Create new ParseExprKind for use by policy expressions.

Policy USING and WITH CHECK expressions were using EXPR_KIND_WHERE for
parse analysis, which results in inappropriate ERROR messages when
the expression contains unsupported constructs such as aggregates.
Create a new ParseExprKind called EXPR_KIND_POLICY and tailor the
related messages to fit.

Reported by Noah Misch. Reviewed by Dean Rasheed, Alvaro Herrera,
and Robert Haas. Back-patch to 9.5 where RLS was introduced.

2 files changed, 18 insertions, 0 deletions

diff --git a/src/test/regress/expected/rowsecurity.out b/src/test/regress/expected/rowsecurity.out
index b146da373c..b0556c2ff1 100644
--- a/src/test/regress/expected/rowsecurity.out
+++ b/src/test/regress/expected/rowsecurity.out
@@ -3024,6 +3024,15 @@ CREATE RULE "_RETURN" AS ON SELECT TO t DO INSTEAD
   SELECT * FROM generate_series(1,5) t0(c); -- succeeds
 ROLLBACK;
 --
+-- Policy expression handling
+--
+BEGIN;
+SET row_security = FORCE;
+CREATE TABLE t (c) AS VALUES ('bar'::text);
+CREATE POLICY p ON t USING (max(c)); -- fails: aggregate functions are not allowed in policy expressions
+ERROR:  aggregate functions are not allowed in policy expressions
+ROLLBACK;
+--
 -- Clean up objects
 --
 RESET SESSION AUTHORIZATION;
diff --git a/src/test/regress/sql/rowsecurity.sql b/src/test/regress/sql/rowsecurity.sql
index 54f2c89eda..300f34ad4b 100644
--- a/src/test/regress/sql/rowsecurity.sql
+++ b/src/test/regress/sql/rowsecurity.sql
@@ -1290,6 +1290,15 @@ CREATE RULE "_RETURN" AS ON SELECT TO t DO INSTEAD
 ROLLBACK;
 
 --
+-- Policy expression handling
+--
+BEGIN;
+SET row_security = FORCE;
+CREATE TABLE t (c) AS VALUES ('bar'::text);
+CREATE POLICY p ON t USING (max(c)); -- fails: aggregate functions are not allowed in policy expressions
+ROLLBACK;
+
+--
 -- Clean up objects
 --
 RESET SESSION AUTHORIZATION;