913bbd88dc
Use the parser's standard type coercion machinery to convert the output column(s) of a SQL function's final SELECT or RETURNING to the type(s) they should have according to the function's declared result type. We'll allow any case where an assignment-level coercion is available. Previously, we failed unless the required coercion was a binary-compatible one (and the documentation ignored this, falsely claiming that the types must match exactly). Notably, the coercion now accounts for typmods, so that cases where a SQL function is declared to return a composite type whose columns are typmod-constrained now behave as one would expect. Arguably this aspect is a bug fix, but the overall behavioral change here seems too large to consider back-patching. A nice side-effect is that functions can now be inlined in a few cases where we previously failed to do so because of type mismatches. Discussion: https://postgr.es/m/18929.1574895430@sss.pgh.pa.us
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/.