CI: demote optional dependencies in deb package

.github/scripts/.package.zsh

@@ -258,6 +258,9 @@ ${_usage_host:-}"
       pushd ${project_root}
       cmake --build build_${target##*-} --config ${config} -t package ${cmake_args}
 
+      # Mark certain deps as optional
+      build-aux/CI/linux/demote-deps.sh ${project_root}/release/*.deb Recommends '(mqtt)|(opencv)|(tesseract)|(usb)|(x11)'
+
       if [ ! -e ${project_root}/release/${output_name}.deb ]; then
         mv ${project_root}/release/*.deb ${project_root}/release/${output_name}.deb
         mv ${project_root}/release/*.ddeb ${project_root}/release/${output_name}.ddeb

build-aux/CI/linux/demote-deps.sh

@@ -0,0 +1,126 @@
+#!/usr/bin/env bash
+# Usage: demote_deps.sh <in.deb> [Recommends|Suggests] [regex]
+# Example: demote_deps.sh build/advanced-scene-switcher_1.31.0_amd64.deb Recommends 'opencv'
+set -euo pipefail
+
+if [[ $# -lt 1 ]]; then
+  echo "Usage: $0 <in.deb> [Recommends|Suggests] [regex]" >&2
+  exit 1
+fi
+
+IN_DEB="$1"
+DEST_FIELD="${2:-Recommends}"     # Recommends or Suggests
+MATCH_REGEX="${3:-opencv}"        # regex to match packages to demote
+
+echo "Demoting dependencies matching '${MATCH_REGEX}' to ${DEST_FIELD}"
+
+TMPDIR="$(mktemp -d)"
+trap 'rm -rf "$TMPDIR"' EXIT
+
+dpkg-deb -R "$IN_DEB" "$TMPDIR"
+CONTROL="$TMPDIR/DEBIAN/control"
+
+# Read a field (single line value), handling continuation lines starting with a space.
+get_field() {
+  local key="$1"
+  awk -v key="$key" '
+    BEGIN { val=""; collecting=0 }
+    $0 ~ "^" key ":" {
+      collecting=1
+      sub("^" key ":[[:space:]]*", "", $0)
+      val=$0
+      next
+    }
+    collecting==1 {
+      if ($0 ~ "^[[:space:]]") {
+        sub("^[[:space:]]+", "", $0)
+        val = val " " $0
+        next
+      } else {
+        collecting=0
+      }
+    }
+    END { print val }
+  ' "$CONTROL"
+}
+
+# Split a comma-separated list into lines, trimming whitespace
+split_csv() {
+  tr ',' '\n' | sed -E 's/^[[:space:]]+//; s/[[:space:]]+$//' | sed '/^$/d'
+}
+
+# Join with ", "
+join_csv() {
+  awk 'BEGIN{first=1}{ if(!first) printf(", "); printf("%s",$0); first=0 } END{print ""}'
+}
+
+# Deduplicate while preserving order
+dedup() {
+  awk '!seen[$0]++'
+}
+
+DEPENDS_VAL="$(get_field Depends)"
+EXIST_DEST_VAL="$(get_field "$DEST_FIELD")"
+
+# Separate opencv-matching vs the rest (preserve tokens exactly)
+mapfile -t DEPENDS_ARR < <(printf "%s\n" "$DEPENDS_VAL" | split_csv)
+declare -a MOVED=()
+declare -a KEPT=()
+for item in "${DEPENDS_ARR[@]}"; do
+  # Skip empty just in case
+  [[ -z "$item" ]] && continue
+  if [[ "$item" =~ $MATCH_REGEX ]]; then
+    MOVED+=("$item")
+  else
+    KEPT+=("$item")
+  fi
+done
+
+# Merge with existing dest field
+if [[ -n "$EXIST_DEST_VAL" ]]; then
+  mapfile -t EXIST_DEST_ARR < <(printf "%s\n" "$EXIST_DEST_VAL" | split_csv)
+  MOVED+=("${EXIST_DEST_ARR[@]}")
+fi
+
+# De-duplicate
+mapfile -t MOVED < <(printf "%s\n" "${MOVED[@]:-}" | sed '/^$/d' | dedup)
+mapfile -t KEPT  < <(printf "%s\n" "${KEPT[@]:-}"  | sed '/^$/d' | dedup)
+
+# Rebuild values
+NEW_DEPENDS="$(printf "%s\n" "${KEPT[@]:-}" | join_csv || true)"
+NEW_DEST="$(printf "%s\n" "${MOVED[@]:-}" | join_csv || true)"
+
+# Write a cleaned control (remove existing Depends/Recommends/Suggests incl. continuations)
+awk '
+  BEGIN { skip=0 }
+  {
+    if ($0 ~ "^(Depends|Recommends|Suggests):") { skip=1; next }
+    if (skip==1) {
+      if ($0 ~ "^[[:space:]]") { next } else { skip=0 }
+    }
+    print
+  }
+' "$CONTROL" > "$CONTROL.clean"
+
+# Append the rebuilt fields
+{
+  cat "$CONTROL.clean"
+  if [[ -n "$NEW_DEPENDS" ]]; then
+    echo "Depends: $NEW_DEPENDS"
+  fi
+  if [[ -n "$NEW_DEST" ]]; then
+    echo "$DEST_FIELD: $NEW_DEST"
+  fi
+} > "$CONTROL.new"
+
+# Clean up empty lines
+sed -i '/^[[:space:]]*$/d' "$CONTROL.new"
+
+mv "$CONTROL.new" "$CONTROL"
+rm -f "$CONTROL.clean"
+
+# Repack
+rm -f "${IN_DEB}"
+OUT_DEB="${IN_DEB}"
+dpkg-deb -b "$TMPDIR" "$OUT_DEB" >/dev/null
+echo "$OUT_DEB"