Merged in PCManticore/pylint/abc (pull request #90)

Add abstract-class-instantiated warning

9 files changed, 165 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index e20d609..1095347 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -23,6 +23,10 @@ ChangeLog for Pylint
     * Emit 'undefined-all-variable' if a package's __all__
       variable contains a missing submodule (closes #126).
 
+    * Add a new warning 'abstract-class-instantiated' for checking
+      that abstract classes created with `abc` module and
+      with abstract methods are instantied.     
+
 2013-12-22  --  1.1.0
     * Add new check for use of deprecated pragma directives "pylint:disable-msg"
       or "pylint:enable-msg" (I0022, deprecated-pragma) which was previously
diff --git a/DEPENDS b/DEPENDS
index 630cec8..e171ef3 100644
--- a/DEPENDS
+++ b/DEPENDS
@@ -1,3 +1,3 @@
 python-logilab-common (>= 0.19.0)
-python-astroid
+python-astroid (>= 1.0.1)
 python-tk
diff --git a/__pkginfo__.py b/__pkginfo__.py
index eff50aa..8d4d65e 100644
--- a/__pkginfo__.py
+++ b/__pkginfo__.py
@@ -21,7 +21,7 @@ modname = distname = 'pylint'
 numversion = (1, 1, 0)
 version = '.'.join([str(num) for num in numversion])
 
-install_requires = ['logilab-common >= 0.53.0', 'astroid >= 0.24.3']
+install_requires = ['logilab-common >= 0.53.0', 'astroid >= 1.0.1']
 
 license = 'GPL'
 description = "python code static checker"
diff --git a/checkers/base.py b/checkers/base.py
index 55e5f36..6795457 100644
--- a/checkers/base.py
+++ b/checkers/base.py
@@ -19,7 +19,7 @@
 import sys
 import astroid
 from logilab.common.ureports import Table
-from astroid import are_exclusive
+from astroid import are_exclusive, InferenceError
 import astroid.bases
 
 from pylint.interfaces import IAstroidChecker
@@ -101,6 +101,8 @@ if sys.version_info < (3, 0):
     PROPERTY_CLASSES = set(('__builtin__.property', 'abc.abstractproperty'))
 else:
     PROPERTY_CLASSES = set(('builtins.property', 'abc.abstractproperty'))
+ABC_METHODS = set(('abc.abstractproperty', 'abc.abstractmethod',
+                   'abc.abstractclassmethod', 'abc.abstractstaticmethod'))
 
 def _determine_function_name_type(node):
     """Determine the name type whose regex the a function's name should match.
@@ -130,6 +132,25 @@ def _determine_function_name_type(node):
             return 'attr'
     return 'method'
 
+def decorated_with_abc(func):
+    """ Determine if the `func` node is decorated
+    with `abc` decorators (abstractmethod et co.)
+    """
+    if func.decorators:
+        for node in func.decorators.nodes:
+            try:
+                infered = node.infer().next()
+            except InferenceError:
+                continue
+            if infered and infered.qname() in ABC_METHODS:
+                return True
+
+def has_abstract_methods(node):
+    """ Determine if the given `node` has
+    abstract methods, defined with `abc` module.
+    """
+    return any(decorated_with_abc(meth)
+               for meth in node.mymethods())
 
 def report_by_type_stats(sect, stats, old_stats):
     """make a report of
@@ -229,6 +250,11 @@ class BasicErrorChecker(_BasicChecker):
               'duplicate-argument-name',
               'Duplicate argument names in function definitions are syntax'
               ' errors.'),
+    'E0110': ('Abstract class with abstract methods instantiated',
+              'abstract-class-instantiated',
+              'Used when an abstract class with `abc.ABCMeta` as metaclass '
+              'has abstract methods and is instantiated.',
+              {'minversion': (3, 0)}),
     'W0120': ('Else clause on loop without a break statement',
               'useless-else-on-loop',
               'Loops should only have an else clause if they can exit early '
@@ -314,6 +340,34 @@ class BasicErrorChecker(_BasicChecker):
             (node.operand.op == node.op)):
             self.add_message('nonexistent-operator', node=node, args=node.op*2)
 
