[3.6] bpo-21720: Restore the Python 2.7 logic in handling a fromlist. (GH-4118) (#4128)

BytesWarning no longer emitted when the fromlist argument of
__import__() or the __all__ attribute of the module contain bytes
instances..
(cherry picked from commit 41c56940c6edf3ea169332a6b039b6c8796f0475)

1 files changed, 43 insertions, 0 deletions

diff --git a/Lib/test/test_importlib/import_/test_fromlist.py b/Lib/test/test_importlib/import_/test_fromlist.py
index 1464003..018c172 100644
--- a/Lib/test/test_importlib/import_/test_fromlist.py
+++ b/Lib/test/test_importlib/import_/test_fromlist.py
@@ -1,5 +1,6 @@
 """Test that the semantics relating to the 'fromlist' argument are correct."""
 from .. import util
+import warnings
 import unittest
 
 
@@ -73,6 +74,13 @@ class HandlingFromlist:
                 self.assertTrue(hasattr(module, 'module'))
                 self.assertEqual(module.module.__name__, 'pkg.module')
 
+    def test_nonexistent_from_package(self):
+        with util.mock_modules('pkg.__init__') as importer:
+            with util.import_state(meta_path=[importer]):
+                module = self.__import__('pkg', fromlist=['non_existent'])
+                self.assertEqual(module.__name__, 'pkg')
+                self.assertFalse(hasattr(module, 'non_existent'))
+
     def test_module_from_package_triggers_ModuleNotFoundError(self):
         # If a submodule causes an ModuleNotFoundError because it tries
         # to import a module which doesn't exist, that should let the
@@ -122,6 +130,41 @@ class HandlingFromlist:
                 self.assertEqual(module.module1.__name__, 'pkg.module1')
                 self.assertEqual(module.module2.__name__, 'pkg.module2')
 
+    def test_nonexistent_in_all(self):
+        with util.mock_modules('pkg.__init__') as importer:
+            with util.import_state(meta_path=[importer]):
+                importer['pkg'].__all__ = ['non_existent']
+                module = self.__import__('pkg', fromlist=['*'])
+                self.assertEqual(module.__name__, 'pkg')
+                self.assertFalse(hasattr(module, 'non_existent'))
+
+    def test_star_in_all(self):
+        with util.mock_modules('pkg.__init__') as importer:
+            with util.import_state(meta_path=[importer]):
+                importer['pkg'].__all__ = ['*']
+                module = self.__import__('pkg', fromlist=['*'])
+                self.assertEqual(module.__name__, 'pkg')
+                self.assertFalse(hasattr(module, '*'))
+
+    def test_invalid_type(self):
+        with util.mock_modules('pkg.__init__') as importer:
+            with util.import_state(meta_path=[importer]), \
+                 warnings.catch_warnings():
+                warnings.simplefilter('error', BytesWarning)
+                with self.assertRaisesRegex(TypeError, r'\bfrom\b'):
+                    self.__import__('pkg', fromlist=[b'attr'])
+                with self.assertRaisesRegex(TypeError, r'\bfrom\b'):
+                    self.__import__('pkg', fromlist=iter([b'attr']))
+
+    def test_invalid_type_in_all(self):
+        with util.mock_modules('pkg.__init__') as importer:
+            with util.import_state(meta_path=[importer]), \
+                 warnings.catch_warnings():
+                warnings.simplefilter('error', BytesWarning)
+                importer['pkg'].__all__ = [b'attr']
+                with self.assertRaisesRegex(TypeError, r'\bpkg\.__all__\b'):
+                    self.__import__('pkg', fromlist=['*'])
+
 
 (Frozen_FromList,
  Source_FromList