Add flag to ignore kotlin-internal methods in methods diff

[owengray-google]

While using diffuse to investigate a refactor, I am seeing output like this:

jarpath: ../../out-old/dist/top-of-tree-m2repository-all-0.zip.unzipped/m2repository/androidx/compose/ui/ui-tooling-data-android/1.8.0-alpha05/ui-tooling-data-android-1.8.0-alpha05.aar.unzipped/classes.jar
../../prebuilts/build-tools/diffuse/diffuse-0.3.0/bin/diffuse diff --jar ../../out-old/dist/top-of-tree-m2repository-all-0.zip.unzipped/m2repository/androidx/compose/ui/ui-tooling-data-android/1.8.0-alpha05/ui-tooling-data-android-1.8.0-alpha05.aar.unzipped/classes.jar ../../out-new/dist/top-of-tree-m2repository-all-0.zip.unzipped/m2repository/androidx/compose/ui/ui-tooling-data-android/1.8.0-alpha05/ui-tooling-data-android-1.8.0-alpha05.aar.unzipped/classes.jar
OLD: classes.jar
NEW: classes.jar

 JAR   │ old      │ new      │ diff   
───────┼──────────┼──────────┼────────
 class │ 79.5 KiB │ 79.4 KiB │ -144 B 
 other │     86 B │     86 B │    0 B 
───────┼──────────┼──────────┼────────
 total │ 79.6 KiB │ 79.5 KiB │ -144 B 

 CLASSES │ old │ new │ diff      
─────────┼─────┼─────┼───────────
 classes │  17 │  17 │ 0 (+0 -0) 
 methods │ 266 │ 266 │ 0 (+1 -1) 
  fields │  68 │  68 │ 0 (+0 -0) 

=================
====   JAR   ====
=================

 size     │ diff   │ path                                                              
──────────┼────────┼───────────────────────────────────────────────────────────────────
          │  -72 B │ - META-INF/ui-tooling-data_release.kotlin_module                  
     72 B │  +72 B │ + META-INF/ui-tooling-data.kotlin_module                          
  2.7 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/CallGroup.class                
 10.7 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/CompositionCallStack.class     
  1.4 KiB │  -16 B │ ∆ androidx/compose/ui/tooling/data/ContextCache.class             
  1.3 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/EmptyGroup.class               
  4.6 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/Group.class                    
  2.9 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/JoinedKey.class                
  2.5 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/NodeGroup.class                
  1.2 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/Parameter.class                
  4.9 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/ParameterInformation.class     
    590 B │   -8 B │ ∆ androidx/compose/ui/tooling/data/ParseError.class               
 31.8 KiB │  -16 B │ ∆ androidx/compose/ui/tooling/data/SlotTreeKt.class               
  1.5 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/SourceContext.class            
    5 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/SourceInformationContext.class 
  3.9 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/SourceLocation.class           
  1.3 KiB │   -8 B │ ∆ androidx/compose/ui/tooling/data/SourceLocationInfo.class       
    796 B │   -8 B │ ∆ androidx/compose/ui/tooling/data/UiToolingDataApi.class         
──────────┼────────┼───────────────────────────────────────────────────────────────────
 77.2 KiB │ -144 B │ (total)                                                           


=====================
====   CLASSES   ====
=====================

METHODS:

   old │ new │ diff      
  ─────┼─────┼───────────
   266 │ 266 │ 0 (+1 -1) 
  
  + androidx.compose.ui.tooling.data.ContextCache getContexts$ui_tooling_data() → Map
  
  - androidx.compose.ui.tooling.data.ContextCache getContexts$ui_tooling_data_release() → Map

Basically, an AGP upgrade is causing the module name of this jar to change from ui_tooling_data_release to ui_tooling_data. The changed method is a kotlin-internal method that is name mangled with that module name, the renamed kotlin_module file is named by the module name, and the lost bytes are due to the shorter module name in the class file header, AIUI.

While this is in a large part an edge case, at minimum it would be nice to have a flag to exclude internal members from a jar diff. Changes to internal members should never be relevant, though excluding @PublishedApi from that exclusion would probably be appropriate (@PublishedApi aren't name-mangled like that, so they did not appear in this diff).

(It might also be nice to have a configuration flag for only printing the CLASSES or METHODS section, but that's easily doable in post-processing, which could get this down to an actionable warning output.)