Add preliminary Python 3.8 support.

.travis.yml

@@ -25,7 +25,6 @@ matrix:
           env: TOXENV=py38,py38-datetime
           dist: xenial
           sudo: true
-    allow_failures:
         - python: "3.8-dev"
           env: TOXENV=py38,py38-datetime
 

docs/CHANGES.rst

@@ -4,7 +4,9 @@ Changes
 4.0b8 (unreleased)
 ------------------
 
-- Nothing changed yet.
+- Add preliminary support for Python 3.8. as of 3.8.0a1 is released.
+
+- Allow the ``...`` (Ellipsis) statement. It is needed to support Python 3.8.
 
 
 4.0b7 (2018-10-30)

setup.py

@@ -53,6 +53,7 @@ def read(*rnames):
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: Implementation :: CPython',
         'Topic :: Security',
     ],

src/RestrictedPython/_compat.py

@@ -9,6 +9,7 @@
 IS_PY35_OR_GREATER = _version.major == 3 and _version.minor >= 5
 IS_PY36_OR_GREATER = _version.major == 3 and _version.minor >= 6
 IS_PY37_OR_GREATER = _version.major == 3 and _version.minor >= 7
+IS_PY38_OR_GREATER = _version.major == 3 and _version.minor >= 8
 
 if IS_PY2:
     basestring = basestring  # NOQA: F821  # Python 2 only built-in function

src/RestrictedPython/transformer.py

@@ -537,17 +537,24 @@ def node_contents_visit(self, node):
     # ast for Literals
 
     def visit_Num(self, node):
-        """Allow integer numbers without restrictions."""
+        """Allow integer numbers without restrictions.
+
+        Replaced by Constant in Python 3.8.
+        """
         return self.node_contents_visit(node)
 
     def visit_Str(self, node):
-        """Allow string literals without restrictions."""
+        """Allow string literals without restrictions.
+
+        Replaced by Constant in Python 3.8.
+        """
         return self.node_contents_visit(node)
 
     def visit_Bytes(self, node):
         """Allow bytes literals without restrictions.
 
         Bytes is Python 3 only.
+        Replaced by Constant in Python 3.8.
         """
         return self.node_contents_visit(node)
 
@@ -567,16 +574,27 @@ def visit_Dict(self, node):
         """Allow dict literals without restrictions."""
         return self.node_contents_visit(node)
 
+    def visit_Constant(self, node):
+        """Allow constant literals without restrictions.
+
+        Constant replaces Num, Str, Bytes, NameConstant and Ellipsis in
+        Python 3.8+.
+        :see: https://docs.python.org/dev/whatsnew/3.8.html#deprecated
+        """
+        return self.node_contents_visit(node)
+
     def visit_Ellipsis(self, node):
-        """Deny using `...`.
+        """Allow using `...`.
 
         Ellipsis is exists only in Python 3.
+        Replaced by Constant in Python 3.8.
         """
-        self.not_allowed(node)
+        return self.node_contents_visit(node)
 
     def visit_NameConstant(self, node):
-        """
+        """Allow constant literals (True, False, None) without restrictions.
 
+        Replaced by Constant in Python 3.8.
         """
         return self.node_contents_visit(node)
 

tests/test_compile.py

@@ -2,6 +2,7 @@
 from RestrictedPython import CompileResult
 from RestrictedPython._compat import IS_PY2
 from RestrictedPython._compat import IS_PY3
+from RestrictedPython._compat import IS_PY38_OR_GREATER
 from tests import c_eval
 from tests import c_exec
 from tests import c_single
@@ -39,7 +40,10 @@ def test_compile__compile_restricted_invalid_mode_input():
 def test_compile__invalid_syntax():
     with pytest.raises(SyntaxError) as err:
         compile_restricted(INVALID_ASSINGMENT, '<string>', 'exec')
-    assert "can't assign to literal at statement:" in str(err.value)
+    if IS_PY38_OR_GREATER:
+        assert "cannot assign to literal at statement:" in str(err.value)
+    else:
+        assert "can't assign to literal at statement:" in str(err.value)
 
 
 @pytest.mark.parametrize(*c_exec)

tests/transformer/test_base_types.py

@@ -1,5 +1,4 @@
 from RestrictedPython._compat import IS_PY2
-from tests import c_exec
 from tests import e_eval
 
 import pytest
@@ -25,8 +24,7 @@ def test_Set(e_eval):
 
 @pytest.mark.skipif(IS_PY2,
                     reason="... is new in Python 3")
-@pytest.mark.parametrize(*c_exec)
-def test_Ellipsis(c_exec):
-    """It prevents using the `ellipsis` statement."""
-    result = c_exec('...')
-    assert result.errors == ('Line 1: Ellipsis statements are not allowed.',)
+@pytest.mark.parametrize(*e_eval)
+def test_Ellipsis(e_eval):
+    """It allows using the `...` statement."""
+    assert e_eval('...') == Ellipsis

tox.ini

@@ -5,6 +5,7 @@ envlist =
     py36,
     py36-datetime,
     py37,
+    py38,
 #    pypy,
 #    pypy3,
     docs,