bug#59038: loading this base64 file makes emacs -Q 28.2 peg a core infinitely

[Chris Hecker]

> It's a single 21,728-character line.

Yeah?  This isn’t 1970.  I have 32gb of ram and a 12 core cpu.   It’s a bug.  It should either parse the file (instantly, it’s 27kb) or it should at least stop after a few ms and tell me it’s lame and needs me to switch manually to another mode.  I mean, given the 28.2 user experience, there is no opportunity to switch to fundamental mode because emacs was hosed.  I don’t even think ctrl-g worked for me.

Chris

On Sat, Nov 5, 2022 at 00:50 Gerd Möllmann <gerd.moellmann@gmail.com> wrote:

On 05.11.22 08:01, Eli Zaretskii wrote:
> What is reproducible, exactly? 

I don't understand.  The infinite loop is reproducible, "pegging one
core" as he expressed it, using up one CPU core.

> Visiting the file is almost
> instantaneous here, in Emacs 29.  What did you do to get Emacs into an
> infloop?

Maybe I switched applications with Cmd-TAB, or something else triggering
redisplay.  Do a M-x or C-l.

> It is IMO unreasonable to expect CC Mode to do something sensible with
> random sequence of characters that don't resemble C in any way.

I think no-one expects that.  The bug is the uninterruptable loop or
whatever causes it.