FYI: update-grub / grub-mkconfig somewhat "broken"

[Colin Watson]

On Mon, Feb 15, 2021 at 12:54:52PM +0100, Tom H wrote:
> On Sun, Feb 14, 2021 at 4:09 PM Robert Heller <heller at deepsoft.com>
> wrote:
> > Also I found an interesting passage in the grub manual:
> >
> > " grub-mkconfig does have some limitations. While adding extra
> > custom menu entries to the end of the list can be done by editing
> > '/etc/grub.d/40_custom' or creating '/boot/grub/custom.cfg',
> > changing the order of menu entries or changing their titles may
> > require making complex changes to shell scripts stored in
> > '/etc/grub.d/'. This may be improved in the future. In the
> > meantime, those who feel that it would be easier to write 'grub.cfg'
> > directly are encouraged to do so (see Chapter 5 [Booting], page 15,
> > and Section 6.3 [Shell-like scripting], page 25), and to disable
> > any system provided by their distribution to automatically run
> > grub-mkconfig."
> >
> > So it seems that even the grub devs don't full trust
> > grub-mkconfig...
> 
> Your dislike of grub's making you misinterpret the above. The
> developers are simply saying that the more that you want to customize
> "/boot/grub/grub.cfg", the more complex the changes that you have to
> make have to be.

Speaking as the author of the passage quoted above (albeit most of ten
years ago), I endorse Tom's interpretation.

More generally, it's OK for tools not to cover all possible cases.
Sometimes it's better to say "if you have unusual requirements, you may
have to do unusual things" rather than contorting tools to handle
absolutely everything.  This isn't about trust, but rather about scope.

-- 
Colin Watson (he/him)                              [cjwatson at ubuntu.com]