fix: update built-in directives print strings to include arguments (#258)

Author: dariuszkuc

src/main/kotlin/com/expedia/graphql/directives/DeprecatedDirective.kt

@@ -4,13 +4,12 @@ import graphql.Scalars
 import graphql.introspection.Introspection
 import graphql.schema.GraphQLArgument
 import graphql.schema.GraphQLDirective
-import graphql.schema.GraphQLNonNull
 
 const val DEPRECATED_DIRECTIVE_NAME = "deprecated"
 
 private val DefaultDeprecatedArgument: GraphQLArgument = GraphQLArgument.newArgument()
     .name("reason")
-    .type(GraphQLNonNull.nonNull(Scalars.GraphQLString))
+    .type(Scalars.GraphQLString)
     .defaultValue("No longer supported")
     .build()
 

src/main/kotlin/com/expedia/graphql/extensions/GraphQLSchemaExtensions.kt

@@ -2,7 +2,10 @@ package com.expedia.graphql.extensions
 
 import com.expedia.graphql.directives.DeprecatedDirective
 import graphql.Directives
+import graphql.schema.GraphQLArgument
+import graphql.schema.GraphQLDirective
 import graphql.schema.GraphQLSchema
+import graphql.schema.GraphQLTypeUtil
 import graphql.schema.idl.SchemaPrinter
 
 /**
@@ -38,10 +41,23 @@ fun GraphQLSchema.print(
         val defaultDirectives = arrayOf(Directives.IncludeDirective, Directives.SkipDirective, DeprecatedDirective)
         val directivesToString = defaultDirectives.joinToString("\n\n") { directive -> """
                 #${directive.description}
-                directive @${directive.name} on ${directive.validLocations().joinToString(" | ") { loc -> loc.name }}
+                directive @${directive.name}${parseDirectiveArguments(directive)} on ${directive.validLocations().joinToString(" | ") { loc -> loc.name }}
             """.trimIndent()
         }
         schemaString += "\n" + directivesToString
     }
     return schemaString
 }
+
+private fun parseDirectiveArguments(directive: GraphQLDirective) = if (directive.arguments.isNotEmpty()) {
+    """(${directive.arguments.joinToString(", ") { argument ->
+        "${argument.name}: ${GraphQLTypeUtil.simplePrint(argument.type)}${parseDirectiveArgumentValue(argument)}" }})"""
+} else {
+    ""
+}
+
+private fun parseDirectiveArgumentValue(argument: GraphQLArgument) = if (null != argument.defaultValue) {
+    " = \"${argument.defaultValue}\""
+} else {
+    ""
+}

src/test/kotlin/com/expedia/graphql/extensions/GraphQLSchemaExtensionsTest.kt

@@ -217,14 +217,14 @@ class GraphQLSchemaExtensionsTest {
             }
 
             #Directs the executor to include this field or fragment only when the `if` argument is true
-            directive @include on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
+            directive @include(if: Boolean!) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
 
             #Directs the executor to skip this field or fragment when the `if`'argument is true.
-            directive @skip on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
+            directive @skip(if: Boolean!) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
 
             #Marks the target field/enum value as deprecated
-            directive @deprecated on FIELD_DEFINITION | ENUM_VALUE
-        """.trimIndent()
+            directive @deprecated(reason: String = "No longer supported") on FIELD_DEFINITION | ENUM_VALUE
+""".trimIndent()
         assertEquals(expected, sdl)
     }
 }