Flutter iOS build failing on BigSur, XCode 12

Question

Flutter iOS build fails due to issues with headers.

I followed the simple steps mentioned on flutter.dev for launching an app on iOS simulator. I've had no problems working with flutter on Android/Web, but this is the first time I've tried running it on iOS.

Summary of error - (Complete Error: https://gist.github.com/mannprerak2/520f8a749431a50b8472783c71d67dda )

...
   #import "Headers/CoreMedia.h"
            ^
    /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator14.4.sdk/System/Library/Frameworks/CoreMedia.framework/Headers/CoreMedia.h:15:10: note: in file included from /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator14.4.sdk/System/Library/Frameworks/CoreMedia.framework/Headers/CoreMedia.h:15:
    #include <CoreMedia/CMFormatDescription.h>
             ^
    /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator14.4.sdk/System/Library/Frameworks/CoreMedia.framework/Headers/CMFormatDescription.h:26:10: error: could not build module 'CoreAudio'
    #include <CoreAudio/CoreAudioTypes.h>
             ^
    /Users/prerakmann/development/test_ios/ios/Runner/Runner-Bridging-Header.h:1:9: note: in file included from /Users/prerakmann/development/test_ios/ios/Runner/Runner-Bridging-Header.h:1:
    #import "GeneratedPluginRegistrant.h"
            ^
    /Users/prerakmann/development/test_ios/ios/Runner/GeneratedPluginRegistrant.h:8:9: error: could not build module 'Flutter'
    #import <Flutter/Flutter.h>
            ^
    192 errors generated.
    <unknown>:0: error: failed to emit precompiled header '/Users/prerakmann/Library/Developer/Xcode/DerivedData/Runner-ahrcvwuwhqnepxdcpfsagztcuwrr/Build/Intermediates.noindex/PrecompiledHeaders/Runner-Bridging-Header-swift_1QEOMJ6SUMBGB-clang_3BG5Q8JCTPBV5.pch' for bridging header '/Users/prerakmann/development/test_ios/ios/Runner/Runner-Bridging-Header.h'
    384 errors generated.
    <unknown>:0: error: generate-pch command failed with exit code 1 (use -v to see invocation)
    note: Using new build system
    note: Building targets in parallel
    note: Planning build
    note: Constructing build description
...

System: Macbook Pro 13 (2020), BigSur 11.2.1, Xcode 12.4

Flutter: Tried on the latest stable and beta channel.

Simulator: Tried on iOS 8, iOS 12.

Steps to reproduce: Create a new flutter app, run it.

Answer 1

Turns out this was happening due to CPATH being defined like this.

╰─$ echo $CPATH
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include

A temporary fix is to set CPATH= in current terminal window, run flutter clean, and then run the app.