Implement shared response types for GraphQL client generator

plugins/client/graphql-kotlin-client-generator/src/main/kotlin/com/expediagroup/graphql/plugin/client/generateClient.kt

@@ -35,7 +35,8 @@ fun generateClient(
     schemaPath: String,
     queries: List<File>,
     useOptionalInputWrapper: Boolean = false,
-    parserOptions: ParserOptions.Builder.() -> Unit = {}
+    parserOptions: ParserOptions.Builder.() -> Unit = {},
+    useSharedResponseTypes: Boolean = false
 ): List<FileSpec> {
     val customScalars = customScalarsMap.associateBy { it.scalar }
     val config = GraphQLClientGeneratorConfig(
@@ -44,7 +45,8 @@ fun generateClient(
         customScalarMap = customScalars,
         serializer = serializer,
         useOptionalInputWrapper = useOptionalInputWrapper,
-        parserOptions = parserOptions
+        parserOptions = parserOptions,
+        useSharedResponseTypes = useSharedResponseTypes
     )
     val generator = GraphQLClientGenerator(schemaPath, config)
     return generator.generate(queries)

plugins/client/graphql-kotlin-client-generator/src/main/kotlin/com/expediagroup/graphql/plugin/client/generator/GraphQLClientGenerator.kt

@@ -66,6 +66,8 @@ class GraphQLClientGenerator(
      */
     fun generate(queries: List<File>): List<FileSpec> {
         val result = mutableListOf<FileSpec>()
+
+        // Generate client code with shared types
         for (query in queries) {
             result.addAll(generate(query))
         }
@@ -119,8 +121,10 @@ class GraphQLClientGenerator(
                 allowDeprecated = config.allowDeprecated,
                 customScalarMap = config.customScalarMap,
                 serializer = config.serializer,
-                useOptionalInputWrapper = config.useOptionalInputWrapper
+                useOptionalInputWrapper = config.useOptionalInputWrapper,
+                config = config
             )
+
             val queryConstName = capitalizedOperationName.toUpperUnderscore()
             val queryConstProp = PropertySpec.builder(queryConstName, STRING)
                 .addModifiers(KModifier.CONST)
@@ -216,6 +220,7 @@ class GraphQLClientGenerator(
             // shared types
             sharedTypes.putAll(context.enumClassToTypeSpecs.mapValues { listOf(it.value) })
             sharedTypes.putAll(context.inputClassToTypeSpecs.mapValues { listOf(it.value) })
+            sharedTypes.putAll(context.responseClassToTypeSpecs.mapValues { listOf(it.value) })
             context.scalarClassToConverterTypeSpecs
                 .values
                 .forEach {

plugins/client/graphql-kotlin-client-generator/src/main/kotlin/com/expediagroup/graphql/plugin/client/generator/GraphQLClientGeneratorConfig.kt

@@ -33,6 +33,8 @@ data class GraphQLClientGeneratorConfig(
     val serializer: GraphQLSerializer = GraphQLSerializer.JACKSON,
     /** Explicit opt-in flag to enable support for optional inputs. */
     val useOptionalInputWrapper: Boolean = false,
+    /** Boolean flag indicating whether to generate shared response types instead of operation-specific duplicates. Defaults to false. */
+    val useSharedResponseTypes: Boolean = false,
     /** Set parser options for processing GraphQL queries and schema definition language documents */
     val parserOptions: ParserOptions.Builder.() -> Unit = {}
 )

plugins/client/graphql-kotlin-client-generator/src/main/kotlin/com/expediagroup/graphql/plugin/client/generator/GraphQLClientGeneratorContext.kt

@@ -21,6 +21,7 @@ import com.squareup.kotlinpoet.TypeAliasSpec
 import com.squareup.kotlinpoet.TypeName
 import com.squareup.kotlinpoet.TypeSpec
 import graphql.language.Document
+import graphql.language.Selection
 import graphql.schema.idl.TypeDefinitionRegistry
 
