@BlrDroid

Deep Dive into KSP with Epoxy

Subhrajyoti Sen

Agenda

• Meta programming
• Intro to KSP
• Intro to Epoxy
• Implementations
• Migration

Meta Programming

Programming technique where programs treat other programs as their input data

Meta Programming - Android

• Dependency Injection - Dagger
• Room
• Moshi
• Epoxy
• Dependency Injection - Dagger-Reflect

Methods

• Reflection

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• Code generation

Reflection

• Slow?

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• JVM feature

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• Slow feedback

Code Generation

• Longer compile time

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• Possibly larger binaries

Kotlin Annotation Processing Tool (kapt)

• Modelled around Java

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• Delegates to javac and hence no multiplatform

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• Slow compile times

Kotlin Symbol Processing - KSP

• Modelled around Kotlin

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• Doesn’t delegate to javac, hence Multiplatform!

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• No stub generation

Minor limitations of KSP

• Cannot process expressions

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• Cannot modify code

Is KSP a Compiler Plugin?

Is KSP a Compiler Plugin?

Yes

Is KSP a Compiler Plugin?

Yes… and no

KSP has 2 parts

• The KSP API

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• The KSP Implementation

How does Epoxy use KSP?

Incremental Processing

• Isolating Mode

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• Aggregating Mode

Incremental Processing Demo

Testing Annotation Processors

• https://github.com/google/compile-testing for Java

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• https://github.com/tschuchortdev/kotlin-compile-testing for Kotlin

Thank You

@iamsubhrajyoti