bug#47718: Fix epa-file-insert-file-contents substring error

[juntaka]

Hi Eli,

In my use case, I'm writing an elisp to show the first line of each file on 
dired.
It does not need to visit and read entire file. So I just try to limit by 
(window-width).
But if Emacs try to decrypt GPG files, then I got such error.

Regards,

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Monday, April 12, 2021 8:57 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> > From: Lars Ingebrigtsen larsi@gnus.org
> > Date: Mon, 12 Apr 2021 10:14:34 +0200
> > Cc: 47718@debbugs.gnu.org
> > juntaka juntaka@protonmail.com writes:
> >
> > > I think substring occurs error when TO is longer than its content.
> > > This patch will fix the substring bug in epa-file-insert-file-contents.
> >
> > Thanks; applied to Emacs 28.
>
> Actually, I wonder whether this is TRT: why should we silently accept
> invalid inputs when substring itself doesn't?
>
> IOW, can we please have a real-life use case where this happens, and
> where silently "fixing" this input is TRT? TIA.