Jeff King [off-list ref] writes:
[2] Somewhere in the list archive is my patch to find partial
collisions like "git commit --sha1=31337", and I did in fact use
that micro-optimization. That, along with multi-threading, made it
feasible to do 6-8 character prefixes, as I recall.
In our testsuite, we have a test that uses many objects, all of
which have object names that begin with 10 '0' characters.
On Thu, Apr 14, 2016 at 07:18:53PM -0700, Junio C Hamano wrote:
Jeff King [off-list ref] writes:
quoted
[2] Somewhere in the list archive is my patch to find partial
collisions like "git commit --sha1=31337", and I did in fact use
that micro-optimization. That, along with multi-threading, made it
feasible to do 6-8 character prefixes, as I recall.
In our testsuite, we have a test that uses many objects, all of
which have object names that begin with 10 '0' characters.
Can you give more details on which test? 10 zeroes is 40 bits, which
means that by random chance, only about one in a trillion objects would
match that. We certainly didn't hit that randomly, and it seems like it
would be computationally expensive to have come up with the input for
even one such object, let alone "many".
-Peff