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-rw-r--r--src/backend/parser/parse_cte.c193
1 files changed, 193 insertions, 0 deletions
diff --git a/src/backend/parser/parse_cte.c b/src/backend/parser/parse_cte.c
index 4e0029c58c9..f4f7041ead0 100644
--- a/src/backend/parser/parse_cte.c
+++ b/src/backend/parser/parse_cte.c
@@ -18,9 +18,13 @@
#include "catalog/pg_type.h"
#include "nodes/nodeFuncs.h"
#include "parser/analyze.h"
+#include "parser/parse_coerce.h"
+#include "parser/parse_collate.h"
#include "parser/parse_cte.h"
+#include "parser/parse_expr.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
+#include "utils/typcache.h"
/* Enumeration of contexts in which a self-reference is disallowed */
@@ -334,6 +338,195 @@ analyzeCTE(ParseState *pstate, CommonTableExpr *cte)
if (lctyp != NULL || lctypmod != NULL || lccoll != NULL) /* shouldn't happen */
elog(ERROR, "wrong number of output columns in WITH");
}
+
+ if (cte->search_clause || cte->cycle_clause)
+ {
+ Query *ctequery;
+ SetOperationStmt *sos;
+
+ if (!cte->cterecursive)
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("WITH query is not recursive"),
+ parser_errposition(pstate, cte->location)));
+
+ /*
+ * SQL requires a WITH list element (CTE) to be "expandable" in order
+ * to allow a search or cycle clause. That is a stronger requirement
+ * than just being recursive. It basically means the query expression
+ * looks like
+ *
+ * non-recursive query UNION [ALL] recursive query
+ *
+ * and that the recursive query is not itself a set operation.
+ *
+ * As of this writing, most of these criteria are already satisfied by
+ * all recursive CTEs allowed by PostgreSQL. In the future, if
+ * further variants recursive CTEs are accepted, there might be
+ * further checks required here to determine what is "expandable".
+ */
+
+ ctequery = castNode(Query, cte->ctequery);
+ Assert(ctequery->setOperations);
+ sos = castNode(SetOperationStmt, ctequery->setOperations);
+
+ /*
+ * This left side check is not required for expandability, but
+ * rewriteSearchAndCycle() doesn't currently have support for it, so
+ * we catch it here.
+ */
+ if (!IsA(sos->larg, RangeTblRef))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("with a SEARCH or CYCLE clause, the left side of the UNION must be a SELECT")));
+
+ if (!IsA(sos->rarg, RangeTblRef))
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("with a SEARCH or CYCLE clause, the right side of the UNION must be a SELECT")));
+ }
+
+ if (cte->search_clause)
+ {
+ ListCell *lc;
+ List *seen = NIL;
+
+ foreach(lc, cte->search_clause->search_col_list)
+ {
+ Value *colname = lfirst(lc);
+
+ if (!list_member(cte->ctecolnames, colname))
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("search column \"%s\" not in WITH query column list",
+ strVal(colname)),
+ parser_errposition(pstate, cte->search_clause->location)));
+
+ if (list_member(seen, colname))
+ ereport(ERROR,
+ (errcode(ERRCODE_DUPLICATE_COLUMN),
+ errmsg("search column \"%s\" specified more than once",
+ strVal(colname)),
+ parser_errposition(pstate, cte->search_clause->location)));
+ seen = lappend(seen, colname);
+ }
+
+ if (list_member(cte->ctecolnames, makeString(cte->search_clause->search_seq_column)))
+ ereport(ERROR,
+ errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("search sequence column name \"%s\" already used in WITH query column list",
+ cte->search_clause->search_seq_column),
+ parser_errposition(pstate, cte->search_clause->location));
+ }
+
+ if (cte->cycle_clause)
+ {
+ ListCell *lc;
+ List *seen = NIL;
+ TypeCacheEntry *typentry;
+ Oid op;
+
+ foreach(lc, cte->cycle_clause->cycle_col_list)
+ {
+ Value *colname = lfirst(lc);
+
+ if (!list_member(cte->ctecolnames, colname))
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("cycle column \"%s\" not in WITH query column list",
