使用 Paging 库示例的 Proguard 问题（在 Google 代码实验室中）

Question

我克隆了 solution branch of Android Paging codelabs 项目，然后通过我的 Android Studio (v3.1) 在本地打开它。我在打开它之前所做的唯一更改是修改插件和库的版本代码，使它们与我的本地环境兼容：

（编辑：我发现 a java version of the same project（将 kotlin 文件转换为 java）。同样的问题确实存在。所以问题与 kotlin 插件或库。）

gradle-wrapper.properties (4.6-all -> 4.4-all):

distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip
# PREVIOUS VALUE: gradle-4.6-all.zip

项目级build.gradle:

buildscript {
    ext.kotlin_version = '1.2.61' // PREVIOUS VALUE: 1.2.21
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.3' // PREVIOUS VALUE: 3.2.0-alpha09
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

ext {
    compileSdkVersion = 27
    minSdkVersion = 15
    targetSdkVersion = 27
    supportLibVersion = "27.1.1"               // PREVIOUS VALUE: 27.1.0
    constraintLayoutVersion = "1.1.2"          // PREVIOUS VALUE: 1.0.2
    archComponentsVersion = "1.1.1"
    roomVersion = "1.1.1"                      // PREVIOUS VALUE: 1.1.0-beta1
    pagingVersion = "1.0.0"                    // PREVIOUS VALUE: 1.1.0-beta1
    retrofitVersion = "2.4.0"                  // PREVIOUS VALUE: 2.3.0
    okhttpLoggingInterceptorVersion = "3.11.0" // PREVIOUS VALUE: 3.9.0

    runnerVersion = "1.0.1"
    rulesVersion = "1.0.1"
    junitVersion = "4.12"
    espressoVersion = "3.0.1"
}

应用模块build.gradle

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-kapt'
apply plugin: 'kotlin-android-extensions'

android {
    compileSdkVersion rootProject.compileSdkVersion
    defaultConfig {
        applicationId "com.example.android.codelabs.paging"
        minSdkVersion rootProject.minSdkVersion
        targetSdkVersion rootProject.targetSdkVersion
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version" // jre7 -> jdk7
    implementation "com.android.support:appcompat-v7:$supportLibVersion"
    implementation "com.android.support.constraint:constraint-layout:$constraintLayoutVersion"
    implementation "com.android.support:design:$supportLibVersion"

    // architecture components
    implementation "android.arch.lifecycle:extensions:$archComponentsVersion"
    implementation "android.arch.lifecycle:runtime:$archComponentsVersion"
    implementation "android.arch.persistence.room:runtime:$roomVersion"
    implementation "android.arch.paging:runtime:$pagingVersion"
    kapt "android.arch.lifecycle:compiler:$archComponentsVersion"
    kapt "android.arch.persistence.room:compiler:$roomVersion"

    // retrofit
    implementation "com.squareup.retrofit2:retrofit:$retrofitVersion"
    implementation "com.squareup.retrofit2:converter-gson:$retrofitVersion"
    implementation "com.squareup.retrofit2:retrofit-mock:$retrofitVersion"
    implementation "com.squareup.okhttp3:logging-interceptor:$okhttpLoggingInterceptorVersion"

    // testing -> ALL REMOVED.
    //testImplementation "junit:junit:$junitVersion"
    //androidTestImplementation "com.android.support.test:runner:$runnerVersion"
    //androidTestImplementation "com.android.support.test.espresso:espresso-core:$espressoVersion"
}

你可以看到我本地的改动（见评论）。删除了其他多余的评论。

然后我将构建变体从 Debug 更改为 Release。一切正常，我可以成功构建 APK (app-release-unsigned.apk)。现在，当我将 minifyEnabled 设置为 true 时，我在构建 APK 文件期间遇到了这些错误：

您可以在本post的末尾看到完整的文本样式的错误消息。

我在网上搜索并找到了 Proguard 的这些相关规则（由于依赖关系）并将它们插入到 proguard-rules.pro 文件中（每组规则引用于最上面）：

###### From https://github.com/square/retrofit#r8--proguard:  

# Retrofit does reflection on generic parameters and InnerClass is required to use Signature.  
-keepattributes Signature, InnerClasses  

