Fix clickhouse-jdbc: skip heredoc literals when extracting ? placeholders - #3036
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…ders JdbcParameterizedQuery.parse() skipped quoted strings and --/ comments but had no notion of a heredoc literal ($$...$$ / $tag$...$tag$), so the contents of a heredoc were parsed as SQL: a '?' inside one was counted as a bind parameter, a ';' was rejected as a multi-statement query, a '\'' broke the scan with "Missing quote: '", and a ':' could be mistaken for the delimiter of the ? : ternary operator, silently dropping a real placeholder. A heredoc is now skipped as an opaque token, both in the placeholder scan and in the ternary lookahead (including inside brackets, where a bracket or quote in a heredoc body used to end the enclosing bracket or string). A '$' only opens a heredoc when it does not continue an identifier (a$b, a$x$), its tag contains word characters only, and a matching closing tag exists - otherwise it stays an ordinary character, matching the server lexer. Fixes: #3035
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This was referenced Aug 4, 2026
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Description
Fixes #3035.
JdbcParameterizedQuery.parse()scans the SQL for?placeholders and knows about quoted strings and--//* */comments, but it has no notion of a ClickHouse heredoc literal ($$...$$/$tag$...$tag$). The contents of a heredoc were therefore parsed as SQL, so a?inside one wascounted as a bind parameter (the application cannot supply a value for it, and its real parameter ends
up bound to the wrong position), a
;was rejected as a multi-statement query, a'made the scan runoff the end of the statement (
Missing quote: '), and a:could be mistaken for the delimiter of the? :ternary operator, silently dropping a real placeholder. The server treats a heredoc as a singlestring literal, so all of these statements execute fine when sent as-is.
A heredoc is now skipped as an opaque token. A
$only opens one when it does not continue anidentifier (
a$b,a$x$), its tag contains word characters only, and a matching closing tag exists —otherwise it stays an ordinary character, matching the server lexer.
Changes
clickhouse-jdbc/.../JdbcParameterizedQuery.javaskipHeredoc? :) is a privateskipUntilTernaryDelimiter— identical toClickHouseUtils.skipContentsUntil(sql, i, len, '?', ':')for input without a heredoc, plus heredocskipping, so a
:or?inside a heredoc body no longer decides whether a?is a placeholderskipBrackets(identical toClickHouseUtils.skipBracketsotherwise, including the "Missing '<bracket>'" error), because a)or
'inside a heredoc used to end the enclosing bracket or string(
select ?, lower($$it's$$)threwMissing quote: ')ClickHouseUtils, whose scanners arealso used for type-name/value parsing where
$is not a heredoc — no shared behavior is changedCHANGELOG.md— entry under Bug FixesTest
JdbcParameterizedQueryTest.testParseQueriesWithHeredoc(@DataProvider, 25 rows): heredoc bodiescontaining
?,:,;,', comment markers and brackets, tagged/empty/numeric-tag heredocs, aheredoc at position 0, one nested in a function call, and a real ternary whose branch is a heredoc.
Contrast rows pin the unchanged behavior of a
$that does not open a heredoc: identifiers(
a$x$,a$b), an unterminated$$, a heredoc inside a quoted string or a comment, and the plain? :ternary. 14 rows fail onmain.JdbcParameterizedQueryTest.testParseInvalidQueriesWithHeredoc: multi-statement rejection still firesfor a
;outside a heredoc, and unterminated brackets/quotes still raiseIllegalArgumentException(passes both before and after — the new bracket helper preserves it).
ClickHousePreparedStatementTest.testQueryWithHeredocLiteral(integration, live path):select $$a?b$$ as s, ? as nreports one parameter and returnsa?b, 42. Fails onmain(
expected [1] but found [2]).mvn -pl clickhouse-jdbc test→ 114 unit tests green;-Dit.test=ClickHousePreparedStatementTest verify→ 93 integration tests green against ClickHouse 26.5.
Compatibility
No public API change. Behavior changes only for statements containing a heredoc literal, which the
driver previously mis-parsed or rejected. Statements without a heredoc are parsed exactly as before,
including the error messages for unbalanced brackets/quotes and multi-statement input.
docs/changes_checklist.mdno dependency or module changes — the change is confined to private parsing logic in one class.
CHANGELOG.mdupdated with the problem, the fix and the issue link.docs/features.mdis not applicable (this isclickhouse-jdbcv1, notclient-v2/jdbc-v2).Pre-PR validation gate
main)AGENTS.md(targeted Maven runs,@DataProviderinstead ofnear-identical methods, no issue numbers/narrative in test code, negative tests added)
Notes
clickhouse-jdbcis the legacy v1 stack — happy to close this if you would rather not take changes toit.
;inside a heredoc truncates the statement in the parser's error recovery), and
com.clickhouse.client.ClickHouseParameterizedQuery(named-parameter mode,clickhouse-client) has thesame heredoc blindness for
:name. jdbc-v2's equivalent of this fix is Fix jdbc-v2: skip // comments and heredocs when scanning for ? placeholders #3010 (issue [jdbc-v2] PreparedStatement placeholder scan misses // comments and $tag$ heredocs, so a ? inside them is counted as a parameter #3009).