Enable jvm-default=all.

buildSrc/src/main/kotlin/Projects.kt

@@ -84,6 +84,8 @@ private inline fun <reified T : BaseExtension> Project.setupBaseModule(
         val arguments = mutableListOf(
             // https://kotlinlang.org/docs/compiler-reference.html#progressive
             "-progressive",
+            // Enable Java default method generation.
+            "-Xjvm-default=all",
             // Generate smaller bytecode by not generating runtime not-null assertions.
             "-Xno-call-assertions",
             "-Xno-param-assertions",

coil-base/api/coil-base.api

@@ -31,24 +31,24 @@ public final class coil/ComponentRegistry$Builder {
 public abstract interface class coil/EventListener : coil/request/ImageRequest$Listener {
 	public static final field Companion Lcoil/EventListener$Companion;
 	public static final field NONE Lcoil/EventListener;
-	public abstract fun decodeEnd (Lcoil/request/ImageRequest;Lcoil/decode/Decoder;Lcoil/request/Options;Lcoil/decode/DecodeResult;)V
-	public abstract fun decodeStart (Lcoil/request/ImageRequest;Lcoil/decode/Decoder;Lcoil/request/Options;)V
-	public abstract fun fetchEnd (Lcoil/request/ImageRequest;Lcoil/fetch/Fetcher;Lcoil/request/Options;Lcoil/fetch/FetchResult;)V
-	public abstract fun fetchStart (Lcoil/request/ImageRequest;Lcoil/fetch/Fetcher;Lcoil/request/Options;)V
-	public abstract fun keyEnd (Lcoil/request/ImageRequest;Ljava/lang/String;)V
-	public abstract fun keyStart (Lcoil/request/ImageRequest;Ljava/lang/Object;)V
-	public abstract fun mapEnd (Lcoil/request/ImageRequest;Ljava/lang/Object;)V
-	public abstract fun mapStart (Lcoil/request/ImageRequest;Ljava/lang/Object;)V
-	public abstract fun onCancel (Lcoil/request/ImageRequest;)V
-	public abstract fun onError (Lcoil/request/ImageRequest;Lcoil/request/ErrorResult;)V
-	public abstract fun onStart (Lcoil/request/ImageRequest;)V
-	public abstract fun onSuccess (Lcoil/request/ImageRequest;Lcoil/request/SuccessResult;)V
-	public abstract fun resolveSizeEnd (Lcoil/request/ImageRequest;Lcoil/size/Size;)V
-	public abstract fun resolveSizeStart (Lcoil/request/ImageRequest;)V
-	public abstract fun transformEnd (Lcoil/request/ImageRequest;Landroid/graphics/Bitmap;)V
-	public abstract fun transformStart (Lcoil/request/ImageRequest;Landroid/graphics/Bitmap;)V
-	public abstract fun transitionEnd (Lcoil/request/ImageRequest;Lcoil/transition/Transition;)V
-	public abstract fun transitionStart (Lcoil/request/ImageRequest;Lcoil/transition/Transition;)V
+	public fun decodeEnd (Lcoil/request/ImageRequest;Lcoil/decode/Decoder;Lcoil/request/Options;Lcoil/decode/DecodeResult;)V
+	public fun decodeStart (Lcoil/request/ImageRequest;Lcoil/decode/Decoder;Lcoil/request/Options;)V
+	public fun fetchEnd (Lcoil/request/ImageRequest;Lcoil/fetch/Fetcher;Lcoil/request/Options;Lcoil/fetch/FetchResult;)V
+	public fun fetchStart (Lcoil/request/ImageRequest;Lcoil/fetch/Fetcher;Lcoil/request/Options;)V
+	public fun keyEnd (Lcoil/request/ImageRequest;Ljava/lang/String;)V
+	public fun keyStart (Lcoil/request/ImageRequest;Ljava/lang/Object;)V
+	public fun mapEnd (Lcoil/request/ImageRequest;Ljava/lang/Object;)V
+	public fun mapStart (Lcoil/request/ImageRequest;Ljava/lang/Object;)V
+	public fun onCancel (Lcoil/request/ImageRequest;)V
+	public fun onError (Lcoil/request/ImageRequest;Lcoil/request/ErrorResult;)V
+	public fun onStart (Lcoil/request/ImageRequest;)V
+	public fun onSuccess (Lcoil/request/ImageRequest;Lcoil/request/SuccessResult;)V
+	public fun resolveSizeEnd (Lcoil/request/ImageRequest;Lcoil/size/Size;)V
+	public fun resolveSizeStart (Lcoil/request/ImageRequest;)V
+	public fun transformEnd (Lcoil/request/ImageRequest;Landroid/graphics/Bitmap;)V
+	public fun transformStart (Lcoil/request/ImageRequest;Landroid/graphics/Bitmap;)V
+	public fun transitionEnd (Lcoil/request/ImageRequest;Lcoil/transition/Transition;)V
+	public fun transitionStart (Lcoil/request/ImageRequest;Lcoil/transition/Transition;)V
 }
 
