Bug#1038974: grub2: Update Linux erases Windows entry in boot list

[Julian Andres Klode]

Control: retitle -1 grub doesn't run os-prober by default anymore, so no more other OS detected
Control: tag -1 wontfix

On Fri, Jun 23, 2023 at 04:31:55PM -0400, bud wrote:
> Package: grub2
> Severity: important
> File: grub2
> X-Debbugs-Cc: budheal508 at gmail.com
> 
> Dear Maintainer,
> 
>    * What led up to the situation?
> I installed the 2023-04-24 weekly build, downloaded the 2023-06-05 build and used that as the jigdo base to download bookworm 12.0.0
> Then I added the 21 DVD images and synaptic suggested adding the online main repository. After apt-get update --allow-insecure-repositories, I rebooted.
>    * What exactly did you do (or not do) that was effective (or
>      ineffective)?
> The computer booted into bookworm. However, the existing option to boot Windows is no longer available. Looking in the Advanced options finds the prior Linux entry. 
> 
> Compare Bugs #1033985, #1008294 and #250626
> 
>    * What was the outcome of this action?
> Without a Windows option, there is a suggestion in bug #1033985 that os-prober will help set me reset the grub list. Otherwise, the Windows DVD will contrarily erase grub. I only added a Linux partition to this laptop to investigate a HDMI bug, as this one has HDMI, VGA and DisplayPort connectors.
>    * What outcome did you expect instead?
> Just because the Linux kernel has been updated, any existing entries should not be erased - except for the one being replaced. 
> 
> An update should not erase the settings the user or administrator has added to customize the system. This looks like a bug.

The followup comment from Chris Carr made me understand that this seems
to be about the os-prober entries. For security reasons, os-prober is
no longer run when writing a new grub.cfg.

You can either re-enable it and get exposed to any bug in grub
filesystem implementations which will then run as root to mount
any disk attached to the system, or add a /etc/grub.d file that
echos additional fixed boot entries for your other OS.

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