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From: jian he <jian.universality@gmail.com>
Date: Thu, 16 Oct 2025 17:14:30 +0800
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 <CACJufxHND276gdo1oHkj_VrOX7=N3z=ymJHD1s2vgxAeESHO+w@mail.gmail.com>
Subject: Re: [PATCH] Add pg_get_policy_ddl() function to reconstruct CREATE
 POLICY statement
To: Akshay Joshi <akshay.joshi@enterprisedb.com>
Cc: Philip Alger <paalger0@gmail.com>,
 pgsql-hackers <pgsql-hackers@postgresql.org>
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hi. I still can not compile your v2.

../../Desktop/pg_src/src1/postgres/src/backend/utils/adt/ruleutils.c:
In function =E2=80=98get_formatted_string=E2=80=99:
../../Desktop/pg_src/src1/postgres/src/backend/utils/adt/ruleutils.c:13770:=
9:
error: function =E2=80=98get_formatted_string=E2=80=99 might be a candidate=
 for
=E2=80=98gnu_printf=E2=80=99 format attribute [-Werror=3Dsuggest-attribute=
=3Dformat]
13770 |         appendStringInfoVA(buf, fmt, args);
      |         ^~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Maybe you can register your patch on https://commitfest.postgresql.org/
then it will run all CI tests on all kinds of OS.

row security policy qual and with_check_qual can contain sublink/subquery.
but pg_get_expr can not cope with sublink/subquery.

see pg_get_expr comments below:
 * Currently, the expression can only refer to a single relation, namely
 * the one specified by the second parameter.  This is sufficient for
 * partial indexes, column default expressions, etc.  We also support
 * Var-free expressions, for which the OID can be InvalidOid.

see commit 6867f96 and
https://www.postgresql.org/message-id/flat/20211219205422.GT17618%40telsaso=
ft.com

I guess (because I can not compile, mentioned above):
"ERROR:  expression contains variables"
can be triggered by the following setup:

create table t(a int);
CREATE POLICY p1 ON t AS RESTRICTIVE FOR ALL
USING (a IS NOT NULL AND (SELECT 1 =3D 1 FROM pg_rewrite WHERE
pg_get_function_arg_default(ev_class, 1) !~~ pg_get_expr(ev_qual, 0,
false)));
SELECT pg_get_policy_ddl('t', 'p1', true);

You can also check my patch at https://commitfest.postgresql.org/patch/6054=
/
which similarly needs to build the POLICY definition for reconstruction.

see RelationBuildRowSecurity, checkExprHasSubLink also.