# Retain service method parameters when optimizing.  
-keepclassmembers,allowshrinking,allowobfuscation interface * {  
 @retrofit2.http.* <methods>;}  

# Ignore annotation used for build tooling.  
-dontwarn org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement  

# Ignore JSR 305 annotations for embedding nullability information.  
-dontwarn javax.annotation.**  

# Guarded by a NoClassDefFoundError try/catch and only used when on the classpath.  
-dontwarn kotlin.Unit  

###### From   
-dontwarn android.arch.util.paging.CountedDataSource  
-dontwarn android.arch.persistence.room.paging.LimitOffsetDataSource  

###### From   
-dontwarn okio.**  
-dontwarn javax.annotation.Nullable  
-dontwarn javax.annotation.ParametersAreNonnullByDefault  
# Platform calls Class.forName on types which do not exist on Android to     determine platform.  
-dontnote retrofit2.Platform  
# Platform used when running on Java 8 VMs. Will not be used at runtime.  
-dontwarn retrofit2.Platform$Java8  
# Retain generic type information for use by reflection by converters     and adapters.  
-keepattributes Signature  
# Retain declared checked exceptions for use by a Proxy instance.  
-keepattributes Exceptions  
-keep class android.content.**  
-dontwarn android.content.**  
-keep class android.animation.**  
-dontwarn android.animation.**  
-keep class me.panavtec.drawableview.**  
-dontwarn me.panavtec.drawableview.**  
-keep class javax.annotation.concurrent.**  
-dontwarn javax.annotation.concurrent.**  
-keep class android.arch.persistence.room.paging.LimitOffsetDataSource  
-keep interface android.arch.persistence.room.paging.LimitOffsetDataSource  
-keep class android.arch.util.paging.CountedDataSource  
-keep interface android.arch.util.paging.CountedDataSource

但是没有效果。错误消息将完全相同。

完整错误信息:

