Instead of omitting the field we ensure that it is present and an empty object

Author: rboustany-crypto

lib/src/main/java/graphql/nadel/result/NadelResultMerger.kt

@@ -62,7 +62,13 @@ internal object NadelResultMerger {
 
             // Ensure field is present in result
             if (topLevelResultKey.value !in data) {
-                data[topLevelResultKey.value] = null
+                val topLevelField = topLevelFields.first { it.resultKey == topLevelResultKey.value }
+                data[topLevelResultKey.value] =
+                    if (isNamespacedField(topLevelField, engineSchema) && children.isEmpty()) {
+                        mutableMapOf<String, Any?>()
+                    } else {
+                        null
+                    }
             }
 
             if (children.isNotEmpty()) {
@@ -121,18 +127,12 @@ internal object NadelResultMerger {
         // NOTE: please ensure all fields are from object types and will NOT have multiple field defs
         // Other code in this file relies on this contract
         for (field in topLevelFields) {
-            val namespaced = isNamespacedField(field, engineSchema)
-
-            if (namespaced && field.children.isEmpty()) {
-                continue
-            }
-
             val requiredChildFields = requiredFields
                 .computeIfAbsent(NadelResultKey(field.resultKey)) {
                     mutableListOf()
                 }
 
-            if (namespaced) {
+            if (isNamespacedField(field, engineSchema)) {
                 requiredChildFields.addAll(field.children)
             }
         }

…amespaced/EmptyNamespaceIsOmittedTest.kt …paced/EmptyNamespaceIsEmptyObjectTest.kttest/src/test/kotlin/graphql/nadel/tests/next/fixtures/namespaced/EmptyNamespaceIsOmittedTest.kt renamed to test/src/test/kotlin/graphql/nadel/tests/next/fixtures/namespaced/EmptyNamespaceIsEmptyObjectTest.kt test/src/test/kotlin/graphql/nadel/tests/next/fixtures/namespaced/EmptyNamespaceIsOmittedTest.kt renamed to test/src/test/kotlin/graphql/nadel/tests/next/fixtures/namespaced/EmptyNamespaceIsEmptyObjectTest.kt

@@ -7,13 +7,13 @@ import graphql.nadel.tests.next.NadelIntegrationTest
  * Regression test for the HOT/bug where an empty namespace was materialised as `"jira": null`.
  *
  * When every child of a namespaced field is skipped (e.g. `@skip(if: true)`), the namespace has no
- * children, no service call is made, and it must be OMITTED from the response entirely - NOT emitted
- * as `jira: null`. Emitting `null` changed the response shape and tripped a downstream Relay non-null
- * handler, turning the whole response into `data: null`.
+ * children and no service call is made. It must be materialised as an empty object `"jira": {}`,
+ * NOT as `"jira": null` (which tripped a downstream Relay non-null handler, turning the whole
+ * response into `data: null`).
  *
- * Expected result: `{ "hello": "world" }` with no `jira` key.
+ * Expected result: `{ "hello": "world", "jira": {} }`.
  */
-class EmptyNamespaceIsOmittedTest : NadelIntegrationTest(
+class EmptyNamespaceIsEmptyObjectTest : NadelIntegrationTest(
     query = """
         query {
           hello

…d/EmptyNamespaceIsOmittedTestSnapshot.kt …ptyNamespaceIsEmptyObjectTestSnapshot.kttest/src/test/kotlin/graphql/nadel/tests/next/fixtures/namespaced/EmptyNamespaceIsOmittedTestSnapshot.kt renamed to test/src/test/kotlin/graphql/nadel/tests/next/fixtures/namespaced/EmptyNamespaceIsEmptyObjectTestSnapshot.kt test/src/test/kotlin/graphql/nadel/tests/next/fixtures/namespaced/EmptyNamespaceIsOmittedTestSnapshot.kt renamed to test/src/test/kotlin/graphql/nadel/tests/next/fixtures/namespaced/EmptyNamespaceIsEmptyObjectTestSnapshot.kt

@@ -10,7 +10,7 @@ import kotlin.collections.List
 import kotlin.collections.listOf
 
 private suspend fun main() {
-    graphql.nadel.tests.next.update<EmptyNamespaceIsOmittedTest>()
+    graphql.nadel.tests.next.update<EmptyNamespaceIsEmptyObjectTest>()
 }
 
 /**
@@ -19,7 +19,7 @@ private suspend fun main() {
  * Refer to [graphql.nadel.tests.next.UpdateTestSnapshots]
  */
 @Suppress("unused")
-public class EmptyNamespaceIsOmittedTestSnapshot : TestSnapshot() {
+public class EmptyNamespaceIsEmptyObjectTestSnapshot : TestSnapshot() {
     /**
      * Query
      *
@@ -63,7 +63,8 @@ public class EmptyNamespaceIsOmittedTestSnapshot : TestSnapshot() {
      * ```json
      * {
      *   "data": {
-     *     "hello": "world"
+     *     "hello": "world",
+     *     "jira": {}
      *   }
      * }
      * ```
@@ -72,7 +73,8 @@ public class EmptyNamespaceIsOmittedTestSnapshot : TestSnapshot() {
             result = """
             | {
             |   "data": {
-            |     "hello": "world"
+            |     "hello": "world",
+            |     "jira": {}
             |   }
             | }
             """.trimMargin(),