Merge heads
diff --git a/Lib/configparser.py b/Lib/configparser.py
index 243efec..e5536a0 100644
--- a/Lib/configparser.py
+++ b/Lib/configparser.py
@@ -959,7 +959,8 @@
 
         # XXX this is not atomic if read_dict fails at any point. Then again,
         # no update method in configparser is atomic in this implementation.
-        self.remove_section(key)
+        if key in self._sections:
+            self._sections[key].clear()
         self.read_dict({key: value})
 
     def __delitem__(self, key):
diff --git a/Lib/test/test_cfgparser.py b/Lib/test/test_cfgparser.py
index 7a9e8a8..cec9b44 100644
--- a/Lib/test/test_cfgparser.py
+++ b/Lib/test/test_cfgparser.py
@@ -797,6 +797,32 @@
         self.assertEqual(set(cf.sections()), set())
         self.assertEqual(set(cf[self.default_section].keys()), {'foo'})
 
+    def test_setitem(self):
+        cf = self.fromstring("""
+            [section1]
+            name1 {0[0]} value1
+            [section2]
+            name2 {0[0]} value2
+            [section3]
+            name3 {0[0]} value3
+        """.format(self.delimiters), defaults={"nameD": "valueD"})
+        self.assertEqual(set(cf['section1'].keys()), {'name1', 'named'})
+        self.assertEqual(set(cf['section2'].keys()), {'name2', 'named'})
+        self.assertEqual(set(cf['section3'].keys()), {'name3', 'named'})
+        self.assertEqual(cf['section1']['name1'], 'value1')
+        self.assertEqual(cf['section2']['name2'], 'value2')
+        self.assertEqual(cf['section3']['name3'], 'value3')
+        self.assertEqual(cf.sections(), ['section1', 'section2', 'section3'])
+        cf['section2'] = {'name22': 'value22'}
+        self.assertEqual(set(cf['section2'].keys()), {'name22', 'named'})
+        self.assertEqual(cf['section2']['name22'], 'value22')
+        self.assertNotIn('name2', cf['section2'])
+        self.assertEqual(cf.sections(), ['section1', 'section2', 'section3'])
+        cf['section3'] = {}
+        self.assertEqual(set(cf['section3'].keys()), {'named'})
+        self.assertNotIn('name3', cf['section3'])
+        self.assertEqual(cf.sections(), ['section1', 'section2', 'section3'])
+
 
 class StrictTestCase(BasicTestCase):
     config_class = configparser.RawConfigParser
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index 5b67da1..bd799b2 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -1057,6 +1057,15 @@
                 f = open(os.path.join(self.dir, fn), 'rb')
                 f.close()
 
+        @unittest.skipUnless(hasattr(os, 'statvfs'),
+                             "need os.statvfs()")
+        def test_statvfs(self):
+            # issue #9645
+            for fn in self.unicodefn:
+                # should not fail with file not found error
+                fullname = os.path.join(self.dir, fn)
+                os.statvfs(fullname)
+
         def test_stat(self):
             for fn in self.unicodefn:
                 os.stat(os.path.join(self.dir, fn))
diff --git a/Misc/NEWS b/Misc/NEWS
index 5ef30af..175518b 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -191,6 +191,17 @@
 
 - Issue #16541: tk_setPalette() now works with keyword arguments.
 
+- Issue #16820: In configparser, `parser.popitem()` no longer raises ValueError.
+  This makes `parser.clean()` work correctly.
+
+- Issue #16820: In configparser, ``parser['section'] = {}`` now preserves
+  section order within the parser. This makes `parser.update()` preserve section
+  order as well.
+
+- Issue #9644: Fix the encoding used by os.statvfs(): use the filesystem
+  encoding with the surrogateescape error handler, instead of UTF-8 in strict
+  mode.
+
 - Issue #16819: IDLE method completion now correctly works for bytes literals.
 
 - Issue #9586: Redefine SEM_FAILED on MacOSX to keep compiler happy.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 0d2919b..e7e5305 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -6463,18 +6463,22 @@
 static PyObject *
 posix_statvfs(PyObject *self, PyObject *args)
 {
+    PyObject *opath, *result = NULL;
     char *path;
     int res;
     struct statvfs st;
-    if (!PyArg_ParseTuple(args, "s:statvfs", &path))
+    if (!PyArg_ParseTuple(args, "O&:statvfs", PyUnicode_FSConverter, &opath))
         return NULL;
+    path = PyBytes_AS_STRING(opath);
     Py_BEGIN_ALLOW_THREADS
     res = statvfs(path, &st);
     Py_END_ALLOW_THREADS
     if (res != 0)
-        return posix_error_with_filename(path);
+        return posix_error_with_allocated_filename(opath);
 
-    return _pystatvfs_fromstructstatvfs(st);
+    result = _pystatvfs_fromstructstatvfs(st);
+    Py_DECREF(opath);
+    return result;
 }
 #endif /* HAVE_STATVFS */