[webkit-dev] Faster Git SVN updates

[Eric Seidel]

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
>>>>>
>>>>>
>>>>
>>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-dev/attachments/20101130/8bd1b464/attachment.html>