5f28b21eb3
This ought to work much like C's "#elif defined(name)"; but the code implemented it in a way equivalent to endif followed by ifdef, so that it didn't matter whether any previous branch of the IF construct had succeeded. Fix that; add some test cases covering elif and nested IFs; and improve the documentation, which also seemed a bit confused. AFAICS the code has been like this since the feature was added in 1999 (commit b57b0e044). So while it's surely wrong, there might be code out there relying on the current behavior. Hence, don't back-patch into stable branches. It seems all right to fix it in v13 though. Per report from Ashutosh Sharma. Reviewed by Ashutosh Sharma and Michael Meskes. Discussion: https://postgr.es/m/CAE9k0P=dQk9X0cU2tN49S7a9tv733-e1pVdpB1P-pWJ5PdTktg@mail.gmail.com
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/.