Add variant compression to reduce generated Bazel targets for Android libraries

[arunkumar9t2]

Summary

Implements variant compression to reduce Bazel targets generated from Android projects with multiple flavors/build types. Equivalent variants are collapsed into fewer targets.

Data Flow

flowchart TB
    subgraph Analysis["Phase 1: Analysis (runs first)"]
        Task[AnalyzeVariantCompressionTask]
        Sorter[TopologicalSorter]
        Extractor[AndroidLibraryDataExtractor]
        Compressor[VariantCompressor]
        Cache[(VariantCompressionService<br/>in-memory cache)]
        
        Task --> Sorter
        Sorter -->|ordered projects| Extractor
        Extractor -->|variant data| Compressor
        Compressor -->|compression result| Cache
    end
    
    subgraph Generation["Phase 2: Generation (runs after)"]
        GenTask[GenerateBazelScriptsTask]
        Builder[ProjectBazelFileBuilder]
        TargetBuilder[AndroidLibraryTargetBuilder]
        Cache2[(VariantCompressionService)]
        Output[BUILD.bazel]
        
        GenTask --> Builder
        Builder --> TargetBuilder
        Cache2 -->|pre-computed targets| TargetBuilder
        TargetBuilder --> Output
    end
    
    Cache -.->|shared service| Cache2

Loading

How It Works

Phase 1 - Analysis:

1. AnalyzeVariantCompressionTask runs first
2. Projects processed in topological order (dependencies before dependents)
3. For each project: extract variant data → compress → register result in service
4. Results cached in VariantCompressionService (Gradle BuildService)

Phase 2 - Generation:

1. GenerateBazelScriptsTask runs per project
2. AndroidLibraryTargetBuilder queries the cache: service.get(project.path)
3. Uses pre-computed compressionResult.targets instead of re-extracting
4. Unit tests deduplicated by grouping variants by compressed suffix

Compression Logic:

• Flavor compression: If freeDebug ≡ paidDebug, emit single -debug target
• Build-type compression: If -debug ≡ -release, emit single target (no suffix)
• Dependency blocking: If dependency is expanded, dependent cannot compress

Key Files

Component	File
Analysis task	AnalyzeVariantCompressionTask.kt
Cache service	VariantCompressionService.kt
Compression engine	VariantCompressor.kt
Target builder	AndroidLibraryTargetBuilder.kt
Task wiring	TasksManager.kt
Topological sort	TopologicalSorter.kt

[arunkumar9t2]

The build is failing due to unrelated cache issue with crashlytics rules, will fix that separately