postgres-github.git / summary / log / commit / refs

commit    9d124a14b3d4803afee5efc4f794dfb72016cb88
Author:   Richard Guo <rguo@postgresql.org>
Date:     Fri May 08 08:21:48 2026 +0000

    Enforce RETURNING typmod for empty-set JSON_ARRAY(query)
    
    Commit 8d829f5a0 introduced a COALESCE wrapper around the
    JSON_ARRAYAGG subquery so that JSON_ARRAY(query) returns '[]' rather
    than NULL when the subquery yields no rows, per the SQL/JSON standard.
    
    The empty-array Const used as the COALESCE fallback was, however,
    built with typmod -1 and the type input function was likewise invoked
    with typmod -1.  As a result, any length restriction from the
    RETURNING clause was silently bypassed on the empty-set path, while
    the non-empty path enforced it via the JSON_ARRAYAGG coercion.
    
    Build the empty-array Const using the typmod of the COALESCE's
    non-empty argument, and pass that typmod to OidInputFunctionCall as
    well so the value is length-checked at parse time.  This makes the
    empty-set and non-empty-set paths behave consistently.
    
    Reported-by: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
    Author: Richard Guo <guofenglinux@gmail.com>
    Discussion: https://postgr.es/m/CAJTYsWXPYqa58YXrU+SQMVonsAhjLS46HNUMU=wO5zm9MgY3_g@mail.gmail.com

[parent: a49b9cfd72d8]