Resolving Dex Merge Errors In Expo SDK 53 With React-native-fast-image

July 8, 2025 by StackCamp Team 71 views

Expo SDK 53 and Old Architecture: Resolving Dex Merge Errors with react-native-fast-image

Introduction

When developing React Native applications with Expo SDK 53 and the old architecture, developers may encounter build failures, especially when integrating libraries like react-native-fast-image. This article addresses a common issue: Dex merge errors during the Android build process on EAS Build. Specifically, the error arises due to the duplicate definition of GeneratedAppGlideModuleImpl. This comprehensive guide will delve into the root cause of the problem, provide step-by-step instructions to reproduce the error, and offer effective solutions to ensure a successful build.

The core issue lies in the conflict arising from multiple definitions of the GeneratedAppGlideModuleImpl class during the Dex merging process. This usually happens when using libraries that depend on Glide, an image loading and caching library for Android. Understanding this conflict is crucial for developers aiming to optimize their build processes and deliver robust applications. We will explore practical steps to identify and resolve such issues, ensuring your React Native project with Expo SDK 53 builds smoothly on Android.

Understanding the Dex Merge Error

Root Cause Analysis

The Dex merge error encountered during the build process of a React Native application using Expo SDK 53 and the old architecture typically stems from duplicate classes in the final APK (Android Package Kit). The error message, "Type com.bumptech.glide.GeneratedAppGlideModuleImpl is defined multiple times," indicates that the GeneratedAppGlideModuleImpl class, which is part of the Glide library, is present in multiple dependencies. This duplication occurs because different libraries might include their own versions of Glide or have overlapping dependencies.

Glide is a popular image loading and caching library for Android, and react-native-fast-image utilizes it for efficient image handling. When building an Android application, the build tools merge all the necessary classes into Dex (Dalvik Executable) files, which are then packaged into the APK. If the same class is found in multiple Dex files, the merge process fails, leading to the Dex merge error. In the context of Expo SDK 53 and the old architecture, this issue is more pronounced due to the way dependencies are handled in the older build system. This problem is not unique to react-native-fast-image; it can occur with any library that transitively includes Glide or has conflicting dependencies.

To effectively resolve this issue, it is essential to understand the project's dependency tree and identify which libraries are causing the duplication. Common causes include direct and transitive dependencies on different versions of Glide or similar image processing libraries. By pinpointing the source of the conflict, developers can implement targeted solutions such as dependency exclusion or version alignment, which we will explore in detail in the subsequent sections. A clear understanding of these underlying mechanisms is crucial for maintaining a stable and efficient build process in your React Native projects.

Error Log Breakdown

To effectively diagnose and resolve Dex merge errors, it is crucial to understand the error log. The error log provides valuable information about the location and nature of the conflict. In the case of the GeneratedAppGlideModuleImpl duplication issue, the error log typically looks like this:

Execution failed for task ':app:mergeDexRelease'.

A failure occurred while executing com.android.build.gradle.internal.tasks.DexMergingTaskDelegate
There was a failure while executing work items
> A failure occurred while executing com.android.build.gradle.internal.tasks.DexMergingWorkAction
> com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
Learn how to resolve the issue at https://developer.android.com/studio/build/dependencies#duplicate_classes.
Type com.bumptech.glide.GeneratedAppGlideModuleImpl is defined multiple times:
/home/expo/workingdir/build/node_modules/@d11/react-native-fast-image/android/build/.transforms/522fffc70c9f354a77e42e68570f28eb/transformed/bundleLibRuntimeToDirRelease/bundleLibRuntimeToDirRelease_dex/com/bumptech/glide/GeneratedAppGlideModuleImpl.dex,
/home/expo/workingdir/build/android/app/build/intermediates/external_libs_dex/release/mergeExtDexRelease/classes.dex

Breaking down this log, the key parts to focus on are:

