lisp/emacs-lisp/autoload.el), when the
autoload processing is done, the order in which elisp files are processed
is random (for some value of "random").  So having elisp files set up so
that they depend on the processing order is a Bad Thing.

Greg, when you changed the eshell source to use `eshell-defgroup' instead
of just plain old `defgroup' (to which it is aliased anyway) on 21st May
2008, was there some overwhelmingly important reason?  It looks like you
intend (or intended?) to add some extra functionality to
`eshell-defgroup' at some stage.  Could that, perhaps, be achieved some
other way?

However, given that we've passed the deadline for new features, I would
like to revert that change for Emacs 23, removing `eshell-defgroup' so as
to firm up the build process.

Perhaps I should also amend the Elisp manual to warn against dependencies
between Elisp files in the autoload bits.

Maybe, at some stage, we could introduce a new construct, something like

    ;;;###autoload-requires eshell.el

, but my gut feeling is that this would be unnecessary complexity.

What do people think?

-- 
Alan Mackenzie (Nuremberg, Germany).