 public final class coil/EventListener$Companion {
@@ -638,10 +638,10 @@ public final class coil/request/ImageRequest$Builder {
 }
 
 public abstract interface class coil/request/ImageRequest$Listener {
-	public abstract fun onCancel (Lcoil/request/ImageRequest;)V
-	public abstract fun onError (Lcoil/request/ImageRequest;Lcoil/request/ErrorResult;)V
-	public abstract fun onStart (Lcoil/request/ImageRequest;)V
-	public abstract fun onSuccess (Lcoil/request/ImageRequest;Lcoil/request/SuccessResult;)V
+	public fun onCancel (Lcoil/request/ImageRequest;)V
+	public fun onError (Lcoil/request/ImageRequest;Lcoil/request/ErrorResult;)V
+	public fun onStart (Lcoil/request/ImageRequest;)V
+	public fun onSuccess (Lcoil/request/ImageRequest;Lcoil/request/SuccessResult;)V
 }
 
 public final class coil/request/ImageRequest$Listener$DefaultImpls {
@@ -833,9 +833,10 @@ public final class coil/size/SizeResolvers {
 }
 
 public abstract interface class coil/size/ViewSizeResolver : coil/size/SizeResolver {
-	public abstract fun getSubtractPadding ()Z
+	public fun getSubtractPadding ()Z
 	public abstract fun getView ()Landroid/view/View;
-	public abstract fun size (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public fun size (Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public static synthetic fun size$suspendImpl (Lcoil/size/ViewSizeResolver;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 }
 
 public final class coil/size/ViewSizeResolver$DefaultImpls {
@@ -873,9 +874,9 @@ public class coil/target/ImageViewTarget : coil/target/GenericViewTarget {
 }
 
 public abstract interface class coil/target/Target {
-	public abstract fun onError (Landroid/graphics/drawable/Drawable;)V
-	public abstract fun onStart (Landroid/graphics/drawable/Drawable;)V
-	public abstract fun onSuccess (Landroid/graphics/drawable/Drawable;)V
+	public fun onError (Landroid/graphics/drawable/Drawable;)V
+	public fun onStart (Landroid/graphics/drawable/Drawable;)V
+	public fun onSuccess (Landroid/graphics/drawable/Drawable;)V
 }
 
 public final class coil/target/Target$DefaultImpls {

coil-base/src/main/java/coil/EventListener.kt

@@ -28,6 +28,7 @@ import coil.transition.TransitionTarget
  *
  * @see ImageLoader.Builder.eventListenerFactory
  */
+@JvmDefaultWithCompatibility
 interface EventListener : ImageRequest.Listener {
 
     /**

coil-base/src/main/java/coil/request/ImageRequest.kt

@@ -270,6 +270,7 @@ class ImageRequest private constructor(
     /**
      * A set of callbacks for an [ImageRequest].
      */
+    @JvmDefaultWithCompatibility
     interface Listener {
 
         /**

coil-base/src/main/java/coil/request/RequestDelegate.kt

@@ -12,30 +12,30 @@ import coil.util.requestManager
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.Job
 
-internal sealed class RequestDelegate : DefaultLifecycleObserver {
+internal sealed interface RequestDelegate : DefaultLifecycleObserver {
 
     /** Throw a [CancellationException] if this request should be cancelled before starting. */
     @MainThread
-    open fun assertActive() {}
+    fun assertActive() {}
 
