Remove hacking rules for python 2/3 compatibility

The Python 2.7 Support has been dropped since Ussuri.
So remove hacking rules for compatibility between python 2 and 3.

- [N325] str() and unicode() cannot be used on an exception.
         Remove or use six.text_type()
- [N327] Do not use xrange(). xrange() is not compatible with Python 3.
         Use range() or six.moves.range() instead.
- [N344] Python 3: do not use dict.iteritems.
- [N345] Python 3: do not use dict.iterkeys.
- [N346] Python 3: do not use dict.itervalues.

See also line 414 in https://etherpad.opendev.org/p/nova-victoria-ptg

Change-Id: If4335b2e8ef5bbabba37598110c1aa8269635c2f
Implements: blueprint six-removal
Signed-off-by: Takashi Natsume <takanattie@gmail.com>

4 files changed, 0 insertions, 187 deletions

diff --git a/HACKING.rst b/HACKING.rst
index 46c17d41a8..6678328fd2 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -31,9 +31,7 @@ Nova Specific Commandments
 - [N322] Method's default argument shouldn't be mutable
 - [N323] Ensure that the _() function is explicitly imported to ensure proper translations.
 - [N324] Ensure that jsonutils.%(fun)s must be used instead of json.%(fun)s
-- [N325] str() and unicode() cannot be used on an exception.  Remove use or use six.text_type()
 - [N326] Translated messages cannot be concatenated.  String should be included in translated message.
-- [N327] Do not use xrange(). xrange() is not compatible with Python 3. Use range() or six.moves.range() instead.
 - [N332] Check that the api_version decorator is the first decorator on a method
 - [N334] Change assertTrue/False(A in/not in B, message) to the more specific
   assertIn/NotIn(A, B, message)
@@ -48,9 +46,6 @@ Nova Specific Commandments
 - [N341] contextlib.nested is deprecated
 - [N342] Config options should be in the central location ``nova/conf/``
 - [N343] Check for common double word typos
-- [N344] Python 3: do not use dict.iteritems.
-- [N345] Python 3: do not use dict.iterkeys.
-- [N346] Python 3: do not use dict.itervalues.
 - [N348] Deprecated library function os.popen()
 - [N349] Check for closures in tests which are not used
 - [N350] Policy registration should be in the central location ``nova/policies/``
diff --git a/nova/hacking/checks.py b/nova/hacking/checks.py
index 595ba89f0e..7922881034 100644
--- a/nova/hacking/checks.py
+++ b/nova/hacking/checks.py
@@ -32,7 +32,6 @@ import os
 import re
 
 from hacking import core
-import six
 
 
 UNDERSCORE_IMPORT_FILES = []
@@ -293,13 +292,6 @@ def assert_equal_type(logical_line):
 
 
 @core.flake8ext
-def check_python3_xrange(logical_line):
-    if re.search(r"\bxrange\s*\(", logical_line):
-        yield (0, "N327: Do not use xrange(). 'xrange()' is not compatible "
-                  "with Python 3. Use range() or six.moves.range() instead.")
-
-
-@core.flake8ext
 def no_translate_logs(logical_line, filename):
     """Check for 'LOG.foo(_('
 
@@ -400,58 +392,6 @@ def check_api_version_decorator(logical_line, previous_logical, blank_before,
         yield (0, msg)
 
