23088673d3
A JSON constructor with a RETURNING clause uses a CaseTestExpr as the
placeholder for its result in the coercion expression. When such a
constructor appears in a WHEN clause of a simple CASE whose test
expression is a constant, eval_const_expressions substituted that
constant for the placeholder, so the coercion produced the CASE's test
value instead of the constructor's result. For instance,
CASE 'x' WHEN JSON_OBJECT('a': 'b' RETURNING text) THEN 1 ELSE 0 END
evaluated to 1.
To fix, keep case_val out of scope while simplifying the coercion, as
is already done for the elemexpr of an ArrayCoerceExpr.
Back-patch to v16, where the SQL/JSON constructor functions were
introduced.
Author: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/CAMbWs48A=VCFbteTkuCoknO1_0-Cu0aMBT0M07dm7vj1QyixDg@mail.gmail.com
Backpatch-through: 16
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/17/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/17/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.