Add extensions.py file

- Necessary for extensions.py to work

- Fully copied over from the 'Python' bot

1 files changed, 34 insertions, 0 deletions

diff --git a/bot/utils/extensions.py b/bot/utils/extensions.py
new file mode 100644
index 00000000..50350ea8
--- /dev/null
+++ b/bot/utils/extensions.py
@@ -0,0 +1,34 @@
+import importlib
+import inspect
+import pkgutil
+from typing import Iterator, NoReturn
+
+from bot import exts
+
+
+def unqualify(name: str) -> str:
+    """Return an unqualified name given a qualified module/package `name`."""
+    return name.rsplit(".", maxsplit=1)[-1]
+
+
+def walk_extensions() -> Iterator[str]:
+    """Yield extension names from the bot.exts subpackage."""
+
+    def on_error(name: str) -> NoReturn:
+        raise ImportError(name=name)  # pragma: no cover
+
+    for module in pkgutil.walk_packages(exts.__path__, f"{exts.__name__}.", onerror=on_error):
+        if unqualify(module.name).startswith("_"):
+            # Ignore module/package names starting with an underscore.
+            continue
+
+        if module.ispkg:
+            imported = importlib.import_module(module.name)
+            if not inspect.isfunction(getattr(imported, "setup", None)):
+                # If it lacks a setup function, it's not an extension.
+                continue
+
+        yield module.name
+
+
+EXTENSIONS = frozenset(walk_extensions())