refactor: lift FILES= keyfile sed to ensure_initramfs_files helper

btrfs.sh's configure_btrfs_initramfs had a six-line inline that ensured mkinitcpio.conf's FILES= line listed the LUKS keyfile: sed-replace the existing FILES= line, then grep + append as a fallback when no FILES= line existed. The pattern is mkinitcpio-specific and self-healing rather than error-on-miss (FILES= is optional in mkinitcpio.conf, so missing means "no extra files," not a broken config).

I lifted the block into ensure_initramfs_files in lib/common.sh next to prepend_grub_cmdline_linux, then collapsed the btrfs.sh call site to a single ensure_initramfs_files line. Added three bats tests for the three cases (FILES= present and empty, FILES= present with a different value, FILES= absent entirely). Bats: 174 → 177.

No behavior change. The helper's logic matches the inline byte-for-byte: same sed pattern, same grep fallback, same final state.

1 files changed, 1 insertions, 5 deletions

diff --git a/installer/lib/btrfs.sh b/installer/lib/btrfs.sh
index 0715ba7..0a34be0 100644
--- a/installer/lib/btrfs.sh
+++ b/installer/lib/btrfs.sh
@@ -212,11 +212,7 @@ configure_luks_initramfs() {
     # Include keyfile in initramfs for testing mode (unattended boot)
     if [[ "${TESTING:-}" == "yes" ]]; then
         info "Testing mode: embedding keyfile in initramfs"
-        sed -i "s|^FILES=.*|FILES=($LUKS_KEYFILE)|" $MNTPOINT/etc/mkinitcpio.conf
-        # If FILES line doesn't exist, add it
-        if ! grep -q "^FILES=" $MNTPOINT/etc/mkinitcpio.conf; then
-            echo "FILES=($LUKS_KEYFILE)" >> $MNTPOINT/etc/mkinitcpio.conf
-        fi
+        ensure_initramfs_files "$LUKS_KEYFILE" "$MNTPOINT/etc/mkinitcpio.conf"
     fi
 
     # Create crypttab.initramfs for sd-encrypt (used by multi-disk LUKS)