Like most experienced iOS developers, I use an automated build system. A colleague of mine and I have spent portions of the last 2 years building up our system so what we do looks like magic to others! As part of this system, we’ve written tools and put together scripts to package our application as an .ipa (iPhone application). An .ipa file is simply a zip file with the extension changed.
Well, it isn’t that simple. It appears that how the zip is created is just as important as the structure of the package. There are various flavors of zip, libraries that do zip, and other tools that zip. In one of our tools, we were using a zip library. It appears that Apple made a change in iOS 9.0.2 or 9.1 that caused applications created by our tool to not install on devices. However, the problem was only present if the app was installed over the air or through iTunes; installed through Xcode’s Devices window succeeded. After an arduous day of debugging trying to determine the failure point (provisioning is usually to blame for failures and they can be super frustrating), I switched our tool to use the command line zip (/usr/bin/zip) and amazingly the problem went away.
It would appear that iTunes, iOS itself, and Xcode use slightly different methods for unzipping and installing applications. Since Apple’s xcrun command for packaging (PackageApplication) uses /usr/bin/zip, I think it is a safe bet. It is invoked using something like:
/usr/bin/xcrun -sdk iphoneos PackageApplication -v MyApp.app -o MyApp.ipa" --sign "iPhone Distribution: Scott Gruby"
On a side note, it also appears that there is an error in the PackageApplication script found at:
In Mac OS X 10.10 and higher, this line is no longer valid, so if you use this command, you need to modify the script.