How come I can install an app store distribution build directly on my device?

I noticed this too and always meant to find out why it worked. It used to be true that you couldn’t install an App Store build but that appears to have changed, I’m guessing either in iOS6 or 5.

I found that I could only install App Store provisioning profile builds when a compatible Ad Hoc profile was already installed. Developer profiles did not work. I did not try wildcard profiles. So it looks like the Ad Hoc rules changed.

I can’t find the rules for installing an Ad Hoc build, but on the topic of launching the “Ad Hoc Provisioning Profiles in Depth” section of Apple’s App Distribution Guide says that

The app successfully launches if the app’s bundle ID matches the App ID, the signature matches the distribution certificate, and the device is in the device list of the ad hoc provisioning profile.

So I guess technically an AppStore builds meet these Ad Hoc requirements because it too is signed with the same distribution certificate. The use of “the” is misleading here because it makes it sound like iOS consults your embedded.mobileprovision, which is untrue. It should read “an” ad hoc profile.

NB: The install only worked when the Ad Hoc profile was already installed on the device, so that’s one reason to make separate ad hoc builds.

NB: This is all conjecture, another explanation could be that Xcode handles the installation of the embedded.mobileprovision and now continues when the AppStore profile installation fails.

This raises another question for me: why does iOS DWIM for App Store builds yet refuses to launch Ad Hoc builds with expired provisioning profiles when a perfectly valid replacement is installed?