gh-117860: Add tests for resolving names when import rebind names (GH-118176)

Add tests for "import", pkgutil.resolve_name() and unittest.mock.path()
for cases when "import a.b as x" and "from a import b as x" give
different results.

Author: serhiy-storchaka

Lib/test/test_import/__init__.py

@@ -1327,6 +1327,34 @@ def test_import_from_unloaded_package(self):
             import package2.submodule1
             package2.submodule1.submodule2
 
+    def test_rebinding(self):
+        # The same data is also used for testing pkgutil.resolve_name()
+        # in test_pkgutil and mock.patch in test_unittest.
+        path = os.path.join(os.path.dirname(__file__), 'data')
+        with uncache('package3', 'package3.submodule'), DirsOnSysPath(path):
+            from package3 import submodule
+            self.assertEqual(submodule.attr, 'rebound')
+            import package3.submodule as submodule
+            self.assertEqual(submodule.attr, 'rebound')
+        with uncache('package3', 'package3.submodule'), DirsOnSysPath(path):
+            import package3.submodule as submodule
+            self.assertEqual(submodule.attr, 'rebound')
+            from package3 import submodule
+            self.assertEqual(submodule.attr, 'rebound')
+
+    def test_rebinding2(self):
+        path = os.path.join(os.path.dirname(__file__), 'data')
+        with uncache('package4', 'package4.submodule'), DirsOnSysPath(path):
+            import package4.submodule as submodule
+            self.assertEqual(submodule.attr, 'submodule')
+            from package4 import submodule
+            self.assertEqual(submodule.attr, 'submodule')
+        with uncache('package4', 'package4.submodule'), DirsOnSysPath(path):
+            from package4 import submodule
+            self.assertEqual(submodule.attr, 'origin')
+            import package4.submodule as submodule
+            self.assertEqual(submodule.attr, 'submodule')
+
 
 class OverridingImportBuiltinTests(unittest.TestCase):
     def test_override_builtin(self):

Lib/test/test_import/data/package3/__init__.py

@@ -0,0 +1,2 @@
+"""Rebinding the package attribute after importing the module."""
+from .submodule import submodule

Lib/test/test_import/data/package3/submodule.py

@@ -0,0 +1,7 @@
+attr = 'submodule'
+class A:
+    attr = 'submodule'
+class submodule:
+    attr = 'rebound'
+    class B:
+        attr = 'rebound'

Lib/test/test_import/data/package4/__init__.py

@@ -0,0 +1,5 @@
+"""Binding the package attribute without importing the module."""
+class submodule:
+    attr = 'origin'
+    class B:
+        attr = 'origin'

Lib/test/test_import/data/package4/submodule.py

@@ -0,0 +1,3 @@
+attr = 'submodule'
+class A:
+    attr = 'submodule'

Lib/test/test_pkgutil.py

@@ -12,6 +12,9 @@
 import shutil
 import zipfile
 
+from test.support.import_helper import DirsOnSysPath
+from test.test_importlib.util import uncache
+
 # Note: pkgutil.walk_packages is currently tested in test_runpy. This is
 # a hack to get a major issue resolved for 3.3b2. Longer term, it should
 # be moved back here, perhaps by factoring out the helper code for
@@ -318,6 +321,38 @@ def test_name_resolution(self):
                 with self.assertRaises(exc):
                     pkgutil.resolve_name(s)
 
+    def test_name_resolution_import_rebinding(self):
+        # The same data is also used for testing import in test_import and
+        # mock.patch in test_unittest.
+        path = os.path.join(os.path.dirname(__file__), 'test_import', 'data')
+        with uncache('package3', 'package3.submodule'), DirsOnSysPath(path):
+            self.assertEqual(pkgutil.resolve_name('package3.submodule.attr'), 'submodule')
+        with uncache('package3', 'package3.submodule'), DirsOnSysPath(path):
+            self.assertEqual(pkgutil.resolve_name('package3.submodule:attr'), 'submodule')
+        with uncache('package3', 'package3.submodule'), DirsOnSysPath(path):
+            self.assertEqual(pkgutil.resolve_name('package3:submodule.attr'), 'rebound')
+            self.assertEqual(pkgutil.resolve_name('package3.submodule.attr'), 'submodule')
+            self.assertEqual(pkgutil.resolve_name('package3:submodule.attr'), 'rebound')
+        with uncache('package3', 'package3.submodule'), DirsOnSysPath(path):
+            self.assertEqual(pkgutil.resolve_name('package3:submodule.attr'), 'rebound')
+            self.assertEqual(pkgutil.resolve_name('package3.submodule:attr'), 'submodule')
+            self.assertEqual(pkgutil.resolve_name('package3:submodule.attr'), 'rebound')
+
+    def test_name_resolution_import_rebinding2(self):
+        path = os.path.join(os.path.dirname(__file__), 'test_import', 'data')
+        with uncache('package4', 'package4.submodule'), DirsOnSysPath(path):
+            self.assertEqual(pkgutil.resolve_name('package4.submodule.attr'), 'submodule')
+        with uncache('package4', 'package4.submodule'), DirsOnSysPath(path):
+            self.assertEqual(pkgutil.resolve_name('package4.submodule:attr'), 'submodule')
+        with uncache('package4', 'package4.submodule'), DirsOnSysPath(path):
+            self.assertEqual(pkgutil.resolve_name('package4:submodule.attr'), 'origin')
+            self.assertEqual(pkgutil.resolve_name('package4.submodule.attr'), 'submodule')
+            self.assertEqual(pkgutil.resolve_name('package4:submodule.attr'), 'submodule')
+        with uncache('package4', 'package4.submodule'), DirsOnSysPath(path):
+            self.assertEqual(pkgutil.resolve_name('package4:submodule.attr'), 'origin')
+            self.assertEqual(pkgutil.resolve_name('package4.submodule:attr'), 'submodule')
+            self.assertEqual(pkgutil.resolve_name('package4:submodule.attr'), 'submodule')
+
 
