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compiler: a scalar subquery's column is nullable - #4654
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A scalar subquery yields NULL when it matches no row, so its column is nullable unless the subquery always yields one row: an aggregate with no GROUP BY, HAVING or LIMIT, or a SELECT with no FROM. Fixes sqlc-dev#4262 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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A scalar subquery yields NULL when it matches no row, but the legacy analyzer gave its column the nullability of the column it selects, so
(select r.id from reviews r where r.book_id = b.id limit 1)came out non-null. This makes it nullable unless the subquery always yields exactly one row: an aggregate with noGROUP BY,HAVINGorLIMIT((select count(*) …)stays non-null), or aSELECTwith noFROM.Fixes #4262. The new
nullable_scalar_subqueryfixture covers a subquery through a view and inline; it fails without the change in both thebaseandmanaged-dbcontexts. With PostgreSQL available, everyTestReplaycase passes, and no existing expected output changes.CASE … ELSE NULL::typehas the same problem on this path; I've left it to #3739, which reworksCASE(see my comment there about column-reference results).🤖 Generated with Claude Code