* What went wrong:
Execution failed for task ':childgit:app:transformDexArchiveWithExternalLibsDexMergerForDebug'.
> java.lang.RuntimeException: java.lang.RuntimeException: com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex

* Try:
Run with --info or --debug option to get more log output.

* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':childgit:app:transformDexArchiveWithExternalLibsDexMergerForDebug'.
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:100)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:70)
    at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:63)
    at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
    at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
    at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:88)
    at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:52)
    at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
    at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54)
    at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
    at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:248)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:197)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:107)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:241)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:230)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:124)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:80)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:105)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:99)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:625)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:580)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:99)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: java.lang.RuntimeException: com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex
    at com.android.builder.dexing.DxDexArchiveMerger.mergeMonoDex(DxDexArchiveMerger.java:177)
    at com.android.builder.dexing.DxDexArchiveMerger.mergeDexArchives(DxDexArchiveMerger.java:118)
    at com.android.build.gradle.internal.transforms.DexMergerTransformCallable.call(DexMergerTransformCallable.java:97)
    at com.android.build.gradle.internal.transforms.ExternalLibsMergerTransform.transform(ExternalLibsMergerTransform.kt:121)
    at com.android.build.gradle.internal.pipeline.TransformTask$2.call(TransformTask.java:222)
    at com.android.build.gradle.internal.pipeline.TransformTask$2.call(TransformTask.java:218)
    at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:102)
    at com.android.build.gradle.internal.pipeline.TransformTask.transform(TransformTask.java:213)
    at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
    at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$IncrementalTaskAction.doExecute(DefaultTaskClassInfoStore.java:173)
    at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$StandardTaskAction.execute(DefaultTaskClassInfoStore.java:134)
    at org.gradle.api.internal.project.taskfactory.DefaultTaskClassInfoStore$StandardTaskAction.execute(DefaultTaskClassInfoStore.java:121)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:122)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:197)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:107)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:111)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:92)
    ... 27 more
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex
    at com.android.builder.dexing.DxDexArchiveMerger.lambda$mergeMonoDex$0(DxDexArchiveMerger.java:171)
Caused by: java.lang.RuntimeException: com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex
Caused by: com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex
    at com.android.builder.dexing.DexArchiveMergerCallable.call(DexArchiveMergerCallable.java:72)
    at com.android.builder.dexing.DexArchiveMergerCallable.call(DexArchiveMergerCallable.java:36)
Caused by: com.android.dex.DexIndexOverflowException: method ID not in [0, 0xffff]: 65536
    at com.android.dx.merge.DexMerger$8.updateIndex(DexMerger.java:565)
    at com.android.dx.merge.DexMerger$IdMerger.mergeSorted(DexMerger.java:276)
    at com.android.dx.merge.DexMerger.mergeMethodIds(DexMerger.java:574)
    at com.android.dx.merge.DexMerger.mergeDexes(DexMerger.java:166)
    at com.android.dx.merge.DexMerger.merge(DexMerger.java:198)
    at com.android.builder.dexing.DexArchiveMergerCallable.call(DexArchiveMergerCallable.java:61)
    ... 1 more

这里要说明的就是仔细看问题,Caused by: com.android.dex.DexIndexOverflowException: method ID not in [0, 0xffff]: 65536这句话才是重点，其他错误信息都无关紧要。
特么矛盾的问题，作为插件加载的话只能变成1个dex但是现在65536了，哈哈，ok既然不能瘦身，要想想其他办法加载multi dex插件了。