bpo-46353: Fix "pydoc -k" when a module fails to load

The 'spec' value, here coming from pkgutil._get_spec(), may be None
because <importer>.find_module() may return None. We account for this in
pydoc's ModuleScanner and skip such modules scan.

Author: dlax

Lib/pydoc.py

@@ -2230,6 +2230,8 @@ def run(self, callback, key=None, completer=None, onerror=None):
                 except SyntaxError:
                     # raised by tests for bad coding cookies or BOM
                     continue
+                if spec is None:
+                    continue
                 loader = spec.loader
                 if hasattr(loader, 'get_source'):
                     try:

Misc/NEWS.d/next/Library/2022-01-12-14-10-42.bpo-46353.wSHF5T.rst

@@ -0,0 +1,2 @@
+Skip scan of modules that fail to load during keyword search in
+:mod:`pydoc`.