Re: Fix bug in handling of dropped columns in pltcl triggers

On Tue, Nov 1, 2016 at 4:17 AM, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com> wrote:
> While reviewing code coverage in pltcl, I uncovered a bug in trigger
> function return handling. If you returned the munged name of a dropped
> column, that would silently be ignored. It would be unusual to hit this,
> since dropped columns end up with names like ".......pg.dropped.2.......",
> but since that's still a legitimate name for a column silently ignoring it
> seems rather bogus.

It seems to me that this patch breaks $TG_relatts and what existing
applications would except from it:
<varlistentry>
<term><varname>$TG_relatts</varname></term>
<listitem>
<para>
A Tcl list of the table column names, prefixed with an empty list
element. So looking up a column name in the list with
<application>Tcl</>'s
<function>lsearch</> command returns the element's number starting
with 1 for the first column, the same way the columns are customarily
numbered in <productname>PostgreSQL</productname>. (Empty list
elements also appear in the positions of columns that have been
dropped, so that the attribute numbering is correct for columns
to their right.)
</para>
</listitem>
</varlistentry>
As this is a behavior present since 2004, it does not sound wise to change it.
--
Michael