Python 3: Filter out None values returned by getmodule(...) to fix the stack inspection

Signed-off-by: Fadi Moukayed <smfadi@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

1 files changed, 4 insertions, 3 deletions

diff --git a/ryu/base/app_manager.py b/ryu/base/app_manager.py
index 340d31a9..5b63e8cd 100644
--- a/ryu/base/app_manager.py
+++ b/ryu/base/app_manager.py
@@ -77,11 +77,12 @@ def require_app(app_name, api_style=False):
 
     If this is used for client application module, set api_style=False.
     """
+    iterable = (inspect.getmodule(frame[0]) for frame in inspect.stack())
+    modules = [module for module in iterable if module is not None]
     if api_style:
-        frm = inspect.stack()[2]  # skip a frame for "api" module
+        m = modules[2]  # skip a frame for "api" module
     else:
-        frm = inspect.stack()[1]
-    m = inspect.getmodule(frm[0])  # client module
+        m = modules[1]
     m._REQUIRED_APP = getattr(m, '_REQUIRED_APP', [])
     m._REQUIRED_APP.append(app_name)
     LOG.debug('require_app: %s is required by %s', app_name, m.__name__)