OpalRing components
Looks like something changed in the way classic AbsBeamline/Component is handled. Whenever I do a field lookup I get a segv. On digging, I see that there is a aperture_m sitting somewhere up the inheritance tree that is not set by default - and field lookups now seem to throw a segv if not set. This breaks the unit tests.
Fix would be to either:
- Check for NULL in aperture_m before assuming it is set
- Set it by default
If it were anywhere else, I would do a NULL check. But because it is right in the inner tracking loop, my preference would be to set aperture_m to a stupid default value (e.g. very large rectangular aperture).