bug#43725: 28.0.50; Include feature/native-comp into master

[Andrea Corallo via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Eli Zaretskii <eliz@gnu.org> writes:

> If I do this:
>
>    $ touch lisp/emacs-lisp/comp.el
>    $ ./src/emacs -Q
>    C-h f apropos RET
>
> then I see that Emacs starts natively-compiling comp.el, even though I
> already have a comp.eln file in the eln-cache.
>
> This is unlike what happens with the .elc files, where Emacs will
> never byte-compile a file without my say-so.  I could perhaps
> understand the automatic compilation if there was no .eln file
> anywhere in sight, but why should Emacs automatically compile Lisp
> files it loads when a .eln file for them does exist?
>
> Does this happen with any .el file, or is comp.el special in some
> sense?
>
> One situation where this gets in the way is when I make some changes
> in a .el file because I'm testing something or debugging some problem.
> In those cases I usually load a .el file manually and later either
> undo the changes or make them permanent, and re-byte-compile at that
> time.  But with natively-compilation it sounds like I've lost control
> on when the file is compiled and which version of it is compiled.
>
> Is this a reasonable default behavior?  Maybe it is reasonable for
> users who just use Emacs.  But for developers that constantly make
> changes in .el files this could be a nuisance, at least sometimes.

Hi Eli,

this is not expected and I cannot reproduce it here.

The file is hashed using the content + its filename so access and
modification times should not come into play.  Are we sure the file
content wasn't modified?  Or we might be possibly looking at different
issue here.

Thanks

  Andrea