Error checking was too aggressive (reported by Chris Tismer)
diff --git a/Lib/collections.py b/Lib/collections.py
index 356d961..e551f20 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -40,7 +40,7 @@
field_names = field_names.replace(',', ' ').split() # names separated by whitespace and/or commas
field_names = tuple(field_names)
for name in (typename,) + field_names:
- if not name.replace('_', '').isalnum():
+ if not all(c.isalnum() or c=='_' for c in name):
raise ValueError('Type names and field names can only contain alphanumeric characters and underscores: %r' % name)
if _iskeyword(name):
raise ValueError('Type names and field names cannot be a keyword: %r' % name)
@@ -48,7 +48,7 @@
raise ValueError('Type names and field names cannot start with a number: %r' % name)
seen_names = set()
for name in field_names:
- if name.startswith('__') and name.endswith('__'):
+ if name.startswith('__') and name.endswith('__') and len(name) > 3:
raise ValueError('Field names cannot start and end with double underscores: %r' % name)
if name in seen_names:
raise ValueError('Encountered duplicate field name: %r' % name)
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 52bae9a..0b0b029 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -29,6 +29,7 @@
self.assertRaises(ValueError, namedtuple, 'abc', 'efg efg ghi') # duplicate field
namedtuple('Point0', 'x1 y2') # Verify that numbers are allowed in names
+ namedtuple('_', '_ __ ___') # Verify that underscores are allowed
def test_instance(self):
Point = namedtuple('Point', 'x y')