Re: BUG #14220: pg_get_expr() with an incorrect relation id crashes the server

On Thu, Jun 30, 2016 at 10:43 AM, <christopher(dot)m(dot)hanks(at)gmail(dot)com> wrote:
> The following bug has been logged on the website:
>
> Bug reference: 14220
> Logged by: Chris Hanks
> Email address: christopher(dot)m(dot)hanks(at)gmail(dot)com
> PostgreSQL version: 9.5.3
> Operating system: Linux Mint 17.2 64-bit
> Description:
>
> SELECT version():
> "PostgreSQL 9.5.3 on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu
> 4.8.2-19ubuntu1) 4.8.2, 64-bit"
>
> Reproduction:
>
> CREATE TABLE "test_table" ("id" serial PRIMARY KEY, "column_1" int4 NOT
> NULL, "column_2" int4);
>
> CREATE INDEX "idx" ON "test_table" ("column_1") WHERE ("column_2" = 4);
>
> SELECT pg_get_expr(i.indpred, i.indexrelid) FROM pg_index i;
>
> I realize that the query is incorrect, in order to retrieve the filter
> expression as SQL I need to call pg_get_expr(i.indpred, i.indrelid). But it
> seems like it should raise an error, rather than causing the server to
> crash.

Maybe the attnum bounds check should be an error rather than an
assertion, like in the attached. Thought perhaps with a better
message...

--
Thomas Munro
http://www.enterprisedb.com