Merge branch 'ps/ci-avoid-broken-sudo-on-ubuntu' into maint-2.51

Our CI script requires "sudo" that can be told to preserve
environment, but Ubuntu replaced with "sudo" with an implementation
that lacks the feature.  Work this around by reinstalling the
original version.

* ps/ci-avoid-broken-sudo-on-ubuntu:
  ci: fix broken jobs on Ubuntu 25.10 caused by switch to sudo-rs(1)

Author: gitster

ci/install-dependencies.sh

@@ -61,6 +61,15 @@ ubuntu-*|i386/ubuntu-*|debian-*)
 		libsecret-1-dev libpcre2-dev meson ninja-build pkg-config \
 		${CC_PACKAGE:-${CC:-gcc}} $PYTHON_PACKAGE
 
+	# Starting with Ubuntu 25.10, sudo can now be provided via either
+	# sudo(1) or sudo-rs(1), with the latter being the default. The problem
+	# is that it does not support `--preserve-env` though, which we rely on
+	# in our CI. We thus revert back to the C implementation.
+	if test -f /etc/alternatives/sudo
+	then
+		sudo update-alternatives --set sudo /usr/bin/sudo.ws
+	fi
+
 	case "$distro" in
 	ubuntu-*)
 		mkdir --parents "$CUSTOM_PATH"