Execution failed for task ':app:mergeDexRelease': This indicates that the error occurred during the Dex merging process, specifically when merging release builds.
com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives: This is the main exception, highlighting that there was an issue while merging Dex archives.
Type com.bumptech.glide.GeneratedAppGlideModuleImpl is defined multiple times: This is the most critical part of the log, directly stating that the class com.bumptech.glide.GeneratedAppGlideModuleImpl is defined in multiple locations.
File Paths: The log provides the paths where the duplicate class is found. In the example above, it is present in:
- /home/expo/workingdir/build/node_modules/@d11/react-native-fast-image/android/build/.transforms/.../com/bumptech/glide/GeneratedAppGlideModuleImpl.dex
- /home/expo/workingdir/build/android/app/build/intermediates/external_libs_dex/release/mergeExtDexRelease/classes.dex

By examining these file paths, developers can identify the libraries or modules that include the conflicting class. In this case, @d11/react-native-fast-image is one of the sources, which is a common culprit due to its dependency on Glide. The other path usually points to the main application's build directory, indicating that Glide or a related library is also included in the main app dependencies.

Understanding the error log enables developers to pinpoint the exact cause of the Dex merge failure, making it easier to implement the correct solutions, such as excluding conflicting dependencies or aligning library versions. This systematic approach is essential for resolving build issues and ensuring a smooth development process when working with Expo SDK 53 and the old architecture.

Reproducing the Error

Step-by-Step Instructions

To effectively troubleshoot and resolve the Dex merge error, reproducing the error in a controlled environment is essential. Here are the steps to reproduce the issue in a React Native project using Expo SDK 53 and the old architecture:

Create a New React Native Project with Expo SDK 53: Start by initializing a new React Native project using Expo. Ensure that you specify the SDK version 53 to replicate the exact environment where the error occurs.
```
expo init MyProject
cd MyProject
expo upgrade 53.0.0
```
Install react-native-fast-image: Add the @d11/react-native-fast-image library to your project. This library is a common dependency that utilizes Glide, making it a frequent cause of Dex merge errors.
```
npx expo install @d11/react-native-fast-image
```
Configure Android Build: Ensure your project's android/build.gradle and android/app/build.gradle files are configured correctly for the old architecture. This typically involves verifying that you are not using the new architecture (Fabric) and that your build configurations are standard for Expo SDK 53.
Run EAS Build for Android: Use Expo Application Services (EAS) to build your Android application. This step is crucial because the Dex merge error often manifests during the build process on EAS, where dependencies are fully resolved and merged.
```
eas build -p android
```
Monitor the Build Process: Observe the build logs on EAS. The build will likely fail during the :app:mergeDexRelease task, and the error message will indicate the duplicate definition of com.bumptech.glide.GeneratedAppGlideModuleImpl.

Expected Outcome

When following the steps above, the expected outcome is a build failure with the following error message in the EAS build logs:

Execution failed for task ':app:mergeDexRelease'.

A failure occurred while executing com.android.build.gradle.internal.tasks.DexMergingTaskDelegate
There was a failure while executing work items
> A failure occurred while executing com.android.build.gradle.internal.tasks.DexMergingWorkAction
> com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
Learn how to resolve the issue at https://developer.android.com/studio/build/dependencies#duplicate_classes.
Type com.bumptech.glide.GeneratedAppGlideModuleImpl is defined multiple times:
/home/expo/workingdir/build/node_modules/@d11/react-native-fast-image/android/build/.transforms/.../com/bumptech/glide/GeneratedAppGlideModuleImpl.dex,
/home/expo/workingdir/build/android/app/build/intermediates/external_libs_dex/release/mergeExtDexRelease/classes.dex

This error confirms that the GeneratedAppGlideModuleImpl class is defined multiple times, causing the Dex merge failure. Successfully reproducing this error allows you to verify that the issue is present and that any solutions you implement are effective in resolving it. By following these steps, developers can create a consistent environment for testing and troubleshooting Dex merge errors in their React Native projects using Expo SDK 53.

Solutions to Resolve Dex Merge Errors

Dependency Exclusion

One effective method to resolve Dex merge errors, particularly the GeneratedAppGlideModuleImpl duplication issue in Expo SDK 53 projects, is through dependency exclusion. This technique involves preventing the inclusion of conflicting dependencies by excluding them from specific libraries that introduce the duplication. In the context of react-native-fast-image and Glide, this means identifying which library is pulling in the conflicting version of Glide and excluding it.

