From d8acf0d9aae71d1897e8f91989bd8bfb4a9ef9c6 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Tue, 7 Apr 2020 16:07:42 +0200
Subject: [PATCH] bpo-37388: Don't check encoding/errors during finalization
 (GH-19409)

str.encode() and str.decode() no longer check the encoding and errors
in development mode or in debug mode during Python finalization. The
codecs machinery can no longer work on very late calls to
str.encode() and str.decode().

This change should help to call _PyObject_Dump() to debug during late
Python finalization.
---
 .../2020-04-07-15-44-29.bpo-37388.stlxBq.rst                | 4 ++++
 Objects/unicodeobject.c                                     | 6 ++++++
 2 files changed, 10 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2020-04-07-15-44-29.bpo-37388.stlxBq.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-04-07-15-44-29.bpo-37388.stlxBq.rst b/Misc/NEWS.d/next/Core and Builtins/2020-04-07-15-44-29.bpo-37388.stlxBq.rst
new file mode 100644
index 00000000000..1da58d11191
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-04-07-15-44-29.bpo-37388.stlxBq.rst	
@@ -0,0 +1,4 @@
+str.encode() and str.decode() no longer check the encoding and errors in
+development mode or in debug mode during Python finalization. The codecs
+machinery can no longer work on very late calls to str.encode() and
+str.decode().
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 9d51c8a685e..da17bfe01f3 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -451,6 +451,12 @@ unicode_check_encoding_errors(const char *encoding, const char *errors)
         return 0;
     }
 
+    /* Disable checks during Python finalization. For example, it allows to
+       call _PyObject_Dump() during finalization for debugging purpose. */
+    if (interp->finalizing) {
+        return 0;
+    }
+
     if (encoding != NULL) {
         PyObject *handler = _PyCodec_Lookup(encoding);
         if (handler == NULL) {