Do not store the WidgetTag + base impl of visitIds

redwood-protocol-host/api/redwood-protocol-host.api

@@ -34,17 +34,17 @@ public final class app/cash/redwood/protocol/host/ProtocolMismatchHandler$Compan
 }
 
 public abstract class app/cash/redwood/protocol/host/ProtocolNode {
-	public synthetic fun <init> (IILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public abstract fun apply (Lapp/cash/redwood/protocol/PropertyChange;Lapp/cash/redwood/protocol/host/UiEventSink;)V
 	public abstract fun children-dBpC-2Y (I)Lapp/cash/redwood/protocol/host/ProtocolChildren;
 	public abstract fun detach ()V
 	public final fun getId-0HhLjSo ()I
 	public abstract fun getWidget ()Lapp/cash/redwood/widget/Widget;
-	public final fun getWidgetTag-BlhN7y0 ()I
+	public abstract fun getWidgetTag-BlhN7y0 ()I
 	public final fun setId-ou3jOuA (I)V
 	public abstract fun toString ()Ljava/lang/String;
 	public final fun updateModifier (Lapp/cash/redwood/Modifier;)V
-	public abstract fun visitIds (Lkotlin/jvm/functions/Function1;)V
+	public fun visitIds (Lkotlin/jvm/functions/Function1;)V
 }
 
 public final class app/cash/redwood/protocol/host/UiEvent {

redwood-protocol-host/api/redwood-protocol-host.klib.api

@@ -34,12 +34,12 @@ sealed interface <#A: kotlin/Any> app.cash.redwood.protocol.host/ProtocolFactory
 }
 
 abstract class <#A: kotlin/Any> app.cash.redwood.protocol.host/ProtocolNode { // app.cash.redwood.protocol.host/ProtocolNode|null[0]
-    constructor <init>(app.cash.redwood.protocol/Id, app.cash.redwood.protocol/WidgetTag) // app.cash.redwood.protocol.host/ProtocolNode.<init>|<init>(app.cash.redwood.protocol.Id;app.cash.redwood.protocol.WidgetTag){}[0]
+    constructor <init>(app.cash.redwood.protocol/Id) // app.cash.redwood.protocol.host/ProtocolNode.<init>|<init>(app.cash.redwood.protocol.Id){}[0]
 
     abstract val widget // app.cash.redwood.protocol.host/ProtocolNode.widget|{}widget[0]
         abstract fun <get-widget>(): app.cash.redwood.widget/Widget<#A> // app.cash.redwood.protocol.host/ProtocolNode.widget.<get-widget>|<get-widget>(){}[0]
-    final val widgetTag // app.cash.redwood.protocol.host/ProtocolNode.widgetTag|{}widgetTag[0]
-        final fun <get-widgetTag>(): app.cash.redwood.protocol/WidgetTag // app.cash.redwood.protocol.host/ProtocolNode.widgetTag.<get-widgetTag>|<get-widgetTag>(){}[0]
+    abstract val widgetTag // app.cash.redwood.protocol.host/ProtocolNode.widgetTag|{}widgetTag[0]
+        abstract fun <get-widgetTag>(): app.cash.redwood.protocol/WidgetTag // app.cash.redwood.protocol.host/ProtocolNode.widgetTag.<get-widgetTag>|<get-widgetTag>(){}[0]
 
     final var id // app.cash.redwood.protocol.host/ProtocolNode.id|{}id[0]
         final fun <get-id>(): app.cash.redwood.protocol/Id // app.cash.redwood.protocol.host/ProtocolNode.id.<get-id>|<get-id>(){}[0]
@@ -49,8 +49,8 @@ abstract class <#A: kotlin/Any> app.cash.redwood.protocol.host/ProtocolNode { //
     abstract fun children(app.cash.redwood.protocol/ChildrenTag): app.cash.redwood.protocol.host/ProtocolChildren<#A>? // app.cash.redwood.protocol.host/ProtocolNode.children|children(app.cash.redwood.protocol.ChildrenTag){}[0]
     abstract fun detach() // app.cash.redwood.protocol.host/ProtocolNode.detach|detach(){}[0]
     abstract fun toString(): kotlin/String // app.cash.redwood.protocol.host/ProtocolNode.toString|toString(){}[0]
-    abstract fun visitIds(kotlin/Function1<app.cash.redwood.protocol/Id, kotlin/Unit>) // app.cash.redwood.protocol.host/ProtocolNode.visitIds|visitIds(kotlin.Function1<app.cash.redwood.protocol.Id,kotlin.Unit>){}[0]
     final fun updateModifier(app.cash.redwood/Modifier) // app.cash.redwood.protocol.host/ProtocolNode.updateModifier|updateModifier(app.cash.redwood.Modifier){}[0]
+    open fun visitIds(kotlin/Function1<app.cash.redwood.protocol/Id, kotlin/Unit>) // app.cash.redwood.protocol.host/ProtocolNode.visitIds|visitIds(kotlin.Function1<app.cash.redwood.protocol.Id,kotlin.Unit>){}[0]
 }
 
 final class <#A: kotlin/Any> app.cash.redwood.protocol.host/HostProtocolAdapter : app.cash.redwood.protocol/ChangesSink { // app.cash.redwood.protocol.host/HostProtocolAdapter|null[0]

redwood-protocol-host/src/commonMain/kotlin/app/cash/redwood/protocol/host/HostProtocolAdapter.kt

