A CFFI -ASDF integration bug

[Robert Brown]

It looks like cffi-wrapper-file does roughly the same thing as
protobuf-source-file in
https://github.com/brown/protobuf/blob/master/protobuf.asd
It runs some program to generate a Lisp file, then compiles and/or
loads the Lisp file.
Perhaps the approach taken by the protobuf ASDF support can be adapted to CFFI.


On Sat, Aug 1, 2020 at 4:25 AM Faré <fahree at gmail.com> wrote:
>
> I'm not developing ASDF anymore (unless for hire) but I believe the
> CFFI toolchain has a new maintainer, who might be willing to devote
> cycles to that (or at least to merging a patch to CFFI).
>
> Note that if the code that builds stuff and the code that tracks the
> dependencies disagree, the right solution is to make the dependencies
> match the actual build, not to make it lie better: make sure that
> files are attributed as the output-files of the action that creates
> it, and as the input-files of the other actions.
>
> —♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org
> Due to circumstances beyond your control, you are master of your fate
> and captain of your soul.
>
>
>
> On Fri, Jul 31, 2020 at 1:18 PM Ilya Perminov <iperminov at gmail.com> wrote:
> >
> > Hi,
> >
> > I found a ASDF-related CFFI bug a couple of days ago. Can anyone think of a good way of fixing it?
> >
> > A method in grovel/asdf.lisp adds output files of process-op to output files of compile-op:
> >
> > ;;; Declare the .o and .so files as compilation outputs,
> > ;;; so they get picked up by bundle operations.
> > #.(when (version<= "3.1.6" (asdf-version))
> >     '(defmethod output-files ((op compile-op) (c wrapper-file))
> >       (destructuring-bind (generated-lisp lib-file c-file o-file) (output-files 'process-op c)
> >         (declare (ignore generated-lisp c-file))
> >         (multiple-value-bind (files translatedp) (call-next-method)
> >           (values (append files (list lib-file o-file)) translatedp)))))
> >
> > As a result inputs and outputs of the ops look like this:
> > process-op:
> >   input: wrapper-file
> >   output: bindings-file.lisp file.c FILE.O FILE.SO
> >
> > compile-op:
> >   input: bindings-file.lisp
> >   output: bindings-file.fasl FILE.O FILE.SO
> >
> > The problem is that process-op generates file.o and file.so before it generates bindings-file.lisp. Thus compile-op gets re-executed all the time, because its output files file.o and file.so are always older than its input file bindings-file.lisp. And an execution of the compile-op does not change anything, because it does not really generate .o and .so.
> > One way to fix it would be to "touch" .o and .so to get the right order of file modification times, but there may be a better way.
> >
> > CFFI bug report: https://bugs.launchpad.net/cffi/+bug/1889491
> >
> > Thanks,
> > Ilya
>