Patch #943206:

`glob.glob()` currently calls itself recursively to build a list of matches of
the dirname part of the pattern and then filters by the basename part. This is
effectively BFS. ``glob.glob('*/*/*/*/*/foo')`` will build a huge list of all
directories 5 levels deep even if only a handful of them contain a ``foo``
entry. A generator-based recusion would never have to store these list at once
by implementing DFS. This patch converts the `glob` function to an `iglob`
recursive generator . `glob()` now just returns ``list(iglob(pattern))``.

I also cleaned up the code a bit (reduced duplicate `has_magic()` checks and
created a second `glob0` helper func so that the main loop need not be
duplicated).

Thanks to Cherniavsky Beni for the patch!

Lib/test/test_glob.py

@@ -61,7 +61,9 @@ class GlobTests(unittest.TestCase):
         else:
             pattern = os.path.join(*parts)
         p = os.path.join(self.tempdir, pattern)
-        return glob.glob(p)
+        res = glob.glob(p)
+        self.assertEqual(list(glob.iglob(p)), res)
+        return res
 
     def assertSequencesEqual_noorder(self, l1, l2):
         self.assertEqual(set(l1), set(l2))