fix: allow arbitrary column aliases in LATERAL VIEW - #2452
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manticore-projects merged 2 commits intoAug 7, 2026
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Hive/Spark LATERAL VIEW supports an arbitrary number of column aliases (e.g. json_tuple yielding many output columns), but the grammar only absorbed the first two aliases (JSQLParser#2088). Any further aliases were silently parsed as comma-separated tables in the FROM clause (implicit cross joins), and because toString() re-emitted them as the join list the broken AST round-tripped identically and was hard to detect by inspection. Generalise the column-alias production to consume any number of aliases after the first two. Fixes JSQLParser#2433 Signed-off-by: 付典 <fudianchn@gmail.com>
manticore-projects
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Aug 7, 2026
Signed-off-by: 付典 <fudianchn@gmail.com>
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What
Allow a Hive/Spark
LATERAL VIEWto declare an arbitrary number of column aliases, not just two.Why
LATERAL VIEW ... x AS c1, c2, c3, ..., cNis valid Hive/Spark SQL —json_tupleand similar UDTFs commonly yield many output columns. The grammar only absorbed the first two aliases (#2088); from the third onward the aliases were silently parsed as comma-separated tables in theFROMclause (implicit cross joins):PlainSelect.joinsincorrectly containedJoin(Table("c3")) ... Join(Table("cN"))LateralView.columnAlias.aliasColumnsstopped at 2Because
toString()re-emits the leaked aliases as the join list, the broken AST round-trips to textually identical SQL, so the bug is invisible to round-trip checks.Reported in #2433.
How
The column-alias production (
LateralView) handled the second alias with an optional[ "," name ]block. This adds a("," name)*loop immediately after it, so the 3rd…Nth aliases are consumed by the lateral view instead of leaking to theFROMclause. The existing single- and two-alias behaviour is unchanged (the loop simply runs zero times).Testing
HiveTest#testLateralViewManyColumnAliasesIssue2433parsesLATERAL VIEW json_tuple(...) x AS c1, c2, c3, c4, c5, c6, c7and asserts at the AST level (a round-trip assertion would be vacuous here):PlainSelect.joinsisnullandLateralView.columnAlias.aliasColumnshas size 7.master(expected: <null> but was: <[c3, c4, c5, c6, c7]>) and passes with this change.mvn clean test: 4648 tests, 0 failures, 0 errors (26 skipped) — the existing two-alias case ([BUG] JSQLParser Version 5.1-SNAPSHOT: Lateral View with two aliases recognizes second alias as table #2088) and all other tests unchanged.mvn spotless:check: clean.Fixes #2433