[java-rd] IJPL-176967: Rewrite XValueDescriptor, so it may be extended by plugins

GitOrigin-RevId: 9fd606e89cbf0680357a12c5159cc99ec3463914

java/debugger/frontend/src/com/intellij/java/debugger/impl/frontend/actions/FrontendViewTextAction.kt

@@ -2,11 +2,10 @@
 package com.intellij.java.debugger.impl.frontend.actions
 
 import com.intellij.java.debugger.impl.shared.actions.ViewTextActionBase
-import com.intellij.java.debugger.impl.shared.engine.JAVA_VALUE_KIND
+import com.intellij.java.debugger.impl.shared.engine.JavaValueDescriptor
 import com.intellij.openapi.actionSystem.AnActionEvent
 import com.intellij.openapi.actionSystem.remoting.ActionRemoteBehaviorSpecification
 import com.intellij.platform.debugger.impl.frontend.evaluate.quick.FrontendXValue
-import com.intellij.xdebugger.frame.XValueType
 import com.intellij.xdebugger.impl.actions.areFrontendDebuggerActionsEnabled
 import com.intellij.xdebugger.impl.ui.tree.actions.XDebuggerTreeActionBase
 import com.intellij.xdebugger.impl.ui.tree.nodes.XValueNodeImpl
@@ -27,9 +26,9 @@ private class FrontendViewTextAction : ViewTextActionBase(), ActionRemoteBehavio
   override fun getStringNode(e: AnActionEvent): XValueNodeImpl? {
     val node = XDebuggerTreeActionBase.getSelectedNodes(e.dataContext).singleOrNull() ?: return null
     val xValue = node.valueContainer as? FrontendXValue ?: return null
-    val descriptor = xValue.descriptor ?: return null
+    val descriptor = (xValue.descriptor as? JavaValueDescriptor) ?: return null
 
-    if (xValue.modifier != null && descriptor.kind == JAVA_VALUE_KIND && descriptor.type is XValueType.StringType) {
+    if (xValue.modifier != null && descriptor.isString) {
       return node
     }
 

java/debugger/impl/src/com/intellij/debugger/engine/JavaValue.java

@@ -22,6 +22,7 @@ import com.intellij.debugger.ui.impl.watch.*;
 import com.intellij.debugger.ui.tree.*;
 import com.intellij.debugger.ui.tree.render.*;
 import com.intellij.debugger.ui.tree.render.Renderer;
+import com.intellij.java.debugger.impl.shared.engine.JavaValueDescriptor;
 import com.intellij.openapi.actionSystem.AnActionEvent;
 import com.intellij.openapi.application.ReadAction;
 import com.intellij.openapi.diagnostic.Logger;
@@ -58,7 +59,7 @@ import java.util.List;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 
-import static com.intellij.java.debugger.impl.shared.engine.XValueTypeKt.JAVA_VALUE_KIND;
+import static com.intellij.java.debugger.impl.shared.engine.JavaValueDescriptorKt.JAVA_VALUE_KIND;
 
 public class JavaValue extends XNamedValue implements NodeDescriptorProvider, XValueTextProvider,
                                                       PinToTopParentValue, PinToTopMemberValue {
@@ -513,14 +514,9 @@ public class JavaValue extends XNamedValue implements NodeDescriptorProvider, XV
   @Override
   public @Nullable CompletableFuture<XValueDescriptor> getXValueDescriptorAsync() {
     return myValueDescriptor.getInitFuture().thenApply(ignored -> {
-      XValueType type;
-      if (myValueDescriptor.isString()) {
-        type = XValueType.StringType.INSTANCE;
-      }
-      else {
-        type = XValueType.Unknown.INSTANCE;
-      }
-      return new XValueDescriptor(JAVA_VALUE_KIND, type);
+      return new JavaValueDescriptor(
+        myValueDescriptor.isString()
+      );
     });
   }
 

