Florian G. Pflug wrote:
> While trying to create a domain over an array type to enforce a certain
> shape or certain contents of an array (like the array being only
> one-dimensional or not containing NULLs), I've stumbled over what I
> believe to be a bug in postgresql 8.4
>
> It seems that check constraints on domains are *not* executed for
> literals of the domain-over-array-type - in other words, for expressions
> like:
> array[...]::<my-domain-over-array-type>.
>
> They are, however, executed if I first force the array to be of the base
> type, and then cast it to the array type.
> ...
> I still have the feeling that this a bug, though. First, because it
> leaves you with no way at guarantee that values of a given domain always
> fulfill certain constraints. And second because "array[...]::arraytype"
> at least *looks* like a cast, and hence should behave like one too.
Agreed, it's a bug. A simpler example is just:
postgres=# create domain myintarray as int[] check (value[1] < 10);
CREATE DOMAIN
postgres=# SELECT array['20']::myintarray; -- should fail
array
───────
{20}
(1 row)
There's a special case in transformExpr function to handle the
"ARRAY[...]::arraytype" construct, which skips the usual type-casting
and just constructs an ArrayExpr with the right target type. However,
it's not taking into account that the target type can be a domain.
Attached patch fixes that. Anyone see a problem with it?
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 04127bd..8ca4a2f 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -169,6 +169,20 @@ transformExpr(ParseState *pstate, Node *expr)
targetType,
elementType,
targetTypmod);
+
+ /*
+ * If the target array type is a domain, we still need
+ * to check the domain constraint. (coerce_to_domain
+ * is a no-op otherwise)
+ */
+ result = coerce_to_domain(result,
+ InvalidOid,
+ -1,
+ targetType,
+ COERCE_IMPLICIT_CAST,
+ tc->location,
+ false,
+ true);
break;
}
--
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