Upgrading to Xcode 7 creates "Missing current version declaration" warning on CoreData model

Question

Figured I'd post a complete question/answer here to the known bug:

When upgrading to Xcode 7 (stable/beta) from a previous release, your build suddenly gives you a new warning: "Missing current version declaration" for your CoreData model file.

Worst of all, double-clicking this warning goes nowhere, & there are no obvious hints within Xcode as to the resolution. How do you resolve this issue?

Answer 1

Note: This was tested on Xcode 6.4 & Xcode 7 beta 3 - As of Xcode 7 beta 4 there appears to be a built-in solution, and manually creating the file no longer works - see accepted answer

Open up Terminal, and navigate to your project directory & model file - your command should look something like this:

cd /Users/YOU/Documents/MyProject/MyProject/MyDataModel.xcdatamodeld

Now list all the contents of your data model directory:

ls -la

If you don't see a file called ".xccurrentversion", it needs to be created.

nano .xccurrentversion

Copy/paste the needed XML for the model version:

<?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">  
<plist version="1.0">  
<dict>  
  <key>_XCCurrentVersionName</key>  
  <string>YOURDATAMODELNAME.xcdatamodel</string>  
</dict>  
</plist>

Replace YOURDATAMODELNAME with the name of the data model directory, minus the extension (e.g. MyDataModel.xcdatamodeld --> MyDataModel).

Now, likely you'll need to fix the permissions for the file:

chmod 775 .xccurrentversion

.. which is sufficient.

Clean the project, restart Xcode, rebuild - warning should go away.

Largely compiled from this thread, with some more specificity + permissions fix: https://forums.developer.apple.com/thread/8861

Answer 2

While in Xcode’s Core Data model editor, in the menu bar select Editor -> Add Model Version.

Then in the version name you are free to specify what you like, you can just type in your model name. (verified on Xcode 7 beta 4)

(This will result in creation .xccurrentversion in your data model bundle)