Keep new packages when migrating from Stream until RockyLinux catches up (#96)

* CentOS Stream changes

* Retain CentOS Stream repositories and packages to avoid version downgrade
  issues.
* Only remove centos-stream-repos from the rpm db, do not actually uninstall the
  files.
* Rename system repositories from CentOS Stream with a "stream-" prefix to avoid
  clashing with Rockylinux system repository names.
* Disable CentOS Stream repositories after the distro-sync.

Note that these changes will leave CentOS Stream packages on the system, likely
until the next RockyLinux point release.  This is intentional to avoid issues
with downgrading package versions.

* Apply stream logic to epel-next-release.

epel-next-release is installed for CentOS stream machines with
EPEL.  Apply similar logic for epel-next as for CentOS stream.

migrate2rocky/migrate2rocky.sh

@@ -125,6 +125,15 @@ repo_urls=(
     [rockyappstream]="https://dl.rockylinux.org/pub/rocky/${SUPPORTED_MAJOR}/AppStream/$ARCH/os/"
 )
 
+# The repos package for CentOS stream requires special handling.
+declare -g -A stream_repos_pkgs
+stream_repos_pkgs=(
+    [rocky-repos]=centos-stream-repos
+    [epel-release]=epel-next-release
+)
+# Prefix to add to CentOS stream repo names when renaming them.
+stream_prefix=stream-
+
 unset CDPATH
 
 exit_message() {
@@ -212,8 +221,8 @@ bin_check() {
 
     local -a missing bins
     bins=(
-	rpm dnf awk column tee tput mkdir cat arch sort uniq
+	rpm dnf awk column tee tput mkdir cat arch sort uniq rmdir
-	rmdir rm head curl sha512sum mktemp systemd-detect-virt
+	rm head curl sha512sum mktemp systemd-detect-virt sed
     )
     if [[ $update_efi ]]; then
 	bins+=(findmnt grub2-mkconfig efibootmgr grep mokutil lsblk)
@@ -539,6 +548,22 @@ $'because continuing with the migration could cause further damage to system.'
  	fi
     done;
 
+    # Special Handling for CentOS Stream Repos
+    installed_sys_stream_repos_pkgs=()
+    installed_stream_repos_pkgs=()
+    for p in "${!stream_repos_pkgs[@]}"; do
+	if [[ ${installed_pkg_map[$p]} &&
+	      ${installed_pkg_map[$p]} == "${stream_repos_pkgs[$p]}" ]]
+	then
+	    # System package that needs to be swapped / disabled
+	    installed_pkg_map[$p]=
+	    installed_sys_stream_repos_pkgs+=( ${stream_repos_pkgs[$p]} )
+	elif rpm --quiet -q "${stream_repos_pkgs[$p]}"; then
+	    # Non-system package, repos just need to be disabled.
+	    installed_stream_repos_pkgs+=( ${stream_repos_pkgs[$p]} )
+	fi
+    done
+
     printf '%s\n' '' "We will replace the following $PRETTY_NAME packages with their Rocky Linux 8 equivalents"
     column -t -s $'\t' -N "Packages to be Removed,Packages to be Installed" < <(
 	for p in "${!installed_pkg_map[@]}"; do
@@ -546,8 +571,24 @@ $'because continuing with the migration could cause further damage to system.'
 	done
     )
 
+    if (( ${#installed_sys_stream_repos_pkgs[@]} )); then
+	printf '%s\n' '' \
+'Also to aid the transition from CentOS Stream the following packages will be '\
+'removed from the rpm database but the included repos will be renamed and '\
+'retained but disabled:' \
+	    "${installed_sys_stream_repos_pkgs[@]}"
+    fi
+
+    if (( ${#installed_stream_repos_pkgs[@]} )); then
+	printf '%s\n' '' \
+'Also to aid the transition from CentOS Stream the repos included in the '\
+'following packages will be renamed and retained but disabled:' \
+	    "${installed_stream_repos_pkgs[@]}"
+    fi
+
     if (( ${#addl_pkg_removes[@]} )); then
-	printf '%s\n' '' "In addition to the above the following system packages will be removed:" \
+	printf '%s\n' '' \
+"In addition to the above the following system packages will be removed:" \
 	    "${addl_pkg_removes[@]}"
     fi
 
