Re: What does "Changing `byte-compile-dest-file'" mean?

[Stefan Monnier <monnier@iro.umontreal.ca>]

> I'm trying to debug a failing bootstrap.  Central to the failure is the
> error message:
>
>     "Changing `byte-compile-dest-file' is obsolete (as of 23.2);
>     set `byte-compile-dest-file-function' instead."
>
> ..  The error message comes from emacs-lisp/bytecomp.el L. 171.

Hmmm... my crystal ball suggests that your bootstrap ends up loading
`bytecomp` recursively, i.e. a first load of `bytecomp` defines
`byte-compile-dest-file` and then before reaching the end of the file,
it recursive tries to load `bytecomp`, causing the warning to be emitted
(because the function is already defined by (featurep 'bytecomp) is
still nil).

> But what does it mean?  In what respect is byte-compile-dest-file being
> changed?

It's about to be redefined by the subsequent `defun`.  That function
used to be considered as something that tools/users were allowed to
redefine locally in order to save .elc files elsewhere than their
standard location.  This practice was made obsolete by introducing
`byte-compile-dest-file-function` instead.

The warning you're seeing should arguably be removed now.
Tho I don't know if it will solve your underlying problem.

> Just that it might have something to do with early versions of
> automake.  (Which we don't use, do we?)

Not anymore, no, indeed.


        Stefan