Aborting Cygwin setup in unattended modes

[David Allsopp]

If Cygwin's setup requires input (for example, to select a mirror),
with --quiet-mode hidden it simply terminates (there's no apparent
exit status or message, though).

With --quiet-mode noinput, Cygwin setup sits at the appropriate
dialog, but it's of course non-responsive.

Would it be possible in these situations for Cygwin to abort,
preferably with a non-zero exit code?

The background to this was running Cygwin setup in GitHub Actions (so
UI not visible), _without_ specifying --site, where the Cygwin
installation had been restored by actions/cache but not the registry
setting in HKLM\SOFTWARE\Cygwin\setup meaning that setup could not
find setup.rc and consequently determine the last-used mirror. The GUI
therefore invisibly froze at mirror selection.

That issue has obviously been fixed, but it would seem sensible that
Cygwin's setup doesn't ever display a dialog _requiring_ input where
all that input has been disabled!


David