From fe8f4c9e87699acfd740dfc38ae5320691598250 Mon Sep 17 00:00:00 2001
From: Steve Dower <steve.dower@microsoft.com>
Date: Wed, 7 Sep 2016 09:31:52 -0700
Subject: [PATCH] Issue #27959: Prevent ImportError from escaping codec search
 function

---
 Lib/encodings/__init__.py | 12 ++++++++----
 Lib/test/test_io.py       |  3 +--
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/Lib/encodings/__init__.py b/Lib/encodings/__init__.py
index 9a9b90b0040..ca07881f345 100644
--- a/Lib/encodings/__init__.py
+++ b/Lib/encodings/__init__.py
@@ -155,9 +155,13 @@ codecs.register(search_function)
 
 if sys.platform == 'win32':
     def _alias_mbcs(encoding):
-        import _bootlocale
-        if encoding == _bootlocale.getpreferredencoding(False):
-            import encodings.mbcs
-            return encodings.mbcs.getregentry()
+        try:
+            import _bootlocale
+            if encoding == _bootlocale.getpreferredencoding(False):
+                import encodings.mbcs
+                return encodings.mbcs.getregentry()
+        except ImportError:
+            # Imports may fail while we are shutting down
+            pass
 
     codecs.register(_alias_mbcs)
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index f9f5d7a7ee8..c48ec3a2396 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -3230,8 +3230,7 @@ def _to_memoryview(buf):
 
 class CTextIOWrapperTest(TextIOWrapperTest):
     io = io
-    shutdown_error = ("ImportError: sys.meta_path is None"
-        if os.name == "nt" else "RuntimeError: could not find io module state")
+    shutdown_error = "RuntimeError: could not find io module state"
 
     def test_initialization(self):
         r = self.BytesIO(b"\xc3\xa9\n\n")