Comparing Exceptions and Errors

[Steven Schveighoffer]

On 6/15/22 3:51 PM, kdevel wrote:
> On Wednesday, 15 June 2022 at 03:09:56 UTC, Steven Schveighoffer wrote:
>> I don't see what you see wrong with the code I wrote. It's 
>> straightforward, obvious, and does the job I need it to do, in a way 
>> that's not prone to future mistakes.
> 
> Sometimes it is not easy to explain why code "feels" wrong and in the 
> case of
> 
> ```
>         scope(success) conn.exec("COMMIT");
> ```
> 
> it was not that clear to me some days ago. The reason why I would not write
> it is: `conn.exec("COMMIT")` may throw! Think of deferred constraints 
> which are checked not before the commit. But "[a] [...] scope(success) 
> statement may not exit with a throw [...]" [1]
> 
> [1] https://dlang.org/spec/statement.html#ScopeGuardStatement

I do depend on the commit (and the rollback) not throwing. I probably 
should swallow any exceptions at that point, and close the connection.

It has not harmed my code though. I tried throwing inside a scope guard, 
and it.... just works, I'm not sure why you can't throw in those?

I've been meaning to add a reentrant transaction system to mysql-native, 
because I hate that I can't do nested transactions. That would solve 
that problem and this problem, by giving me a nothrow function to call 
in the scope guard.

-Steve