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Fix O(n²) performance in TokenList.group_tokens() #16

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Merged
stevephodgson merged 4 commits into from
Feb 24, 2026
Merged

Fix O(n²) performance in TokenList.group_tokens() #16

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824a6fe
Fix O(n²) performance in TokenList.group_tokens() extend path
stevephodgson Feb 23, 2026
dbd42b0
merge conflict
stevephodgson Feb 23, 2026
d5242a7
Merge remote-tracking branch 'origin/hex' into fix/group-tokens-quadr…
stevephodgson Feb 24, 2026
e64afe4
Merge remote-tracking branch 'origin/hex' into fix/group-tokens-quadr…
stevephodgson Feb 24, 2026
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1 change: 0 additions & 1 deletion sqlparse/sql.py
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Original file line number Diff line number Diff line change
Expand Up @@ -350,7 +350,6 @@ def group_tokens(self, grp_cls, start, end,
grp = start
grp.tokens.extend(subtokens)
del self.tokens[start_idx + 1:end_idx]
grp.value = str(start)
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@cursor cursor bot Feb 24, 2026

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Stale group value breaks wrapping

Medium Severity

Removing the grp.value refresh in the extend=True path makes TokenList.value stay at its construction-time cache even when the group grows. Some formatting logic relies on len(token.value) for grouped tokens (e.g., identifiers) to decide wrapping/indentation, so extended groups can be measured too short and produce different (potentially overlong) formatted output.

Fix in Cursor Fix in Web

else:
subtokens = self.tokens[start_idx:end_idx]
grp = grp_cls(subtokens)
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4 changes: 2 additions & 2 deletions tests/test_parse.py
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Original file line number Diff line number Diff line change
Expand Up @@ -545,7 +545,7 @@ def test_configurable_keywords():
tokens = sqlparse.parse(sql)[0]

assert list(
(t.ttype, t.value) for t in tokens if t.ttype not in sqlparse.tokens.Whitespace
(t.ttype, str(t)) for t in tokens if t.ttype not in sqlparse.tokens.Whitespace
) == [
(sqlparse.tokens.Keyword.DML, "select"),
(sqlparse.tokens.Wildcard, "*"),
Expand All @@ -569,7 +569,7 @@ def test_configurable_keywords():
Lexer.get_default_instance().default_initialization()

assert list(
(t.ttype, t.value) for t in tokens if t.ttype not in sqlparse.tokens.Whitespace
(t.ttype, str(t)) for t in tokens if t.ttype not in sqlparse.tokens.Whitespace
) == [
(sqlparse.tokens.Keyword.DML, "select"),
(sqlparse.tokens.Wildcard, "*"),
Expand Down
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