[Python-checkins] bpo-35614: Fix pydoc help() on metaclasses (#11357)

[Nick Coghlan]

https://github.com/python/cpython/commit/b539cef31c060c7eecc331d25a23b80ded0baf08
commit: b539cef31c060c7eecc331d25a23b80ded0baf08
branch: master
author: Sanyam Khurana <8039608+CuriousLearner at users.noreply.github.com>
committer: Nick Coghlan <ncoghlan at gmail.com>
date: 2018-12-31T15:14:47+10:00
summary:

bpo-35614: Fix pydoc help() on metaclasses (#11357)

files:
A Misc/NEWS.d/next/Library/2018-12-30-01-10-50.bpo-35614.cnkM4f.rst
M Lib/pydoc.py
M Lib/test/test_pydoc.py

diff --git a/Lib/pydoc.py b/Lib/pydoc.py
index 1d84b847cf9f..59f6e3935135 100644
--- a/Lib/pydoc.py
+++ b/Lib/pydoc.py
@@ -1255,7 +1255,7 @@ def makename(c, m=object.__module__):
 
         # List the built-in subclasses, if any:
         subclasses = sorted(
-            (str(cls.__name__) for cls in object.__subclasses__()
+            (str(cls.__name__) for cls in type.__subclasses__(object)
              if not cls.__name__.startswith("_") and cls.__module__ == "builtins"),
             key=str.lower
         )
diff --git a/Lib/test/test_pydoc.py b/Lib/test/test_pydoc.py
index 409fea4a5e94..c58a8b13e76d 100644
--- a/Lib/test/test_pydoc.py
+++ b/Lib/test/test_pydoc.py
@@ -636,6 +636,17 @@ class ZeroDivisionError(ArithmeticError)
         # Testing that the subclasses section does not appear
         self.assertNotIn('Built-in subclasses', text)
 
+    def test_builtin_on_metaclasses(self):
+        """Tests help on metaclasses.
+
+        When running help() on a metaclasses such as type, it
+        should not contain any "Built-in subclasses" section.
+        """
+        doc = pydoc.TextDoc()
+        text = doc.docclass(type)
+        # Testing that the subclasses section does not appear
+        self.assertNotIn('Built-in subclasses', text)
+
     @unittest.skipIf(sys.flags.optimize >= 2,
                      'Docstrings are omitted with -O2 and above')
     @unittest.skipIf(hasattr(sys, 'gettrace') and sys.gettrace(),
diff --git a/Misc/NEWS.d/next/Library/2018-12-30-01-10-50.bpo-35614.cnkM4f.rst b/Misc/NEWS.d/next/Library/2018-12-30-01-10-50.bpo-35614.cnkM4f.rst
new file mode 100644
index 000000000000..4d6beffa2be6
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-12-30-01-10-50.bpo-35614.cnkM4f.rst
@@ -0,0 +1 @@
+Fixed help() on metaclasses. Patch by Sanyam Khurana.