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, 17 insertions, 0 deletions

diff --git a/installer/lib/common.sh b/installer/lib/common.sh
index e5f7246..2cd4798 100644
--- a/installer/lib/common.sh
+++ b/installer/lib/common.sh
@@ -328,3 +328,20 @@ prepend_grub_cmdline_linux() {
     grep -qF "GRUB_CMDLINE_LINUX=\"${addition}" "$config_file" \
         || error "GRUB_CMDLINE_LINUX not modified in $config_file (line missing or pattern unmatched)"
 }
+
+#############################
+# Initramfs Configuration
+#############################
+
+# Ensure mkinitcpio.conf's FILES= line lists the given value. Replaces
+# an existing FILES= line, or appends one if absent. Self-healing
+# rather than error-on-miss: FILES= is optional in mkinitcpio.conf, so
+# a missing line means "no extra files," not a broken config.
+ensure_initramfs_files() {
+    local value="$1"
+    local config_file="$2"
+    sed -i "s|^FILES=.*|FILES=(${value})|" "$config_file"
+    if ! grep -q "^FILES=" "$config_file"; then
+        echo "FILES=(${value})" >> "$config_file"
+    fi
+}