@@ -387,8 +387,10 @@ public class HostProtocolAdapter<W : Any>(
 @OptIn(RedwoodCodegenApi::class)
 private class RootProtocolNode<W : Any>(
   children: Widget.Children<W>,
-) : ProtocolNode<W>(Id.Root, UnknownWidgetTag),
+) : ProtocolNode<W>(Id.Root),
   Widget<W> {
+  override val widgetTag: WidgetTag get() = UnknownWidgetTag
+
   private val children = ProtocolChildren(children)
 
   override fun apply(change: PropertyChange, eventSink: UiEventSink) {

redwood-protocol-host/src/commonMain/kotlin/app/cash/redwood/protocol/host/ProtocolNode.kt

@@ -34,8 +34,9 @@ import kotlin.math.min
 public abstract class ProtocolNode<W : Any>(
   /** Updated in place when a node is reused due to pooling. */
   public var id: Id,
-  public val widgetTag: WidgetTag,
 ) {
+  public abstract val widgetTag: WidgetTag
+
   public abstract val widget: Widget<W>
 
   /** The index of [widget] within its parent [container]. */
@@ -65,7 +66,9 @@ public abstract class ProtocolNode<W : Any>(
   public abstract fun children(tag: ChildrenTag): ProtocolChildren<W>?
 
   /** Recursively visit IDs in this widget's tree, starting with this widget's [id]. */
-  public abstract fun visitIds(block: (Id) -> Unit)
+  public open fun visitIds(block: (Id) -> Unit) {
+    block(id)
+  }
 
   /**
    * Detach all child widgets recursively, then clear direct references to them.

redwood-protocol-host/src/commonTest/kotlin/app/cash/redwood/protocol/host/ChildrenNodeIndexTest.kt

@@ -126,7 +126,9 @@ class ChildrenNodeIndexTest {
 }
 
 @OptIn(RedwoodCodegenApi::class)
-private class WidgetNode(override val widget: StringWidget) : ProtocolNode<String>(Id(1), WidgetTag(1)) {
+private class WidgetNode(override val widget: StringWidget) : ProtocolNode<String>(Id(1)) {
+  override val widgetTag: WidgetTag get() = WidgetTag(1)
+
   override fun apply(change: PropertyChange, eventSink: UiEventSink) {
     throw UnsupportedOperationException()
   }
@@ -135,9 +137,6 @@ private class WidgetNode(override val widget: StringWidget) : ProtocolNode<Strin
     throw UnsupportedOperationException()
   }
 
-  override fun visitIds(block: (Id) -> Unit) {
-  }
-
   override fun detach() {
   }
 

redwood-tooling-codegen/src/main/kotlin/app/cash/redwood/tooling/codegen/protocolHostGeneration.kt

@@ -253,7 +253,9 @@ internal class ProtocolButton<W : Any>(
   widget: Button<W>,
   private val json: Json,
   private val mismatchHandler: ProtocolMismatchHandler,
-) : ProtocolNode<W>(id, WidgetTag(4)) {
+) : ProtocolNode<W>(id) {
+  override val widgetTag: WidgetTag get() = WidgetTag(4)
+
   private var _widget: Button<W>? = widget
   override val widget: Widget<W> get() = _widget ?: error("detached")
 
@@ -319,7 +321,15 @@ internal fun generateProtocolNode(
             .build(),
         )
         .addSuperclassConstructorParameter("id")
-        .addSuperclassConstructorParameter("%T(%L)", WidgetTag, widget.tag)
+        .addProperty(
+          PropertySpec.builder("widgetTag", WidgetTag, OVERRIDE)
+            .getter(
+              FunSpec.getterBuilder()
+                .addStatement("return %T(%L)", WidgetTag, widget.tag)
+                .build(),
+            )
+            .build(),
+        )
         .addProperty(
           PropertySpec.builder("_widget", widgetType.copy(nullable = true), PRIVATE)
             .mutable(true)
@@ -487,20 +497,24 @@ internal fun generateProtocolNode(
             }
             .build(),
         )
-        .addFunction(
-          FunSpec.builder("visitIds")
-            .addModifiers(OVERRIDE)
-            .addParameter("block", LambdaTypeName.get(null, Id, returnType = UNIT))
-            .addStatement("block(id)")
-            .apply {
-              for (trait in widget.traits) {
-                if (trait is ProtocolChildren) {
-                  addStatement("%N.visitIds(block)", trait.name)
+        .apply {
+          if (childrens.isNotEmpty()) {
+            addFunction(
+              FunSpec.builder("visitIds")
+                .addModifiers(OVERRIDE)
+                .addParameter("block", LambdaTypeName.get(null, Id, returnType = UNIT))
+                .addStatement("block(id)")
+                .apply {
+                  for (trait in widget.traits) {
+                    if (trait is ProtocolChildren) {
+                      addStatement("%N.visitIds(block)", trait.name)
+                    }
+                  }
                 }
-              }
-            }
-            .build(),
-        )
+                .build(),
+            )
+          }
+        }
         .addFunction(
           FunSpec.builder("detach")
             .addModifiers(OVERRIDE)
@@ -525,7 +539,7 @@ internal fun generateProtocolNode(
             .addStatement("""append("(id=")""")
             .addStatement("append(id.value)")
             .addStatement("""append(", tag=")""")
-            .addStatement("append(widgetTag.value)")
+            .addStatement("append(%L)", widget.tag)
             .addStatement("append(')')")
             .endControlFlow()
             .build(),

redwood-treehouse-host/src/commonTest/kotlin/app/cash/redwood/treehouse/FakeProtocolNode.kt

@@ -33,8 +33,8 @@ import kotlinx.serialization.json.JsonPrimitive
 @RedwoodCodegenApi
 internal class FakeProtocolNode(
   id: Id,
-  tag: WidgetTag,
-) : ProtocolNode<FakeWidget>(id, tag) {
+  override val widgetTag: WidgetTag,
+) : ProtocolNode<FakeWidget>(id) {
   override val widget = FakeWidget()
 
   override fun apply(change: PropertyChange, eventSink: UiEventSink) {