pylint: upgrade to 1.4.1

third_party/pylint/checkers/stdlib.py

 # Copyright 2012 Google Inc.
 #
 # http://www.logilab.fr/ -- mailto:contact@logilab.fr
 # This program is free software; you can redistribute it and/or modify it under
 # the terms of the GNU General Public License as published by the Free Software
 # Foundation; either version 2 of the License, or (at your option) any later
 # version.
 #
 # This program is distributed in the hope that it will be useful, but WITHOUT
 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 # FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details
 #
 # You should have received a copy of the GNU General Public License along with
 # this program; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 """Checkers for various standard library functions."""
 
 import re
+import six
 import sys
 
 import astroid
 from astroid.bases import Instance
 
 from pylint.interfaces import IAstroidChecker
 from pylint.checkers import BaseChecker
 from pylint.checkers import utils
 
-_VALID_OPEN_MODE_REGEX = re.compile(r'^(r?U|[rwa]\+?b?)$')
 
 if sys.version_info >= (3, 0):
     OPEN_MODULE = '_io'
 else:
     OPEN_MODULE = '__builtin__'
 
+
+def _check_mode_str(mode):
+    # check type
+    if not isinstance(mode, six.string_types):
+        return False
+    # check syntax
+    modes = set(mode)
+    _mode = "rwatb+U"
+    creating = False
+    if six.PY3:
+        _mode += "x"
+        creating = "x" in modes
+    if modes - set(_mode) or len(mode) > len(modes):
+        return False
+    # check logic
+    reading = "r" in modes
+    writing = "w" in modes
+    appending = "a" in modes
+    updating = "+" in modes
+    text = "t" in modes
+    binary = "b" in modes
+    if "U" in modes:
+        if writing or appending or creating and six.PY3:
+            return False
+        reading = True
+        if not six.PY3:
+            binary = True
+    if text and binary:
+        return False
+    total = reading + writing + appending + (creating if six.PY3 else 0)
+    if total > 1:
+        return False
+    if not (reading or writing or appending or creating and six.PY3):
+        return False
+    # other 2.x constraints
+    if not six.PY3:
+        if "U" in mode:
+            mode = mode.replace("U", "")
+            if "r" not in mode:
+                mode = "r" + mode
+        return mode[0] in ("r", "w", "a", "U")
+    return True
+
+
 class StdlibChecker(BaseChecker):
     __implements__ = (IAstroidChecker,)
     name = 'stdlib'
 
     msgs = {
         'W1501': ('"%s" is not a valid mode for open.',
                   'bad-open-mode',
-                  'Python supports: r, w, a modes with b, +, and U options. '
+                  'Python supports: r, w, a[, x] modes with b, +, '
+                  'and U (only with r) options. '
                   'See http://docs.python.org/2/library/functions.html#open'),
         'W1502': ('Using datetime.time in a boolean context.',
                   'boolean-datetime',
                   'Using datetetime.time in a boolean context can hide '
                   'subtle bugs when the time they represent matches '
                   'midnight UTC. This behaviour was fixed in Python 3.5. '
                   'See http://bugs.python.org/issue13936 for reference.',
                   {'maxversion': (3, 5)}),
-        }
+        'W1503': ('Redundant use of %s with constant '
+                  'value %r',
+                  'redundant-unittest-assert',
+                  'The first argument of assertTrue and assertFalse is'
+                  'a condition. If a constant is passed as parameter, that'
+                  'condition will be always true. In this case a warning '
+                  'should be emitted.')
+    }
 
-    @utils.check_messages('bad-open-mode')
+    @utils.check_messages('bad-open-mode', 'redundant-unittest-assert')
     def visit_callfunc(self, node):
         """Visit a CallFunc node."""
         if hasattr(node, 'func'):
             infer = utils.safe_infer(node.func)
-            if infer and infer.root().name == OPEN_MODULE:
-                if getattr(node.func, 'name', None) in ('open', 'file'):
-                    self._check_open_mode(node)
+            if infer:
+                if infer.root().name == OPEN_MODULE:
+                    if getattr(node.func, 'name', None) in ('open', 'file'):
+                        self._check_open_mode(node)
+                if infer.root().name == 'unittest.case':
+                    self._check_redundant_assert(node, infer)
 
     @utils.check_messages('boolean-datetime')
     def visit_unaryop(self, node):
         if node.op == 'not':
             self._check_datetime(node.operand)
 
     @utils.check_messages('boolean-datetime')
     def visit_if(self, node):
         self._check_datetime(node.test)
 
     @utils.check_messages('boolean-datetime')
     def visit_ifexp(self, node):
         self._check_datetime(node.test)
 
     @utils.check_messages('boolean-datetime')
     def visit_boolop(self, node):
         for value in node.values:
             self._check_datetime(value)
 
+    def _check_redundant_assert(self, node, infer):
+        if (isinstance(infer, astroid.BoundMethod) and
+                node.args and isinstance(node.args[0], astroid.Const) and
+                infer.name in ['assertTrue', 'assertFalse']):
+            self.add_message('redundant-unittest-assert',
+                             args=(infer.name, node.args[0].value, ),
+                             node=node)
+
     def _check_datetime(self, node):
         """ Check that a datetime was infered.
         If so, emit boolean-datetime warning.
         """
         try:
             infered = next(node.infer())
         except astroid.InferenceError:
             return
         if (isinstance(infered, Instance) and
                 infered.qname() == 'datetime.time'):
             self.add_message('boolean-datetime', node=node)
 
+
     def _check_open_mode(self, node):
         """Check that the mode argument of an open or file call is valid."""
         try:
-            mode_arg = utils.get_argument_from_call(node, position=1, keyword='mode')
-            if mode_arg:
-                mode_arg = utils.safe_infer(mode_arg)
-                if (isinstance(mode_arg, astroid.Const)
-                        and not _VALID_OPEN_MODE_REGEX.match(mode_arg.value)):
-                    self.add_message('bad-open-mode', node=node,
-                                     args=(mode_arg.value))
-        except (utils.NoSuchArgumentError, TypeError):
-            pass
+            mode_arg = utils.get_argument_from_call(node, position=1,
+                                                    keyword='mode')
+        except utils.NoSuchArgumentError:
+            return
+        if mode_arg:
+            mode_arg = utils.safe_infer(mode_arg)
+            if (isinstance(mode_arg, astroid.Const)
+                    and not _check_mode_str(mode_arg.value)):
+                self.add_message('bad-open-mode', node=node,
+                                 args=mode_arg.value)
+
 
 def register(linter):
     """required method to auto register this checker """
     linter.register_checker(StdlibChecker(linter))
-