[darcs-users] GSoC: network optimisation vs cache vs library?

Ganesh Sittampalam ganesh at earth.li
Thu Apr 15 21:45:51 UTC 2010


On Thu, 15 Apr 2010, Max Battcher wrote:

> To my knowledge its certainly possible for darcs to end up commuting a new 
> patch nearly anywhere in the repository's patch order, even on just a 
> pull/apply.

I believe that pull/apply are always append-only. Indeed, off the top of 
my head, only optimize --reorder, obliterate, unrecord and amend-record 
can do anything other than appending, and they just delete from somewhere 
in the middle.

> Usually its quite unlikely, but theoretically it is still possible for 
> the merger of long divergent branches to result in unusual repository 
> orders that don't necessarily reflect the history of either branch very 
> well (other than obvious dependencies, of course)...

Certainly that's true if you if you pull into a fresh repo in random 
order, but if you always pull from one to another then the order of 
patches in the target will persist.

> Even if Trac+Darcs revision numbers don't contort alongside patch order, its 
> still possible for the ``darcs show contents --match "hash patch-hash"`` to 
> produce subtly different results after only a pull/apply due to commutation.

I don't think this statement is true, given the above.

Ganesh


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