[plugin] generate separate file containing type aliases (#755)

Type aliases are unique per package so in order to ensure consistency we should generate separate file that will contain all String type aliases for custom scalars/IDs. Currently we generate typealiases per query file which means that if there are multiple queries referencing IDs (or custom scalars without custom mappers) we end up with invalid generated code due to the type aliases clash.

Resolves: #746

Author: dariuszkuc

plugins/graphql-kotlin-gradle-plugin/src/test/kotlin/com/expediagroup/graphql/plugin/gradle/GraphQLGenerateClientTaskIT.kt

@@ -73,6 +73,7 @@ class GraphQLGenerateClientTaskIT : GraphQLGradlePluginAbstractIT() {
 
         assertEquals(TaskOutcome.SUCCESS, buildResult.task(":$GENERATE_CLIENT_TASK_NAME")?.outcome)
         assertTrue(File(testProjectDirectory, "build/generated/source/graphql/main/com/example/generated/JUnitQuery.kt").exists())
+        assertTrue(File(testProjectDirectory, "build/generated/source/graphql/main/com/example/generated/GraphQLTypeAliases.kt").exists())
         assertEquals(TaskOutcome.SUCCESS, buildResult.task(":run")?.outcome)
     }
 

plugins/graphql-kotlin-maven-plugin/src/integration/generate-client/src/test/kotlin/com/expediagroup/graphql/plugin/maven/GenerateClientMojoTest.kt

@@ -25,7 +25,9 @@ class GenerateClientMojoTest {
     @Test
     fun `verify client code was generated`() {
         val buildDirectory = System.getProperty("buildDirectory")
-        val path = Paths.get(buildDirectory, "generated-sources", "graphql", "com", "expediagroup", "graphql", "plugin", "generated", "ExampleQuery.kt")
-        assertTrue(path.toFile().exists(), "graphql client was generated")
+        val queryFilePath = Paths.get(buildDirectory, "generated-sources", "graphql", "com", "expediagroup", "graphql", "plugin", "generated", "ExampleQuery.kt")
+        assertTrue(queryFilePath.toFile().exists(), "graphql client query file was generated")
+        val typeAliasesFilePath = Paths.get(buildDirectory, "generated-sources", "graphql", "com", "expediagroup", "graphql", "plugin", "generated", "GraphQLTypeAliases.kt")
+        assertTrue(queryFilePath.toFile().exists(), "graphql client type aliases were generated")
     }
 }

plugins/graphql-kotlin-plugin-core/README.md

@@ -32,10 +32,7 @@ using [square/kotlinpoet](https://github.com/square/kotlinpoet) library.
 * Only a single operation per GraphQL query file is supported.
 * Subscriptions are currently NOT supported.
 * You cannot make multiple selections to the same GraphQL object with different fields within a single GraphQL query.
-  But you can have different selection sets across different GraphQL queries, e.g.
-* Anonymous operations are supported but will result in generic `AnonymousQuery` (for query operation) class. Plugins
-  do not keep track of state across different query generations so if you have multiple anonymous operations in a single
-  package your compilation will fail due to the generic class name collisions.
+  But you can have different selection sets across different GraphQL queries
 * Nested queries have limited support as same object will be used for ALL nested results. This means that you have to
   explicitly ask for data from ALL nested levels + the NULL/empty child following it (that may skip recursive field selection
   as it will be NULL)

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

@@ -32,7 +32,5 @@ fun generateClient(
 ): List<FileSpec> {
     val graphQLSchema = SchemaParser().parse(schema)
     val generator = GraphQLClientGenerator(graphQLSchema, config)
-    return queries.map { queryFile ->
-        generator.generate(queryFile)
-    }
+    return generator.generate(queries)
 }

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

@@ -26,6 +26,7 @@ import com.squareup.kotlinpoet.ParameterizedTypeName.Companion.parameterizedBy
 import com.squareup.kotlinpoet.PropertySpec
 import com.squareup.kotlinpoet.STAR
 import com.squareup.kotlinpoet.STRING
+import com.squareup.kotlinpoet.TypeAliasSpec
 import com.squareup.kotlinpoet.TypeSpec
 import graphql.language.ObjectTypeDefinition
 import graphql.language.OperationDefinition
@@ -44,11 +45,30 @@ class GraphQLClientGenerator(
     private val config: GraphQLClientGeneratorConfig
 ) {
     private val documentParser: Parser = Parser()
+    private val typeAliases: MutableMap<String, TypeAliasSpec> = mutableMapOf()
+
+    /**
+     * Generate GraphQL clients for the specified queries.
+     */
+    fun generate(queries: List<File>): List<FileSpec> {
+        val result = mutableListOf<FileSpec>()
+        for (query in queries) {
+            result.add(generate(query))
+        }
+        if (typeAliases.isNotEmpty()) {
+            val typeAliasSpec = FileSpec.builder(packageName = config.packageName, fileName = "GraphQLTypeAliases")
+            typeAliases.forEach { (_, alias) ->
+                typeAliasSpec.addTypeAlias(alias)
+            }
+            result.add(typeAliasSpec.build())
+        }
+        return result
+    }
 
