From 8447c703d1fd0107a52b15de7ce3a7056e1ec160 Mon Sep 17 00:00:00 2001
From: Brett Cannon <brett@python.org>
Date: Fri, 23 May 2014 12:30:37 -0400
Subject: [PATCH] Issue #14710: Fix both pkgutil.find_loader() and get_loader()
 to not raise an exception when a module doesn't exist.

Thanks to Pavel Aslanov for the bug report.
---
 Lib/pkgutil.py           |  4 +++-
 Lib/test/test_pkgutil.py | 14 ++++++++++++++
 Misc/NEWS                |  6 ++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/Lib/pkgutil.py b/Lib/pkgutil.py
index e42b6eb71f6..a54e9474d5b 100644
--- a/Lib/pkgutil.py
+++ b/Lib/pkgutil.py
@@ -456,6 +456,8 @@ def get_loader(module_or_name):
     """
     if module_or_name in sys.modules:
         module_or_name = sys.modules[module_or_name]
+        if module_or_name is None:
+            return None
     if isinstance(module_or_name, ModuleType):
         module = module_or_name
         loader = getattr(module, '__loader__', None)
@@ -487,7 +489,7 @@ def find_loader(fullname):
         # pkgutil previously raised ImportError
         msg = "Error while finding loader for {!r} ({}: {})"
         raise ImportError(msg.format(fullname, type(ex), ex)) from ex
-    return spec.loader
+    return spec.loader if spec is not None else None
 
 
 def extend_path(path, name):
diff --git a/Lib/test/test_pkgutil.py b/Lib/test/test_pkgutil.py
index 9704156a524..e0c8635de16 100644
--- a/Lib/test/test_pkgutil.py
+++ b/Lib/test/test_pkgutil.py
@@ -363,6 +363,20 @@ class ImportlibMigrationTests(unittest.TestCase):
             loader = pkgutil.get_loader(name)
         self.assertIsNone(loader)
 
+    def test_get_loader_None_in_sys_modules(self):
+        name = 'totally bogus'
+        sys.modules[name] = None
+        try:
+            loader = pkgutil.get_loader(name)
+        finally:
+            del sys.modules[name]
+        self.assertIsNone(loader)
+
+    def test_find_loader_missing_module(self):
+        name = 'totally bogus'
+        loader = pkgutil.find_loader(name)
+        self.assertIsNone(loader)
+
     def test_find_loader_avoids_emulation(self):
         with check_warnings() as w:
             self.assertIsNotNone(pkgutil.find_loader("sys"))
diff --git a/Misc/NEWS b/Misc/NEWS
index 6bee579ba98..cb99d561929 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -18,6 +18,12 @@ Core and Builtins
 Library
 -------
 
+- Issue #14710: pkgutil.get_loader() no longer raises an exception when None is
+  found in sys.modules.
+
+- Issue #14710: pkgutil.find_loader() no longer raises an exception when a
+  module doesn't exist.
+
 - Issue #21538: The plistlib module now supports loading of binary plist files
   when reference or offset size is not a power of two.