
ecpg wants to emit a warning if it parses a SQL construct that the backend can parse but will immediately throw a FEATURE_NOT_SUPPORTED error for. The way it was testing for this was to see if the string ERRCODE_FEATURE_NOT_SUPPORTED appeared anywhere in the gram.y code. This is, of course, not nearly good enough, as there are plenty of rules in gram.y that throw that error only conditionally. There was a hack dating to 2008 to suppress the warning in one rule that doesn't even exist anymore, but nothing for other cases we've created since then. End result was that you could get "unsupported feature will be passed to server" warnings while compiling perfectly good SQL code in ecpg. Somehow we'd not heard complaints about this, but it was exposed by the recent addition of an ecpg test for a SQL/JSON construct. To fix, suppress the warning if the rule contains any "if" statement. Manual comparison of gram.y with the generated preproc.y file shows that the warning is now emitted only in rules where it's sensible. This problem has existed for a long time, so back-patch to all supported branches. Discussion: https://postgr.es/m/603615.1712245382@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/.
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