org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:transformClassesAndResourcesWithProguardForRelease'.
    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.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
    at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:62)
    at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
    at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:60)
    at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:97)
    at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:87)
    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$EventFiringTaskWorker.run(DefaultTaskGraphExecuter.java:248)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$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:123)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access0(DefaultTaskPlanExecutor.java:79)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.execute(DefaultTaskPlanExecutor.java:104)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.execute(DefaultTaskPlanExecutor.java:98)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:626)
    at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:581)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)
    at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:59)
    at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:128)
    at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:37)
    at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:37)
    at org.gradle.execution.DefaultBuildExecuter.access[=15=]0(DefaultBuildExecuter.java:23)
    at org.gradle.execution.DefaultBuildExecuter.proceed(DefaultBuildExecuter.java:43)
    at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:46)
    at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:37)
    at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:30)
    at org.gradle.initialization.DefaultGradleLauncher$ExecuteTasks.run(DefaultGradleLauncher.java:314)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
    at org.gradle.initialization.DefaultGradleLauncher.runTasks(DefaultGradleLauncher.java:204)
    at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(DefaultGradleLauncher.java:134)
    at org.gradle.initialization.DefaultGradleLauncher.executeTasks(DefaultGradleLauncher.java:109)
    at org.gradle.internal.invocation.GradleBuildController.call(GradleBuildController.java:78)
    at org.gradle.internal.invocation.GradleBuildController.call(GradleBuildController.java:75)
    at org.gradle.internal.work.DefaultWorkerLeaseService.withLocks(DefaultWorkerLeaseService.java:152)
    at org.gradle.internal.invocation.GradleBuildController.doBuild(GradleBuildController.java:100)
    at org.gradle.internal.invocation.GradleBuildController.run(GradleBuildController.java:75)
    at org.gradle.tooling.internal.provider.runner.ClientProvidedBuildActionRunner.run(ClientProvidedBuildActionRunner.java:62)
    at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
    at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
    at org.gradle.tooling.internal.provider.ValidatingBuildActionRunner.run(ValidatingBuildActionRunner.java:32)
    at org.gradle.launcher.exec.RunAsBuildOperationBuildActionRunner.run(RunAsBuildOperationBuildActionRunner.java:43)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor$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:199)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
    at org.gradle.launcher.exec.RunAsBuildOperationBuildActionRunner.run(RunAsBuildOperationBuildActionRunner.java:40)
    at org.gradle.tooling.internal.provider.SubscribableBuildActionRunner.run(SubscribableBuildActionRunner.java:51)
    at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:47)
    at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:30)
    at org.gradle.launcher.exec.BuildTreeScopeBuildActionExecuter.execute(BuildTreeScopeBuildActionExecuter.java:39)
    at org.gradle.launcher.exec.BuildTreeScopeBuildActionExecuter.execute(BuildTreeScopeBuildActionExecuter.java:25)
    at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:80)
    at org.gradle.tooling.internal.provider.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:53)
    at org.gradle.tooling.internal.provider.ServicesSetupBuildActionExecuter.execute(ServicesSetupBuildActionExecuter.java:57)
    at org.gradle.tooling.internal.provider.ServicesSetupBuildActionExecuter.execute(ServicesSetupBuildActionExecuter.java:32)
    at org.gradle.tooling.internal.provider.GradleThreadBuildActionExecuter.execute(GradleThreadBuildActionExecuter.java:36)
    at org.gradle.tooling.internal.provider.GradleThreadBuildActionExecuter.execute(GradleThreadBuildActionExecuter.java:25)
    at org.gradle.tooling.internal.provider.ParallelismConfigurationBuildActionExecuter.execute(ParallelismConfigurationBuildActionExecuter.java:43)
    at org.gradle.tooling.internal.provider.ParallelismConfigurationBuildActionExecuter.execute(ParallelismConfigurationBuildActionExecuter.java:29)
    at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:69)
    at org.gradle.tooling.internal.provider.StartParamsValidatingActionExecuter.execute(StartParamsValidatingActionExecuter.java:30)
    at org.gradle.tooling.internal.provider.SessionFailureReportingActionExecuter.execute(SessionFailureReportingActionExecuter.java:59)
    at org.gradle.tooling.internal.provider.SessionFailureReportingActionExecuter.execute(SessionFailureReportingActionExecuter.java:44)
    at org.gradle.tooling.internal.provider.SetupLoggingActionExecuter.execute(SetupLoggingActionExecuter.java:45)
    at org.gradle.tooling.internal.provider.SetupLoggingActionExecuter.execute(SetupLoggingActionExecuter.java:30)
    at org.gradle.launcher.daemon.server.exec.ExecuteBuild.doBuild(ExecuteBuild.java:67)
    at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
    at org.gradle.launcher.daemon.server.exec.WatchForDisconnection.execute(WatchForDisconnection.java:37)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
    at org.gradle.launcher.daemon.server.exec.ResetDeprecationLogger.execute(ResetDeprecationLogger.java:26)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
    at org.gradle.launcher.daemon.server.exec.RequestStopIfSingleUsedDaemon.execute(RequestStopIfSingleUsedDaemon.java:34)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
    at org.gradle.launcher.daemon.server.exec.ForwardClientInput.call(ForwardClientInput.java:74)
    at org.gradle.launcher.daemon.server.exec.ForwardClientInput.call(ForwardClientInput.java:72)
    at org.gradle.util.Swapper.swap(Swapper.java:38)
    at org.gradle.launcher.daemon.server.exec.ForwardClientInput.execute(ForwardClientInput.java:72)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
    at org.gradle.launcher.daemon.server.exec.LogAndCheckHealth.execute(LogAndCheckHealth.java:55)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
    at org.gradle.launcher.daemon.server.exec.LogToClient.doBuild(LogToClient.java:62)
    at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
    at org.gradle.launcher.daemon.server.exec.EstablishBuildEnvironment.doBuild(EstablishBuildEnvironment.java:82)
    at org.gradle.launcher.daemon.server.exec.BuildCommandOnly.execute(BuildCommandOnly.java:36)
    at org.gradle.launcher.daemon.server.api.DaemonCommandExecution.proceed(DaemonCommandExecution.java:122)
    at org.gradle.launcher.daemon.server.exec.StartBuildOrRespondWithBusy.run(StartBuildOrRespondWithBusy.java:50)
    at org.gradle.launcher.daemon.server.DaemonStateCoordinator.run(DaemonStateCoordinator.java:295)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
    at org.gradle.internal.concurrent.ManagedExecutorImpl.run(ManagedExecutorImpl.java:46)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.RuntimeException: Job failed, see logs for details
    at com.android.build.gradle.internal.transforms.ProGuardTransform.transform(ProGuardTransform.java:196)
    at com.android.build.gradle.internal.pipeline.TransformTask.call(TransformTask.java:221)
    at com.android.build.gradle.internal.pipeline.TransformTask.call(TransformTask.java:217)
    at com.android.builder.profile.ThreadRecorder.record(ThreadRecorder.java:102)
    at com.android.build.gradle.internal.pipeline.TransformTask.transform(TransformTask.java:212)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
    at org.gradle.api.internal.project.taskfactory.IncrementalTaskAction.doExecute(IncrementalTaskAction.java:46)
    at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:39)
    at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:26)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.run(ExecuteActionsTaskExecuter.java:121)
    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:199)
    at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:110)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:92)
    ... 107 more
Caused by: java.io.IOException: Please correct the above warnings first.
    at proguard.Initializer.execute(Initializer.java:473)
    at proguard.ProGuard.initialize(ProGuard.java:233)
    at proguard.ProGuard.execute(ProGuard.java:98)
    at com.android.build.gradle.internal.transforms.BaseProguardAction.runProguard(BaseProguardAction.java:61)
    at com.android.build.gradle.internal.transforms.ProGuardTransform.doMinification(ProGuardTransform.java:253)
    at com.android.build.gradle.internal.transforms.ProGuardTransform.access[=15=]0(ProGuardTransform.java:63)
    at com.android.build.gradle.internal.transforms.ProGuardTransform.run(ProGuardTransform.java:173)
    at com.android.builder.tasks.Job.runTask(Job.java:47)
    at com.android.build.gradle.tasks.SimpleWorkQueue$EmptyThreadContext.runTask(SimpleWorkQueue.java:41)
    at com.android.builder.tasks.WorkQueue.run(WorkQueue.java:282)
    ... 1 more

