The logical checks can return None; issue #250

2 files changed, 6 insertions, 3 deletions

diff --git a/CHANGES.txt b/CHANGES.txt
index 034cc7f..96d879a 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -20,6 +20,9 @@ Changelog
 * Fix behaviour when ``exclude`` is in the configuration file and
   the current directory is not the project directory. (Issue #247)
 
+* The logical checks can return ``None`` instead of an empty iterator.
+  (Issue #250)
+
 
 1.4.6 (2013-07-02)
 ------------------
diff --git a/pep8.py b/pep8.py
index 695add2..215bde2 100755
--- a/pep8.py
+++ b/pep8.py
@@ -1345,10 +1345,10 @@ class Checker(object):
         for name, check, argument_names in self._logical_checks:
             if self.verbose >= 4:
                 print('   ' + name)
-            for result in self.run_check(check, argument_names):
-                offset, text = result
+            for result in self.run_check(check, argument_names) or ():
+                (offset, text) = result
                 if isinstance(offset, tuple):
-                    orig_number, orig_offset = offset
+                    (orig_number, orig_offset) = offset
                 else:
                     for token_offset, token in self.mapping:
                         if offset >= token_offset: