Re: BUG #19631: currtid2() on a view with GROUP BY ctid crashes with XX000 - Mailing list pgsql-bugs

Hi,

On Wed, 19 Aug 2026 at 14:54, PG Bug reporting form <noreply@postgresql.org> wrote:

The following bug has been logged on the website:

Bug reference:      19631
Logged by:          Zheng Hacker
Email address:      hackerzheng666@gmail.com
PostgreSQL version: 19beta3
Operating system:   Linux x86_64
Description:       

PostgreSQL version: 20devel (commit bdbf662, 2026-08-19)
  OS: Linux x86_64

  Calling currtid2() on a view whose SELECT includes ctid in a GROUP BY
  hits elog(ERROR) without errcode() in tid.c, producing SQLSTATE XX000.

  Reproducer:

  CREATE TABLE tid_tab (a int);
  INSERT INTO tid_tab VALUES (1);
  CREATE VIEW tid_view_with_ctid AS
    SELECT ctid, a FROM tid_tab GROUP BY ctid, a;
  SELECT currtid2('tid_view_with_ctid'::text, '(0,1)'::tid);
  -- ERROR: XX000: currtid cannot handle this view
  -- LOCATION: currtid_for_view, tid.c:435

  Note: the view has a ctid column (so it passes the tididx check at
  line 389 which does have a proper errcode), but the GROUP BY prevents
  the code from resolving the TLE to a simple base-table Var, so it
  falls through to the elog(ERROR) at line 435 which lacks errcode().

  Expected: a proper SQLSTATE (e.g. 0A000 feature_not_supported).

  Found by automated SQL fuzzing.
  Credit: Zheng Wang, Yanjie Zhao, Yiyang Liu

Thanks for the reports.  #19629, #19630 and #19631 share one cause: an
error ordinary SQL can reach is raised without an errcode(), so the user
sees XX000.

I scanned the backend for the same pattern, and the attached patch fixes
those three plus four more sites with the same problem: unicode_assigned()
on a non-UTF8 encoding, the pg_control_*() CRC check, a GiST tuple marked
invalid, and ALTER COLLATION ... REFRESH VERSION on "default".