Re: MPS: weak hash tables

[Eli Zaretskii <eliz@gnu.org>]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: Helmut Eller <eller.helmut@gmail.com>,  pipcet@protonmail.com,
>   emacs-devel@gnu.org
> Date: Sat, 06 Jul 2024 20:14:21 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > The backtrace is inserted into a special backtrace buffer.  The
> > backtrace buffer uses 'invisible' text properties to hide long lines.
> > Then the 'invisible' properties need to be removed when the backtrace
> > is prepared for display on the terminal (which is what ERT wants to
> > do, I believe).
> 
> I don't know where the invisible text property comes into play. What ERT
> does is this:

It isn't in ERT, it's in backtrace.el.

>                (with-temp-buffer
>                ...
>                    (insert (backtrace-to-string
>                             (ert-test-result-with-condition-backtrace result))))
>                  (if (not ert-batch-backtrace-right-margin)
>                      (message "%s"
>                               (buffer-substring-no-properties (point-min)
>                                                               (point-max)))
>                    (goto-char (point-min))
>                    (while (not (eobp))
>                      (let ((start (point))
>                            (end (line-end-position)))
>                        (setq end (min end
>                                       (+ start
>                                          ert-batch-backtrace-right-margin)))
>                        (message "%s" (buffer-substring-no-properties
>                                       start end)))
>                      (forward-line 1))))

As you see, it calls backtrace.el functions (look there to see what
they do), and then removes properties from the text produced by
backtrace.el functions.