escape 'companion' in Kotlin (#4630)

libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo3/compiler/codegen/kotlin/file/FragmentBuilder.kt

@@ -48,7 +48,8 @@ internal class FragmentBuilder(
           superClassName = if (it.id == fragment.dataModelGroup.baseModelId) KotlinSymbols.FragmentData else null,
           path = listOf(packageName, simpleName),
           hasSubclassesInSamePackage = true,
-          adaptableWith = null
+          adaptableWith = null,
+          reservedNames = setOf("Companion")
       )
     }
   } else {

libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo3/compiler/codegen/kotlin/file/OperationBuilder.kt

@@ -66,6 +66,7 @@ internal class OperationBuilder(
         path = listOf(packageName, simpleName),
         hasSubclassesInSamePackage = true,
         adaptableWith = if (it.id == operation.dataModelGroup.baseModelId) it.id else null,
+        reservedNames = setOf("Companion")
     )
   }
 

libraries/apollo-compiler/src/main/kotlin/com/apollographql/apollo3/compiler/codegen/kotlin/model/ModelBuilder.kt

@@ -29,7 +29,8 @@ internal class ModelBuilder(
     private val superClassName: ClassName?,
     private val path: List<String>,
     private val hasSubclassesInSamePackage: Boolean,
-    private val adaptableWith: String?
+    private val adaptableWith: String?,
+    private val reservedNames: Set<String> = emptySet()
 ) {
   private val nestedBuilders = model.modelGroups.flatMap {
     it.models.map {
@@ -43,11 +44,12 @@ internal class ModelBuilder(
       )
     }
   }
+  private val simpleName = if (reservedNames.contains(model.modelName)) "${model.modelName}_" else model.modelName
 
   fun prepare() {
     context.resolver.registerModel(
         model.id,
-        ClassName.from(path + model.modelName)
+        ClassName.from(path + simpleName)
     )
     nestedBuilders.forEach { it.prepare() }
   }
@@ -74,14 +76,14 @@ internal class ModelBuilder(
     } + listOfNotNull(superClassName)
 
     val typeSpecBuilder = if (isInterface) {
-      TypeSpec.interfaceBuilder(modelName)
+      TypeSpec.interfaceBuilder(simpleName)
           // All interfaces can be sealed except if implementations exist in different packages (not allowed in Kotlin)
           .applyIf(context.isTargetLanguageVersionAtLeast(KOTLIN_1_5) && hasSubclassesInSamePackage) {
             addModifiers(KModifier.SEALED)
           }
           .addProperties(properties)
     } else {
-      TypeSpec.classBuilder(modelName)
+      TypeSpec.classBuilder(simpleName)
           .makeDataClassFromProperties(properties)
     }
 

libraries/apollo-compiler/src/test/graphql/com/example/companion/TestOperation.graphql

@@ -0,0 +1,5 @@
+query TestQuery {
+  companion {
+    foo
+  }
+}