BUG #15539: Deadcode in OpenTableList

The following bug has been logged on the website:

Bug reference: 15539
Logged by: Pan Bian
Email address: bianpan2016@163.com
PostgreSQL version: 11.1
Operating system: Linux
Description:

File: src/backend/commands/publicationcmds.c
Function: OpenTableList
Issue details:
The function OpenTableList performs the condition check " if
(list_member_oid(relids, childrelid))" twice. The second condition will
always evaluate to FALSE. As a result, the code (i.e., heap_close) on the
true branch of the second condition check is deadcode.

For your convenience, I copy-and-paste related code as follows.

static List *
OpenTableList(List *tables)
{
...
foreach(lc, tables)
{
...
if (recurse)
{
...
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);

if (list_member_oid(relids, childrelid)) //### first
check
continue;

/*
* Skip duplicates if user specified both parent and child
* tables.
*/
if (list_member_oid(relids, childrelid)) //### second
check, always be false
{ //### deadcode
heap_close(rel, ShareUpdateExclusiveLock);
continue;
}

/* find_all_inheritors already got lock */
rel = heap_open(childrelid, NoLock);
rels = lappend(rels, rel);
relids = lappend_oid(relids, childrelid);
}
}
}

list_free(relids);

return rels;
}

Thank you,
Pan Bian