1 files changed, 55 insertions, 21 deletions
diff --git a/django/utils/module_loading.py b/django/utils/module_loading.py
index 9bcdd276fd..f251035387 100644
--- a/django/utils/module_loading.py
+++ b/django/utils/module_loading.py
@@ -1,26 +1,60 @@
-import os
 import imp
+import os
+import sys
 
-def module_has_submodule(mod, submod_name):
-    # If the module was loaded from an egg, __loader__ will be set and
-    # its find_module must be used to search for submodules.
-    loader = getattr(mod, '__loader__', None)
-    if loader:
-        mod_path = "%s.%s" % (mod.__name__.rsplit('.',1)[-1], submod_name)
-        x = loader.find_module(mod_path)
-        if x is None:
-            # zipimport.zipimporter.find_module is documented to take
-            # dotted paths but in fact through Python 2.7 is observed
-            # to require os.sep in place of dots...so try using os.sep
-            # if the dotted path version failed to find the requested
-            # submodule.
-            x = loader.find_module(mod_path.replace('.', os.sep))
-        return x is not None
 
-    try:
-        imp.find_module(submod_name, mod.__path__)
+def module_has_submodule(package, module_name):
+    """See if 'module' is in 'package'."""
+    name = ".".join([package.__name__, module_name])
+    if name in sys.modules:
         return True
-    except ImportError:
+    for finder in sys.meta_path:
+        if finder.find_module(name):
+            return True
+    for entry in package.__path__:  # No __path__, then not a package.
+        try:
+            # Try the cached finder.
+            finder = sys.path_importer_cache[entry]
+            if finder is None:
+                # Implicit import machinery should be used.
+                try:
+                    file_, _, _ = imp.find_module(module_name, [entry])
+                    if file_:
+                        file_.close()
+                    return True
+                except ImportError:
+                    continue
+            # Else see if the finder knows of a loader.
+            elif finder.find_module(name):
+                return True
+            else:
+                continue
+        except KeyError:
+            # No cached finder, so try and make one.
+            for hook in sys.path_hooks:
+                try:
+                    finder = hook(entry)
+                    # XXX Could cache in sys.path_importer_cache
+                    if finder.find_module(name):
+                        return True
+                    else:
+                        # Once a finder is found, stop the search.
+                        break
+                except ImportError:
+                    # Continue the search for a finder.
+                    continue
+            else:
+                # No finder found.
+                # Try the implicit import machinery if searching a directory.
+                if os.path.isdir(entry):
+                    try:
+                        file_, _, _ = imp.find_module(module_name, [entry])
+                        if file_:
+                            file_.close()
+                        return True
+                    except ImportError:
+                        pass
+                # XXX Could insert None or NullImporter
+    else:
+        # Exhausted the search, so the module cannot be found.
         return False
-
-