 /**
@@ -36,7 +37,8 @@ data class GraphQLClientGeneratorContext(
     val allowDeprecated: Boolean = false,
     val customScalarMap: Map<String, GraphQLScalar> = mapOf(),
     val serializer: GraphQLSerializer = GraphQLSerializer.JACKSON,
-    val useOptionalInputWrapper: Boolean = false
+    val useOptionalInputWrapper: Boolean = false,
+    val config: GraphQLClientGeneratorConfig
 ) {
     // per operation caches
     val typeSpecs: MutableMap<ClassName, TypeSpec> = mutableMapOf()
@@ -45,13 +47,16 @@ data class GraphQLClientGeneratorContext(
     // shared type caches
     val enumClassToTypeSpecs: MutableMap<ClassName, TypeSpec> = mutableMapOf()
     val inputClassToTypeSpecs: MutableMap<ClassName, TypeSpec> = mutableMapOf()
+    val responseClassToTypeSpecs: MutableMap<ClassName, TypeSpec> = mutableMapOf()
     val scalarClassToConverterTypeSpecs: MutableMap<ClassName, ScalarConverterInfo> = mutableMapOf()
     val typeAliases: MutableMap<String, TypeAliasSpec> = mutableMapOf()
     internal fun isTypeAlias(typeName: String) = typeAliases.containsKey(typeName)
 
     // class name and type selection caches
     val classNameCache: MutableMap<String, MutableList<ClassName>> = mutableMapOf()
     val typeToSelectionSetMap: MutableMap<String, Set<String>> = mutableMapOf()
+    val responseTypeToSelectionSetMap: MutableMap<String, MutableSet<Selection<*>>> = mutableMapOf()
+    val sharedTypeVariantToSelectionSetMap: MutableMap<String, Set<String>> = mutableMapOf()
 
     private val customScalarClassNames: Set<ClassName> = customScalarMap.values.map { it.className }.toSet()
     internal fun isCustomScalar(typeName: TypeName): Boolean = customScalarClassNames.contains(typeName)

plugins/client/graphql-kotlin-client-generator/src/main/kotlin/com/expediagroup/graphql/plugin/client/generator/types/generateTypeName.kt

@@ -111,8 +111,50 @@ internal fun generateCustomClassName(context: GraphQLClientGeneratorContext, gra
             // generate corresponding type spec
             when (graphQLTypeDefinition) {
                 is ObjectTypeDefinition -> {
-                    className = generateClassName(context, graphQLTypeDefinition, selectionSet)
-                    context.typeSpecs[className] = generateGraphQLObjectTypeSpec(context, graphQLTypeDefinition, selectionSet)
+                    if (context.config.useSharedResponseTypes) {
+                        // Use cross-operation reuse logic similar to existing single-operation logic
+                        val globalCachedTypes = context.responseClassToTypeSpecs.keys.filter { it.simpleName.startsWith(graphQLTypeDefinition.name) }
+
+                        if (globalCachedTypes.isNotEmpty()) {
+                            // Check if any existing shared type matches this selection set
+                            var foundMatch = false
+                            for (cachedType in globalCachedTypes) {
+                                if (isCachedTypeApplicableForSharedType(context, cachedType, graphQLTypeDefinition, selectionSet)) {
+                                    className = cachedType
+                                    foundMatch = true
+                                    break
+                                }
+                            }
+
+                            if (!foundMatch) {
+                                // Generate new variant (ComplexObject2, ComplexObject3, etc.)
+                                val variantNumber = globalCachedTypes.size + 1
+                                val variantName = if (variantNumber == 1) graphQLTypeDefinition.name else "${graphQLTypeDefinition.name}$variantNumber"
+                                className = ClassName("${context.packageName}.responses", variantName)
+                                context.responseClassToTypeSpecs[className] = generateGraphQLObjectTypeSpec(context, graphQLTypeDefinition, selectionSet, variantName)
+
+                                // Track selection set for this variant
+                                if (selectionSet != null) {
+                                    val selectedFields = calculateSelectedFields(context, graphQLTypeDefinition.name, selectionSet)
+                                    context.sharedTypeVariantToSelectionSetMap[variantName] = selectedFields
+                                }
+                            }
+                        } else {
+                            // First occurrence - create base shared type
+                            className = ClassName("${context.packageName}.responses", graphQLTypeDefinition.name)
+                            context.responseClassToTypeSpecs[className] = generateGraphQLObjectTypeSpec(context, graphQLTypeDefinition, selectionSet)
+
+                            // Track selection set for this variant
+                            if (selectionSet != null) {
+                                val selectedFields = calculateSelectedFields(context, graphQLTypeDefinition.name, selectionSet)
+                                context.sharedTypeVariantToSelectionSetMap[graphQLTypeDefinition.name] = selectedFields
+                            }
+                        }
+                    } else {
+                        // Use original logic for operation-specific types
+                        className = generateClassName(context, graphQLTypeDefinition, selectionSet)
+                        context.typeSpecs[className] = generateGraphQLObjectTypeSpec(context, graphQLTypeDefinition, selectionSet)
+                    }
                 }
                 is InputObjectTypeDefinition -> {
                     className = generateClassName(context, graphQLTypeDefinition, selectionSet, packageName = "${context.packageName}.inputs")
@@ -258,3 +300,19 @@ private fun calculateSelectedFields(
     }
     return result
 }
+
+/**
+ * Helper function to check if a cached shared type matches the current selection set.
+ */
+private fun isCachedTypeApplicableForSharedType(
+    context: GraphQLClientGeneratorContext,
+    cachedClassName: ClassName,
+    graphQLTypeDefinition: TypeDefinition<*>,
+    selectionSet: SelectionSet?
+): Boolean {
+    if (selectionSet == null) return true
+
+    val selectedFields = calculateSelectedFields(context, graphQLTypeDefinition.name, selectionSet)
+    val cachedTypeFields = context.sharedTypeVariantToSelectionSetMap[cachedClassName.simpleName]
+    return selectedFields == cachedTypeFields
+}

