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f7ae51312f
If the given input_type yields valid results from both
get_element_type and get_array_type, initArrayResultAny believed the
former and treated the input as an array type. However this is
inconsistent with what get_promoted_array_type does, leading to
situations where the output of an ARRAY() subquery is labeled with
the wrong type: it's labeled as oidvector[] but is really a 2-D
array of OID. That at least results in strange output, and can
result in crashes if further processing such as unnest() is applied.
AFAIK this is only possible with the int2vector and oidvector
types, which are special-cased to be treated mostly as true arrays
even though they aren't quite.
Fix by switching the logic to match get_promoted_array_type by
testing get_array_type not get_element_type, and remove an Assert
thereby made pointless. (We need not introduce a symmetrical
check for get_element_type in the other if-branch, because
initArrayResultArr will check it.) This restores the behavior
that existed before bac27394a introduced initArrayResultAny:
the output really is int2vector[] or oidvector[].
Comparable confusion exists when an input of an ARRAY[] construct
is int2vector or oidvector: transformArrayExpr decides it's dealing
with a multidimensional array constructor, and we end up with
something that's a multidimensional OID array but is alleged to be
of type oidvector. I have not found a crashing case here, but it's
easy to demonstrate totally-wrong results. Adjust that code so
that what you get is an oidvector[] instead, for consistency with
ARRAY() subqueries. (This change also makes these types work like
domains-over-arrays in this context, which seems correct.)
Bug: #18840
Reported-by: yang lei <ylshiyu@126.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/18840-fbc9505f066e50d6@postgresql.org
Backpatch-through: 13
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. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.