     /**
      * Generate GraphQL client wrapper class and data classes that match the specified query.
      */
-    fun generate(queryFile: File): FileSpec {
+    internal fun generate(queryFile: File): FileSpec {
         val queryConst = queryFile.readText()
         val queryDocument = documentParser.parseDocument(queryConst)
 
@@ -60,7 +80,7 @@ class GraphQLClientGenerator(
         val fileSpec = FileSpec.builder(packageName = config.packageName, fileName = queryFile.nameWithoutExtension.capitalize())
 
         operationDefinitions.forEach { operationDefinition ->
-            val operationName = operationDefinition.name ?: "anonymous${operationDefinition.operation.name.toLowerCase().capitalize()}"
+            val operationName = operationDefinition.name ?: queryFile.nameWithoutExtension.capitalize()
             val operationTypeName = operationName.capitalize()
             val context = GraphQLClientGeneratorContext(
                 packageName = config.packageName,
@@ -102,18 +122,16 @@ class GraphQLClientGenerator(
                 .initializer("graphQLClient").build())
             operationTypeSpec.addFunction(funSpec.build())
 
-            context.typeAliases.forEach { (_, alias) ->
-                fileSpec.addTypeAlias(alias)
-            }
             context.typeSpecs.forEach {
                 operationTypeSpec.addType(it.value)
             }
             fileSpec.addProperty(PropertySpec.builder(queryConstName, STRING)
                 .addModifiers(KModifier.CONST)
                 .initializer("%S", queryConst).build())
             fileSpec.addType(operationTypeSpec.build())
-        }
 
+            typeAliases.putAll(context.typeAliases)
+        }
         return fileSpec.build()
     }
 

plugins/graphql-kotlin-plugin-core/src/test/kotlin/com/expediagroup/graphql/plugin/generator/GraphQLTestUtils.kt

@@ -16,6 +16,7 @@
 
 package com.expediagroup.graphql.plugin.generator
 
+import com.squareup.kotlinpoet.FileSpec
 import graphql.schema.idl.SchemaParser
 import graphql.schema.idl.TypeDefinitionRegistry
 import kotlin.test.assertEquals
@@ -27,17 +28,23 @@ internal fun testSchema(): TypeDefinitionRegistry {
     }
 }
 
-internal fun verifyGraphQLClientGeneration(
+internal fun generateTestFileSpec(
     query: String,
-    expected: String,
     graphQLConfig: GraphQLClientGeneratorConfig = GraphQLClientGeneratorConfig(packageName = "com.expediagroup.graphql.plugin.generator.integration")
-) {
+): List<FileSpec> {
     val queryFile = createTempFile(suffix = ".graphql")
     queryFile.deleteOnExit()
     queryFile.writeText(query)
 
     val generator = GraphQLClientGenerator(testSchema(), graphQLConfig)
-    val fileSpec = generator.generate(queryFile)
+    return generator.generate(listOf(queryFile))
+}
 
-    assertEquals(expected, fileSpec.toString().trim())
+internal fun verifyGeneratedFileSpecContents(
+    query: String,
+    expected: String,
+    graphQLConfig: GraphQLClientGeneratorConfig = GraphQLClientGeneratorConfig(packageName = "com.expediagroup.graphql.plugin.generator.integration")
+) {
+    val fileSpecs = generateTestFileSpec(query, graphQLConfig)
+    assertEquals(expected, fileSpecs.first().toString().trim())
 }

plugins/graphql-kotlin-plugin-core/src/test/kotlin/com/expediagroup/graphql/plugin/generator/types/GenerateGraphQLCustomScalarTypeAliasIT.kt

@@ -16,27 +16,35 @@
 
 package com.expediagroup.graphql.plugin.generator.types
 
-import com.expediagroup.graphql.plugin.generator.verifyGraphQLClientGeneration
+import com.expediagroup.graphql.plugin.generator.generateTestFileSpec
 import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
 
 class GenerateGraphQLCustomScalarTypeAliasIT {
 
     @Test
     fun `verify can generate type aliases for GraphQL ID and custom scalars`() {
-        val expected = """
+        val expectedGraphQLAliasTypeSpec = """
             package com.expediagroup.graphql.plugin.generator.integration
 
-            import com.expediagroup.graphql.client.GraphQLClient
-            import com.expediagroup.graphql.types.GraphQLResponse
             import kotlin.String
 
