Replace byte-buddy with ASM for runtime method interception#2310
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colinmarsch wants to merge 2 commits intomasterfrom
Open
Replace byte-buddy with ASM for runtime method interception#2310colinmarsch wants to merge 2 commits intomasterfrom
colinmarsch wants to merge 2 commits intomasterfrom
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Byte-buddy was used solely for redefining class methods at runtime (e.g., intercepting View.isInEditMode()). This replaces it with direct ASM bytecode transformation + JDK Attach/Instrumentation APIs, removing ~2 transitive dependencies. Key changes: - AgentInstaller: self-attaches via VirtualMachine to obtain Instrumentation, replacing ByteBuddyAgent.install() - InterceptorRegistrar: uses ASM ClassVisitor to rewrite method bodies and Instrumentation.retransformClasses() to apply them, replacing ByteBuddy's redefine/MethodDelegation - retransformClasses (not redefineClasses) ensures compatibility with classes already modified by build-time ASM transforms - JVM flags -Djdk.attach.allowAttachSelf=true and -XX:+EnableDynamicAgentLoading added to test tasks Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
saket
approved these changes
Mar 17, 2026
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Summary
Byte-buddy (
byte-buddy+byte-buddy-agent, ~3.5 MB) was used solely for one thing: redefiningView.isInEditMode()at runtime viaInterceptorRegistrar. This replaces both dependencies with direct ASM bytecode transformation and the JDK Attach/Instrumentation APIs.Why: byte-buddy is a large, general-purpose bytecode library. Paparazzi's interception needs are minimal (replace a method body with a static delegate call), so ASM's lower-level API is a better fit — smaller dependency footprint, fewer transitive deps, and more transparent bytecode manipulation.
What changed
AgentInstaller.kt(new) — self-attaches to the current JVM viaVirtualMachine.attach()to obtain ajava.lang.instrument.Instrumentationinstance. ReplacesByteBuddyAgent.install().InterceptorRegistrar.kt(rewritten) — uses ASMClassReader/ClassWriter/ClassVisitorto rewrite target method bodies withINVOKESTATICcalls to interceptor classes. UsesInstrumentation.retransformClasses()(notredefineClasses) to apply transforms, which ensures compatibility with classes already modified by build-time ASM transforms.PaparazziSdk.kt— removedByteBuddyAgent.install()call; agent installation is now handled internally byInterceptorRegistrar.registerMethodInterceptors().PaparazziPlugin.kt— adds-Djdk.attach.allowAttachSelf=trueand-XX:+EnableDynamicAgentLoadingJVM flags to consumer test tasks (required for the JDK Attach API).libs.versions.toml/build.gradle— replacedbytebuddy-agent+bytebuddy-corewithorg.ow2.asm:asm:9.7.1.Test plan
InterceptorRegistrarTestpasses — verifies ASM-based method interception and class retransformation:paparazzi:testtests pass:sample:testDebugpasses — full end-to-end: agent install → ASM transform ofandroid.view.View.isInEditMode()→ layoutlib rendering → snapshot comparison🤖 Generated with Claude Code