+ strVal(colname)),
+ parser_errposition(pstate, cte->cycle_clause->location)));
+
+ if (list_member(seen, colname))
+ ereport(ERROR,
+ (errcode(ERRCODE_DUPLICATE_COLUMN),
+ errmsg("cycle column \"%s\" specified more than once",
+ strVal(colname)),
+ parser_errposition(pstate, cte->cycle_clause->location)));
+ seen = lappend(seen, colname);
+ }
+
+ if (list_member(cte->ctecolnames, makeString(cte->cycle_clause->cycle_mark_column)))
+ ereport(ERROR,
+ errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("cycle mark column name \"%s\" already used in WITH query column list",
+ cte->cycle_clause->cycle_mark_column),
+ parser_errposition(pstate, cte->cycle_clause->location));
+
+ cte->cycle_clause->cycle_mark_value = transformExpr(pstate, cte->cycle_clause->cycle_mark_value,
+ EXPR_KIND_CYCLE_MARK);
+ cte->cycle_clause->cycle_mark_default = transformExpr(pstate, cte->cycle_clause->cycle_mark_default,
+ EXPR_KIND_CYCLE_MARK);
+
+ if (list_member(cte->ctecolnames, makeString(cte->cycle_clause->cycle_path_column)))
+ ereport(ERROR,
+ errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("cycle path column name \"%s\" already used in WITH query column list",
+ cte->cycle_clause->cycle_path_column),
+ parser_errposition(pstate, cte->cycle_clause->location));
+
+ if (strcmp(cte->cycle_clause->cycle_mark_column,
+ cte->cycle_clause->cycle_path_column) == 0)
+ ereport(ERROR,
+ errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("cycle mark column name and cycle path column name are the same"),
+ parser_errposition(pstate, cte->cycle_clause->location));
+
+ cte->cycle_clause->cycle_mark_type = select_common_type(pstate,
+ list_make2(cte->cycle_clause->cycle_mark_value,
+ cte->cycle_clause->cycle_mark_default),
+ "CYCLE", NULL);
+ cte->cycle_clause->cycle_mark_value = coerce_to_common_type(pstate,
+ cte->cycle_clause->cycle_mark_value,
+ cte->cycle_clause->cycle_mark_type,
+ "CYCLE/SET/TO");
+ cte->cycle_clause->cycle_mark_default = coerce_to_common_type(pstate,
+ cte->cycle_clause->cycle_mark_default,
+ cte->cycle_clause->cycle_mark_type,
+ "CYCLE/SET/DEFAULT");
+
+ cte->cycle_clause->cycle_mark_typmod = select_common_typmod(pstate,
+ list_make2(cte->cycle_clause->cycle_mark_value,
+ cte->cycle_clause->cycle_mark_default),
+ cte->cycle_clause->cycle_mark_type);
+
+ cte->cycle_clause->cycle_mark_collation = select_common_collation(pstate,
+ list_make2(cte->cycle_clause->cycle_mark_value,
+ cte->cycle_clause->cycle_mark_default),
+ true);
+
+ typentry = lookup_type_cache(cte->cycle_clause->cycle_mark_type, TYPECACHE_EQ_OPR);
+ if (!typentry->eq_opr)
+ ereport(ERROR,
+ errcode(ERRCODE_UNDEFINED_FUNCTION),
+ errmsg("could not identify an equality operator for type %s",
+ format_type_be(cte->cycle_clause->cycle_mark_type)));
+ op = get_negator(typentry->eq_opr);
+ if (!op)
+ ereport(ERROR,
+ errcode(ERRCODE_UNDEFINED_FUNCTION),
+ errmsg("could not identify an inequality operator for type %s",
+ format_type_be(cte->cycle_clause->cycle_mark_type)));
+
+ cte->cycle_clause->cycle_mark_neop = op;
+ }
+
+ if (cte->search_clause && cte->cycle_clause)
+ {
+ if (strcmp(cte->search_clause->search_seq_column,
+ cte->cycle_clause->cycle_mark_column) == 0)
+ ereport(ERROR,
+ errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("search sequence column name and cycle mark column name are the same"),
+ parser_errposition(pstate, cte->search_clause->location));
+
+ if (strcmp(cte->search_clause->search_seq_column,
+ cte->cycle_clause->cycle_path_column) == 0)
+ ereport(ERROR,
+ errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("search_sequence column name and cycle path column name are the same"),
+ parser_errposition(pstate, cte->search_clause->location));
+ }
}
/*
generated by cgit v1.2.3 (git 2.46.0) at 2025-08-10 16:44:39 +0000