Re: VC and bzr.

[Óscar Fuentes]

Stefan Monnier <address@hidden> writes:

>>>> and if that doesn't reduce the required time to something
>>>> reasonable, the Bazaar people have the means for fixing the
>>>> problem.
>>> I don't know what that means or if it's true.
>> The problem now is that bzr must operate on a remote filesystem and a
>> commit may require quite a bit of file I/O.
>> Once you have a friendly buddy on the other end, there is no reason for
>> a commit to a remote branch taking much more time than a local one,
>> being the setup of the ssh session the most expensive addition.
>
> Actually, that's not true.
> For a "lightweight remote checkout", the commit (even over a smart
> server) would be more difficult to make efficient than locally because
> the commit requires a potentially large transfer of data because you
> need to compare the new files (on one host) to the old files (on the
> other host).

I don't know why you care about lightweight remote checkouts, but
anyways it is not necessary to send the entire file over the wire. rsync
doesn't need to do that, why should bzr? Oh, wait... the bzr guys
doesn't particulary care about efficiency, do they?

> For other situations, the commit is really a commit+push, and the push
> is equivalent to a "pull", just done the other way around.  And if
> you've followed Bzr development, you'll know that Bzr is not that great
> at doing pulls efficiently and it's unlikely to improve soon.

Yes, they are happy enough with the current performance. Maybe if there
comes to be known among the crowd the fact about Emacs hackers not being
very pleased with their bzr experience, maybe the bzr guys would
reconsider their attitude and start caring about middle-sized projects
like Emacs.

It is a bit appalling to see how they boast about "bzr is now mature
enough to the point of being the choice for big projects like Emacs."

Oh, and I think that support for asyncrhonous commits on VC is good to
have, but with bzr sometimes taking *minutes* for a commit, special
situations must be considered, like the user editing and saving files
while the commit is on the way, or trying to commit something while the
previous one is not finished yet. It is not unlikely that some of those
scenarios may end with some breakage.