Great information, David.<br><br>Sounds like a useful blog post!<br><br><div class="gmail_quote">On Thu, Apr 17, 2008 at 7:49 AM, David Chelimsky <<a href="mailto:dchelimsky@gmail.com">dchelimsky@gmail.com</a>> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="Ih2E3d">On Apr 17, 2008, at 7:11 AM, David Chelimsky wrote:<br>
<br>
> On Apr 17, 2008, at 5:20 AM, Jonathan Leighton<br>
> <<a href="mailto:j@jonathanleighton.com">j@jonathanleighton.com</a>> wrote:<br>
><br>
>> Hi David,<br>
>><br>
>> Is there any chance you could elaborate on the problems please, so<br>
>> that<br>
>> other projects can make an informed decision whether to use<br>
>> submodules<br>
>> or not?<br>
><br>
> There is always a chance :)<br>
<br>
</div>What I learned was that submodules are great for things like consuming<br>
plugins in your rails projects, but not so great for a development<br>
effort in multiple people are pushing and pulling to multiple<br>
repositories with dependencies and no multi-project transaction support.<br>
<br>
The parent repository depends on specific versions of the subs. As<br>
you're making changes in your local repos, the last thing you do is<br>
commit the parent with the references to the new versions of the subs.<br>
Every time you make a change to any of the subs you have to commit a<br>
change to the parent. These changes are useful as documentation if<br>
you're updating a plugin to the latest release. Not that useful if the<br>
log is polluted with these for every commit to every submodule.<br>
<br>
When you pull, you pull the parent first, and then use git-submodule<br>
to pull the correct versions of the subs. The parent is in control of<br>
the situation and it somewhat guarantees that you're getting all the<br>
right stuff. This is GREAT for consumers, but problematic for<br>
contributors. And even then, if consumers are pulling from a<br>
development branch while developers are pushing to it, then consumers<br>
might run into problems.<br>
<br>
Let's say you're doing a pull while I'm doing a push. If I push the<br>
parent first, and I push it before you do, there is a chance that when<br>
you go to pull the subs those versions of the subs might not be there<br>
yet. Conversely, if I push the subs first and you grab an old parent,<br>
you'll be pulling old subs. No problem when you're pulling, but it's<br>
going to create problems when you go to push because you're that much<br>
further down the history.<br>
<br>
Of course, these problems exist even when you're dealing with a single<br>
repository on a team that believes in frequent commits, continuous<br>
integration, etc. And just by virtue of the fact that we have several<br>
repos with dependencies means that we're going to run into conflicts<br>
now and then. It just seems that the explicit references from parent<br>
to children adds a layer of complexity to this for both consumers and<br>
developers.<br>
<br>
This all make sense?<br>
<div><div></div><div class="Wj3C7c"><br>
<br>
>> Cheers,<br>
>> Jon<br>
>><br>
>> On Wed, 2008-04-16 at 22:39 -0400, David Chelimsky wrote:<br>
>>> Hey all,<br>
>>><br>
>>> We ran into some problems last night with the repos up at github. We<br>
>>> initially thought it was a git-submodules bug. We learned that it<br>
>>> was<br>
>>> something else, but in the process of trying to find the source of<br>
>>> the<br>
>>> bug, we learned a few things about git-submodules and have decided<br>
>>> that it creates an unfortunate set of complications and dependencies<br>
>>> for a development effort like ours.<br>
>>><br>
>>> To that end, we have simplified. No more submodules. To update, do<br>
>>> the<br>
>>> following:<br>
>>><br>
>>> cd rspec-dev<br>
>>> git pull<br>
>>> rake git:update<br>
>>><br>
>>> See <a href="http://github.com/dchelimsky/rspec-dev/wikis/contributingpatches" target="_blank">http://github.com/dchelimsky/rspec-dev/wikis/contributingpatches</a><br>
>>> for more info.<br>
>>><br>
>>> Cheers,<br>
>>> David<br>
<br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br>Bryan Ray<br><a href="http://www.bryanray.net">http://www.bryanray.net</a><br><br>"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."