 
-class CheckForStrUnicodeExc(BaseASTChecker):
-    """Checks for the use of str() or unicode() on an exception.
-
-    This currently only handles the case where str() or unicode()
-    is used in the scope of an exception handler.  If the exception
-    is passed into a function, returned from an assertRaises, or
-    used on an exception created in the same scope, this does not
-    catch it.
-    """
-
-    name = 'check_for_string_unicode_exc'
-    version = '1.0'
-
-    CHECK_DESC = ('N325 str() and unicode() cannot be used on an '
-                  'exception.  Remove or use six.text_type()')
-
-    def __init__(self, tree, filename):
-        super(CheckForStrUnicodeExc, self).__init__(tree, filename)
-        self.name = []
-        self.already_checked = []
-
-    # Python 2 produces ast.TryExcept and ast.TryFinally nodes, but Python 3
-    # only produces ast.Try nodes.
-    if six.PY2:
-        def visit_TryExcept(self, node):
-            for handler in node.handlers:
-                if handler.name:
-                    self.name.append(handler.name.id)
-                    super(CheckForStrUnicodeExc, self).generic_visit(node)
-                    self.name = self.name[:-1]
-                else:
-                    super(CheckForStrUnicodeExc, self).generic_visit(node)
-    else:
-        def visit_Try(self, node):
-            for handler in node.handlers:
-                if handler.name:
-                    self.name.append(handler.name)
-                    super(CheckForStrUnicodeExc, self).generic_visit(node)
-                    self.name = self.name[:-1]
-                else:
-                    super(CheckForStrUnicodeExc, self).generic_visit(node)
-
-    def visit_Call(self, node):
-        if self._check_call_names(node, ['str', 'unicode']):
-            if node not in self.already_checked:
-                self.already_checked.append(node)
-                if isinstance(node.args[0], ast.Name):
-                    if node.args[0].id in self.name:
-                        self.add_error(node.args[0])
-        super(CheckForStrUnicodeExc, self).generic_visit(node)
-
-
 class CheckForTransAdd(BaseASTChecker):
     """Checks for the use of concatenation on a translated string.
 
@@ -724,30 +664,6 @@ def check_doubled_words(physical_line, filename):
 
 
 @core.flake8ext
-def check_python3_no_iteritems(logical_line):
-    msg = ("N344: Use items() instead of dict.iteritems().")
-
-    if re.search(r".*\.iteritems\(\)", logical_line):
-        yield (0, msg)
-
-
-@core.flake8ext
-def check_python3_no_iterkeys(logical_line):
-    msg = ("N345: Use six.iterkeys() instead of dict.iterkeys().")
-
-    if re.search(r".*\.iterkeys\(\)", logical_line):
-        yield (0, msg)
-
-
-@core.flake8ext
-def check_python3_no_itervalues(logical_line):
-    msg = ("N346: Use six.itervalues() instead of dict.itervalues().")
-
-    if re.search(r".*\.itervalues\(\)", logical_line):
-        yield (0, msg)
-
-
-@core.flake8ext
 def no_os_popen(logical_line):
     """Disallow 'os.popen('
 
diff --git a/nova/tests/unit/test_hacking.py b/nova/tests/unit/test_hacking.py
index 35ffb30083..f562763724 100644
--- a/nova/tests/unit/test_hacking.py
+++ b/nova/tests/unit/test_hacking.py
@@ -285,71 +285,6 @@ class HackingTestCase(test.NoDBTestCase):
     def _assert_has_no_errors(self, code, checker, filename=None):
         self._assert_has_errors(code, checker, filename=filename)
 