     /** Register all lifecycle observers. */
     @MainThread
-    open fun start() {}
+    fun start() {}
 
     /** Called when this request's job is cancelled or completes successfully/unsuccessfully. */
     @MainThread
-    open fun complete() {}
+    fun complete() {}
 
     /** Cancel this request's job and clear all lifecycle observers. */
     @MainThread
-    open fun dispose() {}
+    fun dispose() {}
 }
 
 /** A request delegate for a one-shot requests with no target or a non-[ViewTarget]. */
 internal class BaseRequestDelegate(
     private val lifecycle: Lifecycle,
     private val job: Job
-) : RequestDelegate() {
+) : RequestDelegate {
 
     override fun start() {
         lifecycle.addObserver(this)
@@ -59,7 +59,7 @@ internal class ViewTargetRequestDelegate(
     private val target: ViewTarget<*>,
     private val lifecycle: Lifecycle,
     private val job: Job
-) : RequestDelegate() {
+) : RequestDelegate {
 
     /** Repeat this request with the same [ImageRequest]. */
     @MainThread

coil-base/src/main/java/coil/size/ViewSizeResolver.kt

@@ -25,6 +25,7 @@ fun <T : View> ViewSizeResolver(
 /**
  * A [SizeResolver] that measures the size of a [View].
  */
+@JvmDefaultWithCompatibility
 interface ViewSizeResolver<T : View> : SizeResolver {
 
     /** The [View] to measure. This field should be immutable. */

coil-base/src/main/java/coil/target/Target.kt

@@ -6,6 +6,7 @@ import androidx.annotation.MainThread
 /**
  * A listener that accepts the result of an image request.
  */
+@JvmDefaultWithCompatibility
 interface Target {
 
     /**

coil-base/src/main/java/coil/target/ViewTarget.kt

@@ -10,6 +10,7 @@ import androidx.lifecycle.LifecycleObserver
  * Optionally, [ViewTarget]s can implement [LifecycleObserver]. They are automatically registered
  * when the request starts and unregistered when the request completes.
  */
+@JvmDefaultWithCompatibility
 interface ViewTarget<T : View> : Target {
 
     /**

coil-base/src/main/java/coil/transition/TransitionTarget.kt

@@ -7,6 +7,7 @@ import coil.target.Target
 /**
  * A [Target] that supports applying [Transition]s.
  */
+@JvmDefaultWithCompatibility
 interface TransitionTarget : Target {
 
     /**

coil-base/src/main/java/coil/util/HardwareBitmaps.kt

@@ -21,27 +21,25 @@ internal fun HardwareBitmapService(logger: Logger?): HardwareBitmapService = whe
 }
 
 /** Decides if a request can use [Bitmap.Config.HARDWARE]. */
-internal sealed class HardwareBitmapService {
+internal sealed interface HardwareBitmapService {
 
     /** Return 'true' if we are currently able to create [Bitmap.Config.HARDWARE]. */
     @MainThread
-    abstract fun allowHardwareMainThread(size: Size): Boolean
+    fun allowHardwareMainThread(size: Size): Boolean
 
     /** Perform any hardware bitmap allocation checks that cannot be done on the main thread. */
     @WorkerThread
-    abstract fun allowHardwareWorkerThread(): Boolean
+    fun allowHardwareWorkerThread(): Boolean
 }
 
 /** Returns a fixed value for [allowHardwareMainThread] and [allowHardwareWorkerThread]. */
-private class ImmutableHardwareBitmapService(private val allowHardware: Boolean) : HardwareBitmapService() {
+private class ImmutableHardwareBitmapService(private val allowHardware: Boolean) : HardwareBitmapService {
     override fun allowHardwareMainThread(size: Size) = allowHardware
     override fun allowHardwareWorkerThread() = allowHardware
 }
 
 /** Guards against running out of file descriptors. */
-private class LimitedFileDescriptorHardwareBitmapService(
-    private val logger: Logger?
-) : HardwareBitmapService() {
+private class LimitedFileDescriptorHardwareBitmapService(private val logger: Logger?) : HardwareBitmapService {
 
     override fun allowHardwareMainThread(size: Size): Boolean {
         return size.width.pxOrElse { Int.MAX_VALUE } > MIN_SIZE_DIMENSION &&