java/debugger/shared/resources/intellij.java.debugger.impl.shared.xml

@@ -4,5 +4,7 @@
     <applicationSettings service="com.intellij.debugger.settings.DebuggerSettings"/>
     <xdebugger.hotSwapUiExtension implementation="com.intellij.debugger.impl.hotswap.JvmHotSwapUiExtension"/>
     <rdct.remoteSettingProvider implementation="com.intellij.debugger.settings.JavaDebuggerSettingsProvider"/>
+    <xdebugger.xValueCustomDescriptorSerializerProvider
+      implementation="com.intellij.java.debugger.impl.shared.engine.JavaValueDescriptorSerializerProvider"/>
   </extensions>
 </idea-plugin>

java/debugger/shared/src/com/intellij/java/debugger/impl/shared/engine/JavaValueDescriptor.kt

@@ -0,0 +1,26 @@
+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.java.debugger.impl.shared.engine
+
+import com.intellij.xdebugger.frame.XValueCustomDescriptorSerializerProvider
+import com.intellij.xdebugger.frame.XValueDescriptor
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.modules.PolymorphicModuleBuilder
+import kotlinx.serialization.modules.subclass
+import org.jetbrains.annotations.ApiStatus
+
+@ApiStatus.Internal
+const val JAVA_VALUE_KIND: String = "JavaValue"
+
+@ApiStatus.Internal
+@Serializable
+class JavaValueDescriptor(
+  val isString: Boolean,
+) : XValueDescriptor {
+  override val kind: String = JAVA_VALUE_KIND
+}
+
+private class JavaValueDescriptorSerializerProvider : XValueCustomDescriptorSerializerProvider {
+  override fun registerSerializer(builder: PolymorphicModuleBuilder<XValueDescriptor>) {
+    builder.subclass(JavaValueDescriptor::class)
+  }
+}

java/debugger/shared/src/com/intellij/java/debugger/impl/shared/engine/XValueType.kt

@@ -1,7 +0,0 @@
-// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
-package com.intellij.java.debugger.impl.shared.engine
-
-import org.jetbrains.annotations.ApiStatus
-
-@ApiStatus.Internal
-const val JAVA_VALUE_KIND: String = "JavaValue"

platform/xdebugger-api/src/com/intellij/xdebugger/frame/XValueDescriptor.kt

@@ -1,16 +1,40 @@
 // Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.xdebugger.frame
 
+import com.intellij.openapi.components.Service
+import com.intellij.openapi.components.service
+import com.intellij.openapi.extensions.ExtensionPointAdapter
+import com.intellij.openapi.extensions.ExtensionPointName
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.serialization.KSerializer
 import kotlinx.serialization.Serializable
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.decodeFromJsonElement
+import kotlinx.serialization.json.encodeToJsonElement
+import kotlinx.serialization.modules.PolymorphicModuleBuilder
+import kotlinx.serialization.modules.SerializersModule
+import kotlinx.serialization.modules.polymorphic
 import org.jetbrains.annotations.ApiStatus
 
 /**
- * Provides additional information about XValue which can be used by UI and actions.
+ * Provides additional information about XValue which can be used by UI and actions on the Frontend.
  *
+ * Internal plugins may extend this interface providing custom implementation, but they should be serializable.
+ * Also, it is required to provide serializer for the implementation using
+ * [com.intellij.xdebugger.frame.XValueCustomDescriptorSerializerProvider].
+ * Otherwise, the default implementation will be used during a serialization/deserialization process.
+ *
+ *
+ * @see createXValueDescriptor
+ * @see XValueCustomDescriptorSerializerProvider
  */
 @ApiStatus.Internal
-@Serializable
-data class XValueDescriptor(
+@Serializable(with = XValueDescriptorSerializer::class)
+interface XValueDescriptor {
   /**
    * [kind] is used to differentiate various implementations of XValue by their type instead of using `instanceOf` on [XValue].
    * Examples of possible kinds: "JavaValue", "PhpValue", "RubyValue"
@@ -19,25 +43,75 @@ data class XValueDescriptor(
    * which makes `instanceOf` comparisons of XValue impossible, this property provides a way to
    * differentiate between various types of XValue on the frontend.
    */
-  val kind: String,
+  val kind: String
+}
 
