5 Feb 2008 Roberta Allsman LSST Corporation LSST Data Management DC2 Post-mortem

2 DC2 LSSTException Use Vision of Use Reality of Use The Future

3 Vision of Use The core set of LSST Exceptions would support runtime exception situations. Developers would be able to create module specific exceptions derived from base LsstException class.

4 Vision of Use The state of the environment at the 'throw' –would be passed up the exception chain enabling the receiving exception handlers to support real-time recovery. –The data would be formatted as LSST DataProperties. The class throwing an LSST exception –would document all data provided to the receiver's exception handler.

5 Reality of Lsst Exception Use

6 Reality of Use Some Modules are using generic system exceptions C++ –mwi (Policy), fw, events Python –Mwi (Policy), fw, dps, events Some Modules define additional system exceptions C++ –Mwi (Policy), events

7 Reality of Use No Module adds extra data to Lsst Exceptions. Simple search showed 71 documented '\throw' I suspect some thrown exceptions are not be documented.

8 The Future Uniformity –mwi:Policy should use LsstException Intent is there since there is a “// TODO: use LSST exceptions” in mwi/src/Policy/Policy.cc –events and dps should consider using LsstException –other modules should examine their use of non- LsstException exceptions.

9 The Future Question Should Lsst Exceptions continue to support passing debug data to the exception handler?