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setTargetTable threw an error if the proposed target RangeVar's relname matched any visible CTE or ENR. This breaks backwards compatibility in the CTE case, since pre-v10 we never looked for a CTE here at all, so that CTE names did not mask regular tables. It does seem like a good idea to throw an error for the ENR case, though, thus causing ENRs to mask tables for this purpose; ENRs are new in v10 so we're not breaking existing code, and we may someday want to allow them to be the targets of DML. To fix that, replace use of getRTEForSpecialRelationTypes, which was overkill anyway, with use of scanNameSpaceForENR. A second problem was that the check neglected to verify null schemaname, so that a CTE or ENR could incorrectly be thought to match a qualified RangeVar. That happened because getRTEForSpecialRelationTypes relied on its caller to have checked for null schemaname. Even though the one remaining caller got it right, this is obviously bug-prone, so move the check inside getRTEForSpecialRelationTypes. Also, revert commit 18ce3a4ab's extremely poorly thought out decision to add a NULL return case to parserOpenTable --- without either documenting that or adjusting any of the callers to check for it. The current bug seems to have arisen in part due to working around that bad idea. In passing, remove the one-line shim functions transformCTEReference and transformENRReference --- they don't seem to be adding any clarity or functionality. Per report from Hugo Mercier (via Julien Rouhaud). Back-patch to v10 where the bug was introduced. Thomas Munro, with minor editing by me Discussion: https://postgr.es/m/CAOBaU_YdPVH+PTtiKSSLOiiW3mVDYsnNUekK+XPbHXiP=wrFLA@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.