QFileInfo ::isbundle() returns incorrect value

The function QFileInfo::isbundle() return false for some bundles and true for others.

I tested Qt4.6 32bits, Qt4.8 32bits and 4.8 64bits. All have the bug.

Test protocole with my application :

• An application declares a bundle document in its info.plist (IsBundle.app declares .qtbu as document)
• I move the application to let the system takes care of the info.plist
• This application creates a bundle with QDir().mkdir()
  o The Finder understands it is a bundle, thanks to the info.plist
  o The function QFileInfo ::isbundle() returns false. It should return true.
• I create a directory with the finder called Test.qtbu
  o The Finder understands it is a bundle, thanks to the info.plist
  o The function QFileInfo ::isbundle() returns false. It should return true.

Test protocole with iDVD :

• iDVD is an application delivered by default by my mac.
• I create TestA.dvdproj with iDVD
  o QFileInfo ::isbundle() returns true
• I create TestB.dvdproj with the Finder
  o QFileInfo() ::isbundle() returns false. It should return true.

A bundle is just a directory with an extension, so in all cases the function QFileInfo::isBundle() should in all these cases return true.

I have browsed the Qt sources and found possible causes.

I found in the Qt's code that a function of mac is used : CFBundleGetPackageInfoInDirectory.
This function is normaly used to find the creator and the type of the bundle and return false if not found. I think this function can't assure that the directory is a bundle, juste if it is a bundle with a creator and type.
Hence, it should not be used by QFileInfo() ::isbundle() . It is not the proper function to use there, I think.

I also found in the .dvdproj a little file named Pkginfo. This file contains the creator and the type. But the Mac OS documentation explains this file is not necessary but can improve performance for code that accesses this information :
https://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/BPRuntimeConfig/Articles/ConfigApplications.html

• To confirme that, if I remove this file from TestA.dvdproj, it is still recognize as bundle in the Mac OS Finder AND by the test application.
• If I add this file in a bundle, the function QFileInfo ::isbundle() return true but it is not a solution, this file is not in all bundles.