Add discover

autopackage.py

@@ -19,6 +19,7 @@ from __future__ import annotations
 
 import argparse
 import base64
+import json
 import os
 import shlex
 import shutil
@@ -355,6 +356,9 @@ def main(argv: List[str]) -> int:
                     help="Scratch directory for clones/builds")
     ap.add_argument("--only", nargs="*", default=[],
                     help="Only build these package directory names")
+    ap.add_argument("--list-json", action="store_true",
+                    help="Print discovered package names as a JSON array and exit "
+                         "(used to build the CI matrix)")
     ap.add_argument("--cleanbuild", action="store_true",
                     help="Pass --cleanbuild to makepkg")
     ap.add_argument("--sign", action="store_true",
@@ -388,6 +392,11 @@ def main(argv: List[str]) -> int:
     args = ap.parse_args(argv)
     cfg = build_config(args)
 
+    if args.list_json:
+        pkgs = discover_packages(cfg, args.only)
+        print(json.dumps([p.name for p in pkgs]))
+        return 0
+
     pkgs = discover_packages(cfg, args.only)
     if not pkgs:
         print("No package directories found.", file=sys.stderr)