bug#46617: 28.0.50; nativecomp: native compile cache is not invalidated when file is re-byte compiled and changes

[Aaron Jensen]

On Fri, Mar 26, 2021 at 2:54 AM Andrea Corallo <akrl@sdf.org> wrote:
>
> Andrea Corallo via "Bug reports for GNU Emacs, the Swiss army knife of
> text editors" <bug-gnu-emacs@gnu.org> writes:
>
> > Aaron Jensen <aaronjensen@gmail.com> writes:
> >
> >> On Sun, Mar 21, 2021 at 3:54 PM Andrea Corallo <akrl@sdf.org> wrote:
> >>>
> >>> Andrea Corallo via "Bug reports for GNU Emacs, the Swiss army knife of
> >>> text editors" <bug-gnu-emacs@gnu.org> writes:
> >>>
> >>>
> >>> Okay I've added `comp-lookup-eln' son now the user can search if a
> >>> certain .eln is in reach in `comp-eln-load-path' for a given .el.
> >>>
> >>> So now one can use the following to force a native load.
> >>>
> >>> (load (comp-lookup-eln ".../foo.el"))
> >>
> >> Okay, and that would return nil if it's not native compiled, which
> >> would be their cue to native compile it, yes?
> >
> > Yes `comp-lookup-eln' will return nil if the eln is not found.
> >
> >> That's nice to be able
> >> to force load it.
> >>
> >> Without doing the modification date stuff you mentioned or purge
> >> before byte compile, native compilation ends up having to be a concern
> >> of anything that's doing byte compiling, which is unfortunate.
> >
> > Say anything that's doing byte compiling deliberately capturing
> > environment values yes.
> >
> >   Andrea
>
> I've reintroduced the file timestamp check on the eln files being loaded
> with 79b8b6ca45.  This should protect us from loading stale eln that
> captured some stale env during compilation.

What does it compare the timestamp of the eln to? It doesn't appear
that it's the elc, which I believe is the only thing that would help
with the issue we're seeing in straight.el. Is it the el or something
else?

A related issue I've found is that now when you load an elc
explicitly, it triggers a native compile for that file regardless of
whether or not one has already been done.

One general question is, is the eln a compilation of the elc or the el?

Thanks,

Aaron