Bug#602682: grub-pc: postinst should cope better with broken update-grub

[Jonathan Nieder]

found 602682 grub2/1.99-15
quit

Jonathan Nieder wrote:

> 1. I get a debconf dialog saying
>
> 	GRUB failed to install to the following devices:
>
> 	/dev/sda
>
> 	Do you want to continue anyway?  If you do, your computer may
> 	not start up properly.
>
> The answer is no, obviously.  Why would I want my computer not to
> start up properly?
>
> 2. I get a peek at the console.
>
> Setting up grub-pc (1.98+20100804-8) ...
[...different error...]
>
> 3. Another debconf dialog.
>
> 	The grub-pc package is being upgraded.  This menu allows you
> 	to select which devices you'd like grub-install to be
> 	automatically run for, if any.
>
> My choices are /dev/sda and /dev/dm-0.  I choose /dev/sda, of course.
>
> 4. Go back to step 1.

Happened again.  The psychological effect of trapping the user in a
"Do you want me to break your system? [Yes] [Ask again]" loop is still
just as bad as before. ;-)

Why isn't there a third option, "[Exit with nonzero status so the user
or package manager can cancel the grub upgrade]"?  I had to catch it
and hit ^C in step 2 to do that.

Will file the messages/failure of update-grub in a separate report.

Thanks,
Jonathan