XCode 10 app size much bigger

I noticed that my app built using XCode 10.0 doubled in size. Diggging into the app itself (in Finder), I noticed the culprit is the file assets.car, which is Apple's way of storing the asset catalog. Specifically:


Compiled in XCode 9.4.1, assets.car is 25.3 MB


Compiled in XCode 10.0, assets.car is 52.6 MB


That is more than double the size of before. I didn't notice the difference until it was already live in the App Store. Now my users are donwloading the update which is double in size...


Anyone know anything about this? Bug?

Post marked as unsolved Up vote post of ashort Down vote post of ashort
4.6k views

6 Replies

The App Store sizes (as displayed in the App Store) were wrong (massively inflated). Apple has since fixed the bug.

>We update the asset catalog file with versions of the assets that are optimized for the particular version of the OS that its running on.


Ah, thanks - that was what I expected/wondered about. Question now is what happens on an OS when OS-centric 'optimized' assets are missing... Say an app that was built prior to iOS 12 that is installed on iOS 12.

I posted a bug and Apple replied that this is by design. They said:


"This is expected behavior. We update the asset catalog file with versions of the assets that are optimized for the particular version of the OS that its running on. When the final application gets thinned then only what is necessary will be present."


To verify this, I checked how much space the app takes on my devices. For example, the iPhone App Store says my app is 66.3 MB. But when the app is installed on my iPhone, it has been thinned to 34.9 MB (I checked this using Settings / General / iPhone Storage).


I also checked the iPad App Store, which says my app is 66.3 MB. But when the app is installed on my iPad, it has been thinned to 32.9 MB.

The file count is basically the same. Just 2 new images in the asset catalog. Nothing fishy about them.


I forgot to say that assets.car is more than double in size in the ARCHIVE build, which is what gets uploaded to the App Store.


However if you look at the Derived Data (the normal builds), then assets.car is normal size.


So, recompiling in XCode 10.0 gives me this:


Archive: assets.car is 61.2 MB


Derived Data (device build): assets.car is 24.7 MB

I had the exact smae issue. If you are using CoCopods or another version then do a pod update, that helped me. However, my binary is still larger than I think it should be.

What is that asset file's file count, one vs. the other?