REASSERT Code review request for 8012044: Give more information about self-suppression from Throwable.addSuppressed (original) (raw)

Remi Forax forax at univ-mlv.fr
Tue Apr 23 10:23:35 UTC 2013

On 04/23/2013 07:51 AM, Joe Darcy wrote:

Hi David,

On 04/22/2013 10:25 PM, David Holmes wrote: Hi Joe,

On 23/04/2013 9:05 AM, Joseph Darcy wrote: Hello,

Just reasserting the request for a review of the latest version of this patch: http://cr.openjdk.java.net/~darcy/8012044.2 I believe this version does an appropriate job of propagating exception information when there is misuse of the methods on Throwable. I still find the use of addSuppressed in initCause to be questionable. Given: catch(SomeException s) { sharedException.initCause(s); // oops already has a cause throw sharedException; } then the ISE isn't suppressing 's', but replacing/suppressing sharedException in my view, as it is what would have been thrown had the ISE not occurred. I understand the desire to not lose sight of the fact that 's' was thrown, but this is really no different to a finally block losing the original exception info. (And fixing that was rejected when the suppression mechanism was added.) Project Coin discussions did note try-catch-finally and try-with-resources were inconsistent on this point. While the try-with-resources behavior is regarded as preferable, we thought it would be too large a change to redefine the long-standing semantics of try-catch-finally. Anyway this isn't a "block" (not that such a thing exists), just a comment. The change isn't harmful and may be useful. Cheers, David Yes, I would describe the intention of this change as provding programmers more information to debug when the methods are Throwable and used improperly. Thanks, -Joe

Like David, I think that the use of addSuppressed is a bit too much, suppressed exception are exceptions that were thrown and there is no guarantee that a cause was thrown before (it's sometime the case, but sometimes the cause is used as a 'tunelling' mechanism, If I want to throw ThatException but the method only throw ThisException so I will create a ThisException that used a newly created ThatException as cause. In that case, the cause was never thrown and register it has a suppressed exception is weird IMO.

cheers, Rémi

More information about the core-libs-dev mailing list