plugins/client/graphql-kotlin-client-generator/src/test/data/generator/cross_operation_reuse_types/Operation1.graphql

@@ -0,0 +1,33 @@
+query Operation1 {
+  first: complexObjectQuery {
+    id
+    name
+  }
+  second: complexObjectQuery {
+    id
+    name
+    details {
+      id
+      value
+    }
+  }
+  third: complexObjectQuery {
+    id
+    name
+    details {
+      id
+    }
+  }
+  fourth: complexObjectQuery {
+    id
+    name
+  }
+  fifth: complexObjectQuery {
+    id
+    name
+    details {
+      id
+      value
+    }
+  }
+}

plugins/client/graphql-kotlin-client-generator/src/test/data/generator/cross_operation_reuse_types/Operation1.kt

@@ -0,0 +1,51 @@
+package com.expediagroup.graphql.generated
+
+import com.expediagroup.graphql.client.Generated
+import com.expediagroup.graphql.client.types.GraphQLClientRequest
+import com.expediagroup.graphql.generated.responses.ComplexObject
+import com.expediagroup.graphql.generated.responses.ComplexObject2
+import com.expediagroup.graphql.generated.responses.ComplexObject3
+import com.fasterxml.jackson.`annotation`.JsonProperty
+import kotlin.String
+import kotlin.reflect.KClass
+
+public const val OPERATION1: String =
+    "query Operation1 {\n  first: complexObjectQuery {\n    id\n    name\n  }\n  second: complexObjectQuery {\n    id\n    name\n    details {\n      id\n      value\n    }\n  }\n  third: complexObjectQuery {\n    id\n    name\n    details {\n      id\n    }\n  }\n  fourth: complexObjectQuery {\n    id\n    name\n  }\n  fifth: complexObjectQuery {\n    id\n    name\n    details {\n      id\n      value\n    }\n  }\n}"
+
+@Generated
+public class Operation1 : GraphQLClientRequest<Operation1.Result> {
+  override val query: String = OPERATION1
+
+  override val operationName: String = "Operation1"
+
+  override fun responseType(): KClass<Operation1.Result> = Operation1.Result::class
+
+  @Generated
+  public data class Result(
+    /**
+     * Query returning an object that references another object
+     */
+    @get:JsonProperty(value = "first")
+    public val first: ComplexObject,
+    /**
+     * Query returning an object that references another object
+     */
+    @get:JsonProperty(value = "second")
+    public val second: ComplexObject2,
+    /**
+     * Query returning an object that references another object
+     */
+    @get:JsonProperty(value = "third")
+    public val third: ComplexObject3,
+    /**
+     * Query returning an object that references another object
+     */
+    @get:JsonProperty(value = "fourth")
+    public val fourth: ComplexObject,
+    /**
+     * Query returning an object that references another object
+     */
+    @get:JsonProperty(value = "fifth")
+    public val fifth: ComplexObject2,
+  )
+}

plugins/client/graphql-kotlin-client-generator/src/test/data/generator/cross_operation_reuse_types/Operation2.graphql

