bpo-35381 Remove all static state from posixmodule (GH-15892)

After #9665, this moves the remaining types in posixmodule to be heap-allocated to make it compatible with PEP384 as well as modifying all the type accessors to fully make the type opaque.

The original PR that got messed up a rebase: #10854. All the issues in that commit have now been addressed since #11661 got committed.

This change also removes any state from the data segment and onto the module state itself.


https://bugs.python.org/issue35381



Automerge-Triggered-By: @encukou

Lib/test/test_os.py

@@ -3638,6 +3638,24 @@ def test_os_all(self):
         self.assertIn('walk', os.__all__)
 
 
+class TestDirEntry(unittest.TestCase):
+    def setUp(self):
+        self.path = os.path.realpath(support.TESTFN)
+        self.addCleanup(support.rmtree, self.path)
+        os.mkdir(self.path)
+
+    def test_uninstantiable(self):
+        self.assertRaises(TypeError, os.DirEntry)
+
+    def test_unpickable(self):
+        filename = create_file(os.path.join(self.path, "file.txt"), b'python')
+        entry = [entry for entry in os.scandir(self.path)].pop()
+        self.assertIsInstance(entry, os.DirEntry)
+        self.assertEqual(entry.name, "file.txt")
+        import pickle
+        self.assertRaises(TypeError, pickle.dumps, entry, filename)
+
+
 class TestScandir(unittest.TestCase):
     check_no_resource_warning = support.check_no_resource_warning
 
@@ -3672,6 +3690,18 @@ def assert_stat_equal(self, stat1, stat2, skip_fields):
         else:
             self.assertEqual(stat1, stat2)
 
+    def test_uninstantiable(self):
+        scandir_iter = os.scandir(self.path)
+        self.assertRaises(TypeError, type(scandir_iter))
+        scandir_iter.close()
+
+    def test_unpickable(self):
+        filename = self.create_file("file.txt")
+        scandir_iter = os.scandir(self.path)
+        import pickle
+        self.assertRaises(TypeError, pickle.dumps, scandir_iter, filename)
+        scandir_iter.close()
+
     def check_entry(self, entry, name, is_dir, is_file, is_symlink):
         self.assertIsInstance(entry, os.DirEntry)
         self.assertEqual(entry.name, name)

Misc/NEWS.d/next/C API/2019-01-18-17-05-26.bpo-35381.9CbeW3.rst

@@ -0,0 +1,2 @@
+Convert posixmodule.c statically allocated types ``DirEntryType`` and
+``ScandirIteratorType`` to heap-allocated types.