+            typealias ID = String
+
             /**
              * Custom scalar representing UUID
              */
             typealias UUID = String
+        """.trimIndent()
+        val expectedQueryFileSpec = """
+            package com.expediagroup.graphql.plugin.generator.integration
+
+            import com.expediagroup.graphql.client.GraphQLClient
+            import com.expediagroup.graphql.types.GraphQLResponse
+            import kotlin.String
 
             const val SCALAR_ALIAS_TEST_QUERY: String =
-                "query ScalarAliasTestQuery {\n  scalarQuery {\n    custom\n  }\n}"
+                "query ScalarAliasTestQuery {\n  scalarQuery {\n    id\n    custom\n  }\n}"
 
             class ScalarAliasTestQuery(
               private val graphQLClient: GraphQLClient<*>
@@ -48,6 +56,10 @@ class GenerateGraphQLCustomScalarTypeAliasIT {
                * Wrapper that holds all supported scalar types
                */
               data class ScalarWrapper(
+                /**
+                 * ID represents unique identifier that is not intended to be human readable
+                 */
+                val id: ID,
                 /**
                  * Custom scalar
                  */
@@ -66,10 +78,14 @@ class GenerateGraphQLCustomScalarTypeAliasIT {
         val query = """
             query ScalarAliasTestQuery {
               scalarQuery {
+                id
                 custom
               }
             }
         """.trimIndent()
-        verifyGraphQLClientGeneration(query, expected)
+        val fileSpecs = generateTestFileSpec(query)
+        assertEquals(2, fileSpecs.size)
+        assertEquals(expectedQueryFileSpec, fileSpecs[0].toString().trim())
+        assertEquals(expectedGraphQLAliasTypeSpec, fileSpecs[1].toString().trim())
     }
 }

plugins/graphql-kotlin-plugin-core/src/test/kotlin/com/expediagroup/graphql/plugin/generator/types/GenerateGraphQLCustomScalarTypeSpecIT.kt

@@ -18,7 +18,7 @@ package com.expediagroup.graphql.plugin.generator.types
 
 import com.expediagroup.graphql.plugin.generator.GraphQLClientGeneratorConfig
 import com.expediagroup.graphql.plugin.generator.ScalarConverterMapping
-import com.expediagroup.graphql.plugin.generator.verifyGraphQLClientGeneration
+import com.expediagroup.graphql.plugin.generator.verifyGeneratedFileSpecContents
 import org.junit.jupiter.api.Test
 
 class GenerateGraphQLCustomScalarTypeSpecIT {
@@ -90,7 +90,7 @@ class GenerateGraphQLCustomScalarTypeSpecIT {
             }
         """.trimIndent()
 
-        verifyGraphQLClientGeneration(
+        verifyGeneratedFileSpecContents(
             query,
             expected,
             GraphQLClientGeneratorConfig(

plugins/graphql-kotlin-plugin-core/src/test/kotlin/com/expediagroup/graphql/plugin/generator/types/GenerateGraphQLEnumTypeSpecIT.kt

@@ -16,7 +16,7 @@
 
 package com.expediagroup.graphql.plugin.generator.types
 
-import com.expediagroup.graphql.plugin.generator.verifyGraphQLClientGeneration
+import com.expediagroup.graphql.plugin.generator.verifyGeneratedFileSpecContents
 import org.junit.jupiter.api.Test
 
 class GenerateGraphQLEnumTypeSpecIT {
@@ -82,6 +82,6 @@ class GenerateGraphQLEnumTypeSpecIT {
             }
         """.trimIndent()
 
-        verifyGraphQLClientGeneration(query, expected)
+        verifyGeneratedFileSpecContents(query, expected)
     }
 }

plugins/graphql-kotlin-plugin-core/src/test/kotlin/com/expediagroup/graphql/plugin/generator/types/GenerateGraphQLInputObjectTypeSpecIT.kt

@@ -16,7 +16,7 @@
 
 package com.expediagroup.graphql.plugin.generator.types
 
-import com.expediagroup.graphql.plugin.generator.verifyGraphQLClientGeneration
+import com.expediagroup.graphql.plugin.generator.verifyGeneratedFileSpecContents
 import org.junit.jupiter.api.Test
 
 class GenerateGraphQLInputObjectTypeSpecIT {
@@ -54,7 +54,7 @@ class GenerateGraphQLInputObjectTypeSpecIT {
               inputObjectQuery(criteria: { min: 1.0, max: 5.0 } )
             }
         """.trimIndent()
-        verifyGraphQLClientGeneration(query, expected)
+        verifyGeneratedFileSpecContents(query, expected)
     }
 
     @Test
@@ -95,6 +95,6 @@ class GenerateGraphQLInputObjectTypeSpecIT {
               second: inputObjectQuery(criteria: { min: 5.0, max: 10.0 } )
             }
         """.trimIndent()
-        verifyGraphQLClientGeneration(query, expected)
+        verifyGeneratedFileSpecContents(query, expected)
     }
 }