Make our use of Exceptions consistent about flint

[AlkaDas991]

Hello @Patamap I would like to work on this issue, so can you please elaborate what I need to do to fix this issue?

[AlkaDas991]

@Patamap can you please explain me a little bit about the issue

[aornugent]

@mfellows - could you please add a brief description to help @AlkaDas991? I know exception handling was one of your bugbears.

[mfellows]

Hi Alka, thanks for your interest in this issue -

One example would be spatialtiledlocaldomaincontroller.cpp lines 794-840, you can see the huge variety of exceptions in there - which in theory should be helpful to narrow errors down, but in reality you need a try/catch block a mile long to extract all the information out of the different exception types.

This is particularly a problem in user (module) code where instead of catching all the different exception types in flintexceptions.h, we (well, I...) lazily catch FLINTException, and then all those boost::error_info details get lost. I think it would tidy things up a lot if we either got rid of all the specialized exceptions and stuck with a single one like SimulationError, or required FLINTException subclasses to override what() or some other method that rolls up all the details into some user or developer-friendly text.

There's a fair amount of flexibility for fixing this issue, steps would basically be:

• have a look through the code (i.e. spatialtiledlocaldomaincontroller) and notice how ugly the exception stuff currently is
• propose a strategy for improving the situation: could be one of my suggestions above or something completely different, but probably best to let people have a look before investing effort into coding
• implement whatever solution you come up with

[SlipperyGnome]

Hey @mfellows @aornugent Can I be assigned this issue, it has been inactive for a while and I think I can implement my solution here.

[aornugent]

That's fine - could you please also coordinate with @AlkaDas991 so that you can both learn together? I'll connect you on Slack.

[SlipperyGnome]

Hi @mfellows, I discussed this with @aornugent and it would be great if you look into this as well.
So I have thought of shifting all the boost::get_error_info and _spaciallocationinfo parts of SimulationError and LocalDomainError to flintexception.h that way it'll tidy up the spacialtiledlocaldomaincontroller.cpp file as these try/catch blocks have been used everywhere in that file. This way the exceptions.h file and flintexception.h file will have a similar layout and it'll be easier for a developer to go through this file.