Merge pull request #15 from zopefoundation/central-version-checks

Centralize the Python version checks
zopefoundation · Jan 31, 2017 · 7dc6e5f · 7dc6e5f
2 parents cf1485b + 5addea8
commit 7dc6e5f
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Showing 6 changed files with 54 additions and 62 deletions.
diff --git a/src/RestrictedPython/Guards.py b/src/RestrictedPython/Guards.py
@@ -15,7 +15,7 @@
 # AccessControl.ZopeGuards contains a large set of wrappers for builtins.
 # DocumentTemplate.DT_UTil contains a few.
 
-import sys
+from ._compat import IS_PY2
 
 
 try:
@@ -104,8 +104,7 @@
     'ZeroDivisionError',
 ]
 
-version = sys.version_info
-if version >= (2, 7) and version < (2, 8):
+if IS_PY2:
     _safe_names.extend([
         'basestring',
         'cmp',
@@ -118,22 +117,6 @@
         'StandardError',
     ])
 
-if version >= (3, 0):
-    _safe_names.extend([
-
-    ])
-    _safe_exceptions.extend([
-
-    ])
-
-if version >= (3, 5):
-    _safe_names.extend([
-
-    ])
-    _safe_exceptions.extend([
-
-    ])
-
 
 for name in _safe_names:
     safe_builtins[name] = getattr(builtins, name)
@@ -246,7 +229,7 @@ def __init__(self, ob):
 def _full_write_guard():
     # Nested scope abuse!
     # safetype and Wrapper variables are used by guard()
-    safetype = {dict: True, list: True}.has_key if version < (3, 0) else {dict: True, list: True}.keys
+    safetype = {dict: True, list: True}.has_key if IS_PY2 else {dict: True, list: True}.keys
     Wrapper = _write_wrapper()
 
     def guard(ob):

diff --git a/src/RestrictedPython/_compat.py b/src/RestrictedPython/_compat.py
@@ -0,0 +1,8 @@
+import sys
+
+
+_version = sys.version_info
+IS_PY2 = _version.major == 2
+IS_PY3 = _version.major == 3
+IS_PY34_OR_GREATER = _version.major == 3 and _version.minor >= 4
+IS_PY35_OR_GREATER = _version.major == 3 and _version.minor >= 5
diff --git a/src/RestrictedPython/transformer.py b/src/RestrictedPython/transformer.py
@@ -22,9 +22,13 @@
 # http://docs.plone.org/develop/styleguide/python.html
 
 
+from ._compat import IS_PY2
+from ._compat import IS_PY3
+from ._compat import IS_PY34_OR_GREATER
+from ._compat import IS_PY35_OR_GREATER
+
 import ast
 import contextlib
-import sys
 
 
 # if any of the ast Classes should not be whitelisted, please comment them out
@@ -144,9 +148,7 @@
     ast.FloorDiv: '//='
 }
 
-
-version = sys.version_info
-if version >= (2, 7) and version < (2, 8):
+if IS_PY2:
     AST_WHITELIST.extend([
         ast.Print,
         ast.Raise,
@@ -155,7 +157,7 @@
         ast.ExceptHandler,
     ])
 
-if version >= (3, 4):
+if IS_PY3:
     AST_WHITELIST.extend([
         ast.Bytes,
         ast.Starred,
@@ -166,7 +168,7 @@
         ast.withitem
     ])
 
-if version >= (3, 5):
+if IS_PY35_OR_GREATER:
     IOPERATOR_TO_STR[ast.MatMult] = '@='
 
     AST_WHITELIST.extend([
@@ -178,10 +180,6 @@
         #ast.AsyncWith,  # No Async Elements should be supported
     ])
 
-if version >= (3, 6):
-    AST_WHITELIST.extend([
-    ])
-
 
 # When new ast nodes are generated they have no 'lineno' and 'col_offset'.
 # This function copies these two fields from the incoming node
@@ -282,7 +280,7 @@ def guard_iter(self, node):
         return node
 
     def is_starred(self, ob):
-        if version.major == 3:
+        if IS_PY3:
             return isinstance(ob, ast.Starred)
         else:
             return False
@@ -409,7 +407,7 @@ def gen_unpack_wrapper(self, node, target, ctx='store'):
         try_body = [ast.Assign(targets=[target], value=converter)]
         finalbody = [self.gen_del_stmt(tmp_name)]
 
