How to use Git properly with Xcode? - ios

Question

I have been an iphone developer for a while, and I have recently been including git in my workflow. I have used git settings found on http://shanesbrain.net/2008/7/9/using-xcode-with-git for my workflow so far.
Those settings tell git to exclude *.pbxproj from merges? Is there a real reason for doing this? For example, when I add a file to the project and push to origin, my fellow developers will not have that file added to their xcode project when they pull. Then if one of them builds a release this file may not be included. Shouldn't I just let git handle the merges for the project file? Why or why not this file should be in merges and how to properly handle the situation when files are added to the project?

Answer 1

I have worked on iPhone applications full time since the SDK launch, most of that time spent working on teams with multiple developers.
The truth is that it's way more harmful to disallow merging of that .pbxproj file than it is helpful. As you say, when you add a file unless other people get that file, they have to also add it to their project - in an application of any size, that sucks and it also takes away a huge benefit of source code control in that you cannot really revert to a complete earlier project state just through git.
The .pbxproj file is simply a property list (similar to XML). From experience, just about the ONLY merge conflict you were ever get is if two people have added files at the same time. The solution in 99% of the merge conflict cases is to keep both sides of the merge, which for git at least simply involves removing any >>>>, <<<<, and ==== lines. In fact this is so common that I have created a simple shell script to fix a .pbxproj file in a merge state from git, I run this from within the project directory (at the Classes level):
#!/bin/sh
projectfile=`find -d . -name 'project.pbxproj'`
projectdir=`echo *.xcodeproj`
projectfile="${projectdir}/project.pbxproj"
tempfile="${projectdir}/project.pbxproj.out"
savefile="${projectdir}/project.pbxproj.mergesave"
cat $projectfile | grep -v "<<<<<<< HEAD" | grep -v "=======" | grep -v "^>>>>>>> " > $tempfile
cp $projectfile $savefile
mv $tempfile $projectfile
Worst case if it fails (you ask XCode to load the project and it fails to load), you simply delete the .pbxproj file, check out the master from git, and re-add your files. But I've never had that happen in many months of use with this script, again working full time on iPhone applications with several other developers.
Another option (pointed out in comments below) that you can try using in place of the script, is to add this line to a .gitattributes file:
*.pbxproj text -crlf -diff -merge=union
Then git will always take both sides of a merge for the .pbxproject files, having the same effect as the script I provided only without any extra work.
Lastly, here is my complete .gitignore file, showing what I do have it set to ignore as there are a few things you don't want - in my case really just emacs remnants and the whole build directory:
# xcode noise
build/*
*.pbxuser
*.mode1v3
*~
# old skool
.svn
# osx noise
.DS_Store
profile

Answer 2

This works for me in Xcode 4.6 and Git 1.7.5.
Add and commit .gitattributes file with this:
*.pbxproj binary merge=union
I've tested this with another team member and works great.
Taken from:
http://robots.thoughtbot.com/post/33796217972/xcode-and-git-bridging-the-gap

Answer 3

Frankly, the existing answers are misleading.
If you never delete or rename files, then using the merge=union strategy, which just combines the differences in different commits directly, is a good idea.
However, in the real world, we do need to delete or rename files sometimes. Merging the differences without any modification would make a lot of problems under these situations, and these problems usually lead to the "Workspace Integrity - Couldn't load project" issue, which makes you even not able to run the project.
The best solution I got so far:
1) Design the project well and add all the needed files at the beginning, so you would seldom need to change the project.pbxproj.
2) Make your features tiny. Don't do too many things in a branch.
3) For any reason, if you need to modify the file structure and get conflicts in project.pbxproj, use your favorite text editor to solve them manually. As you make your tasks tiny, the conflicts might be easy to solve.

Answer 4

The short answer is that even if you don't include that line in .gitattributes, you may not be able to easily merge two modified versions of a .pbxproj. It's better for git to treat it as a binary.
See here for details: Git and pbxproj
Update: Even though the git book still agrees with this answer, I no longer do. I version control my .pbxproj just like any other non-binary source file.

Answer 5

I did create a Python script that can handle merge conflicts in XCode Project files.
If you want to try it, you can check it out here: https://github.com/simonwagner/mergepbx
You will have to install it as a merge driver, so it gets called automatically when you have a merge conflict in your project file (the README.md will tell you how to do that).
It should work much better than using merge=union as mergepbx understands the semantics of your project file and therefore will resolve the conflict correctly.
However the project is still alpha, don't expect it to understand every project file that is out there.