 class PkgutilPEP302Tests(unittest.TestCase):
 

Lib/test/test_unittest/testmock/testpatch.py

@@ -7,9 +7,11 @@
 from collections import OrderedDict
 
 import unittest
+import test
 from test.test_unittest.testmock import support
 from test.test_unittest.testmock.support import SomeClass, is_instance
 
+from test.support.import_helper import DirsOnSysPath
 from test.test_importlib.util import uncache
 from unittest.mock import (
     NonCallableMock, CallableMixin, sentinel,
@@ -1728,6 +1730,71 @@ def test(mock):
                             'exception traceback not propagated')
 
 
+    def test_name_resolution_import_rebinding(self):
+        # Currently mock.patch uses pkgutil.resolve_name(), but repeat
+        # similar tests just for the case.
+        # The same data is also used for testing import in test_import and
+        # pkgutil.resolve_name() in test_pkgutil.
+        path = os.path.join(os.path.dirname(test.__file__), 'test_import', 'data')
+        def check(name):
+            p = patch(name)
+            p.start()
+            p.stop()
+        def check_error(name):
+            p = patch(name)
+            self.assertRaises(AttributeError, p.start)
+        with uncache('package3', 'package3.submodule'), DirsOnSysPath(path):
+            check('package3.submodule.A.attr')
+            check_error('package3.submodule.B.attr')
+        with uncache('package3', 'package3.submodule'), DirsOnSysPath(path):
+            check('package3.submodule:A.attr')
+            check_error('package3.submodule:B.attr')
+        with uncache('package3', 'package3.submodule'), DirsOnSysPath(path):
+            check('package3:submodule.B.attr')
+            check_error('package3:submodule.A.attr')
+            check('package3.submodule.A.attr')
+            check_error('package3.submodule.B.attr')
+            check('package3:submodule.B.attr')
+            check_error('package3:submodule.A.attr')
+        with uncache('package3', 'package3.submodule'), DirsOnSysPath(path):
+            check('package3:submodule.B.attr')
+            check_error('package3:submodule.A.attr')
+            check('package3.submodule:A.attr')
+            check_error('package3.submodule:B.attr')
+            check('package3:submodule.B.attr')
+            check_error('package3:submodule.A.attr')
+
+    def test_name_resolution_import_rebinding2(self):
+        path = os.path.join(os.path.dirname(test.__file__), 'test_import', 'data')
+        def check(name):
+            p = patch(name)
+            p.start()
+            p.stop()
+        def check_error(name):
+            p = patch(name)
+            self.assertRaises(AttributeError, p.start)
+        with uncache('package4', 'package4.submodule'), DirsOnSysPath(path):
+            check('package4.submodule.A.attr')
+            check_error('package4.submodule.B.attr')
+        with uncache('package4', 'package4.submodule'), DirsOnSysPath(path):
+            check('package4.submodule:A.attr')
+            check_error('package4.submodule:B.attr')
+        with uncache('package4', 'package4.submodule'), DirsOnSysPath(path):
+            check('package4:submodule.B.attr')
+            check_error('package4:submodule.A.attr')
+            check('package4.submodule.A.attr')
+            check_error('package4.submodule.B.attr')
+            check('package4:submodule.A.attr')
+            check_error('package4:submodule.B.attr')
+        with uncache('package4', 'package4.submodule'), DirsOnSysPath(path):
+            check('package4:submodule.B.attr')
+            check_error('package4:submodule.A.attr')
+            check('package4.submodule:A.attr')
+            check_error('package4.submodule:B.attr')
+            check('package4:submodule.A.attr')
+            check_error('package4:submodule.B.attr')
+
+
     def test_create_and_specs(self):
         for kwarg in ('spec', 'spec_set', 'autospec'):
             p = patch('%s.doesnotexist' % __name__, create=True,

Makefile.pre.in

@@ -2380,6 +2380,8 @@ TESTSUBDIRS=	idlelib/idle_test \
 		test/test_import/data/circular_imports/subpkg2/parent \
 		test/test_import/data/package \
 		test/test_import/data/package2 \
+		test/test_import/data/package3 \
+		test/test_import/data/package4 \
 		test/test_import/data/unwritable \
 		test/test_importlib \
 		test/test_importlib/builtin \