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When expanding an updatable view that is an INSERT's target, the rewriter failed to rewrite Vars in the ON CONFLICT UPDATE clause. This accidentally worked if the view was just "SELECT * FROM ...", as the transformation would be a no-op in that case. With more complicated view targetlists, this omission would often lead to "attribute ... has the wrong type" errors or even crashes, as reported by Mario De Frutos Dieguez. Fix by adding code to rewriteTargetView to fix up the data structure correctly. The easiest way to update the exclRelTlist list is to rebuild it from scratch looking at the new target relation, so factor the code for that out of transformOnConflictClause to make it sharable. In passing, avoid duplicate permissions checks against the EXCLUDED pseudo-relation, and prevent useless view expansion of that relation's dummy RTE. The latter is only known to happen (after this patch) in cases where the query would fail later due to not having any INSTEAD OF triggers for the view. But by exactly that token, it would create an unintended and very poorly tested state of the query data structure, so it seems like a good idea to prevent it from happening at all. This has been broken since ON CONFLICT was introduced, so back-patch to 9.5. Dean Rasheed, based on an earlier patch by Amit Langote; comment-kibitzing and back-patching by me Discussion: https://postgr.es/m/CAFYwGJ0xfzy8jaK80hVN2eUWr6huce0RU8AgU04MGD00igqkTg@mail.gmail.com
src/backend/parser/README Parser ====== This directory does more than tokenize and parse SQL queries. It also creates Query structures for the various complex queries that are passed to the optimizer and then executor. parser.c things start here scan.l break query into tokens scansup.c handle escapes in input strings gram.y parse the tokens and produce a "raw" parse tree analyze.c top level of parse analysis for optimizable queries parse_agg.c handle aggregates, like SUM(col1), AVG(col2), ... parse_clause.c handle clauses like WHERE, ORDER BY, GROUP BY, ... parse_coerce.c handle coercing expressions to different data types parse_collate.c assign collation information in completed expressions parse_cte.c handle Common Table Expressions (WITH clauses) parse_expr.c handle expressions like col, col + 3, x = 3 or x = 4 parse_func.c handle functions, table.column and column identifiers parse_node.c create nodes for various structures parse_oper.c handle operators in expressions parse_param.c handle Params (for the cases used in the core backend) parse_relation.c support routines for tables and column handling parse_target.c handle the result list of the query parse_type.c support routines for data type handling parse_utilcmd.c parse analysis for utility commands (done at execution time) See also src/common/keywords.c, which contains the table of standard keywords and the keyword lookup function. We separated that out because various frontend code wants to use it too.