To implement dependency exclusion, you need to modify the android/app/build.gradle file in your React Native project. Within the dependencies block, you can specify exclusions for particular dependencies. For example, if react-native-fast-image is the library causing the conflict, you can exclude Glide from its transitive dependencies.

Here’s how to exclude Glide from react-native-fast-image:

dependencies {
    implementation(project(':react-native-fast-image')) {
        exclude group: 'com.github.bumptech.glide', module: 'glide'
    }
    // Other dependencies...
}

In this code snippet:

implementation(project(':react-native-fast-image')) declares the dependency on react-native-fast-image.
exclude group: 'com.github.bumptech.glide', module: 'glide' specifies that any transitive dependency on Glide should be excluded from react-native-fast-image.

After adding the exclusion, you may need to include Glide directly as a dependency in your project to ensure it is still available if other parts of your application require it. This can be done by adding a specific version of Glide to your dependencies block:

dependencies {
    implementation(project(':react-native-fast-image')) {
        exclude group: 'com.github.bumptech.glide', module: 'glide'
    }
    implementation 'com.github.bumptech.glide:glide:4.12.0' // Specify the version
    annotationProcessor 'com.github.bumptech.glide:compiler:4.12.0' // If Glide version requires annotationProcessor
    // Other dependencies...
}

It's important to choose a Glide version that is compatible with both react-native-fast-image and any other libraries in your project that depend on Glide. Checking the documentation or release notes of react-native-fast-image can provide guidance on compatible versions.

By excluding the conflicting dependency and potentially re-including a specific version, you can resolve the Dex merge error caused by duplicate GeneratedAppGlideModuleImpl classes. This approach ensures that only one version of Glide is included in your final APK, eliminating the conflict and allowing your build to complete successfully. Dependency exclusion is a powerful tool for managing complex dependency trees and resolving build issues in React Native projects with Expo SDK 53 and the old architecture.

Aligning Library Versions

Another effective strategy for resolving Dex merge errors, particularly those arising from duplicate classes like GeneratedAppGlideModuleImpl in Expo SDK 53 projects, is aligning library versions. This approach involves ensuring that all libraries in your project that depend on a common dependency, such as Glide, use the same version. Inconsistent versions can lead to duplicate class definitions, causing Dex merge failures during the build process.

To align library versions, you need to identify all dependencies in your project that rely on the conflicting library (in this case, Glide) and then ensure they all use the same version. This often involves examining your project’s build.gradle files (both the root-level and app-level) and the dependencies of any third-party libraries you are using.

Here are the steps to align library versions:

Identify Glide Dependencies: First, determine which libraries in your project depend on Glide. Common culprits include react-native-fast-image and other image-related libraries. You can check the dependencies of these libraries by looking at their build.gradle files or their documentation.
Check Current Versions: Review your project’s android/app/build.gradle file to see if Glide is explicitly included as a dependency. If it is, note the version. Also, check the dependencies of any libraries that use Glide to see if they specify a version. Sometimes, a library might include Glide transitively without explicitly stating the version.
Enforce Consistent Versions: Use the configurations.all block in your android/app/build.gradle file to enforce a consistent version of Glide across all dependencies. This ensures that all libraries use the same version, preventing duplication.
```
configurations.all {
    resolutionStrategy {
        force 'com.github.bumptech.glide:glide:4.12.0' // Replace with your desired version
    }
}
```
In this code snippet:
- configurations.all applies the resolution strategy to all configurations.
- resolutionStrategy { force 'com.github.bumptech.glide:glide:4.12.0' } forces all dependencies to use version 4.12.0 of Glide. Replace 4.12.0 with the version you want to enforce.
Verify Compatibility: Ensure that the version of Glide you choose is compatible with all the libraries in your project that depend on it. Check the documentation or release notes of these libraries for compatibility information.
Clean and Rebuild: After making these changes, clean your build and rebuild the project to ensure the new dependency resolution strategy is applied.
```
cd android
./gradlew clean
cd ..
eas build -p android --profile development
```

By aligning library versions, you ensure that only one version of Glide is included in your final APK, resolving the Dex merge error. This approach is particularly useful in projects with complex dependency trees where multiple libraries might introduce conflicting versions of common dependencies. Consistently managing library versions is a crucial aspect of maintaining a stable and efficient build process in React Native projects using Expo SDK 53.

