checker.py: Report undefined names in __all__

This allows pyflakes to report undefined names
in __all__ when import * is used, without having
to use pyflakes 2 times to detect the errors.

Fixes https://github.com/PyCQA/pyflakes/issues/280

2 files changed, 12 insertions, 4 deletions

diff --git a/pyflakes/checker.py b/pyflakes/checker.py
index 756b77e..9937685 100644
--- a/pyflakes/checker.py
+++ b/pyflakes/checker.py
@@ -665,9 +665,16 @@ class Checker(object):
 
                 # mark all import '*' as used by the undefined in __all__
                 if scope.importStarred:
+                    from_list = []
                     for binding in scope.values():
                         if isinstance(binding, StarImportation):
                             binding.used = all_binding
+                            from_list.append(binding.fullName)
+                    # report * usage, with a list of possible sources
+                    from_list = ', '.join(sorted(from_list))
+                    for name in undefined:
+                        self.report(messages.ImportStarUsage,
+                                    scope['__all__'].source, name, from_list)
 
             # Look for imported names that aren't used.
             for value in scope.values():
diff --git a/pyflakes/test/test_imports.py b/pyflakes/test/test_imports.py
index 4272186..193f9d3 100644
--- a/pyflakes/test/test_imports.py
+++ b/pyflakes/test/test_imports.py
@@ -1110,12 +1110,13 @@ class TestSpecialAll(TestCase):
 
     def test_importStarExported(self):
         """
-        Do not report undefined if import * is used
+        Report undefined if import * is used
         """
         self.flakes('''
-        from foolib import *
-        __all__ = ["foo"]
-        ''', m.ImportStarUsed)
+        from math import *
+        __all__ = ['sin', 'cos']
+        csc(1)
+        ''', m.ImportStarUsed, m.ImportStarUsage, m.ImportStarUsage, m.ImportStarUsage)
 
     def test_importStarNotExported(self):
         """Report unused import when not needed to satisfy __all__."""