bug#14473: 24.3; emacs locks up when eshell attempts to display a dialog

[Stefan Kangas <stefan@marxist.se>]

Joseph Mingrone <jrm@ftfl.ca> writes:

> It's still a problem (26.3 and 2019-09-15 master-branch build) in that the dialog is not displayed, but the Emacs process no longer consumes 100% CPU.

Thanks for reporting back.

> Here is a simple recipe to reproduce the problem.  It assumes the FreeBSD ports tree is installed in the default location, which is /usr/ports.

Can you think of any way to reproduce this if you are not using
FreeBSD?  Is there some particular command run by "make config" that
makes eshell freeze for example?  It seems to me that very few Emacs
developers are using FreeBSD, and I personally don't have access to
any FreeBSD systems for debugging.

> Instead of the dialog displaying, eshell becomes unusable (blank screen and no keys will return the prompt).  Trying to exit by hitting TAB/Enter reports
>
> Completion function pcomplete-completions-at-point uses a deprecated calling convention
> Warning: pcomplete-completions-at-point failed to return valid completion data!
>
> You can switch buffers and kill the eshell process now though.

What happens if you run M-x toggle-debug-on-error before trying to
reproduce?  Do you then get a backtrace?

Best regards,
Stefan Kangas