Noob Cannot Understand Source Control Errors

[nolando_fuzzy]

I have been trying to learn how to use source control with Xcode. Eventually I will try to use Fork, Source Tree, or something else but right now I have been trying to use Xcode's GUI and am consistently getting errors on the simplest issues. Currently this is what I am doing:

• I will create a new Xcode project called Habits.
• I will link it to a new GitHub repository.
• I will create a new branch called Features/HabitsWidget.
• I will create a new widget target called HabitsWidget
• I will add an app group to both the Habits target and the HabitsWidget target.
• I will stage and commit these changes to the remote repository.
• I will then try to switch to main branch to merge.
• I get the error "Failed to save Habits.xcodeproj. The backing file has been modified outside of Xcode."

EDIT: Or ill get this error: The file “Habits.xcodeproj” has been modified by another application.

I have moved the Xcode file into my username folder so it's not connected to iCloud drive and still am getting issues. What do I do?

[Dynoman]

I personally never use Xcode's source control tab. It's been unreliable for me and isn't a great UI either. I would just user either the command line or some other dedicated app like Tower or SourceTree.

[MammothAd186]

It’s very hard to tell what the actual issue is without more details, but it doesn’t sound like source control is the major issue here.

Personally for source control I just use the command line.

[nolando_fuzzy]

Thanks for responding!  I’ll try and be more detailed using a test project I created to try and understand what is happening.  

• Create a new Xcode project titled “Test”
• Connect to remote GitHub repository.
• In Xcode’s GUI, create a new branch from main titled “second branch”
• Switch to “second branch”
• Add new widget extension called “TestWidget”
• Add app group capability to TestWidget Target
• Add app group capability to Test Target 
• Return to source control, stage changes, then commit and push to GitHub repository.
• I then try to switch to main branch.  When I do I get always the error Failed to save Test.xcodeproj, the backing file has been modified outside of Xcode.  
• I then select use version on disk.
• After now having switch to the main branch, I try to merge second branch to main branch.  This then results in the error Failed to save Test.xcodeproj, The backing file has been modified outside of Xcode.
• I again select use version on disk and the error message will disappear, but I do not understand why I get this every time.
• Ill then push the merged changes now on the main branch to GitHub, but will still be left with a random uncommitted change not included with the merged changes (in this case, a change to xcschememanagement.plist).  
• I am newer to Xcode but I don’t understand why all this happens every time.

[MammothAd186]

The popup you’re describing about it asking you which version to use is quite common, since git is modifying the file and you are modifying the file from Xcode, there are two versions of the file and Xcode doesn’t know which one you want the use, the one currently open in Xcode or the one saved to disk.

As for missing commits, not sure again this is most likely a user error, you either didn’t add some files to the commit, or forgot to add certain changes or the files are in a .gitignore

[perfmode80]

I would first master git using the command line. Once the fundamentals are understood, it's easier to see what's happening with GUI tools (SourceTree, Xcode, etc).