Fix: classify.is_f_string()'s pre-3.12 fallback (added in PR #330) flags ANY...

src/docformatter/classify.py

@@ -343,19 +343,23 @@ def is_f_string(token: tokenize.TokenInfo, prev_token: tokenize.TokenInfo) -> bo
     bool
         True if the token is an f-string, False otherwise.
     """
+    # On Python 3.12+, PEP 701 tokenizes an f-string as a FSTRING_START /
+    # FSTRING_MIDDLE / FSTRING_END sequence, so adjacent tokens must be
+    # stitched back together onto the same row.
     if PY312:
         if tokenize.FSTRING_MIDDLE in [token.type, prev_token.type]:
             return True
-    elif any(
-        [
-            token.string.startswith('f"""'),
-            prev_token.string.startswith('f"""'),
-            token.string.startswith("f'''"),
-            prev_token.string.startswith("f'''"),
-        ]
-    ):
-        return True
 
+        return False
+
+    # Before Python 3.12, an f-string is always tokenized as a single STRING
+    # token, so there is nothing to stitch together and this function should
+    # never fire.  Naively checking the string prefix here (regardless of
+    # bracket/assignment context) used to misclassify *any* f\"\"\"/f''' token
+    # -- e.g. one nested inside a parenthesized expression or tuple -- as
+    # needing row-continuation treatment, corrupting the row bookkeeping in
+    # ``_get_unmatched_start_end_indices`` and causing
+    # ``tokenize.untokenize`` to raise ``ValueError`` (see issue #367).
     return False
 
 

tests/_data/string_files/do_format_code.toml

@@ -1260,3 +1260,17 @@ expected="def foo():\n    \"\"\"Summary.\"\"\"\n    x = 1\n    # next line has 4
 [issue_360_no_trailing_newline]
 source="def foo():\n    \"\"\"\n    Hello foo.\n    \"\"\"\n    x = 1"
 expected="def foo():\n    \"\"\"Hello foo.\"\"\"\n    x = 1"
+
+[issue_367]
+source='''def build(x):
+    return (
+        f"""a
+{x}""",
+    )
+'''
+expected='''def build(x):
+    return (
+        f"""a
+{x}""",
+    )
+'''

tests/formatter/test_do_format_code.py

@@ -143,6 +143,7 @@
         ("issue_331_black_module_docstring", ["--black", ""]),
         ("issue_355", NO_ARGS),
         ("issue_360_no_trailing_newline", NO_ARGS),
+        ("issue_367", NO_ARGS),
     ],
 )
 def test_do_format_code(test_key, test_args, args):