+    @check_messages('abstract-class-instantiated')
+    def visit_callfunc(self, node):
+        """ Check instantiating abstract class with
+        abc.ABCMeta as metaclass. 
+        """
+        try:
+            infered = node.func.infer().next()
+        except astroid.InferenceError:
+            return
+        if not isinstance(infered, astroid.Class):
+            return
+        # __init__ was called
+        metaclass = infered.metaclass()
+        if metaclass is None:
+            # Python 3.4 has `abc.ABC`, which won't be detected
+            # by ClassNode.metaclass()
+            for ancestor in infered.ancestors():
+                if (ancestor.qname() == 'abc.ABC' and
+                    has_abstract_methods(infered)):
+
+                    self.add_message('abstract-class-instantiated', node=node)
+                    break
+            return
+        if (metaclass.qname() == 'abc.ABCMeta' and
+            has_abstract_methods(infered)):
+
+            self.add_message('abstract-class-instantiated', node=node)
+   
     def _check_else_on_loop(self, node):
         """Check that any loop with an else clause has a break statement."""
         if node.orelse and not _loop_exits_early(node):
diff --git a/debian/control b/debian/control
index ecc265b..313445a 100644
--- a/debian/control
+++ b/debian/control
@@ -19,7 +19,7 @@ Architecture: all
 Depends: ${python:Depends},
          ${misc:Depends},
 	 python-logilab-common (>= 0.53.0),
-	 python-astroid
+	 python-astroid (>= 1.0.1)
 Suggests: python-tk
 XB-Python-Version: ${python:Versions}
 Description: python code static checker and UML diagram generator
diff --git a/test/input/func_abstract_class_instantiated_py30.py b/test/input/func_abstract_class_instantiated_py30.py
new file mode 100644
index 0000000..4bcfd3f
--- /dev/null
+++ b/test/input/func_abstract_class_instantiated_py30.py
@@ -0,0 +1,43 @@
+"""Check that instantiating a class with
+`abc.ABCMeta` as metaclass fails if it defines
+abstract methods.
+"""
+
+# pylint: disable=too-few-public-methods, missing-docstring, abstract-class-not-used
+
+__revision__ = 0
+
+import abc
+

+class GoodClass(object, metaclass=abc.ABCMeta):

+    pass

+

+class SecondGoodClass(object, metaclass=abc.ABCMeta):

+    def test(self):

+        """ do nothing. """

+        pass

+

+class ThirdGoodClass(object, metaclass=abc.ABCMeta):

+    """ This should not raise the warning. """

+    def test(self):

+        raise NotImplementedError()

+

+class BadClass(object, metaclass=abc.ABCMeta):

+    @abc.abstractmethod

+    def test(self):

+        """ do nothing. """

+        pass

+

+class SecondBadClass(object, metaclass=abc.ABCMeta):

+    @property

+    @abc.abstractmethod

+    def test(self):

+        """ do nothing. """

+

+def main():

+    """ do nothing """

+    GoodClass()

+    SecondGoodClass()

+    ThirdGoodClass()

+    BadClass()

+    SecondBadClass()

diff --git a/test/input/func_abstract_class_instantiated_py34.py b/test/input/func_abstract_class_instantiated_py34.py
new file mode 100644
index 0000000..1814f34
--- /dev/null
+++ b/test/input/func_abstract_class_instantiated_py34.py
@@ -0,0 +1,55 @@
+"""Check that instantiating a class with
+`abc.ABCMeta` as metaclass fails if it defines
+abstract methods.
+"""
+
+# pylint: disable=too-few-public-methods, missing-docstring, abstract-class-not-used, no-init
+
+__revision__ = 0
+
+import abc
+

+class GoodClass(object, metaclass=abc.ABCMeta):

+    pass

+

+class SecondGoodClass(object, metaclass=abc.ABCMeta):

+    def test(self):

+        """ do nothing. """

+        pass

+

+class ThirdGoodClass(object, metaclass=abc.ABCMeta):

+    """ This should not raise the warning. """

+    def test(self):

+        raise NotImplementedError()

+

+class FourthGoodClass(abc.ABC):

+    """ Neither this. """

+    def test(self):

+        pass

+

+class BadClass(object, metaclass=abc.ABCMeta):

+    @abc.abstractmethod

+    def test(self):

+        """ do nothing. """

+        pass

+

+class SecondBadClass(object, metaclass=abc.ABCMeta):

+    @property

+    @abc.abstractmethod

+    def test(self):

+        """ do nothing. """

+

+class ThirdBadClass(abc.ABC):

+    @abc.abstractmethod

+    def test(self):

+        pass

+

+def main():

+    """ do nothing """

+    GoodClass()

+    SecondGoodClass()

+    ThirdGoodClass()

+    FourthGoodClass()

+    BadClass()

+    SecondBadClass()

+    ThirdBadClass()

diff --git a/test/messages/func_abstract_class_instantiated_py30.txt b/test/messages/func_abstract_class_instantiated_py30.txt
new file mode 100644
index 0000000..28dc11e
--- /dev/null
+++ b/test/messages/func_abstract_class_instantiated_py30.txt
@@ -0,0 +1,2 @@
+E: 42:main: Abstract class with abstract methods instantiated

+E: 43:main: Abstract class with abstract methods instantiated
\ No newline at end of file
diff --git a/test/messages/func_abstract_class_instantiated_py34.txt b/test/messages/func_abstract_class_instantiated_py34.txt
new file mode 100644
index 0000000..310f8ea
--- /dev/null
+++ b/test/messages/func_abstract_class_instantiated_py34.txt
@@ -0,0 +1,3 @@
+E: 53:main: Abstract class with abstract methods instantiated

+E: 54:main: Abstract class with abstract methods instantiated

+E: 55:main: Abstract class with abstract methods instantiated
\ No newline at end of file