[webkit-dev] Faster Git SVN updates

[Dirk Pranke]

Really? XCode isn't installed on the default Mac OS X install. I mean,
sure, the easier it is to get started and all, but that's hardly a big
hurdle.

-- Dirk

On Tue, Nov 30, 2010 at 3:15 PM, Eric Seidel <eric at webkit.org> wrote:
> I'm not sure git can be the "default" way to checkout webkit until it's
> installed on the default Mac OS X install. :)
> -eric
>
> On Tue, Nov 30, 2010 at 3:07 PM, Ojan Vafai <ojan at chromium.org> wrote:
>>
>> On Tue, Nov 30, 2010 at 2:59 PM, Eric Seidel <eric at webkit.org> wrote:
>>>
>>> I think it's time that we consider adding a "git" section
>>> to http://webkit.org/building/checkout.html.
>>
>> +1
>> Anecdotally, I imagine there are more webkit developers using git now than
>> svn.
>>
>>>
>>> -eric
>>>
>>> On Tue, Nov 30, 2010 at 2:20 PM, Eric Seidel <eric at webkit.org> wrote:
>>>>
>>>> I've now posted a patch to fix update-webkit as well:
>>>> https://bugs.webkit.org/show_bug.cgi?id=50273
>>>> Once that lands, I'll move the EWS bots over to using this "new" setup.
>>>>  Assuming those stay working, we can teach the tools to offer to fix "old"
>>>> setups.
>>>> -eric
>>>>
>>>> On Mon, Nov 22, 2010 at 4:58 PM, Ojan Vafai <ojan at chromium.org> wrote:
>>>>>
>>>>> http://trac.webkit.org/changeset/72575 for having scm.py do the right
>>>>> thing.
>>>>>
>>>>> On Thu, Nov 18, 2010 at 4:11 PM, Eric Seidel <eric at webkit.org> wrote:
>>>>>>
>>>>>> OK.  Sounds we should make this setup default.  I'll see if we can't
>>>>>> educate update-webkit and webkitpy/common/checkout/scm.py about detecting
>>>>>> this setup and doing the right thing in that case.
>>>>>> I'll file a separate bug about making scm.py's Git object use
>>>>>> --no-rebase during dcommit.
>>>>>> -eric
>>>>>>
>>>>>> On Thu, Nov 18, 2010 at 4:08 PM, Evan Martin <evan at chromium.org>
>>>>>> wrote:
>>>>>>>
>>>>>>> On Thu, Nov 18, 2010 at 3:36 PM, David Levin <levin at google.com>
>>>>>>> wrote:
>>>>>>> >> It's some magical setup by which your git svn fetchs will be much
>>>>>>> >> faser.
>>>>>>> >>  But I've heard it's buggy?  Can lead to local repository
>>>>>>> >> corruption?
>>>>>>> >> Can someone set me straight?
>>>>>>>
>>>>>>> No magic, just standard git: complicated, but logical once you
>>>>>>> understand how it works. :\
>>>>>>>
>>>>>>> It means that both "git pull" and "git svn fetch" will be updating
>>>>>>> the
>>>>>>> same branch.  When the latter sees the former has pulled down new
>>>>>>> stuff (quickly, via the fast git protocol), it knows to rebuild its
>>>>>>> metadata from the new stuff you fetched (rather than fetching it all
>>>>>>> over again via the slow svn protocol).
>>>>>>>
>>>>>>> There's a catch: if you "git svn fetch", that creates new commits
>>>>>>> locally.  When you later "git pull", you get the commits that were
>>>>>>> constructed by git.webkit.org, which don't match (due to differing
>>>>>>> timestamps).  This may screw up rebase, but I believe it's smart
>>>>>>> enough to recognize the commits are "the same" (applied the same
>>>>>>> diff;
>>>>>>> in git jargon, they have the same patch-id).  In practice you don't
>>>>>>> even run "git svn fetch" except when the git server is behind, so I
>>>>>>> don't know if there are corner cases here that I haven't run into.
>>>>>>>  (I
>>>>>>> also haven't tried this on Windows in a while -- kind of terrified of
>>>>>>> git there, though I hear it works for others.)
>>>>>>>
>>>>>>> In particular for bots that are not committing, I see no catch, other
>>>>>>> than that they will be behind whenever git.webkit.org is behind.
>>>>>>>
>>>>>>> >> The current git svn fetch is *super* slow.  Especially if you're
>>>>>>> >> behind by
>>>>>>> >> more than a day or two.
>>>>>>> >> If there was a way to make this faster method safe, by wrapping it
>>>>>>> >> in some
>>>>>>> >> other (error-checking) command which knew how to fall back to git
>>>>>>> >> svn
>>>>>>> >> rebase, etc. when necessary I would love to make it the default
>>>>>>> >> method for
>>>>>>> >> all WebKit get users.
>>>>>>>
>>>>>>> I have instructed all Chrome git users to use this method since
>>>>>>> (checking the commit history...) Feb 2009 and it seems to work for
>>>>>>> us.
>>>>>>>  Note that you need git >= 1.6.1 or so for it to work properly.  I
>>>>>>> also use this method for working on WebKit (though I've only
>>>>>>> committed
>>>>>>> around 60 patches so I mostly use it for pulling down new code).
>>>>>>>
>>>>>>> PS: our tools also run svn dcommit with "--no-rebase" to avoid
>>>>>>> needlessly going out to svn again after committing.
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> webkit-dev mailing list
>>>>>> webkit-dev at lists.webkit.org
>>>>>> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>>>>>>
>>>>>
>>>>
>>>
>>
>
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