Fix infinite crash loop when quitting gp interpreter

[vdelecroix]

sage: %gp
pari: quit
PARI/GP interpreter crashed -- automatically restarting.
PARI/GP interpreter crashed -- automatically restarting.
PARI/GP interpreter crashed -- automatically restarting.
PARI/GP interpreter crashed -- automatically restarting.
...

Initially reported in ​this question on ask.sagemath.org

[chapoton]

Part of this is normal. Quitting works when using

sage: gp.console()

Whereas %gp is an interactive access to the unique pari/gp session used by sage, which is automatically restarted when crashed.

What is not normal is the infinite restarting loop..

[slelievre]

One way to gracefully exit the gp console seems to be using Ctrl + D.

sage: %gp

  --> Switching to PARI/GP interpreter <--

pari: <Ctrl + D>

  --> Exiting back to Sage <--

sage:

Should this be documented somewhere?

Can we prevent the infinite loop and make quit behave the same as Ctrl + D?

Demoting from 'critical' to 'major'.

[mkoeppe]

Sage development has entered the release candidate phase for 9.3. Setting a new milestone for this ticket based on a cursory review of ticket status, priority, and last modification date.