Merge pull request #890 from asottile/noop-named-escape

fix string formatting with named escape adjacent to placeholder
asottile · Sep 19, 2023 · ecaf736 · ecaf736
2 parents a61ea87 + 5dd175d
commit ecaf736
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diff --git 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
@@ -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):