Answer 1

问题已解决。为 Retrofit 和 OkHttp 库发布的规则就足够了：

###### From https://github.com/square/retrofit#r8--proguard:
# Retrofit does reflection on generic parameters and InnerClass is required to use Signature.
-keepattributes Signature, InnerClasses

# Retain service method parameters when optimizing.
-keepclassmembers,allowshrinking,allowobfuscation interface * {
    @retrofit2.http.* <methods>;
}

# Ignore annotation used for build tooling.
-dontwarn org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement

# Ignore JSR 305 annotations for embedding nullability information.
-dontwarn javax.annotation.**

# Guarded by a NoClassDefFoundError try/catch and only used when on the classpath.
-dontwarn kotlin.Unit

# Top-level functions that can only be used by Kotlin.
-dontwarn retrofit2.-KotlinExtensions

###### From https://github.com/square/okhttp#r8--proguard:
# JSR 305 annotations are for embedding nullability information.
-dontwarn javax.annotation.**

# A resource is loaded with a relative path so the package of this class must be preserved.
-keepnames class okhttp3.internal.publicsuffix.PublicSuffixDatabase

# Animal Sniffer compileOnly dependency to ensure APIs are compatible with older versions of Java.
-dontwarn org.codehaus.mojo.animal_sniffer.*

# OkHttp platform used only on JVM and when Conscrypt dependency is available.
-dontwarn okhttp3.internal.platform.ConscryptPlatform

我省略了 OkHttp 规则。 勾选here and here for updated rules (or directly here and here).

使用 Paging 库示例的 Proguard 问题（在 Google 代码实验室中）

Proguard problem with example of Paging library usage (in Google Codelabs)

android

android-proguard

retrofit2

android-room

android-paging