-        if version.major == 2:
+        if IS_PY2:
             cleanup = ast.TryFinally(body=try_body, finalbody=finalbody)
         else:
             cleanup = ast.Try(
@@ -431,7 +429,7 @@ def gen_unpack_wrapper(self, node, target, ctx='store'):
         return (tmp_target, cleanup)
 
     def gen_none_node(self):
-        if version >= (3, 4):
+        if IS_PY34_OR_GREATER:
             return ast.NameConstant(value=None)
         else:
             return ast.Name(id='None', ctx=ast.Load())
@@ -517,7 +515,7 @@ def check_function_argument_names(self, node):
         # which is gone in python3.
         # See https://www.python.org/dev/peps/pep-3113/
 
-        if version.major == 2:
+        if IS_PY2:
             # Needed to handle nested 'tuple parameter unpacking'.
             # For example 'def foo((a, b, (c, (d, e)))): pass'
             to_check = list(node.args.args)
@@ -956,17 +954,17 @@ def visit_Call(self, node):
         # '*args' can be detected by 'ast.Starred' nodes.
         # '**kwargs' can be deteced by 'keyword' nodes with 'arg=None'.
 
-        if version < (3, 5):
-            if (node.starargs is not None) or (node.kwargs is not None):
-                needs_wrap = True
-        else:
+        if IS_PY35_OR_GREATER:
             for pos_arg in node.args:
                 if isinstance(pos_arg, ast.Starred):
                     needs_wrap = True
 
             for keyword_arg in node.keywords:
                 if keyword_arg.arg is None:
                     needs_wrap = True
+        else:
+            if (node.starargs is not None) or (node.kwargs is not None):
+                needs_wrap = True
 
         node = self.generic_visit(node)
 
@@ -1364,7 +1362,7 @@ def visit_ExceptHandler(self, node):
 
         node = self.generic_visit(node)
 
-        if version.major == 3:
+        if IS_PY3:
             return node
 
         if not isinstance(node.name, ast.Tuple):
@@ -1385,7 +1383,7 @@ def visit_With(self, node):
 
         node = self.generic_visit(node)
 
-        if version.major == 2:
+        if IS_PY2:
             items = [node]
         else:
             items = node.items
@@ -1422,7 +1420,7 @@ def visit_FunctionDef(self, node):
             node = self.generic_visit(node)
             self.inject_print_collector(node)
 
-        if version.major == 3:
+        if IS_PY3:
             return node
 
         # Protect 'tuple parameter unpacking' with '_getiter_'.
@@ -1447,7 +1445,7 @@ def visit_Lambda(self, node):
 
         node = self.generic_visit(node)
 
-        if version.major == 3:
+        if IS_PY3:
             return node
 
         # Check for tuple parameters which need _getiter_ protection

diff --git a/tests/test_print_stmt.py b/tests/test_print_stmt.py
@@ -1,19 +1,18 @@
 from RestrictedPython.PrintCollector import PrintCollector
-
-import pytest
+from RestrictedPython._compat import IS_PY2, IS_PY3
 import RestrictedPython
+import pytest
 import six
-import sys
 
 
 pytestmark = pytest.mark.skipif(
-    sys.version_info.major == 3,
+    IS_PY3,
     reason="print statement no longer exists in Python 3")
 
 
 compilers = ('compiler', [RestrictedPython.compile.compile_restricted_exec])
 
-if sys.version_info.major == 2:
+if IS_PY2:
     from RestrictedPython import RCompile
     compilers[1].append(RCompile.compile_restricted_exec)
 

diff --git a/tests/test_transformer.py b/tests/test_transformer.py
@@ -1,18 +1,17 @@
 from RestrictedPython.Guards import guarded_iter_unpack_sequence
 from RestrictedPython.Guards import guarded_unpack_sequence
-
+from RestrictedPython._compat import IS_PY2, IS_PY3
+import RestrictedPython
 import contextlib
 import pytest
-import RestrictedPython
 import six
-import sys
 import types
 
 
 # Define the arguments for @pytest.mark.parametrize to be able to test both the
 # old and the new implementation to be equal:
 compile = ('compile', [RestrictedPython.compile.compile_restricted_exec])
-if sys.version_info < (3,):
+if IS_PY2:
     from RestrictedPython import RCompile
     compile[1].append(RCompile.compile_restricted_exec)
 
@@ -62,7 +61,7 @@ def no_exec():
 """
 
