# HG changeset patch
# Parent  83fa2e9b0038db72dc29be5fbcfcb126841c3b05
pkgutil.iter_modules() and walk_packages() now yield built-in modules

diff -r 83fa2e9b0038 Doc/library/pkgutil.rst
--- a/Doc/library/pkgutil.rst	Mon Nov 02 00:39:56 2015 -0500
+++ b/Doc/library/pkgutil.rst	Mon Nov 02 10:39:35 2015 +0000
@@ -140,7 +140,8 @@
 .. function:: iter_modules(path=None, prefix='')
 
    Yields ``(module_finder, name, ispkg)`` for all submodules on *path*, or, if
-   path is ``None``, all top-level modules on ``sys.path``.
+   *path* is ``None``, all built-in modules and top-level modules on
+   ``sys.path``.
 
    *path* should be either ``None`` or a list of paths to look for modules in.
 
@@ -150,13 +151,17 @@
 
       Only works for a :term:`finder` which defines an ``iter_modules()``
       method. This interface is non-standard, so the module also provides
-      implementations for :class:`importlib.machinery.FileFinder` and
+      implementations for :class:`importlib.machinery.FileFinder`,
+      :class:`~importlib.machinery.BuiltinImporter` and
       :class:`zipimport.zipimporter`.
 
    .. versionchanged:: 3.3
       Updated to be based directly on :mod:`importlib` rather than relying
       on the package internal PEP 302 import emulation.
 
+   .. versionchanged:: 3.6
+      Now yields built-in modules.
+
 
 .. function:: walk_packages(path=None, prefix='', onerror=None)
 
@@ -189,13 +194,17 @@
 
       Only works for a :term:`finder` which defines an ``iter_modules()``
       method. This interface is non-standard, so the module also provides
-      implementations for :class:`importlib.machinery.FileFinder` and
+      implementations for :class:`importlib.machinery.FileFinder`,
+      :class:`~importlib.machinery.BuiltinImporter` and
       :class:`zipimport.zipimporter`.
 
    .. versionchanged:: 3.3
       Updated to be based directly on :mod:`importlib` rather than relying
       on the package internal PEP 302 import emulation.
 
+   .. versionchanged:: 3.6
+      Now yields built-in modules.
+
 
 .. function:: get_data(package, resource)
 
diff -r 83fa2e9b0038 Doc/whatsnew/3.6.rst
--- a/Doc/whatsnew/3.6.rst	Mon Nov 02 00:39:56 2015 -0500
+++ b/Doc/whatsnew/3.6.rst	Mon Nov 02 10:39:35 2015 +0000
@@ -113,6 +113,13 @@
 Storchaka in :issue:`24164`.)
 
 
+pkgutil
+-------
+
+The :func:`~pkgutil.iter_modules` and :func:`~pkgutil.walk_packages`
+functions now yield built-in modules.
+
+
 rlcomplete
 ----------
 
@@ -226,6 +233,9 @@
 * The :mod:`imp` module now raises a :exc:`DeprecationWarning` instead of
   :exc:`PendingDeprecationWarning`.
 
+* :func:`pkgutil.iter_modules` and :func:`~pkgutil.walk_packages` now
+  yield built-in modules.
+
 
 Changes in the C API
 --------------------
diff -r 83fa2e9b0038 Lib/pkgutil.py
--- a/Lib/pkgutil.py	Mon Nov 02 00:39:56 2015 -0500
+++ b/Lib/pkgutil.py	Mon Nov 02 10:39:35 2015 +0000
@@ -1,6 +1,6 @@
 """Utilities to support packages."""
 
-from functools import singledispatch as simplegeneric
+from functools import singledispatch
 import importlib
 import importlib.util
 import importlib.machinery
@@ -103,7 +103,8 @@
 
 def iter_modules(path=None, prefix=''):
     """Yields (module_loader, name, ispkg) for all submodules on path,
-    or, if path is None, all top-level modules on sys.path.
+    or, if path is None, all built-in modules and top-level modules on
+    sys.path.
 
