Fix dependency tracking for package imports.

jparise · jparise · commit 08976eac4d48 · 2013-01-20T11:49:04.000-08:00
We were previously relying on direct name-based `sys.modules` lookups to resolve module references. This was an attempt to work around __import__()'s behavior of returning the package object for an import in the form `import package.module` (instead of the module itself). Unfortunately, the import names did not always match the module names, causing some of this lookups to fail. This resulted in an incomplete dependency map. We now manually walk through the the imported module hierarchy to more definitively locate the desired module object. Closes jparise#15
diff --git a/reloader.py b/reloader.py
@@ -154,17 +154,20 @@ def _import(name, globals=None, locals=None, fromlist=None, level=_default_level
     parent = _parent
     _parent = name
 
-    # Perform the actual import using the base import function.
+    # Perform the actual import work using the base import function.
     base = _baseimport(name, globals, locals, fromlist, level)
 
-    # If this is a nested import for a reloadable (source-based) module, we
-    # append ourself to our parent's dependency list.
-    if parent is not None:
-        # We get the module directly from sys.modules because the import
-        # function only returns the top-level module reference for a nested
+    if base is not None and parent is not None:
+        # We manually walk through the imported hierarchy because the import
+        # function only returns the top-level package reference for a nested
         # import statement (e.g. 'package' for `import package.module`).
-        m = sys.modules.get(name, None)
-        if m is not None and hasattr(m, '__file__'):
+        m = base
+        for component in name.split('.')[1:]:
+            m = getattr(m, component)
+
+        # If this is a nested import for a reloadable (source-based) module,
+        # we append ourself to our parent's dependency list.
+        if hasattr(m, '__file__'):
             l = _dependencies.setdefault(parent, [])
             l.append(m)
 
