From debd30a47a7e6d3772795689ff546ca23cedc1a8 Mon Sep 17 00:00:00 2001
From: Sergey Vardanyan <sergey.vardanyan@jetbrains.com>
Date: Wed, 1 Oct 2025 20:24:45 +0400
Subject: [PATCH] Support custom builder types in `@GeneratedBuilder`
 annotation

- Extended the `@GeneratedBuilder` annotation to accept a `type` parameter of `KClass`.

GitOrigin-RevId: 2a54a95853367cd1a8c9de269d4d74ad93d5e7d7
---
 platform/eel/codegen/BuildersGeneratorTest.kt | 26 +++++++++++++++++--
 .../intellij/platform/eel/GeneratedBuilder.kt | 17 +++++++++++-
 2 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/platform/eel/codegen/BuildersGeneratorTest.kt b/platform/eel/codegen/BuildersGeneratorTest.kt
index 4b3a84430a2b..6fe68ffdbb72 100644
--- a/platform/eel/codegen/BuildersGeneratorTest.kt
+++ b/platform/eel/codegen/BuildersGeneratorTest.kt
@@ -474,11 +474,33 @@ private fun findBuilders(psiFile: PsiFile, methods: MutableList<BuilderRequest>)
         element is KtImportDirective -> {
           imports += element.text
         }
-        element is KtAnnotationEntry && element.typeReference?.renderWithFqnTypes() == "com.intellij.platform.eel.GeneratedBuilder" -> {
+        element is KtAnnotationEntry && element.typeReference?.renderWithFqnTypes()?.contains("GeneratedBuilder") ?: false -> {
           val valueParameter = element.parent.parent as? KtParameter ?: return
+
+          // Resolves the fully qualified type name for a value parameter by analyzing annotation arguments.
+          // First attempts to extract the type from a class literal expression in the annotation's first argument,
+          // then falls back to the value parameter's declared type if no annotation type is found.
+          // Filters out the GeneratedBuilder type and ensures type compatibility before returning the FQN.
           val typeFqn = analyze(valueParameter) {
-            valueParameter.typeReference?.type?.toString()?.replace("/", ".") ?: return
+            val valueParameterType = valueParameter.typeReference?.type ?: error("Parameter type is null")
+            val valueParameterTypeFqn = valueParameterType.toString().replace("/", ".")
+
+            val annotationParameterExpression = (element.valueArguments.firstOrNull() as KtValueArgument?)?.getArgumentExpression() as KtClassLiteralExpression?
+            if (annotationParameterExpression == null) return@analyze valueParameterTypeFqn
+
+            return@analyze analyze(annotationParameterExpression) {
+              val annotationParameterType = annotationParameterExpression.receiverType ?: return@analyze null
+              val annotationParameterTypeFqn = annotationParameterType.toString().replace("/", ".").takeIf {
+                it != "com.intellij.platform.eel.GeneratedBuilder"
+              }
+              if (annotationParameterTypeFqn == null) return@analyze null
+
+              assert(annotationParameterType.isSubtypeOf(valueParameterType)) { "Specified type $this is not a subtype of the value parameter type $valueParameterType" }
+
+              return@analyze annotationParameterTypeFqn
+            } ?: valueParameterTypeFqn
           }
+
           val fn = valueParameter.parent.parent as? KtNamedFunction ?: return
           val methodName = fn.name ?: return
           val methodCls = valueParameter.containingClass()?.fqName ?: return
diff --git a/platform/eel/src/com/intellij/platform/eel/GeneratedBuilder.kt b/platform/eel/src/com/intellij/platform/eel/GeneratedBuilder.kt
index 2ec24454e205..cb813b576ce8 100644
--- a/platform/eel/src/com/intellij/platform/eel/GeneratedBuilder.kt
+++ b/platform/eel/src/com/intellij/platform/eel/GeneratedBuilder.kt
@@ -2,15 +2,30 @@
 package com.intellij.platform.eel
 
 import org.jetbrains.annotations.ApiStatus
+import kotlin.reflect.KClass
 
 /**
  * `com.intellij.platform.eel.codegen.BuildersGeneratorTest` generates builders for all methods
  * that have a single argument with this annotation.
+ *
+ * @property type The class type associated with the generated builder.
+ * It must be a subtype of the annotated argument's type.
+ * Default value of the type property is `GeneratedBuilder::class` which means that the annotated argument's type will be used.
+ *
+ * Examples:
+ * ```kotlin
+ * // Generates a builder for `ExecuteProcessWindowsOptions`
+ * fun spawnProcess(@GeneratedBuilder(ExecuteProcessWindowsOptions::class) generatedBuilder: ExecuteProcessOptions)
+ * ```
+ * `````kotlin
+ * // Generates a builder for `ExecuteProcessOptions`
+ * fun spawnProcess(@GeneratedBuilder() generatedBuilder: ExecuteProcessOptions)
+ * ```
  */
 @Retention(AnnotationRetention.SOURCE)
 @Target(AnnotationTarget.VALUE_PARAMETER)
 @ApiStatus.Internal
-annotation class GeneratedBuilder {
+annotation class GeneratedBuilder(val type: KClass<*> = GeneratedBuilder::class) {
   /**
    * The only purpose of this annotation is to help to find generated builders via "Find Usages".
    */