cb98b23da3
Commit a83586b554 decided to scribble on the caller's fcinfo but failed
to take into account that const arguments are written once at expression
init and assumed never to change.
The use_json_null branch overwrote fcinfo->args[2] with a jsonb null
built in the per-tuple expression context. In later rows,
args[2].isnull is still false and args[2].value still holds that
pointer, but the per-tuple context has been reset. Later rows find
args[2].isnull = false, short-circuit past the NULL handling at the top
of the function, and jump straight to jsonb_set with the stale pointer
regardless of their own null_value_treatment argument, which is never
read.
To fix, call jsonb_set through its own call frame instead. Arguments 0,
1 and 3 were already checked non-NULL above, so we can use
DirectFunctionCall4.
Add regression tests covering use_json_null followed by delete_key and
return_target, and a multi-row default-treatment query.
Reported-by: Evan Si <evsi@amazon.com>
Discussion: https://postgr.es/m/CANWCAZY-PS=ev8TiiV1j=NoR2xLopEL8fDq0fyQZahHiP5b+Pw@mail.gmail.com
Backpatch-through: 14
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/19/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/19/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/.