[Python-Dev] Fault handler updated, now disabled by default

[Stephen J. Turnbull]

Michael Foord writes:

 > It seemed from the discussion that the biggest barrier to enabling it by 
 > default was possible difficulties when embedding Python (multiple 
 > interpreters, potential conflicts with application signal handling). A 
 > public C-API to disable the functionality per interpreter would be one 
 > option for this.

That's not really good enough.  The point of installing a handler like
this is to "catch them squirmers".  All you have to do is override
some incautious developer's own squirmer-trap handler once, and Python
has made an Enemy-For-Life.  (This happened to XEmacs with esound.  I
immediately removed esound and anything that depends on it from my
workstation. ;-)  YMMV and you may think that that is not so important;
my point is that the proposal to provide a way to disable does not at
all address the objection.

 > Another possibility would be providing a C-API to enable it and
 > have the Python interpreter application call this, so that the
 > functionality remains off by default for embedded interpreters but
 > on for normal uses.

I think this is heading in the right direction.

Note: My own experience with such handlers has been positive, but it
does not involve embedding interpreters in either direction, so not
really helpful in addressing this objection.  Precisely *because* my
own experience has been positive, I worry about interfering with some
third party's handler.