How to Resolve Undefined Symbols Error in KMP for iOS

Introduction Are you experiencing the "Undefined symbols for architecture arm64" error when building your KMP (Kotlin Multiplatform) iOS app? This issue can be quite frustrating as it prevents your application from compiling successfully. In this article, we will delve into the reasons why this error occurs and offer a comprehensive solution to help you overcome it. Understanding the Issue The error message you encounter, particularly "Undefined symbols for architecture arm64: ..." often indicates a problem with symbols not being found during the linking phase of your iOS build. This could be due to several reasons, especially when working with KMP, Kotlin's Multiplatform project structure, and libraries like Koin and Compose. Possible Causes Mismatched Library Versions: Sometimes, the versions of libraries like Koin, Compose, or the Kotlin version itself might not be fully compatible. For instance, your Kotlin version is 2.1.20, while Koin 4.0.4 and Compose 1.8.0-rc01 might have specific requirements. Incorrect Configuration: If your Gradle settings or project configuration do not correctly define your iOS source sets or dependencies, you may face linking errors. Platform-Specific Code: Libraries or code that is not correctly configured for the arm64 architecture could lead to such errors. Step-by-Step Solution To resolve the issue, follow these steps: Step 1: Check Library Compatibility Ensure that the versions of your libraries are compatible with each other. You might need to check the official documentation for Koin, Compose, and Kotlin to find compatible versions. Consider upgrading or downgrading as necessary. Step 2: Configure Your Gradle Build Make certain that your build.gradle.kts file correctly defines your iOS target. Ensure that all dependencies are correctly added under the ios() block. For example: kotlin { ios { binaries { framework { baseName = "Shared" } } } } This ensures that shared code compiles properly for all platforms. Step 3: Ensure Proper Source Sets Check that your source sets for iOS are correctly configured in the common module. A common setup might look like this: sourceSets { val iosMain by getting { dependencies { implementation("io.insert-koin:koin-core:4.0.4") implementation("androidx.lifecycle:lifecycle-viewmodel-compose:2.1.20") } } } Make sure that the androidx.lifecycle.viewmodel.compose library is indeed linked in your iOS target. Step 4: Clean and Rebuild Your Project After making changes to your configurations, it's always a good practice to clean and rebuild your project. In your terminal, run: ./gradlew clean ./gradlew build This can clear out build artifacts that might be causing issues. Step 5: Check for Architecture Support As the error relates to the arm64 architecture, ensure that your project and all libraries support this architecture. You can check this from the Build Settings in Xcode under Architectures, ensuring arm64 is included. Step 6: Review CMake or Bundling Configurations If you're using CMake or a similar tool, ensure your configurations support the targets you are building for. Any misconfiguration here can lead to unresolved symbols in your build. Frequently Asked Questions (FAQ) What is KMP? KMP, or Kotlin Multiplatform, is a Kotlin feature enabling developers to share code between different platforms like iOS, Android, and web applications. Why do I get linking errors while building for iOS? Linking errors usually stem from missing or mismatched symbols in your build configuration, often related to incompatibilities in library versions or incorrect setup in source sets. How can I check for library version compatibility? You can refer to the documentation of each library or search for compatibility matrices provided by the Kotlin community or the library maintainers. Conclusion Encountering the "Undefined symbols for architecture arm64" error can be a stumbling block when building Kotlin Multiplatform apps for iOS. By verifying library compatibility, ensuring proper configuration in your Gradle setup, and cleaning your project, you can resolve this common issue efficiently. Following these steps will not only help you build your KMP app successfully for iOS but also enhance your understanding of the build processes involved. Remember, troubleshooting these issues can sometimes require a bit of patience and systematic investigation. Happy coding!

May 7, 2025 - 03:50

How to Resolve Undefined Symbols Error in KMP for iOS

Introduction

Are you experiencing the "Undefined symbols for architecture arm64" error when building your KMP (Kotlin Multiplatform) iOS app? This issue can be quite frustrating as it prevents your application from compiling successfully. In this article, we will delve into the reasons why this error occurs and offer a comprehensive solution to help you overcome it.

Understanding the Issue

The error message you encounter, particularly "Undefined symbols for architecture arm64: ..." often indicates a problem with symbols not being found during the linking phase of your iOS build. This could be due to several reasons, especially when working with KMP, Kotlin's Multiplatform project structure, and libraries like Koin and Compose.

Possible Causes

Mismatched Library Versions: Sometimes, the versions of libraries like Koin, Compose, or the Kotlin version itself might not be fully compatible. For instance, your Kotlin version is 2.1.20, while Koin 4.0.4 and Compose 1.8.0-rc01 might have specific requirements.
Incorrect Configuration: If your Gradle settings or project configuration do not correctly define your iOS source sets or dependencies, you may face linking errors.
Platform-Specific Code: Libraries or code that is not correctly configured for the arm64 architecture could lead to such errors.

Step-by-Step Solution

To resolve the issue, follow these steps:

Step 1: Check Library Compatibility

Ensure that the versions of your libraries are compatible with each other. You might need to check the official documentation for Koin, Compose, and Kotlin to find compatible versions. Consider upgrading or downgrading as necessary.

Step 2: Configure Your Gradle Build

Make certain that your build.gradle.kts file correctly defines your iOS target. Ensure that all dependencies are correctly added under the ios() block. For example:

kotlin {
    ios {
        binaries {
            framework {
                baseName = "Shared"
            }
        }
    }
}

This ensures that shared code compiles properly for all platforms.

Step 3: Ensure Proper Source Sets

Check that your source sets for iOS are correctly configured in the common module. A common setup might look like this:

sourceSets {
    val iosMain by getting {
        dependencies {
            implementation("io.insert-koin:koin-core:4.0.4")
            implementation("androidx.lifecycle:lifecycle-viewmodel-compose:2.1.20")
        }
    }
}

Make sure that the androidx.lifecycle.viewmodel.compose library is indeed linked in your iOS target.

Step 4: Clean and Rebuild Your Project

After making changes to your configurations, it's always a good practice to clean and rebuild your project. In your terminal, run:

./gradlew clean 
./gradlew build

This can clear out build artifacts that might be causing issues.

Step 5: Check for Architecture Support

As the error relates to the arm64 architecture, ensure that your project and all libraries support this architecture. You can check this from the Build Settings in Xcode under Architectures, ensuring arm64 is included.

Step 6: Review CMake or Bundling Configurations

If you're using CMake or a similar tool, ensure your configurations support the targets you are building for. Any misconfiguration here can lead to unresolved symbols in your build.

Frequently Asked Questions (FAQ)

What is KMP?

KMP, or Kotlin Multiplatform, is a Kotlin feature enabling developers to share code between different platforms like iOS, Android, and web applications.

Why do I get linking errors while building for iOS?

Linking errors usually stem from missing or mismatched symbols in your build configuration, often related to incompatibilities in library versions or incorrect setup in source sets.

How can I check for library version compatibility?

You can refer to the documentation of each library or search for compatibility matrices provided by the Kotlin community or the library maintainers.

Conclusion

Encountering the "Undefined symbols for architecture arm64" error can be a stumbling block when building Kotlin Multiplatform apps for iOS. By verifying library compatibility, ensuring proper configuration in your Gradle setup, and cleaning your project, you can resolve this common issue efficiently. Following these steps will not only help you build your KMP app successfully for iOS but also enhance your understanding of the build processes involved.

Remember, troubleshooting these issues can sometimes require a bit of patience and systematic investigation. Happy coding!