From 5dd175d859217c93050030cf2504584b979f91c9 Mon Sep 17 00:00:00 2001
From: Anthony Sottile <asottile@umich.edu>
Date: Tue, 19 Sep 2023 13:56:26 -0400
Subject: [PATCH] fix string formatting with named escape adjacent to
 placeholder

---
 pyupgrade/_string_helpers.py           | 2 +-
 tests/features/format_literals_test.py | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/pyupgrade/_string_helpers.py b/pyupgrade/_string_helpers.py
index 42718399..1c15655d 100644
--- a/pyupgrade/_string_helpers.py
+++ b/pyupgrade/_string_helpers.py
@@ -19,7 +19,7 @@ def parse_format(s: str) -> list[DotFormatPart]:
 
     for part in NAMED_UNICODE_RE.split(s):
         if NAMED_UNICODE_RE.fullmatch(part):
-            if not ret:
+            if not ret or ret[-1][1:] != (None, None, None):
                 ret.append((part, None, None, None))
             else:
                 ret[-1] = (ret[-1][0] + part, None, None, None)
diff --git a/tests/features/format_literals_test.py b/tests/features/format_literals_test.py
index aaa6ef05..837e593d 100644
--- a/tests/features/format_literals_test.py
+++ b/tests/features/format_literals_test.py
@@ -25,6 +25,8 @@
         '("{0}" # {1}\n"{2}").format(1, 2, 3)',
         # don't touch f-strings (these are wrong but don't make it worse)
         'f"{0}".format(a)',
+        # shouldn't touch the format spec
+        r'"{}\N{SNOWMAN}".format("")',
     ),
 )
 def test_format_literals_noop(s):