feat(scripts): add changelog generation script

- Introduces a script to generate Debian-style changelogs via git-cliff
- Supports CLI options for config, tag, output file, and debug mode
- Validates required tools, config file, and output directory
- Enhances automation of changelog creation for releases

scripts/generate-changelog.sh

@@ -0,0 +1,63 @@
+#!/usr/bin/env bash
+# generate-changelog.sh – generates a Debian-style changelog via git-cliff
+#
+# Usage:
+#   ./generate-changelog.sh -c cliff.debian.toml -t v2.9.1 -o debian/changelog
+#
+# Options:
+#   -c, --config <file>   Path to a valid git-cliff config file (required)
+#   -t, --tag    <tag>    Git tag used as the starting point for the changelog (required)
+#   -o, --out    <file>   Target changelog file to write to (required, unless --debug)
+#   -d, --debug          Print changelog to stdout instead of writing the file
+#   -h, --help           Show this help message
+#
+# Behaviour:
+#   • Verifies git-cliff, sed, and git are installed.
+#   • Checks that the config file exists and is readable.
+#   • Ensures the parent directory of the output file exists (unless --debug).
+#   • Generates the changelog; removes a leading empty line.
+set -euo pipefail
+
+# ───────────────────────────────────────────────
+CONFIG_FILE=""
+TAG=""
+OUT_FILE=""
+DEBUG=false
+# ───────────────────────────────────────────────
+
+show_help() { sed -n '2,18p' "$0"; }
+
+# 1 Parse CLI options
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    -c|--config) [[ $# -lt 2 ]] && { echo "❌ $1 requires a value"; exit 1; }; CONFIG_FILE="$2"; shift 2 ;;
+    -t|--tag)    [[ $# -lt 2 ]] && { echo "❌ $1 requires a value"; exit 1; }; TAG="$2";         shift 2 ;;
+    -o|--out)    [[ $# -lt 2 ]] && { echo "❌ $1 requires a value"; exit 1; }; OUT_FILE="$2";    shift 2 ;;
+    -d|--debug)  DEBUG=true; shift ;;
+    -h|--help)   show_help; exit 0 ;;
+    *)           echo "❌ Unknown option: $1"; show_help; exit 1 ;;
+  esac
+done
+
+# 2 Basic validation
+[[ -z "$CONFIG_FILE" || -z "$TAG" ]] && { echo "❌ --config and --tag are required"; show_help; exit 1; }
+[[ "$DEBUG" = false && -z "$OUT_FILE" ]] && { echo "❌ --out is required unless --debug is set"; show_help; exit 1; }
+[[ ! -r "$CONFIG_FILE" ]] && { echo "❌ Config file not found or unreadable: $CONFIG_FILE"; exit 1; }
+if [[ "$DEBUG" = false ]]; then
+  OUT_DIR=$(dirname "$OUT_FILE")
+  [[ ! -d "$OUT_DIR" ]] && { echo "❌ Output directory does not exist: $OUT_DIR"; exit 1; }
+fi
+
+# 3 Required tools
+need() { command -v "$1" >/dev/null || { echo "❌ $1 is required but not installed"; exit 1; }; }
+need git; need git-cliff; need sed
+
+# 4 Generate changelog
+if $DEBUG; then
+  echo "📝 Generating changelog (debug mode – stdout only)"
+  git cliff --config "$CONFIG_FILE" -t "$TAG" -s all
+else
+  echo "📝 Generating changelog → $OUT_FILE"
+  git cliff --config "$CONFIG_FILE" -t "$TAG" -s all > "$OUT_FILE"
+  echo "✅ Changelog written to $OUT_FILE"
+fi