Be robust to SDL schemas that already contain builtin definitions (#3241

)

apollo-graphql-ast/src/main/kotlin/com/apollographql/apollo3/ast/gqldocument.kt

@@ -61,8 +61,15 @@ private fun GQLDocument.withoutDefinitions(definitions: List<GQLDefinition>): GQ
   )
 }
 
+/**
+ * Adds [definitions] to the [GQLDocument]
+ *
+ * If a definition alreay exists, it is kept as is and a warning is logged
+ *
+ * See https://spec.graphql.org/draft/#sel-FAHnBPLCAACCcooU
+ */
 private fun GQLDocument.withDefinitions(definitions: List<GQLDefinition>): GQLDocument {
-  val mergedDefinitions = definitions.toMutableList()
+  val mergedDefinitions = this.definitions.toMutableList()
 
   definitions.forEach { builtInTypeDefinition ->
     check(builtInTypeDefinition is GQLNamed) {

apollo-graphql-ast/src/main/kotlin/com/apollographql/apollo3/ast/internal/SchemaValidationScope.kt

@@ -12,7 +12,7 @@ internal class SchemaValidationScope(document: GQLDocument) : ValidationScope {
    * The builtin definitions are required to validate directives amongst other
    * things so add them early in the validation proccess.
    */
-  val allDefinitions = document.definitions + builtinDefinitions()
+  val allDefinitions = document.withBuiltinDefinitions().definitions
   override val typeDefinitions = getTypeDefinitions(allDefinitions)
   override val directiveDefinitions = getDirectives(allDefinitions)
 

apollo-graphql-ast/src/test/kotlin/com/apollographql/apollo3/graphql/ast/test/SchemaTest.kt

@@ -0,0 +1,23 @@
+package com.apollographql.apollo3.graphql.ast.test
+
+import com.apollographql.apollo3.ast.toSchema
+import org.junit.Test
+
+class SchemaTest {
+  @Test
+  fun schemaMayContainBuiltinDirectives() {
+    val schemaString = """
+      "Directs the executor to include this field or fragment only when the `if` argument is true"
+      directive @include(
+          "Included when true."
+          if: Boolean!
+      ) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
+      
+      type Query {
+        foo: Int
+      }
+    """.trimIndent()
+
+    schemaString.toSchema()
+  }
+}