bug#62009: 29.0.60; Emacs crashes on setf symbol-name

[Dmitry Gutov]

On 10/03/2023 14:24, Daniel Mendler wrote:
> On 3/10/23 13:13, Eli Zaretskii wrote:
> > > Date: Fri, 10 Mar 2023 12:36:17 +0100
> > > Cc: Gregory Heytings<gregory@heytings.org>,
> > >   Philip Kaludercic<philipk@posteo.net>,michael_heerdegen@web.de,
> > >   monnier@iro.umontreal.ca,62009@debbugs.gnu.org, Eli Zaretskii
> > >   <eliz@gnu.org>, Augusto Stoffel<arstoffel@gmail.com>
> > > From: Daniel Mendler<mail@daniel-mendler.de>
> > >
> > > >        /* Number of characters in string; MSB is used as the mark bit.  */
> > > >        ptrdiff_t size;
> > > >        /* If nonnegative, number of bytes in the string (which is multibyte).
> > > >          If negative, the string is unibyte:
> > > >          -1 for data normally allocated
> > > >          -2 for data in rodata (C string constants)
> > > >          -3 for data that must be immovable (used for bytecode)  */
> > > >        ptrdiff_t size_byte;
> > > Thanks! That's good. Given that a read only flag already exists, it is
> > > easy to fix the issue. We just have to make sure that the size is
> > > negative for the symbol names and add a check in `aset`.
> > Let's not do that!
> Why not? There won't be a performance cost.

Perhaps we could use some exact benchmark results.