Frankly, I am quite amazed that I even need to write this post. Source Control is such a basic part of the development process that I didn't want to believe there could be anything to say about it.
In the previous release of Entity Framework, there were deal breaker issues in the source control story. In short, it didn't work. I installed Visual Studio 2008 SP1 Beta to check how the new bits behave.
Let us start from the simplest scenario, defining a model with two classes, and commit to source control:
Now, let us say that Jane wants to add a Total property to the Order class:
At the same time, Joe is adding a Name property to the Customer class:
Jane commits first, and then Joe attempts to commit. Here is the result:
This is bad.
In fact, I would say that calling this unacceptable is not going far enough.
I made two unrelated modifications in the model, something that happens... all the time, and it puked on me.
This is not an acceptable Source Control story.
Now, to be fair, I dug a little deeper and tried to find what has cause the conflict. Here is what I find in the Model1.edmx file:
The conflict is in the visualization section of the file. This is a huge improvement over the previous version, but is is still broken. Leaving aside the fact that I have no idea why the visualization information is in the same file as the actual model, I shouldn't get merge conflicts on this trivial a change.
I didn't check the generated code, but there were conflicts there as well, which might cause additional issues. They could be regenerated, I assume.
In the end, I was able to get to the model that I wanted, after manually fixing the merge conflicts:
In summary, this is a huge improvement from the previous version, but it is still fall far from the minimum expected bar.
Please note that I have tested the most trivial scenario that I could, I have no idea what the behavior would be when dealing with more advance scenarios.