-  /**
-   * [XValue] type (see instances of the [XValueType]).
-   * Typically, the client may use the type to check the availability of some action or show XValue differently in UI.
-   */
-  val type: XValueType,
-)
+// TODO: should be called just XValueDescriptor, but it won't be available in Java then
+@ApiStatus.Internal
+fun createXValueDescriptor(kind: String): XValueDescriptor {
+  return XValueDescriptorImpl(kind)
+}
 
 @ApiStatus.Internal
+interface XValueCustomDescriptorSerializerProvider {
+  companion object {
+    internal val EP_NAME = ExtensionPointName<XValueCustomDescriptorSerializerProvider>("com.intellij.xdebugger.xValueCustomDescriptorSerializerProvider")
+  }
+
+  fun registerSerializer(builder: PolymorphicModuleBuilder<XValueDescriptor>)
+}
+
 @Serializable
-sealed interface XValueType {
-  // TODO: add other types of XValue
-  @Serializable
-  data object StringType : XValueType
+private data class XValueDescriptorImpl(override val kind: String) : XValueDescriptor
 
-  @Serializable
-  data class Other(val rawType: String) : XValueType
 
-  @Serializable
-  data object Unknown : XValueType
+private object XValueDescriptorSerializer : KSerializer<XValueDescriptor> {
+  override val descriptor: SerialDescriptor = JsonElement.serializer().descriptor
+
+  override fun serialize(encoder: Encoder, value: XValueDescriptor) {
+    val json = service<XValueDescriptorJsonProvider>().json
+    val element = json.encodeToJsonElement(value)
+    encoder.encodeSerializableValue(JsonElement.serializer(), element)
+  }
+
+  override fun deserialize(decoder: Decoder): XValueDescriptor {
+    val json = service<XValueDescriptorJsonProvider>().json
+    val element = decoder.decodeSerializableValue(JsonElement.serializer())
+    return json.decodeFromJsonElement(element)
+  }
+}
+
+@Service
+private class XValueDescriptorJsonProvider(cs: CoroutineScope) {
+  @Volatile
+  var json = Json {
+    ignoreUnknownKeys = true
+    encodeDefaults = true
+  }
+
+  init {
+    updateJson()
+    XValueCustomDescriptorSerializerProvider.EP_NAME.addExtensionPointListener(cs, object : ExtensionPointAdapter<XValueCustomDescriptorSerializerProvider>() {
+      override fun extensionListChanged() {
+        updateJson()
+      }
+    })
+  }
+
+  private fun updateJson() {
+    json = Json {
+      ignoreUnknownKeys = true
+      encodeDefaults = true
+      serializersModule = SerializersModule {
+        polymorphic(XValueDescriptor::class) {
+          for (provider in XValueCustomDescriptorSerializerProvider.EP_NAME.extensionList) {
+            provider.registerSerializer(this)
+          }
+          defaultDeserializer {
+            XValueDescriptorImpl.serializer()
+          }
+        }
+      }
+    }
+  }
 }

platform/xdebugger-impl/resources/META-INF/xdebugger.xml

@@ -28,6 +28,9 @@
     <extensionPoint name="xdebugger.controlExceptionBreakpointSupport" interface="com.intellij.xdebugger.codeinsight.ControlExceptionBreakpointSupport" dynamic="true"/>
 
     <extensionPoint name="xdebugger.hotSwapUiExtension" interface="com.intellij.xdebugger.impl.hotswap.HotSwapUiExtension" dynamic="true"/>
+
+    <extensionPoint name="xdebugger.xValueCustomDescriptorSerializerProvider"
+                    interface="com.intellij.xdebugger.frame.XValueCustomDescriptorSerializerProvider" dynamic="true"/>
   </extensionPoints>
 
   <extensions defaultExtensionNs="com.intellij">