-    def test_str_unicode_exception(self):
-
-        checker = checks.CheckForStrUnicodeExc
-        code = """
-               def f(a, b):
-                   try:
-                       p = str(a) + str(b)
-                   except ValueError as e:
-                       p = str(e)
-                   return p
-               """
-        errors = [(5, 16, 'N325')]
-        self._assert_has_errors(code, checker, expected_errors=errors)
-
-        code = """
-               def f(a, b):
-                   try:
-                       p = unicode(a) + str(b)
-                   except ValueError as e:
-                       p = e
-                   return p
-               """
-        self._assert_has_no_errors(code, checker)
-
-        code = """
-               def f(a, b):
-                   try:
-                       p = str(a) + str(b)
-                   except ValueError as e:
-                       p = unicode(e)
-                   return p
-               """
-        errors = [(5, 20, 'N325')]
-        self._assert_has_errors(code, checker, expected_errors=errors)
-
-        code = """
-               def f(a, b):
-                   try:
-                       p = str(a) + str(b)
-                   except ValueError as e:
-                       try:
-                           p  = unicode(a) + unicode(b)
-                       except ValueError as ve:
-                           p = str(e) + str(ve)
-                       p = e
-                   return p
-               """
-        errors = [(8, 20, 'N325'), (8, 29, 'N325')]
-        self._assert_has_errors(code, checker, expected_errors=errors)
-
-        code = """
-               def f(a, b):
-                   try:
-                       p = str(a) + str(b)
-                   except ValueError as e:
-                       try:
-                           p  = unicode(a) + unicode(b)
-                       except ValueError as ve:
-                           p = str(e) + unicode(ve)
-                       p = str(e)
-                   return p
-               """
-        errors = [(8, 20, 'N325'), (8, 33, 'N325'), (9, 16, 'N325')]
-        self._assert_has_errors(code, checker, expected_errors=errors)
-
     def test_api_version_decorator_check(self):
         code = """
                @some_other_decorator
@@ -571,27 +506,6 @@ class HackingTestCase(test.NoDBTestCase):
         code = "'This is the then best comment'\n"
         self._assert_has_no_errors(code, checks.check_doubled_words)
 
-    def test_dict_iteritems(self):
-        self.assertEqual(1, len(list(checks.check_python3_no_iteritems(
-            "obj.iteritems()"))))
-
-        self.assertEqual(0, len(list(checks.check_python3_no_iteritems(
-            "six.iteritems(ob))"))))
-
-    def test_dict_iterkeys(self):
-        self.assertEqual(1, len(list(checks.check_python3_no_iterkeys(
-            "obj.iterkeys()"))))
-
-        self.assertEqual(0, len(list(checks.check_python3_no_iterkeys(
-            "six.iterkeys(ob))"))))
-
-    def test_dict_itervalues(self):
-        self.assertEqual(1, len(list(checks.check_python3_no_itervalues(
-            "obj.itervalues()"))))
-
-        self.assertEqual(0, len(list(checks.check_python3_no_itervalues(
-            "six.itervalues(ob))"))))
-
     def test_no_os_popen(self):
         code = """
                import os
@@ -685,13 +599,6 @@ class HackingTestCase(test.NoDBTestCase):
         """
         self._assert_has_no_errors(code, checks.check_policy_enforce)
 
-    def test_check_python3_xrange(self):
-        func = checks.check_python3_xrange
-        self.assertEqual(1, len(list(func('for i in xrange(10)'))))
-        self.assertEqual(1, len(list(func('for i in xrange    (10)'))))
-        self.assertEqual(0, len(list(func('for i in range(10)'))))
-        self.assertEqual(0, len(list(func('for i in six.moves.range(10)'))))
-
     def test_log_context(self):
         code = """
                   LOG.info("Rebooting instance",
diff --git a/tox.ini b/tox.ini
index 911465a9d2..620bf441a2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -288,7 +288,6 @@ extension =
   N323 = checks:check_explicit_underscore_import
   N324 = checks:use_jsonutils
   N332 = checks:check_api_version_decorator
-  N325 = checks:CheckForStrUnicodeExc
   N326 = checks:CheckForTransAdd
   N334 = checks:assert_true_or_false_with_in
   N336 = checks:dict_constructor_with_list_copy
@@ -300,10 +299,6 @@ extension =
   N350 = checks:check_policy_registration_in_central_place
   N351 = checks:check_policy_enforce
   N343 = checks:check_doubled_words
-  N344 = checks:check_python3_no_iteritems
-  N345 = checks:check_python3_no_iterkeys
-  N346 = checks:check_python3_no_itervalues
-  N327 = checks:check_python3_xrange
   N348 = checks:no_os_popen
   N352 = checks:no_log_warn
   N349 = checks:CheckForUncalledTestClosure