     'path' should be either None or a list of paths to look for
     modules in.
@@ -125,14 +126,20 @@
                 yield i, name, ispkg
 
 
-@simplegeneric
+@singledispatch
 def iter_importer_modules(importer, prefix=''):
-    if not hasattr(importer, 'iter_modules'):
+    if hasattr(importer, 'iter_modules'):
+        return importer.iter_modules(prefix)
+    elif importer is importlib.machinery.BuiltinImporter:
+        # Not instantiated because it has no instance methods, therefore not
+        # handled by @singledispatch
+        return _iter_builtin_modules(importer, prefix)
+    else:
         return []
-    return importer.iter_modules(prefix)
 
 
 # Implement a file walker for the normal importlib path hook
+@iter_importer_modules.register(importlib.machinery.FileFinder)
 def _iter_file_finder_modules(importer, prefix=''):
     if importer.path is None or not os.path.isdir(importer.path):
         return
@@ -173,8 +180,11 @@
             yielded[modname] = 1
             yield prefix + modname, ispkg
 
-iter_importer_modules.register(
-    importlib.machinery.FileFinder, _iter_file_finder_modules)
+
+@iter_importer_modules.register(importlib.machinery.BuiltinImporter)
+def _iter_builtin_modules(importer, prefix=''):
+    for modname in sys.builtin_module_names:
+        yield (prefix + modname, False)
 
 
 def _import_imp():
@@ -360,6 +370,7 @@
     import zipimport
     from zipimport import zipimporter
 
+    @iter_importer_modules.register(zipimporter)
     def iter_zipimport_modules(importer, prefix=''):
         dirlist = sorted(zipimport._zip_directory_cache[importer.archive])
         _prefix = importer.prefix
@@ -388,8 +399,6 @@
                 yielded[modname] = 1
                 yield prefix + modname, False
 
-    iter_importer_modules.register(zipimporter, iter_zipimport_modules)
-
 except ImportError:
     pass
 
diff -r 83fa2e9b0038 Lib/pydoc.py
--- a/Lib/pydoc.py	Mon Nov 02 00:39:56 2015 -0500
+++ b/Lib/pydoc.py	Mon Nov 02 10:39:35 2015 +0000
@@ -2060,19 +2060,6 @@
     def run(self, callback, key=None, completer=None, onerror=None):
         if key: key = key.lower()
         self.quit = False
-        seen = {}
-
-        for modname in sys.builtin_module_names:
-            if modname != '__main__':
-                seen[modname] = 1
-                if key is None:
-                    callback(None, modname, '')
-                else:
-                    name = __import__(modname).__doc__ or ''
-                    desc = name.split('\n')[0]
-                    name = modname + ' - ' + desc
-                    if name.lower().find(key) >= 0:
-                        callback(None, modname, desc)
 
         for importer, modname, ispkg in pkgutil.walk_packages(onerror=onerror):
             if self.quit:
@@ -2087,6 +2074,7 @@
                     # raised by tests for bad coding cookies or BOM
                     continue
                 loader = spec.loader
+                source = None
                 if hasattr(loader, 'get_source'):
                     try:
                         source = loader.get_source(modname)
@@ -2094,12 +2082,13 @@
                         if onerror:
                             onerror(modname)
                         continue
+                if source is not None:
                     desc = source_synopsis(io.StringIO(source)) or ''
                     if hasattr(loader, 'get_filename'):
                         path = loader.get_filename(modname)
                     else:
                         path = None
-                else:
+                else:  # No get_source(), or source is None (built-in module)
                     try:
                         module = importlib._bootstrap._load(spec)
                     except ImportError:
diff -r 83fa2e9b0038 Lib/test/test_pkgutil.py
--- a/Lib/test/test_pkgutil.py	Mon Nov 02 00:39:56 2015 -0500
+++ b/Lib/test/test_pkgutil.py	Mon Nov 02 10:39:35 2015 +0000
@@ -2,6 +2,7 @@
 import unittest
 import sys
 import importlib
+from importlib.machinery import BuiltinImporter
 from importlib.util import spec_from_file_location
 import pkgutil
 import os
@@ -101,6 +102,18 @@
         for t in pkgutil.walk_packages(path=[self.dirname]):
             self.fail("unexpected package found")
 
+    def test_iter_builtin(self):
+        # iter_modules() should yield built-in modules
+        for [finder, name, ispkg] in pkgutil.iter_modules():
+            if name == "sys":
+                break
+        else:
+            self.fail("sys module missing")
+        # BuiltinImporter only has class methods, so uninstantiated is okay
+        self.assertTrue(isinstance(finder, BuiltinImporter) or
+            issubclass(finder, BuiltinImporter))
+        self.assertFalse(ispkg)
+
 class PkgutilPEP302Tests(unittest.TestCase):
 
     class MyTestLoader(object):
diff -r 83fa2e9b0038 Misc/NEWS
--- a/Misc/NEWS	Mon Nov 02 00:39:56 2015 -0500
+++ b/Misc/NEWS	Mon Nov 02 10:39:35 2015 +0000
@@ -66,6 +66,8 @@
 Library
 -------
 
+- pkgutil.iter_modules() and walk_packages() now yield built-in modules.
+
 - Issue #18973: Command-line interface of the calendar module now uses argparse
   instead of optparse.