[darcs-users] darcs patch: resolve issue395: warn the user when the... (and 5 more)

Ganesh Sittampalam ganesh at earth.li
Mon Oct 27 19:36:50 UTC 2008


On Mon, 27 Oct 2008, David Roundy wrote:

>> Sat Oct 25 13:18:57 BST 2008  Ganesh Sittampalam <ganesh at earth.li>
>>   * accumulate hash strictly in hash/hashPS
>
> I've applied the above.
>
>> Sat Oct 25 13:23:31 BST 2008  Ganesh Sittampalam <ganesh at earth.li>
>>   * just hash the last 20 characters in LCS
>
> Is there a particular bug that this fixes? It sounds like the sort of
> change that could easily be a pessimization (due to increased hash
> collisions), so I'd like to see some sort of numbers to justify it.

It was intended as a "belt and braces" fix for 1017, as well as something 
that's likely to be a good idea in its own right. I'll see if I can 
provide some numbers while benchmarking some other work I did on slurpies, 
but I doubt it's that important or worth worrying about.

I think increased hash collisions in the general case are highly unlikely, 
the risk would be for some weird kinds of data.

>> Sat Oct 25 13:27:54 BST 2008  Ganesh Sittampalam <ganesh at earth.li>
>>   * issue 1017 now fixed
>
> When was this fixed? It still fails for me?

Either accumulating the hash strictly, or limiting the characters hashed, 
should fix it.

Ganesh


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