Xcode12 CoreNFC simulator library not loaded

Question

Our app uses CoreNFC to scan NFC tags or you can use QR if NFC is not supported. This worked pretty well and we were able to run the app in the simulator for (ui) testing purposes.
Until Xcode12 / iOS14 GM builds. In iOS13 (or lower) we wouldn't have any issues running it on a simulator.

But in Xcode12 running it on a iOS14 simulator iPhone11 we would get the following:

dyld: launch, loading dependent libraries
DYLD_SHARED_CACHE_DIR=/Users/xxx/Library/Developer/CoreSimulator/Caches/dyld/19G73/com.apple.CoreSimulator.SimRuntime.iOS-14-0.18A372
DYLD_ROOT_PATH=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot
DYLD_LIBRARY_PATH=/Users/xxx/Library/Developer/Xcode/DerivedData/xxx-awnlestrbvesqqbynrhmluzhbcsc/Build/Products/Debug-iphonesimulator:/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/usr/lib/system/introspection
DYLD_INSERT_LIBRARIES=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libBacktraceRecording.dylib:/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSi
dyld: Library not loaded: /usr/lib/libnfshared.dylib
  Referenced from: /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/Frameworks/CoreNFC.framework/CoreNFC
  Reason: no suitable image found.  Did find:
    /usr/lib/libnfshared.dylib: mach-o, but not built for platform iOS-sim

That the simulator crashes makes sense to me, since the simulator can't scan NFC tags, but this is what I've done:

• I already linked to the CoreNFC framework and made it optional, like described here: Xcode 10, Swift 4 app with CoreNFC crashes in review on iOS 12
• Put #if canImport(CoreNFC) around import CoreNFC and it's underlying NFC code.
• Cleaning the build folder and deleting derived data.
• Created an empty Xcode12 project: https://github.com/basvankuijck/CoreNFCCrashProject, same result.
• Removed all the listed simulators and re-added one
• Added -weak_framework "CoreNFC" to the Other Linker Flags build setting

Obviously removing any references to the CoreNFC framework by either commenting out code sections and removing the framework link, makes the crash disappear. But that's not a suitable option.

Running it from Xcode12 on an iOS13 simulator 'device' works perfectly. So I can't seem to figure out what is causing this behavior

Answer 1

Apple obviously forgot to add libnfshared.dylib for whatever reason in the final version of Xcode 12 for iOS 14 simulators. A working workaround until Apple fixes this is to copy the missing lib from Xcode 12 beta 6 over (download the beta from Apple's developer download section). The missing lib can be found here and must go into the same directory for final Xcode 12

This works for me. 💯

If you want to avoid the hassle of downloading 11.25GB Xcode 12.2 beta for a single file. I have the file to share.

You may execute the following command to download and place it inside the Xcode package:

sudo curl https://storage.googleapis.com/mobile-simulator-build/libnfshared.dylib -o /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libnfshared.dylib

Hope it helps 😉

Answer 2

Apple obviously forgot to add libnfshared.dylib for whatever reason in the final version of Xcode 12 for iOS 14 simulators. A working workaround until Apple fixes this is to copy the missing lib from Xcode 12 beta 6 over (download the beta from Apple's developer download section). The missing lib can be found here and must go into the same directory for final Xcode 12:

Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/usr/lib

Answer 3

A bit in later, but maybe useful for others...

scenario:

• App must use NFC (where available)
• Must work also on pre-NFC device (i.es. iPhone 6 with iOS12)
• Build for iOS12

Some "good to use" technics:

#if canImport(CoreNFC)

import CoreNFC
...

instead of old:

 @available(iOS 11.0, *) .. and similar..

Notes:

"canImport" works at compile time, so if You want to solve:

"dyld: Library not loaded: /System/Library/Frameworks/CoreNFC.framework/CoreNFC Referenced from: /var/... Reason: image not found" message

we have to pay attention to LINK section.

Link section:

• Xcode 12.5 does not allow "optional" linking in its menus
• we must go to "Other Linker flags" and add:

-weak_framework CoreNFC

on 2 lines

(in text will be: OTHER_LDFLAGS = -weak_framework CoreNFC -lstdc++ )

Answer 4

Linker says that the file libnfshared (mach-o) doesn't include the binary for a simulator, which is strange because it's Apple core framework.

Create a new project with Xcode 12 and import the NFC framework. Build it and run it on a simulator. If it doesn't crash then compare the build settings specially for DYLD between those projects.

If this doesn't help, delete all the simulators and recreate new ones.

Updated:

It's bug in IOS 14 and someone has submitted a radar: openradar.appspot.com/FB8699389