bpo-40296: Fix supporting generic aliases in pydoc

Lib/pydoc.py

@@ -69,6 +69,7 @@ class or function within a module or module in a package.  If the
 import sysconfig
 import time
 import tokenize
+import types
 import urllib.parse
 import warnings
 from collections import deque
@@ -90,21 +91,24 @@ def pathdirs():
             normdirs.append(normdir)
     return dirs
 
+def _isclass(object):
+    return inspect.isclass(object) and not isinstance(object, types.GenericAlias)
+
 def _findclass(func):
     cls = sys.modules.get(func.__module__)
     if cls is None:
         return None
     for name in func.__qualname__.split('.')[:-1]:
         cls = getattr(cls, name)
-    if not inspect.isclass(cls):
+    if not _isclass(cls):
         return None
     return cls
 
 def _finddoc(obj):
     if inspect.ismethod(obj):
         name = obj.__func__.__name__
         self = obj.__self__
-        if (inspect.isclass(self) and
+        if (_isclass(self) and
             getattr(getattr(self, name, None), '__func__') is obj.__func__):
             # classmethod
             cls = self
@@ -118,7 +122,7 @@ def _finddoc(obj):
     elif inspect.isbuiltin(obj):
         name = obj.__name__
         self = obj.__self__
-        if (inspect.isclass(self) and
+        if (_isclass(self) and
             self.__qualname__ + '.' + name == obj.__qualname__):
             # classmethod
             cls = self
@@ -205,7 +209,7 @@ def classname(object, modname):
 
 def isdata(object):
     """Check if an object is of a type that probably means it's data."""
-    return not (inspect.ismodule(object) or inspect.isclass(object) or
+    return not (inspect.ismodule(object) or _isclass(object) or
                 inspect.isroutine(object) or inspect.isframe(object) or
                 inspect.istraceback(object) or inspect.iscode(object))
 
@@ -470,7 +474,7 @@ def document(self, object, name=None, *args):
         # by lacking a __name__ attribute) and an instance.
         try:
             if inspect.ismodule(object): return self.docmodule(*args)
-            if inspect.isclass(object): return self.docclass(*args)
+            if _isclass(object): return self.docclass(*args)
             if inspect.isroutine(object): return self.docroutine(*args)
         except AttributeError:
             pass
@@ -772,7 +776,7 @@ def docmodule(self, object, name=None, mod=None, *ignored):
         modules = inspect.getmembers(object, inspect.ismodule)
 
         classes, cdict = [], {}
-        for key, value in inspect.getmembers(object, inspect.isclass):
+        for key, value in inspect.getmembers(object, _isclass):
             # if __all__ exists, believe it.  Otherwise use old heuristic.
             if (all is not None or
                 (inspect.getmodule(value) or object) is object):
@@ -1212,7 +1216,7 @@ def docmodule(self, object, name=None, mod=None):
             result = result + self.section('DESCRIPTION', desc)
 
         classes = []
-        for key, value in inspect.getmembers(object, inspect.isclass):
+        for key, value in inspect.getmembers(object, _isclass):
             # if __all__ exists, believe it.  Otherwise use old heuristic.
             if (all is not None
                 or (inspect.getmodule(value) or object) is object):
@@ -1696,7 +1700,7 @@ def describe(thing):
         return 'member descriptor %s.%s.%s' % (
             thing.__objclass__.__module__, thing.__objclass__.__name__,
             thing.__name__)
-    if inspect.isclass(thing):
+    if _isclass(thing):
         return 'class ' + thing.__name__
     if inspect.isfunction(thing):
         return 'function ' + thing.__name__
@@ -1757,7 +1761,7 @@ def render_doc(thing, title='Python Library Documentation: %s', forceload=0,
         desc += ' in module ' + module.__name__
 
     if not (inspect.ismodule(object) or
-              inspect.isclass(object) or
+              _isclass(object) or
               inspect.isroutine(object) or
               inspect.isdatadescriptor(object) or
               _getdoc(object)):

Lib/test/test_pydoc.py

@@ -996,6 +996,43 @@ class C: "New-style class"
         expected = 'C in module %s object' % __name__
         self.assertIn(expected, pydoc.render_doc(c))
 
+    def test_generic_alias(self):
+        self.assertEqual(pydoc.describe(typing.List[int]), '_GenericAlias')
+        doc = pydoc.render_doc(typing.List[int], renderer=pydoc.plaintext)
+        self.assertIn('_GenericAlias in module typing', doc)
+        self.assertIn('List = class list(object)', doc)
+        self.assertIn(list.__doc__.strip().splitlines()[0], doc)
+
+        self.assertEqual(pydoc.describe(list[int]), 'GenericAlias')
+        doc = pydoc.render_doc(list[int], renderer=pydoc.plaintext)
+        self.assertIn('GenericAlias in module builtins', doc)
+        self.assertIn('\nclass list(object)', doc)
+        self.assertIn(list.__doc__.strip().splitlines()[0], doc)
+
+    def test_union_type(self):
+        self.assertEqual(pydoc.describe(typing.Union[int, str]), '_UnionGenericAlias')
+        doc = pydoc.render_doc(typing.Union[int, str], renderer=pydoc.plaintext)
+        self.assertIn('_UnionGenericAlias in module typing', doc)
+        self.assertIn('Union = typing.Union', doc)
+        if typing.Union.__doc__:
+            self.assertIn(typing.Union.__doc__.strip().splitlines()[0], doc)
+
+        self.assertEqual(pydoc.describe(int | str), 'UnionType')
+        doc = pydoc.render_doc(int | str, renderer=pydoc.plaintext)
+        self.assertIn('UnionType in module types object', doc)
+        self.assertIn('\nclass UnionType(builtins.object)', doc)
+        self.assertIn(types.UnionType.__doc__.strip().splitlines()[0], doc)
+
+    def test_special_form(self):
+        self.assertEqual(pydoc.describe(typing.Any), '_SpecialForm')
+        doc = pydoc.render_doc(typing.Any, renderer=pydoc.plaintext)
+        self.assertIn('_SpecialForm in module typing', doc)
+        if typing.Any.__doc__:
+            self.assertIn('Any = typing.Any', doc)
+            self.assertIn(typing.Any.__doc__.strip().splitlines()[0], doc)
+        else:
+            self.assertIn('Any = class _SpecialForm(_Final)', doc)
+
     def test_typing_pydoc(self):
         def foo(data: typing.List[typing.Any],
                 x: int) -> typing.Iterator[typing.Tuple[int, typing.Any]]:

Misc/NEWS.d/next/Library/2021-12-25-14-13-14.bpo-40296.p0YVGB.rst

@@ -0,0 +1 @@
+Fix supporting generic aliases in :mod:`pydoc`.