In my opinion different aspects should be handled separately.

This issue was about a SEGFAULT under rare circunstances (threads, errors, exit, tsv access).  As far as I can see the changes discussed in previous messages prevent the SEGFAULT.

If thread exit handlers do not run reliably a new ticket should be opened with some details.  Using the following script with printfs in SvFinalize, it seems to run every time:

~~~
package require Thread
set tid [thread::create -joinable];
::thread::release $tid;
::thread::join $tid;
::exit
~~~

With regards to enabling or disabling thread finalization altogether, I would suggest contacting the authors the reasons for the comment and whether it has been considered before enabling the feature.  See and where it is disabled; and later  where it is enabled.  It would seem to me that the comment is obsolete.

Best regards,
Adrián.