Don't consider a class abstract if its members can't be properly inferred.

This fixes a false positive related to abstract-class-instantiated.
Closes issue #648.

6 files changed, 55 insertions, 14 deletions

diff --git a/ChangeLog b/ChangeLog
index abd0ad3..30365f2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -303,6 +303,12 @@ ChangeLog for Pylint
     * 'deprecated-module' can be shown for modules which aren't
        available. Closes issue #362.
 
+    * Don't consider a class abstract if its members can't
+      be properly inferred.
+
+      This fixes a false positive related to abstract-class-instantiated.
+      Closes issue #648.
+
 
 
 2015-03-14 -- 1.4.3
diff --git a/pylint/checkers/utils.py b/pylint/checkers/utils.py
index 767bba8..dda5f44 100644
--- a/pylint/checkers/utils.py
+++ b/pylint/checkers/utils.py
@@ -524,6 +524,12 @@ def unimplemented_abstract_methods(node, is_abstract_cb=None):
             if isinstance(obj, astroid.AssignName):
                 infered = safe_infer(obj)
                 if not infered:
+                    # Might be an abstract function,
+                    # but since we don't have enough information
+                    # in order to take this decision, we're taking
+                    # the *safe* decision instead.
+                    if obj.name in visited:
+                        del visited[obj.name]
                     continue
                 if not isinstance(infered, astroid.FunctionDef):
                     if obj.name in visited:
diff --git a/pylint/test/functional/abstract_class_instantiated_py2.py b/pylint/test/functional/abstract_class_instantiated_py2.py
index 9b3f315..d30c1a5 100644
--- a/pylint/test/functional/abstract_class_instantiated_py2.py
+++ b/pylint/test/functional/abstract_class_instantiated_py2.py
@@ -5,12 +5,12 @@ abstract methods.
 
 # pylint: disable=too-few-public-methods, missing-docstring
 # pylint: disable=no-absolute-import, metaclass-assignment
-# pylint: disable=abstract-method
-
-__revision__ = 0
+# pylint: disable=abstract-method, import-error, wildcard-import
 
 import abc
 from abc import ABCMeta
+from lala import Bala
+
 
 class GoodClass(object):
     __metaclass__ = abc.ABCMeta
@@ -56,6 +56,20 @@ class FourthBadClass(ThirdBadClass):
     pass
 
 
+class SomeMetaclass(object):
+    __metaclass__ = ABCMeta
+
+    @abc.abstractmethod
+    def prop(self):
+        pass
+
+class FifthGoodClass(SomeMetaclass):
+    """Don't consider this abstract if some attributes are
+    there, but can't be inferred.
+    """
+    prop = Bala # missing
+
+
 def main():
     """ do nothing """
     GoodClass()
@@ -66,3 +80,4 @@ def main():
     SecondBadClass() # [abstract-class-instantiated]
     ThirdBadClass() # [abstract-class-instantiated]
     FourthBadClass() # [abstract-class-instantiated]
+
diff --git a/pylint/test/functional/abstract_class_instantiated_py2.txt b/pylint/test/functional/abstract_class_instantiated_py2.txt
index 68e7eb5..1e4a72d 100644
--- a/pylint/test/functional/abstract_class_instantiated_py2.txt
+++ b/pylint/test/functional/abstract_class_instantiated_py2.txt
@@ -1,4 +1,4 @@
-abstract-class-instantiated:65:main:Abstract class 'BadClass' with abstract methods instantiated

-abstract-class-instantiated:66:main:Abstract class 'SecondBadClass' with abstract methods instantiated

-abstract-class-instantiated:67:main:Abstract class 'ThirdBadClass' with abstract methods instantiated

-abstract-class-instantiated:68:main:Abstract class 'FourthBadClass' with abstract methods instantiated

+abstract-class-instantiated:79:main:Abstract class 'BadClass' with abstract methods instantiated

+abstract-class-instantiated:80:main:Abstract class 'SecondBadClass' with abstract methods instantiated

+abstract-class-instantiated:81:main:Abstract class 'ThirdBadClass' with abstract methods instantiated

+abstract-class-instantiated:82:main:Abstract class 'FourthBadClass' with abstract methods instantiated

diff --git a/pylint/test/functional/abstract_class_instantiated_py3.py b/pylint/test/functional/abstract_class_instantiated_py3.py
index 0b2dd4a..f373189 100644
--- a/pylint/test/functional/abstract_class_instantiated_py3.py
+++ b/pylint/test/functional/abstract_class_instantiated_py3.py
@@ -4,12 +4,12 @@ abstract methods.
 """
 
 # pylint: disable=too-few-public-methods, missing-docstring
-# pylint: disable=abstract-method
-
-__revision__ = 0
+# pylint: disable=abstract-method, import-error
 
 import abc
 import weakref
+from lala import Bala
+
 
 class GoodClass(object, metaclass=abc.ABCMeta):
     pass
@@ -82,11 +82,25 @@ class NoMroAbstractMethods(Container, Iterator, Sizable, Hashable):
 class BadMroAbstractMethods(Container, Iterator, AbstractSizable):
     pass
 
+class SomeMetaclass(metaclass=abc.ABCMeta):
+
+    @abc.abstractmethod
+    def prop(self):
+        pass
+
+class FourthGoodClass(SomeMetaclass):
+    """Don't consider this abstract if some attributes are
+    there, but can't be inferred.
+    """
+    prop = Bala # missing
+
+
 def main():
     """ do nothing """
     GoodClass()
     SecondGoodClass()
     ThirdGoodClass()
+    FourthGoodClass()
     weakref.WeakKeyDictionary()
     weakref.WeakValueDictionary()
     NoMroAbstractMethods()
diff --git a/pylint/test/functional/abstract_class_instantiated_py3.txt b/pylint/test/functional/abstract_class_instantiated_py3.txt
index 6469929..629eec7 100644
--- a/pylint/test/functional/abstract_class_instantiated_py3.txt
+++ b/pylint/test/functional/abstract_class_instantiated_py3.txt
@@ -1,4 +1,4 @@
-abstract-class-instantiated:94:main:Abstract class 'BadMroAbstractMethods' with abstract methods instantiated

-abstract-class-instantiated:95:main:Abstract class 'BadClass' with abstract methods instantiated

-abstract-class-instantiated:96:main:Abstract class 'SecondBadClass' with abstract methods instantiated

-abstract-class-instantiated:97:main:Abstract class 'ThirdBadClass' with abstract methods instantiated

+abstract-class-instantiated:108:main:Abstract class 'BadMroAbstractMethods' with abstract methods instantiated

+abstract-class-instantiated:109:main:Abstract class 'BadClass' with abstract methods instantiated

+abstract-class-instantiated:110:main:Abstract class 'SecondBadClass' with abstract methods instantiated

+abstract-class-instantiated:111:main:Abstract class 'ThirdBadClass' with abstract methods instantiated