From c999d014c136fb2964ff4ddeff682814f49330ec Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Mon, 18 Nov 2024 19:18:28 +0200
Subject: [PATCH] Revert "Change error message."

This reverts commit 57ad6d2a928e821cbb42e3a9538491808e4a9925.
---
 Lib/test/test_codecs.py | 2 +-
 Lib/test/test_io.py     | 4 ++--
 Lib/tokenize.py         | 5 +++--
 Python/codecs.c         | 2 +-
 4 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/Lib/test/test_codecs.py b/Lib/test/test_codecs.py
index 6799948478aa2a..e51f7e0ee12b1f 100644
--- a/Lib/test/test_codecs.py
+++ b/Lib/test/test_codecs.py
@@ -3196,7 +3196,7 @@ def test_multiple_args(self):
 
     # http://bugs.python.org/issue19609
     def test_codec_lookup_failure(self):
-        msg = f"^encoding '{self.codec_name}' is not registered$"
+        msg = "^unknown encoding: {}$".format(self.codec_name)
         with self.assertRaisesRegex(LookupError, msg):
             "str input".encode(self.codec_name)
         with self.assertRaisesRegex(LookupError, msg):
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index cb93be703ba8b2..aa1b8268592ff7 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -3939,7 +3939,7 @@ def _to_memoryview(buf):
 
 class CTextIOWrapperTest(TextIOWrapperTest):
     io = io
-    shutdown_error = "LookupError: encoding 'ascii' is not registered"
+    shutdown_error = "LookupError: unknown encoding: ascii"
 
     def test_initialization(self):
         r = self.BytesIO(b"\xc3\xa9\n\n")
@@ -4039,7 +4039,7 @@ def write(self, data):
 
 class PyTextIOWrapperTest(TextIOWrapperTest):
     io = pyio
-    shutdown_error = "LookupError: encoding 'ascii' is not registered"
+    shutdown_error = "LookupError: unknown encoding: ascii"
 
 
 class IncrementalNewlineDecoderTest(unittest.TestCase):
diff --git a/Lib/tokenize.py b/Lib/tokenize.py
index 41ae0ed3e03915..7ece4e9b70d31b 100644
--- a/Lib/tokenize.py
+++ b/Lib/tokenize.py
@@ -398,9 +398,10 @@ def find_cookie(line):
         except LookupError:
             # This behaviour mimics the Python interpreter
             if filename is None:
-                msg = f"encoding '{encoding}' is not registered"
+                msg = "unknown encoding: " + encoding
             else:
-                msg = f"encoding '{encoding}' is not registered for {filename!r}"
+                msg = "unknown encoding for {!r}: {}".format(filename,
+                        encoding)
             raise SyntaxError(msg)
 
         if bom_found:
diff --git a/Python/codecs.c b/Python/codecs.c
index fbc6a1996ee530..2cb3875db35058 100644
--- a/Python/codecs.c
+++ b/Python/codecs.c
@@ -204,7 +204,7 @@ PyObject *_PyCodec_Lookup(const char *encoding)
     if (result == NULL) {
         /* XXX Perhaps we should cache misses too ? */
         PyErr_Format(PyExc_LookupError,
-                     "encoding '%s' is not registered", encoding);
+                     "unknown encoding: %s", encoding);
         goto onError;
     }