fixup! Add users option to both GitHub and Gitea restricting project owners

Signed-off-by: magic_rb <richard@brezak.sk>

Author: MagicRB

buildbot_nix/buildbot_nix/common.py

@@ -123,11 +123,16 @@ def filter_repos(
     user: Callable[[Y], str],
     topics: Callable[[Y], list[str]],
 ) -> list[Y]:
+    # This is a bit complicated so let me explain:
+    # If both `user_allowlist` and `repo_allowlist` are `None` then we want to allow everything,
+    # however if either are non-`None`, then the one that is non-`None` determines whether to
+    # allow a repo, or both if both are non-+None`.
+
     return list(
         filter(
             lambda repo: (user_allowlist is None and repo_allowlist is None)
-            or (user_allowlist is None or user(repo) in user_allowlist)
-            or (repo_allowlist is None or repo_name(repo) in repo_allowlist),
+            or (user_allowlist is not None and user(repo) in user_allowlist)
+            or (repo_allowlist is not None and repo_name(repo) in repo_allowlist),
             filter(
                 lambda repo: topic is None or topic in topics(repo),
                 repos,