bug#48578: 28.0.50; Native-compiled files of some preloaded files not loaded at dump time

[Eli Zaretskii <eliz@gnu.org>]

> From: Andrea Corallo <akrl@sdf.org>
> Cc: Eli Zaretskii <eliz@gnu.org>, 48578@debbugs.gnu.org
> Date: Tue, 25 May 2021 13:22:39 +0000
> 
> diff --git a/src/comp.c b/src/comp.c
> index 340ed85038..8e40ea0f25 100644
> --- a/src/comp.c
> +++ b/src/comp.c
> @@ -4008,15 +4008,15 @@ DEFUN ("comp-el-to-eln-rel-filename", Fcomp_el_to_eln_rel_filename,
>  {
>    CHECK_STRING (filename);
>  
> -  /* Use `file-truename' or fall back to `expand-file-name' when the
> -     first is not available (bug#44701).
> -
> -     `file-truename' is not available only for a short phases of the
> -     bootstrap before file.el is loaded, given we do not symlink
> -     inside the build directory this should work.  */
> -  filename = NILP (Ffboundp (intern_c_string ("file-truename")))
> -    ? Fexpand_file_name (filename, Qnil)
> -    : CALL1I (file-truename, filename);
> +  /* `file-truename' is not available only during bootstrap before
> +     file.el is loaded.  */
> +#ifndef WINDOWSNT
> +  char *file_normalized = realpath (SSDATA (filename), NULL);
> +#else
> +  char *file_normalized = ??? ;
> +#endif
> +  filename = Fexpand_file_name (build_string (file_normalized), Qnil);
> +  xfree (file_normalized);
>  
>    if (NILP (Ffile_exists_p (filename)))
>      xsignal1 (Qfile_missing, filename);

Thanks, this works.  But I have a few questions/comments:

  . why do you use Fexpand_file_name _after_ realpath? shouldn't we
    call it before realpath instead?
  . we need to encode the file name before passing it to realpath, and
    decode the result, right?
  . realpath could potentially return NULL, and we should check for
    that, and return the result of Fexpand_file_name if it does
  . we don't need to support remote files here via file-handlers,
    right?

If you agree with the above, I will prepare a proper patch and install
it, including the necessary changes for WINDOWSNT.