 
-@pytest.mark.skipif(sys.version_info >= (3, 0),
+@pytest.mark.skipif(IS_PY3,
                     reason="exec statement no longer exists in Python 3")
 @pytest.mark.parametrize(*compile)
 def test_transformer__RestrictingNodeTransformer__generic_visit__102(compile):
@@ -72,7 +71,7 @@ def test_transformer__RestrictingNodeTransformer__generic_visit__102(compile):
 
 
 @pytest.mark.skipif(
-    sys.version_info < (3, 0),
+    IS_PY2,
     reason="exec statement in Python 3 raises SyntaxError itself")
 @pytest.mark.parametrize(*compile)
 def test_transformer__RestrictingNodeTransformer__generic_visit__103(compile):
@@ -249,7 +248,7 @@ def test_transformer__RestrictingNodeTransformer__visit_Attribute__7(compile, mo
     assert ret == 2
 
 
-@pytest.mark.skipif(sys.version_info < (3, 0),
+@pytest.mark.skipif(IS_PY2,
                     reason="exec is a statement in Python 2")
 @pytest.mark.parametrize(*compile)
 def test_transformer__RestrictingNodeTransformer__visit_Call__1(compile):
@@ -704,7 +703,7 @@ def test_transformer__RestrictingNodeTransformer__visit_FunctionDef_1(compile):
     assert code is None
     assert errors[0] == err_msg
 
-    if sys.version_info.major == 2:
+    if IS_PY2:
         code, errors = compile("def foo((a, _bad)): pass")[:2]
         assert code is None
         assert errors[0] == err_msg
@@ -715,7 +714,7 @@ def test_transformer__RestrictingNodeTransformer__visit_FunctionDef_1(compile):
             assert code is None
             assert errors[0] == err_msg
 
-    if sys.version_info.major == 3:
+    if IS_PY3:
         code, errors = compile("def foo(good, *, _bad): pass")[:2]
         assert code is None
         assert errors[0] == err_msg
@@ -731,7 +730,7 @@ def nested_with_order((a, b), (c, d)):
 
 
 @pytest.mark.skipif(
-    sys.version_info.major == 3,
+    IS_PY3,
     reason="tuple parameter unpacking is gone in python 3")
 @pytest.mark.parametrize(*compile)
 def test_transformer__RestrictingNodeTransformer__visit_FunctionDef_2(compile, mocker):
@@ -798,7 +797,7 @@ def test_transformer__RestrictingNodeTransformer__visit_Lambda_1(compile):
     assert code is None
     assert errors[0] == err_msg
 
-    if sys.version_info.major == 2:
+    if IS_PY2:
         # The old one did not support tuples at all.
         if compile is RestrictedPython.compile.compile_restricted_exec:
             code, errors = compile("lambda (a, _bad): None")[:2]
@@ -809,14 +808,14 @@ def test_transformer__RestrictingNodeTransformer__visit_Lambda_1(compile):
             assert code is None
             assert errors[0] == err_msg
 
-    if sys.version_info.major == 3:
+    if IS_PY3:
         code, errors = compile("lambda good, *, _bad: None")[:2]
         assert code is None
         assert errors[0] == err_msg
 
 
 @pytest.mark.skipif(
-    sys.version_info.major == 3,
+    IS_PY3,
     reason="tuple parameter unpacking is gone in python 3")
 @pytest.mark.parametrize(*compile)
 def test_transformer__RestrictingNodeTransformer__visit_Lambda_2(compile, mocker):
@@ -870,7 +869,7 @@ def test_transformer__RestrictingNodeTransformer__visit_Assign(compile, mocker):
 
 
 @pytest.mark.skipif(
-    sys.version_info.major == 2,
+    IS_PY2,
     reason="starred assignments are python3 only")
 @pytest.mark.parametrize(*compile)
 def test_transformer__RestrictingNodeTransformer__visit_Assign2(compile, mocker):
@@ -1001,7 +1000,7 @@ def tuple_unpack(err):
 
 
 @pytest.mark.skipif(
-    sys.version_info.major == 3,
+    IS_PY3,
     reason="tuple unpacking on exceptions is gone in python3")
 @pytest.mark.parametrize(*compile)
 def test_transformer__RestrictingNodeTransformer__visit_ExceptHandler(compile, mocker):

diff --git a/tox.ini b/tox.ini
@@ -46,6 +46,11 @@ basepython = python2.7
 deps = isort
 commands = isort --check-only --recursive {toxinidir}/src {posargs}
 
+[testenv:isort-apply]
+basepython = python2.7
+deps = isort
+commands = isort --apply --recursive {toxinidir}/src {posargs}
+
 [testenv:flake8]
 basepython = python2.7
 deps = flake8