Open Radar

 
From Apple:
I think you want “$(EXPANDED_CODE_SIGN_IDENTITY) not ${CODE_SIGN_IDENTITY}. “Mac Developer” is a placeholder that Xcode swaps out for a real signing identity behind the scenes, it’s not passed directly to codesign.

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The current default setting for the Code Signing Identity of the Debug configuration in Xcode 6.3 is "Mac Developer". This has been true for a long time. Unfortunately, it's a poor choice because it's ambiguous on a system which can build for Mac App Store deployment. This is because it matches both "3rd Party Mac Developer Application: SmileOnMyMac, LLC" _and_ "Mac Developer: Greg Scown". Therefore, it's better to use "Mac Developer: ", which only matches the latter.

To reproduce:

1. Use a system which has both a developer and deployment certificate for the Mac App Store
2. Use a project which has a script build phase which calls codesign, for example:

codesign -f -s "${CODE_SIGN_IDENTITY}" "$TARGET_BUILD_DIR/TextExpander.app/Contents/Library/QuickLook/TextExpanderQuickLook.qlgenerator"

(It may be that this can be reproduced without #2, but I figured I should report my specific case.)

Expected Results:

Expected build to succeed.

Actual Results:

Build fails because the Code Signing Identity is ambiguous. Specifically: "Mac Developer: ambiguous (matches "3rd Party Mac Developer Application: SmileOnMyMac, LLC (XXXXXXXXXX)" and "Mac Developer: Greg Scown (XXXXXXXXXX)" in /Users/gscown/Library/Keychains/login.keychain)"

Configuration:
MacBook Pro (Retina, 15-inch, Late 2013)
2.6 GHz Intel Core i7
16 GB 1600 MHz DDR3
NVIDIA GeForce GT 750M 2048 MB

Xcode Version/Build & OS X Version/Build
6.3/6D570
10.10.3/14D131