chain of exceptions, next method
snarwin at gmail.com
Sun Aug 14 02:30:43 UTC 2022
On Sunday, 14 August 2022 at 02:07:05 UTC, Ali Çehreli wrote:
> This automatic "combining" of exceptions happens for cleanup
> code like scope(exit). (I remember bug(s) for scope(failure).):
To be precise, an exception thrown inside a 'finally' block gets
chained onto the previous exception, but an exception thrown
inside a 'catch' block does not. scope(exit) and scope(failure)
are just syntax sugar for 'finally' and 'catch', respectively.
Relevant spec paragraph:
> If an exception is raised in the FinallyStatement and is not
> caught before
> the original exception is caught, it is chained to the previous
> exception via
> the next member of Throwable. Note that, in contrast to most
> programming languages, the new exception does not replace the
> exception. Instead, later exceptions are regarded as
> 'collateral damage'
> caused by the first exception. The original exception must be
> caught, and
> this results in the capture of the entire chain.
So, once an exception is caught, the chain ends, and any
exception thrown after that begins a new chain.
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