Fix no-context-manager test breakage in due to astroid changes

Require no-context-manager to infer paths before walking the tree

Fixes #1874

1 files changed, 16 insertions, 2 deletions

diff --git a/pylint/checkers/typecheck.py b/pylint/checkers/typecheck.py
index 9df65a5de..9d338be84 100644
--- a/pylint/checkers/typecheck.py
+++ b/pylint/checkers/typecheck.py
@@ -36,6 +36,7 @@ import operator
 import re
 import shlex
 import sys
+import types
 
 import six
 
@@ -81,6 +82,15 @@ def _unflatten(iterable):
             # We're interested only in the first element.
             yield elem
 
+def _flatten_container(iterable):
+    # Flatten nested containers into a single iterable
+    for item in iterable:
+        if isinstance(item, (list, tuple, types.GeneratorType)):
+            for elem in _flatten_container(item):
+                yield elem
+        else:
+            yield item
+
 
 def _is_owner_ignored(owner, name, ignored_classes, ignored_modules):
     """Check if the given owner should be ignored
@@ -1143,8 +1153,12 @@ accessed. Python regular expressions are accepted.'}
                 # manager and give up, otherwise emit not-context-manager.
                 # See the test file for not_context_manager for a couple
                 # of self explaining tests.
-                for path in six.moves.filter(None, _unflatten(context.path)):
-                    scope = path.scope()
+
+                # Retrieve node from all previusly visited nodes in the the inference history
+                context_path_names = filter(None, _unflatten(context.path))
+                inferred_paths = _flatten_container(path.infer() for path in context_path_names)
+                for inf_path in inferred_paths:
+                    scope = inf_path.scope()
                     if not isinstance(scope, astroid.FunctionDef):
                         continue
                     if decorated_with(scope,