@@ -661,6 +702,25 @@ package_swaps() {
 	dnfparameters+=( "--setopt=${repo}.gpgkey=file://${gpg_key_file}" )
     done
 
+    # CentOS Stream specific processing
+    if (( ${#installed_stream_repos_pkgs[@]} )); then
+	# Get a list of the repo files.
+	local -a repos_files
+	readarray -t repos_files < <(
+	    saferpm -ql "${installed_sys_stream_repos_pkgs[@]}" \
+		"${installed_stream_repos_pkgs[@]}" |
+	    grep '^/etc/yum\.repos\.d/.\+\.repo$'
+	)
+
+	# Remove the package from the rpm db.
+	saferpm -e --justdb --nodeps -a "${installed_sys_stream_repos_pkgs[@]}" ||
+	    exit_message \
+"Could not remove packages from the rpm db: ${installed_sys_stream_repos_pkgs[@]}"
+
+	# Rename the stream repos with a prefix.
+	sed -i 's/^\[/['"$stream_prefix"'/' "${repos_files[@]}"
+    fi
+
     # Use dnf shell to swap the system packages out.
     safednf -y shell --disablerepo=\* --noautoremove \
 	--setopt=protected_packages= --setopt=keepcache=True \
@@ -757,7 +817,7 @@ EOF
 
     # Distrosync
     infomsg $'Ensuring repos are enabled before the package swap\n'
-    safednf -y --enableplugin=config-manager config-manager \
+    safednf -y --enableplugin=config_manager config-manager \
 	--set-enabled "${!repo_map[@]}" || {
 	printf '%s\n' 'Repo name missing?'
 	exit 25
@@ -788,7 +848,7 @@ EOF
     	    exit_message "Can't enable modules ${enabled_modules[*]}"
     fi
 
-    # Make sure that excluded repos are disabled.
+    # Make sure that excluded modules are disabled.
     infomsg $'Disabling excluded modules\n\n'
     safednf -y module disable "${module_excludes[@]}" ||
     	exit_message "Can't disable modules ${module_excludes[*]}"
@@ -796,8 +856,39 @@ EOF
     infomsg $'\nSyncing packages\n\n'
     dnf -y distro-sync || exit_message "Error during distro-sync."
 
+    # Disable Stream repos.
+    if (( ${#installed_sys_stream_repos_pkgs[@]} ||
+	  ${#installed_stream_repos_pkgs[@]} )); then
+	dnf -y --enableplugin=config_manager config-manager --set-disabled \
+	    "$stream_prefix*" ||
+	    errmsg \
+$'Failed to disable CentOS Stream repos, please check and disable manually.\n'
+
+	infomsg $'\nCentOS Stream Migration Notes:\n\n'
+	cat <<EOF
+Because CentOS Stream leads RockyLinux by the next point release many packages
+in Stream will have higher version numbers than those in RockyLinux, some will
+even be rebased to a new upstream version.  Downgrading these packages to the
+versions in RockyLinux carries the risk that the older version may not
+recognize config files, data or other files generated by the newer version in
+Stream.
+
+To avoid issues with this the newer package versions from CentOS Stream have
+been retained.  Also the CentOS Stream repositories have been retained but
+renamed with a prefix of "stream-" to avoid clashing with RockyLinux
+repositories, but these same repos have also been disabled so that future
+package installs will come from the stock RockyLinux repositories.
+
+If you do nothing except update to the next point release of RockyLinux when it
+becomes available then the packages retained from Stream should be replaced at
+that time.  If you need to update a package from Stream (eg: to fix a bug or
+security issue) then you will need to enable the appropriate repository to do
+so.
+EOF
+    fi
+
     if rpm --quiet -q subscription-manager; then
-	infomsg $'Subscription Manager found on system.\n'
+	infomsg $'\nSubscription Manager found on system.\n\n'
 	cat <<EOF
 If you're converting from a subscription-managed distribution such as RHEL then
 you may no longer need subscription-manager or dnf-plugin-subscription-manager.
@@ -812,7 +903,6 @@ The subscription-manager dnf plugin may be enabled for the benefit of
 Subscription Management. If no longer desired, you can use
 "subscription-manager config --rhsm.auto_enable_yum_plugins=0" to block this
 behavior.
-
 EOF
     fi
     if [[ $tmp_sm_ca_dir ]]; then