bug#68546: 29.1.90; end-of-file has incorrect data when signaled within a load

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

> diff --git a/src/lread.c b/src/lread.c
> index 95c6891c205..ec0c68e1843 100644
> --- a/src/lread.c
> +++ b/src/lread.c
> @@ -2329,8 +2329,8 @@ readevalloop_1 (int old)
>  static AVOID
>  end_of_file_error (void)
>  {
> -  if (STRINGP (Vload_true_file_name))
> -    xsignal1 (Qend_of_file, Vload_true_file_name);
> +  if (!NILP (Vread_end_of_file_data))
> +    xsignal1 (Qend_of_file, Vread_end_of_file_data);

Hmm... why call it `Vread_end_of_file_name`?
How 'bout something like `read--source`?  I suspect it could be useful to
include similar info in other read errors than `Qend_of_file`.
Also it could make sense to allow that var to indicate when we're
reading from a buffer (rather than a file).

>    xsignal0 (Qend_of_file);
>  }
> @@ -2434,6 +2434,8 @@ readevalloop (Lisp_Object readcharfun,
>    while (continue_reading_p)
>      {
>        specpdl_ref count1 = SPECPDL_INDEX ();
> +      if (NILP (Vread_end_of_file_data))
> +        specbind (Qread_end_of_file_name, Vload_true_file_name);

Why the `if` condition here?  Sounds like it could lead to problems for
nested loads and such.


        Stefan