Merged in PCManticore/pylint/metaclass_undefined (pull request #111)

Emit 'undefined-variable' for undefined names used as metaclasses with Python 3 `metaclass=` syntax.

5 files changed, 28 insertions, 7 deletions

diff --git a/ChangeLog b/ChangeLog
index 35e4753..2d2006a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -46,6 +46,9 @@ ChangeLog for Pylint
     * Definition order is considered for classes, function arguments
       and annotations. Closes issue #257.
 
+    * Don't emit 'unused-variable' when assigning to a nonlocal.
+      Closes issue #275.
+
 2014-04-30  --  1.2.1
     * Restore the ability to specify the init-hook option via the
       configuration file, which was accidentally broken in 1.2.0.
diff --git a/checkers/__init__.py b/checkers/__init__.py
index af7965b..693a5ff 100644
--- a/checkers/__init__.py
+++ b/checkers/__init__.py
@@ -42,7 +42,6 @@ import sys
 import tokenize
 import warnings
 
-from astroid.utils import ASTWalker
 from logilab.common.configuration import OptionsProviderMixIn
 
 from pylint.reporters import diff_string
@@ -69,7 +68,7 @@ def table_lines_from_stats(stats, old_stats, columns):
     return lines
 
 
-class BaseChecker(OptionsProviderMixIn, ASTWalker):
+class BaseChecker(OptionsProviderMixIn):
     """base class for checkers"""
     # checker name (you may reuse an existing one)
     name = None
@@ -87,7 +86,6 @@ class BaseChecker(OptionsProviderMixIn, ASTWalker):
 
         linter is an object implementing ILinter
         """
-        ASTWalker.__init__(self, self)
         self.name = self.name.lower()
         OptionsProviderMixIn.__init__(self)
         self.linter = linter
diff --git a/checkers/strings.py b/checkers/strings.py
index 4fe16dd..ad63580 100644
--- a/checkers/strings.py
+++ b/checkers/strings.py
@@ -327,10 +327,10 @@ class StringMethodsChecker(BaseChecker):
             self.add_message('bad-format-string', node=node)
             return
 
-        manual_fields = {field[0] for field in fields
-                         if isinstance(field[0], int)}
-        named_fields = {field[0] for field in fields
-                        if isinstance(field[0], str)}
+        manual_fields = set(field[0] for field in fields
+                            if isinstance(field[0], int))
+        named_fields = set(field[0] for field in fields
+                           if isinstance(field[0], str))
         if manual_fields and num_args:
             self.add_message('format-combined-specification',
                              node=node)
diff --git a/checkers/variables.py b/checkers/variables.py
index aa63177..8f8ee87 100644
--- a/checkers/variables.py
+++ b/checkers/variables.py
@@ -422,8 +422,11 @@ builtins. Remember that you should avoid to define new builtins when possible.'
         called_overridden = False
         argnames = node.argnames()
         global_names = set()
+        nonlocal_names = set()
         for global_stmt in node.nodes_of_class(astroid.Global):
             global_names.update(set(global_stmt.names))
+        for nonlocal_stmt in node.nodes_of_class(astroid.Nonlocal):
+            nonlocal_names.update(set(nonlocal_stmt.names))
 
         for name, stmts in not_consumed.iteritems():
             # ignore some special names specified by user configuration
@@ -470,6 +473,9 @@ builtins. Remember that you should avoid to define new builtins when possible.'
                     continue
                 self.add_message('unused-argument', args=name, node=stmt)
             else:
+                if stmt.parent and isinstance(stmt.parent, astroid.Assign):
+                    if name in nonlocal_names:
+                        continue
                 self.add_message('unused-variable', args=name, node=stmt)
 
     @check_messages('global-variable-undefined', 'global-variable-not-assigned', 'global-statement',
diff --git a/test/input/func_noerror_unused_variable_py30.py b/test/input/func_noerror_unused_variable_py30.py
new file mode 100644
index 0000000..ffcc978
--- /dev/null
+++ b/test/input/func_noerror_unused_variable_py30.py
@@ -0,0 +1,14 @@
+""" Test nonlocal uses and unused-variable. """
+
+__revision__ = 1
+
+def test_nonlocal():
+    """ Test that assigning to a nonlocal does not trigger
+    an 'unused-variable' warnings.
+    """
+    attr = True
+    def set_value(val):
+        """ Set the value in a nonlocal. """
+        nonlocal attr
+        attr = val
+    return set_value