Upgrading or Downgrading Dependencies

In some cases, Dex merge errors in Expo SDK 53 projects can be resolved by upgrading or downgrading dependencies. This approach is particularly effective when the issue stems from a known bug in a specific version of a library or incompatibility between different libraries. The GeneratedAppGlideModuleImpl duplication error, often encountered with react-native-fast-image and Glide, can sometimes be mitigated by adjusting the versions of these libraries.

Upgrading Dependencies

Upgrading to the latest version of a library can often resolve issues, as newer versions typically include bug fixes and improvements. If you suspect that the Dex merge error is due to a bug in an older version of react-native-fast-image or Glide, upgrading might be the solution.

To upgrade dependencies:

Check for Updates: Start by checking for available updates for react-native-fast-image and Glide. You can use npm or yarn to find the latest versions.
```
npm outdated @d11/react-native-fast-image
# or
yarn outdated @d11/react-native-fast-image
```

Update the Library: If a newer version is available, update the library using your package manager.

npx expo install @d11/react-native-fast-image@latest
# or
yarn add @d11/react-native-fast-image@latest

Update Glide Version: If you are explicitly including Glide in your project, update it to the latest compatible version.

// android/app/build.gradle
dependencies {
    implementation 'com.github.bumptech.glide:glide:4.13.0' // Use the latest version
    annotationProcessor 'com.github.bumptech.glide:compiler:4.13.0'
}

Test the Build: After upgrading, clean your build and rebuild the project to see if the issue is resolved.

Downgrading Dependencies

In contrast, downgrading a dependency might be necessary if the latest version introduces new issues or incompatibilities. This is less common but can be effective if a specific version is known to work well with your project setup.

To downgrade dependencies:

Identify a Stable Version: Determine a stable version of the library that is known to work with your project. Check release notes, community forums, or issue trackers for information on stable versions.
Downgrade the Library: Downgrade the library using your package manager, specifying the version you want to use.
```
npx expo install @d11/react-native-fast-image@<version>
# or
yarn add @d11/react-native-fast-image@<version>
```
Replace <version> with the specific version number you want to downgrade to.
Downgrade Glide Version: If necessary, downgrade the Glide version in your android/app/build.gradle file to match the requirements of the downgraded library.
Test the Build: Clean and rebuild your project after downgrading to verify if the issue is resolved.

By carefully upgrading or downgrading dependencies, you can address Dex merge errors caused by library incompatibilities or bugs. It’s crucial to test your build after making these changes to ensure stability and functionality. This approach provides a flexible way to manage dependencies and maintain a healthy build process in React Native projects using Expo SDK 53.

Conclusion

In conclusion, resolving Dex merge errors, particularly the GeneratedAppGlideModuleImpl duplication issue, in Expo SDK 53 projects with the old architecture requires a systematic approach. This article has outlined the root cause of the error, provided step-by-step instructions to reproduce it, and presented three effective solutions: dependency exclusion, aligning library versions, and upgrading or downgrading dependencies.

Dependency exclusion allows you to prevent conflicting libraries from being included in your build, ensuring that only one version of a problematic dependency like Glide is present.
Aligning library versions ensures that all dependencies that rely on a common library use the same version, preventing duplication and conflicts.
Upgrading or downgrading dependencies can address issues caused by bugs or incompatibilities in specific library versions, providing a flexible way to manage your project's dependencies.

By understanding the error logs and applying these solutions, developers can effectively troubleshoot and resolve Dex merge errors, leading to smoother build processes and more stable applications. Maintaining a well-managed dependency tree is crucial for the long-term health of your React Native projects. Remember to always test your build thoroughly after making changes to ensure that the issue is resolved and no new problems have been introduced. With these strategies, you can confidently tackle Dex merge errors and build robust applications with Expo SDK 53.