mirror of
https://github.com/postgres/postgres.git
synced 2025-11-07 19:06:32 +03:00
b4a71cf65d
Commit a3c7a993d fixed some cases involving target columns that are
arrays or composites by applying transformAssignedExpr to the VALUES
entries, and then stripping off any assignment ArrayRefs or
FieldStores that the transformation added. But I forgot about domains
over arrays or composites :-(. Such cases would either fail with
surprising complaints about mismatched datatypes, or insert unexpected
coercions that could lead to odd results. To fix, extend the
stripping logic to get rid of CoerceToDomain if it's atop an ArrayRef
or FieldStore.
While poking at this, I realized that there's a poorly documented and
not-at-all-tested behavior nearby: we coerce each VALUES column to
the domain type separately, and rely on the rewriter to merge those
operations so that the domain constraints are checked only once.
If that merging did not happen, it's entirely possible that we'd get
unexpected domain constraint failures due to checking a
partially-updated container value. There's no bug there, but while
we're here let's improve the commentary about it and add some test
cases that explicitly exercise that behavior.
Per bug #18393 from Pablo Kharo. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/18393-65fedb1a0de9260d@postgresql.org
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_enr.c handle ephemeral named rels (trigger transition tables, ...) parse_func.c handle functions, table.column and column identifiers parse_merge.c handle MERGE 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.