Issue #17941: Add a *module* parameter to collections.namedtuple()

rhettinger · rhettinger · commit 0d5048cb21e4 · 2016-09-12T00:18:31.000-07:00
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
@@ -763,7 +763,7 @@ Named tuples assign meaning to each position in a tuple and allow for more reada
 self-documenting code.  They can be used wherever regular tuples are used, and
 they add the ability to access fields by name instead of position index.
 
-.. function:: namedtuple(typename, field_names, *, verbose=False, rename=False)
+.. function:: namedtuple(typename, field_names, *, verbose=False, rename=False, module=None)
 
     Returns a new tuple subclass named *typename*.  The new subclass is used to
     create tuple-like objects that have fields accessible by attribute lookup as
@@ -790,6 +790,9 @@ they add the ability to access fields by name instead of position index.
     built.  This option is outdated; instead, it is simpler to print the
     :attr:`_source` attribute.
 
+    If *module* is defined, the ``__module__`` attribute of the named tuple is
+    set to that value.
+
     Named tuple instances do not have per-instance dictionaries, so they are
     lightweight and require no more memory than regular tuples.
 
@@ -800,6 +803,8 @@ they add the ability to access fields by name instead of position index.
        The *verbose* and *rename* parameters became
        :ref:`keyword-only arguments <keyword-only_parameter>`.
 
+    .. versionchanged:: 3.6
+       Added the *module* parameter.
 
 .. doctest::
     :options: +NORMALIZE_WHITESPACE
diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
@@ -353,7 +353,7 @@ def __getnewargs__(self):
     {name} = _property(_itemgetter({index:d}), doc='Alias for field number {index:d}')
 '''
 
-def namedtuple(typename, field_names, *, verbose=False, rename=False):
+def namedtuple(typename, field_names, *, verbose=False, rename=False, module=None):
     """Returns a new subclass of tuple with named fields.
 
     >>> Point = namedtuple('Point', ['x', 'y'])
@@ -434,11 +434,15 @@ def namedtuple(typename, field_names, *, verbose=False, rename=False):
     # For pickling to work, the __module__ variable needs to be set to the frame
     # where the named tuple is created.  Bypass this step in environments where
     # sys._getframe is not defined (Jython for example) or sys._getframe is not
-    # defined for arguments greater than 0 (IronPython).
-    try:
-        result.__module__ = _sys._getframe(1).f_globals.get('__name__', '__main__')
-    except (AttributeError, ValueError):
-        pass
+    # defined for arguments greater than 0 (IronPython), or where the user has
+    # specified a particular module.
+    if module is None:
+        try:
+            module = _sys._getframe(1).f_globals.get('__name__', '__main__')
+        except (AttributeError, ValueError):
+            pass
+    if module is not None:
+        result.__module__ = module
 
     return result
 
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
@@ -242,6 +242,10 @@ def test_name_fixer(self):
         ]:
             self.assertEqual(namedtuple('NT', spec, rename=True)._fields, renamed)
 
+    def test_module_parameter(self):
+        NT = namedtuple('NT', ['x', 'y'], module=collections)
+        self.assertEqual(NT.__module__, collections)
+
     def test_instance(self):
         Point = namedtuple('Point', 'x y')
         p = Point(11, 22)
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -159,6 +159,8 @@ Library
 - Issue #10740: sqlite3 no longer implicitly commit an open transaction
   before DDL statements.
 
+- Issue #17941: Add a *module* parameter to collections.namedtuple().
+
 - Issue #22493: Inline flags now should be used only at the start of the
   regular expression.  Deprecation warning is emitted if uses them in the
   middle of the regular expression.
