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I have an iOS app built with Swift 2.2 and started having a problem recently. It works fine when building and running via Xcode, but after stopping the app from Xcode and then trying to open it again directly from the phone (both real device and simulator), it crashes before loading the initial view controller.

I was able to symbolicate the crash logs and the first line inside Thread 0 Crashed contains:

0x001aa754 specialized AppDelegate.application(UIApplication, didFinishLaunchingWithOptions : [NSObject : AnyObject]?) -> Bool (AppDelegate.swift:417)

On the line inside AppDelegate I have:

let buildFor = NSProcessInfo.processInfo().environment["BUILD_FOR"]! as String

I confirmed that was the cause of the crash because after commenting out that line and replacing it with let buildFor = "DEV" I was able to open the app from the home screen without any problem after closing it in Xcode.

I have two schemes, one where the BUILD_FOR environment variable is DEV and the other where it is PROD. What causes that value to be present when running via Xcode but not from the device/simulator, and how can I change that? That environment variable is used in multiple places (primarily in AppDelegate) to determine which URLs to use, either for production or development server, as well as using appropriate API keys for third-party services. I would like to have it set to DEV for the TestFlight build and PROD for when it's in the App Store.

Pat Needham
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  • How are you setting the environment variables for the non-Xcode execution? (The ones in the scheme are only in effect while running in Xcode; they aren't baked into the app in any way.) – Phillip Mills Dec 13 '16 at 14:53
  • I'm not setting them for the non-Xcode execution, which could be the problem. How am I supposed to set them? – Pat Needham Dec 13 '16 at 14:55
  • There's a discussion of 4 or 5 ways at: http://stackoverflow.com/questions/603785/environment-variables-in-mac-os-x/4567308#4567308 – Phillip Mills Dec 13 '16 at 15:16
  • Same issue here.. any luck? – vikzilla Apr 27 '17 at 04:24

1 Answers1

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I eventually went with another approach instead of using NSProcessInfo.processInfo(). Under Targets -> Build Settings -> Other Swift Flags, I went with two different flags, DEBUG and RELEASE like this: enter image description here

Then within AppDelegate.swift I use the Swift preprocessor macros #if/#else/#end to define my original buildFor boolean variable:

#if DEBUG
    let buildFor = "DEV"
    print("it is DEV")
#else
    let buildFor = "PROD"
    print("it is PROD")
#endif

// setting appropriate API keys, server URLs, etc
let apiKey = buildFor == "DEV" ? "testing api key" : "production one"

Doing it this way doesn't require multiple Xcode schemes.

Pat Needham
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