Expose demo for Gradio Spaces hot reload and update main launch logic

app.py

@@ -218,6 +218,11 @@ def create_app():
     return demo
 
 
+# Bound at module scope on purpose: Hugging Face Spaces' hot reloader looks up
+# `demo` in __main__ after every reload and fails if the name is missing.
+demo = create_app()
+
+
 if __name__ == "__main__":
     if not LOGIN_PASSWORD:
         print(
@@ -225,4 +230,4 @@ if __name__ == "__main__":
             "authentication and anyone who can reach it can spend endpoint quota."
         )
 
-    create_app().launch(auth=verify_login if LOGIN_PASSWORD else None)
+    demo.launch(auth=verify_login if LOGIN_PASSWORD else None)

test_app.py

@@ -321,3 +321,10 @@ def test_stream_completion_raises_on_malformed_chunk(monkeypatch):
 
     with pytest.raises(ValueError):
         list(app.stream_completion([], "m"))
+
+
+def test_module_exposes_demo_for_spaces_hot_reload():
+    """Spaces' reloader does getattr(__main__, "demo") after every reload."""
+    import gradio as gr
+
+    assert isinstance(app.demo, gr.Blocks)