Simplified module_has_submodule on Python >= 3.3.

Stopped using the imp module on Python >= 3.3. Refs #21628.

django/utils/module_loading.py

@@ -1,7 +1,6 @@
 from __future__ import absolute_import  # Avoid importing `importlib` from this package.
 
 import copy
-import imp
 from importlib import import_module
 import os
 import sys
@@ -87,67 +86,88 @@ def autodiscover_modules(*args, **kwargs):
                 raise
 
 
-def module_has_submodule(package, module_name):
-    """See if 'module' is in 'package'."""
-    name = ".".join([package.__name__, module_name])
-    try:
-        # None indicates a cached miss; see mark_miss() in Python/import.c.
-        return sys.modules[name] is not None
-    except KeyError:
-        pass
-    try:
-        package_path = package.__path__   # No __path__, then not a package.
-    except AttributeError:
-        # Since the remainder of this function assumes that we're dealing with
-        # a package (module with a __path__), so if it's not, then bail here.
-        return False
-    for finder in sys.meta_path:
-        if finder.find_module(name, package_path):
-            return True
-    for entry in package_path:
+if sys.version_info[:2] >= (3, 3):
+    if sys.version_info[:2] >= (3, 4):
+        from importlib.util import find_spec as importlib_find
+    else:
+        from importlib import find_loader as importlib_find
+
+    def module_has_submodule(package, module_name):
+        """See if 'module' is in '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
+            package_name = package.__name__
+            package_path = package.__path__
+        except AttributeError:
+            # package isn't a package.
+            return False
+
+        full_module_name = package_name + '.' + module_name
+        return importlib_find(full_module_name, package_path) is not None
+
+else:
+    import imp
+
+    def module_has_submodule(package, module_name):
+        """See if 'module' is in 'package'."""
+        name = ".".join([package.__name__, module_name])
+        try:
+            # None indicates a cached miss; see mark_miss() in Python/import.c.
+            return sys.modules[name] is not None
         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):
+            pass
+        try:
+            package_path = package.__path__   # No __path__, then not a package.
+        except AttributeError:
+            # Since the remainder of this function assumes that we're dealing with
+            # a package (module with a __path__), so if it's not, then bail here.
+            return False
+        for finder in sys.meta_path:
+            if finder.find_module(name, package_path):
+                return True
+        for entry in package_path:
+            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:
-                        pass
-                # XXX Could insert None or NullImporter
-    else:
-        # Exhausted the search, so the module cannot be found.
-        return False
+                        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