Re: Improved error handling (Was: [PATCH 1/2] sequencer: factor out rewrite_file())

> On Sat, Nov 18, 2017 at 10:01:45AM +0100, Johannes Sixt wrote:
> 
>>> Yeah, I have mixed feelings on that. I think it does make the control
>>> flow less clear. At the same time, what I found was that handlers like
>>> die/ignore/warn were the thing that gave the most reduction in
>>> complexity in the callers.
>>
>> Would you not consider switching over to C++? With exceptions, you get the
>> error context without cluttering the API. (Did I mention that
>> librarification would become a breeze? Do not die in library routines: not a
>> problem anymore, just catch the exception. die_on_error parameters? Not
>> needed anymore. Not to mention that resource leaks would be much, MUCH
>> simpler to treat.)
> 
> I threw this email on my todo pile since I was traveling when it came,
> but I think it deserves a response (albeit quite late).
> 
> It's been a long while since I've done any serious C++, but I did really
> like the RAII pattern coupled with exceptions. That said, I think it's
> dangerous to do it half-way, and especially to retrofit an existing code
> base. It introduces a whole new control-flow pattern that is invisible
> to the existing code, so you're going to get leaks and variables in
> unexpected states whenever you see an exception.
> 
> I also suspect there'd be a fair bit of in converting the existing code
> to something that actually compiles as C++.

> So if we were starting the project from scratch and thinking about using
> C++ with RAII and exceptions, sure, that's something I'd entertain[1]
> (and maybe even Linus has softened on his opinion of C++ these days ;) ).
> But at this point, it doesn't seem like the tradeoff for switching is
> there.