pgsql: pg_surgery: Fix infinite loop on large TID arrays

pg_surgery: Fix infinite loop on large TID arrays

heap_force_common() tracked the current position in the caller-supplied
tid[] using OffsetNumber, which is only 16 bits wide, so when the array
held more than 65535 entries, the updated index wrapped around and the
outer loop never reached the exit condition. A SQL call with a
sufficiently large TID array would then run until interrupted.

Fix by tracking the tid[] position using int instead of OffsetNumber.
A regress case based on the report is included.

Author: Andrey Rachitskiy <pl0h0yp1(at)gmail(dot)com>
Reviewed-by: Andrey Borodin <x4mmm(at)yandex-team(dot)ru>
Reported-by: Yuelin Wang <1217816127(at)qq(dot)com>
Backpatch-through: 14
Bug: #19607
Discussion: https://postgr.es/m/19607-2f256a66481c514b@postgresql.org

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/346fbdcc2a92e86c7e964d637f8333c7b8197143

Modified Files
--------------
contrib/pg_surgery/expected/heap_surgery.out | 17 +++++++++++++++++
contrib/pg_surgery/heap_surgery.c | 6 +++---
contrib/pg_surgery/sql/heap_surgery.sql | 8 ++++++++
3 files changed, 28 insertions(+), 3 deletions(-)