Emit a warning when sys.exc_clear is accessed

4 files changed, 23 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 758967329..79631acad 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,6 +8,8 @@ What's New in Pylint 1.9.0?
 
 Release date:
 
+    * Added a new `deprecated-sys-function`, emitted when accessing removed sys members.
+
     * Added `xreadlines-attribute`, emitted when the `xreadlines()` attribute is accessed.
 
     * The Python 3 porting mode can now run with Python 3 as well.
diff --git a/doc/whatsnew/1.9.rst b/doc/whatsnew/1.9.rst
index f9e60111f..a15658dd4 100644
--- a/doc/whatsnew/1.9.rst
+++ b/doc/whatsnew/1.9.rst
@@ -45,6 +45,11 @@ New checkers
 
       a = ur'...'
 
+* Added a new `deprecated-sys-function`, emitted when accessing removed `sys` members.
+
+* Added `xreadlines-attribute`, emitted when the `xreadlines()` attribute is accessed
+  on a file object.
+
 
 Other Changes
 =============
diff --git a/pylint/checkers/python3.py b/pylint/checkers/python3.py
index b9e1e299e..111d9bde9 100644
--- a/pylint/checkers/python3.py
+++ b/pylint/checkers/python3.py
@@ -409,6 +409,10 @@ class Python3Checker(checkers.BaseChecker):
                   'xreadlines-attribute',
                   'Used when accessing the xreadlines() function on a file stream, '
                   'removed in Python 3.',),
+        'W1660': ('Accessing a removed attribute on the sys module',
+                  'deprecated-sys-function',
+                  'Used when accessing a field on sys module that has been '
+                  'removed in Python 3.',),
     }
 
     _bad_builtins = frozenset([
@@ -526,6 +530,9 @@ class Python3Checker(checkers.BaseChecker):
                 'urlopen', 'urlretrieve'
             }),
         },
+        'deprecated-sys-function': {
+            'sys': frozenset({'exc_clear'}),
+        }
     }
 
     if (3, 4) <= sys.version_info < (3, 4, 4):
diff --git a/pylint/test/unittest_checker_python3.py b/pylint/test/unittest_checker_python3.py
index c5800f493..6f8b57944 100644
--- a/pylint/test/unittest_checker_python3.py
+++ b/pylint/test/unittest_checker_python3.py
@@ -717,6 +717,15 @@ class TestPython3Checker(testutils.CheckerTestCase):
         with self.assertAddsMessages(message):
             self.checker.visit_attribute(node)
 
+    def test_bad_sys_attribute(self):
+        node = astroid.extract_node('''
+        import sys
+        sys.exc_clear #@
+        ''')
+        message = testutils.Message('deprecated-sys-function', node=node)
+        with self.assertAddsMessages(message):
+            self.checker.visit_attribute(node)
+
     def test_bad_urllib_attribute(self):
         nodes = astroid.extract_node('''
         import urllib