I encountered this problem: getting an “already under source control” error when I tried to add my *.xcodeproj file to svn.
I was struggling with some issues after I renamed my iPhone project. I had done this before with another project. The file in question was my iPhone project file, “*.xcodeproj”. It appears as a file, but actually, it’s a directory! Everything became clear after that. In source control, within directories you will find a “.svn” file. This controls the presence of the file in the repository.
In command line, you can access the directory, and view the “.svn” file (or turn on hidden files in System Preferences, though you still can’t open the xcode file).
>svn status
? [my project].xcodeproj
>add *.codeproj
>svn: warning: '[my project].xcodeproj' is already under version control
>cd [myproject].xcodeproj
>rm -rf *.svn
>cd ..
>svn add [my project].xcodeproj
A [my project].xcodeproj
A [my project].xcodeproj/me.mode1v3
A [my project].xcodeproj/me.pbxuser
A [my project].xcodeproj/project.pbxproj
I’m using Google Code- which I love more than GitHub- and otherwise have had no issue with the otherwise very straighforward environment. I haven’t set my properties in svn, and I haven’t really done anything that complex besides adding new classes to the repo.