@@ -0,0 +1,33 @@
+query Operation2 {
+  first: complexObjectQuery {
+    id
+    name
+  }
+  second: complexObjectQuery {
+    id
+    name
+    details {
+      id
+      value
+    }
+  }
+  third: complexObjectQuery {
+    id
+    name
+    details {
+      id
+    }
+  }
+  fourth: complexObjectQuery {
+    id
+    name
+  }
+  fifth: complexObjectQuery {
+    id
+    name
+    details {
+      id
+      value
+    }
+  }
+}

plugins/client/graphql-kotlin-client-generator/src/test/data/generator/cross_operation_reuse_types/Operation2.kt

@@ -0,0 +1,51 @@
+package com.expediagroup.graphql.generated
+
+import com.expediagroup.graphql.client.Generated
+import com.expediagroup.graphql.client.types.GraphQLClientRequest
+import com.expediagroup.graphql.generated.responses.ComplexObject
+import com.expediagroup.graphql.generated.responses.ComplexObject2
+import com.expediagroup.graphql.generated.responses.ComplexObject3
+import com.fasterxml.jackson.`annotation`.JsonProperty
+import kotlin.String
+import kotlin.reflect.KClass
+
+public const val OPERATION2: String =
+    "query Operation2 {\n  first: complexObjectQuery {\n    id\n    name\n  }\n  second: complexObjectQuery {\n    id\n    name\n    details {\n      id\n      value\n    }\n  }\n  third: complexObjectQuery {\n    id\n    name\n    details {\n      id\n    }\n  }\n  fourth: complexObjectQuery {\n    id\n    name\n  }\n  fifth: complexObjectQuery {\n    id\n    name\n    details {\n      id\n      value\n    }\n  }\n}"
+
+@Generated
+public class Operation2 : GraphQLClientRequest<Operation2.Result> {
+  override val query: String = OPERATION2
+
+  override val operationName: String = "Operation2"
+
+  override fun responseType(): KClass<Operation2.Result> = Operation2.Result::class
+
+  @Generated
+  public data class Result(
+    /**
+     * Query returning an object that references another object
+     */
+    @get:JsonProperty(value = "first")
+    public val first: ComplexObject,
+    /**
+     * Query returning an object that references another object
+     */
+    @get:JsonProperty(value = "second")
+    public val second: ComplexObject2,
+    /**
+     * Query returning an object that references another object
+     */
+    @get:JsonProperty(value = "third")
+    public val third: ComplexObject3,
+    /**
+     * Query returning an object that references another object
+     */
+    @get:JsonProperty(value = "fourth")
+    public val fourth: ComplexObject,
+    /**
+     * Query returning an object that references another object
+     */
+    @get:JsonProperty(value = "fifth")
+    public val fifth: ComplexObject2,
+  )
+}

plugins/client/graphql-kotlin-client-generator/src/test/data/generator/cross_operation_reuse_types/responses/ComplexObject.kt

@@ -0,0 +1,25 @@
+package com.expediagroup.graphql.generated.responses
+
+import com.expediagroup.graphql.client.Generated
+import com.fasterxml.jackson.`annotation`.JsonProperty
+import kotlin.Int
+import kotlin.String
+
+/**
+ * Multi line description of a complex type.
+ * This is a second line of the paragraph.
+ * This is final line of the description.
+ */
+@Generated
+public data class ComplexObject(
+  /**
+   * Some unique identifier
+   */
+  @get:JsonProperty(value = "id")
+  public val id: Int,
+  /**
+   * Some object name
+   */
+  @get:JsonProperty(value = "name")
+  public val name: String,
+)

plugins/client/graphql-kotlin-client-generator/src/test/data/generator/cross_operation_reuse_types/responses/ComplexObject2.kt

@@ -0,0 +1,30 @@
+package com.expediagroup.graphql.generated.responses
+
+import com.expediagroup.graphql.client.Generated
+import com.fasterxml.jackson.`annotation`.JsonProperty
+import kotlin.Int
+import kotlin.String
+
+/**
+ * Multi line description of a complex type.
+ * This is a second line of the paragraph.
+ * This is final line of the description.
+ */
+@Generated
+public data class ComplexObject2(
+  /**
+   * Some unique identifier
+   */
+  @get:JsonProperty(value = "id")
+  public val id: Int,
+  /**
+   * Some object name
+   */
+  @get:JsonProperty(value = "name")
+  public val name: String,
+  /**
+   * Some additional details
+   */
+  @get:JsonProperty(value = "details")
+  public val details: DetailsObject,
+)