Make “pydoc somebuiltin.somemethod” work (#8887)

Lib/pydoc.py

@@ -1482,13 +1482,14 @@ def locate(path, forceload=0):
         else: break
     if module:
         object = module
-        for part in parts[n:]:
-            try: object = getattr(object, part)
-            except AttributeError: return None
-        return object
     else:
-        if hasattr(builtins, path):
-            return getattr(builtins, path)
+        object = builtins
+    for part in parts[n:]:
+        try:
+            object = getattr(object, part)
+        except AttributeError:
+            return None
+    return object
 
 # --------------------------------------- interactive interpreter interface
 

Lib/test/test_pydoc.py

 import os
 import sys
+import builtins
 import difflib
 import inspect
 import pydoc
@@ -419,6 +420,23 @@ class TestDescriptions(unittest.TestCase):
         expected = 'C in module %s object' % __name__
         self.assertIn(expected, pydoc.render_doc(c))
 
+    def test_builtin(self):
+        for name in ('str', 'str.translate', 'builtins.str',
+                     'builtins.str.translate'):
+            # test low-level function
+            self.assertIsNotNone(pydoc.locate(name))
+            # test high-level function
+            try:
+                pydoc.render_doc(name)
+            except ImportError:
+                self.fail('finding the doc of {!r} failed'.format(o))
+
+        for name in ('notbuiltins', 'strrr', 'strr.translate',
+                     'str.trrrranslate', 'builtins.strrr',
+                     'builtins.str.trrranslate'):
+            self.assertIsNone(pydoc.locate(name))
+            self.assertRaises(ImportError, pydoc.render_doc, name)
+
 
 @unittest.skipUnless(threading, 'Threading required for this test.')
 class PydocServerTest(unittest.TestCase):

Misc/NEWS

@@ -41,6 +41,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #8887: "pydoc somebuiltin.somemethod" (or help('somebuiltin.somemethod')
+  in Python code) now finds the doc of the method.
+
 - Issue #12603: Fix pydoc.synopsis() on files with non-negative st_mtime.
 
 - Issue #12514: Use try/finally to assure the timeit module restores garbage