Flutter 에서 flutter pub upgrade 후 빌드 에러 해결하기

아무 생각없이 flutter pub upgrade 이후 아래와 같은 오류가 발생하네요.

$ flutter run
Launching lib/main.dart on SM S***N in debug mode...
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/FollowChannelHandlerActivity.kt:5:38 Unresolved reference: CustomTabsActivity
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/FollowChannelHandlerActivity.kt:6:5 'onNewIntent' overrides nothing
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/FollowChannelHandlerActivity.kt:7:15 Unresolved reference: onNewIntent
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/FollowChannelHandlerActivity.kt:11:9 Unresolved reference: setResult
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/FollowChannelHandlerActivity.kt:11:19 Unresolved reference: RESULT_OK
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/FollowChannelHandlerActivity.kt:12:9 Unresolved reference: finish
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/IntentFactory.kt:59:27 Unresolved reference: AuthCodeCustomTabsActivity
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:41:40 Unresolved reference: Utility
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:51:36 Unresolved reference: Utility
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:57:36 Unresolved reference: Utility
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:82:55 Unresolved reference: AuthCodeCustomTabsActivity
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:100:26 Unresolved reference: Utility
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:121:36 Unresolved reference: Utility
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:130:36 Unresolved reference: Utility
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:143:22 Unresolved reference: Utility
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:171:55 Type argument is not within its bounds: should be subtype of 'Activity'
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:218:49 Unresolved reference: IntentResolveClient
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:237:21 Unresolved reference: Utility
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:258:21 Unresolved reference: Utility
e: file:///home/doogle/.pub-cache/hosted/pub.dev/kakao_flutter_sdk_common-1.8.0/android/src/main/kotlin/com/kakao/sdk/flutter/KakaoFlutterSdkPlugin.kt:274:40 Unresolved reference: Utility

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':kakao_flutter_sdk_common:compileDebugKotlin'.
> A failure occurred while executing org.jetbrains.kotlin.compilerRunner.GradleCompilerRunnerWithWorkers$GradleKotlinCompilerWorkAction
   > Compilation error. See log for more details

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 8s
Running Gradle task 'assembleDebug'...                              8.9s
Exception: Gradle task assembleDebug failed with exit code 1

갑자기 에러가 나서 구글링해보는데 app/build.gradle 파일에 있는 ex.kotlin_version 을 올려보라는 말이 있어서 해보니 정상적으로 빌드가 됩니다. 휴…

buildscript {
    ext.kotlin_version = '1.9.21'

    ...

}

위 ext.kotlin_version = ‘1.9.21’ 부분을 ext.kotlin_version = ‘1.9.22’ 로 변경하고 다시 flutter run 을 실행해보니 잘 빌드되네요. 순간 당황했습니다.

참고자료

• https://kjmhercules.tistory.com/7