Best Practices for Managing and Resolving Dependency Conflicts in Gradle

As our Application grows and we incorporate numerous Android dependencies and third-party libraries, these may include the same dependencies with different versions, limiting our ability to manage them effectively.

Dependency conflicts in Gradle can lead to build failures or unexpected behaviour in your application. This article explores strategies to resolve dependency conflicts in Gradle.

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Analyzing Dependencies

1. The External Libraries dropdown provides a comprehensive list of all the libraries your project depends on. This includes

• Android SDK Libraries
• Third-Party Libraries
• Module Dependencies

2. Viewing the Dependency Tree: we need to analyze the external libraries and view the dependency tree. Use the following command to generate a detailed:

./gradlew app:dependencies

Strategies for Resolving Dependency Conflicts

1. Force a Specific Version

• Use the force method to enforce a specific version of a dependency.

configurations.all {
    resolutionStrategy {
        force 'com.squareup.okhttp3:okhttp:4.9.0'
    }
}

2. Exclude Transitive Dependencies

• Exclude conflicting transitive dependencies from specific libraries.

dependencies {
    implementation("com.example:library:1.0.0") {
        exclude group: "com.squareup.okhttp3", module: "okhttp"
    }
}

3. Use Dependency Constraints

• Define constraints to specify acceptable versions for dependencies.

dependencies {
    constraints {
        implementation("com.squareup.okhttp3:okhttp") {
            version {
                strictly("4.9.0")
            }
        }
    }
}

4. Use BOM (Bill of Materials)

• Use BOM to manage versions of related libraries, ensuring compatibility.

dependencies {
    implementation platform('com.google.firebase:firebase-bom:28.4.1')
    implementation 'com.google.firebase:firebase-analytics'
    implementation 'com.google.firebase:firebase-auth'
}

5. Resolve Conflicts with Resolution Strategy

• Customize the resolution strategy to handle conflicts.

configurations.all {
    resolutionStrategy {
        eachDependency { details ->
            if (details.requested.group == 'com.squareup.retrofit2') {
                details.useVersion '2.9.0'
            }
        }
    }
}

Best Practices for Managing Dependencies

1. Centralize Dependency Versions

• Define all dependency versions in a single place to avoid version conflicts and make updates easier.

// build.gradle (Project level)
ext {
    versions = [
        kotlin: '1.5.21',
        coroutines: '1.5.0',
        retrofit: '2.9.0'
    ]
}

2. Use Dependency Management Plugins

• Use plugins like buildSrc or Version Catalogs to manage dependencies in a more structured way.

// build.gradle (Project level)
plugins {
    id 'com.android.application' version '7.0.0' apply false
    id 'org.jetbrains.kotlin.android' version '1.5.21' apply false
}

3. Group Dependencies by Functionality

• Organize dependencies by their functionality to improve readability and maintainability.

// build.gradle (Module level)
dependencies {
    // Core libraries
    implementation "org.jetbrains.kotlin:kotlin-stdlib:${versions.kotlin}"
    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:${versions.coroutines}"

    // Networking
    implementation "com.squareup.retrofit2:retrofit:${versions.retrofit}"
    implementation "com.squareup.retrofit2:converter-gson:${versions.retrofit}"
}

4. Use BOM (Bill of Materials) for Consistent Versions

• Use BOM to manage versions of related libraries, ensuring compatibility.

// build.gradle (Module level)
dependencies {
    implementation platform('com.google.firebase:firebase-bom:28.4.1')
    implementation 'com.google.firebase:firebase-analytics'
    implementation 'com.google.firebase:firebase-auth'
}

5. Avoid Hardcoding Versions in Dependencies

• Reference versions from a centralized location instead of hardcoding them in the dependencies block.

// build.gradle (Module level)
dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib:${versions.kotlin}"
}

6. Use Gradle’s Dependency Resolution Strategies

• Configure resolution strategies to handle version conflicts and enforce specific versions.

// build.gradle (Project level)
configurations.all {
    resolutionStrategy {
        force 'com.squareup.okhttp3:okhttp:4.9.0'
        eachDependency { details ->
            if (details.requested.group == 'com.squareup.retrofit2') {
                details.useVersion '2.9.0'
            }
        }
    }
}

Conclusion

Effective dependency management in Gradle is essential for maintaining a clean and efficient Android project. By centralizing dependency versions, using management plugins, grouping dependencies by functionality, and leveraging Gradle’s resolution strategies, you can ensure a robust and maintainable project structure. Implement these best practices to streamline your dependency management process in Android projects.