grub2-15_ostree: Graceful exit if /etc/default/grub doesn't exist

See: https://github.com/ostreedev/ostree/pull/3150
See: https://github.com/fedora-silverblue/issue-tracker/issues/530

0001-grub2-15_ostree-Graceful-exit-if-etc-default-grub-do.patch

@@ -0,0 +1,43 @@
+From c281da8352378cbb3ea244ab6d2b557aada32cc4 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Timoth=C3=A9e=20Ravier?= <tim@siosm.fr>
+Date: Wed, 31 Jan 2024 15:38:31 +0100
+Subject: [PATCH 1/2] grub2-15_ostree: Graceful exit if /etc/default/grub
+ doesn't exist
+
+With the new bootupd installation path in Anaconda, the
+`/etc/default/grub` config file is not written anymore as we are only
+using BLS configs with new enough bootloaders.
+
+We thus don't need to generate (duplicated) legacy boot entries.
+
+We still need to keep this logic in place in Atomic Desktops
+(Silverblue, etc.) until we've actually landed bootupd there and forced
+a bootloader update for everybody.
+
+See: https://github.com/fedora-silverblue/issue-tracker/issues/530
+See: https://github.com/fedora-silverblue/issue-tracker/issues/120
+See: https://fedoraproject.org/wiki/Changes/FedoraSilverblueBootupd
+---
+ src/boot/grub2/grub2-15_ostree | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/src/boot/grub2/grub2-15_ostree b/src/boot/grub2/grub2-15_ostree
+index ecd618c9..a4c69730 100644
+--- a/src/boot/grub2/grub2-15_ostree
++++ b/src/boot/grub2/grub2-15_ostree
+@@ -24,6 +24,12 @@ if ! test -d /ostree/repo; then
+     exit 0
+ fi
+ 
++# Gracefully exit if we can not find the grub2 'default' configuration as it is
++# the case on new installations with bootupd where it is not needed.
++if ! test -f /etc/default/grub; then
++    exit 0
++fi
++
+ # Gracefully exit if the grub2 configuration has BLS enabled,
+ # and the installed version has support for the blscfg module.
+ # Since there is no need to create menu entries for that case.
+-- 
+2.43.0
+

ostree.spec

@@ -15,6 +15,7 @@ Name: ostree
 Version: 2024.1
 Release: %autorelease
 Source0: https://github.com/ostreedev/%{name}/releases/download/v%{version}/libostree-%{version}.tar.xz
+Patch1:  0001-grub2-15_ostree-Graceful-exit-if-etc-default-grub-do.patch
 License: LGPL-2.0-or-later
 URL: https://ostree.readthedocs.io/en/latest/