From f6974073524925ab4767dfa469c1dcc36a2e2fce Mon Sep 17 00:00:00 2001
From: John Belmonte <john@neggie.net>
Date: Mon, 1 May 2023 20:46:02 +0900
Subject: [PATCH 1/2] gh-104018: disallow "z" format specifier in %-format of
 byte strings

PEP-0682 specified that %-formatting would not support the "z"
specifier, but it was unintentionally allowed for a byte strings.

Issue: #104018
---
 Lib/test/test_format.py | 2 ++
 Objects/bytesobject.c   | 1 -
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/Lib/test/test_format.py b/Lib/test/test_format.py
index 69b0d5f1c5a515..6fa49dbc0b730c 100644
--- a/Lib/test/test_format.py
+++ b/Lib/test/test_format.py
@@ -619,6 +619,8 @@ def test_specifier_z_error(self):
         error_msg = re.escape("unsupported format character 'z'")
         with self.assertRaisesRegex(ValueError, error_msg):
             "%z.1f" % 0  # not allowed in old style string interpolation
+        with self.assertRaisesRegex(ValueError, error_msg):
+            b"%z.1f" % 0
 
 
 if __name__ == "__main__":
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 27b2ad4f2cb38f..e7e85cc19cda75 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -705,7 +705,6 @@ _PyBytes_FormatEx(const char *format, Py_ssize_t format_len,
                 case ' ': flags |= F_BLANK; continue;
                 case '#': flags |= F_ALT; continue;
                 case '0': flags |= F_ZERO; continue;
-                case 'z': flags |= F_NO_NEG_0; continue;
                 }
                 break;
             }

From ffe6f51d56474f6633e6105cdbd67109220dd860 Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Mon, 1 May 2023 12:03:57 +0000
Subject: [PATCH 2/2] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../2023-05-01-12-03-52.gh-issue-104018.PFxGS4.rst               | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2023-05-01-12-03-52.gh-issue-104018.PFxGS4.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-05-01-12-03-52.gh-issue-104018.PFxGS4.rst b/Misc/NEWS.d/next/Core and Builtins/2023-05-01-12-03-52.gh-issue-104018.PFxGS4.rst
new file mode 100644
index 00000000000000..f3cadaee0e32d9
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-05-01-12-03-52.gh-issue-104018.PFxGS4.rst	
@@ -0,0 +1 @@
+Disallow the "z" format specifier in %-format of bytes objects.