alpm: make `repo` option optional

docs/usage.rst

@@ -814,10 +814,10 @@ alpm
   Name of the package.
 
 repo
-  Name of the package repository in which the package resides.
+  Name of the package repository in which the package resides. If not provided, nvchecker will search ``core``, ``extra``, ``community`` and ``multilib``, in that order.
 
 dbpath
-  Path to the ALPM database directory. Default: ``/var/lib/pacman``.
+  Path to the ALPM database directory. Default: ``/var/lib/pacman``. You need to update the database yourself.
 
 strip_release
   Strip the release part, only return the part before ``-``.

nvchecker_source/alpm.py

@@ -1,5 +1,5 @@
 # MIT licensed
-# Copyright (c) 2020 DDoSolitary <DDoSolitary@gmail.com>, et al.
+# Copyright (c) 2020-2021 DDoSolitary <DDoSolitary@gmail.com>, et al.
 
 from nvchecker.api import GetVersionError
 from pyalpm import Handle
@@ -15,11 +15,21 @@ async def open_db(info):
 async def get_version(name, conf, *, cache, **kwargs):
   pkgname = conf.get('alpm', name)
   dbpath = conf.get('dbpath', '/var/lib/pacman')
-  repo = conf['repo']
   strip_release = conf.get('strip_release', False)
   provided = conf.get('provided')
-  db = (await cache.get((dbpath, repo), open_db))[1]
-  pkg = db.get_pkg(pkgname)
+
+  repo = conf.get('repo')
+  if repo is None:
+    repos = ['core', 'extra', 'community', 'multilib']
+  else:
+    repos = [repo]
+
+  for repo in repos:
+    db = (await cache.get((dbpath, repo), open_db))[1]
+    pkg = db.get_pkg(pkgname)
+    if pkg is not None:
+      break
+
   if pkg is None:
     raise GetVersionError('package not found in the ALPM database')
   if provided is None: