Add Apollo Server end-to-end tests

Author: BoD

.github/workflows/defer-with-apollo-server-tests.yml

@@ -0,0 +1,37 @@
+name: defer-router-tests
+
+on:
+  schedule:
+    - cron: '0 3 * * *'
+env:
+  DEVELOCITY_ACCESS_KEY: ${{ secrets.DEVELOCITY_ACCESS_KEY }}
+
+jobs:
+  defer-with-router-tests:
+    runs-on: ubuntu-latest
+    if: github.repository == 'apollographql/apollo-kotlin'
+    steps:
+      - name: Checkout project
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 #v4.1.7
+
+      - name: Install and run graph
+        working-directory: tests/defer/apollo-server/
+        run: |
+          npm install --legacy-peer-deps
+          npx patch-package
+          APOLLO_PORT=4000 npm start &
+
+      - name: Setup Java
+        uses: actions/setup-java@99b8673ff64fbf99d8d325f52d9a5bdedb8483e9 #v4.2.1
+        with:
+          distribution: 'temurin'
+          java-version: 17
+
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@dbbdc275be76ac10734476cc723d82dfe7ec6eda #v3.4.2
+
+      - name: Run Apollo Kotlin @defer tests
+        env:
+          DEFER_WITH_APOLLO_SERVER_TESTS: true
+        run: |
+          ./gradlew --no-daemon --console plain -p tests :defer:allTests

libraries/apollo-runtime/src/commonMain/kotlin/com/apollographql/apollo/internal/DeferredJsonMerger.kt

@@ -52,30 +52,29 @@ class DeferredJsonMerger {
   }
 
   fun merge(payload: JsonMap): JsonMap {
+    val completed = payload["completed"] as? List<JsonMap>
     if (merged.isEmpty()) {
       // Initial payload, no merging needed (strip some fields that should not appear in the final result)
       _merged += payload - "hasNext" - "pending"
       handlePending(payload)
-      handleCompleted(payload)
+      handleCompleted(completed)
       return merged
     }
     handlePending(payload)
 
     val incrementalList = payload["incremental"] as? List<JsonMap>
-    if (incrementalList == null) {
-      isEmptyPayload = true
-    } else {
-      isEmptyPayload = false
+    if (incrementalList != null) {
       for (incrementalItem in incrementalList) {
         mergeIncrementalData(incrementalItem)
         // Merge errors (if any) of the incremental item
         (incrementalItem["errors"] as? List<JsonMap>)?.let { getOrPutMergedErrors() += it }
       }
     }
+    isEmptyPayload = completed == null && incrementalList == null
 
     hasNext = payload["hasNext"] as Boolean? ?: false
 
-    handleCompleted(payload)
+    handleCompleted(completed)
 
     (payload["extensions"] as? JsonMap)?.let { getOrPutExtensions() += it }
 
@@ -98,8 +97,7 @@ class DeferredJsonMerger {
     }
   }
 
-  private fun handleCompleted(payload: JsonMap) {
-    val completed = payload["completed"] as? List<JsonMap>
+  private fun handleCompleted(completed: List<JsonMap>?) {
     if (completed != null) {
       for (completedItem in completed) {
         // Merge errors (if any) of the completed item

tests/defer/README.md

@@ -16,3 +16,16 @@ To run them locally:
    subgraph: `(cd tests/defer/router/subgraphs/computers && npm install && APOLLO_PORT=4001 npm start)&`
 2. Run the router: `path/to/router --supergraph tests/defer/router/simple-supergraph.graphqls &`
 3. Run the tests: `DEFER_WITH_ROUTER_TESTS=true ./gradlew -p tests :defer:allTests`
+
+## End-to-end tests with Apollo Server
+
+The tests in `DeferWithApolloServerTest` are not run by default (they are excluded in the gradle conf) because they
+expect an instance of [Apollo Server](https://www.apollographql.com/docs/apollo-server) running locally.
+
+They are enabled only when running from the specific `defer-with-apollo-server-tests` CI workflow.
+
+To run them locally:
+
+1. Install and run the
+   subgraph: `(cd tests/defer/apollo-server && npm install --legacy-peer-deps && npx patch-package && APOLLO_PORT=4000 npm start)&`
+2. Run the tests: `DEFER_WITH_APOLLO_SERVER_TESTS=true ./gradlew -p tests :defer:allTests`

tests/defer/apollo-server/README.md

@@ -0,0 +1,4 @@
+# Test server using Apollo Server, for `@defer` tests
+
+- This uses graphql-js `17.0.0-alpha.7`, which implements the latest draft of the `@defer` incremental format (as of 2024-12-16).
+- Apollo Server `4.11.2` needs a patch (in `patches`) to surface this format in the responses.

tests/defer/apollo-server/computers.graphqls

@@ -0,0 +1,27 @@
+type Query {
+  computers: [Computer!]!
+  computer(id: ID!): Computer
+}
+
+type Mutation {
+  computers: [Computer!]!
+}
+
+type Computer {
+  id: ID!
+  cpu: String!
+  year: Int!
+  screen: Screen!
+  errorField: String
+  nonNullErrorField: String!
+}
+
+type Screen {
+  resolution: String!
+  isColor: Boolean!
+}
+
+directive @defer(
+  if: Boolean! = true
+  label: String
+) on FRAGMENT_SPREAD | INLINE_FRAGMENT

tests/defer/apollo-server/computers.js

@@ -0,0 +1,40 @@
+import {ApolloServer} from '@apollo/server';
+import {startStandaloneServer} from '@apollo/server/standalone';
+import {readFileSync} from 'fs';
+
+const port = process.env.APOLLO_PORT || 4000;
+
+const computers = [
+    {id: 'Computer1', cpu: "386", year: 1993, screen: {resolution: "640x480", isColor: false}},
+    {id: 'Computer2', cpu: "486", year: 1996, screen: {resolution: "800x600", isColor: true}},
+]
+
+const typeDefs = readFileSync('./computers.graphqls', {encoding: 'utf-8'});
+const resolvers = {
+    Query: {
+        computers: (_, args, context) => {
+            return computers;
+        },
+        computer: (_, args, context) => {
+            return computers.find(p => p.id === args.id);
+        }
+    },
+    Mutation: {
+        computers: (_, args, context) => {
+            return computers;
+        }
+    },
+    Computer: {
+        errorField: (_, args, context) => {
+            throw new Error("Error field");
+        },
+        nonNullErrorField: (_, args, context) => {
+            return null;
+        }
+    }
+}
+const server = new ApolloServer({typeDefs, resolvers});
+const {url} = await startStandaloneServer(server, {
+    listen: {port: port},
+});
+console.log(`🚀 Computers subgraph ready at ${url}`);

tests/defer/apollo-server/package.json

@@ -0,0 +1,18 @@
+{
+  "type": "module",
+  "name": "subgraph-computers",
+  "version": "1.1.0",
+  "description": "",
+  "main": "computers.js",
+  "scripts": {
+    "start": "node computers.js"
+  },
+  "dependencies": {
+    "@apollo/server": "4.11.2",
+    "graphql": "17.0.0-alpha.7",
+    "patch-package": "^8.0.0"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "MIT"
+}

tests/defer/apollo-server/patches/@apollo+server+4.11.2.patch

@@ -0,0 +1,28 @@
+diff --git a/node_modules/@apollo/server/dist/esm/runHttpQuery.js b/node_modules/@apollo/server/dist/esm/runHttpQuery.js
+index 96ef0ab..0d341fa 100644
+--- a/node_modules/@apollo/server/dist/esm/runHttpQuery.js
++++ b/node_modules/@apollo/server/dist/esm/runHttpQuery.js
+@@ -187,6 +187,7 @@ function orderExecutionResultFields(result) {
+ }
+ function orderInitialIncrementalExecutionResultFields(result) {
+     return {
++        ...result,
+         hasNext: result.hasNext,
+         errors: result.errors,
+         data: result.data,
+@@ -196,6 +197,7 @@ function orderInitialIncrementalExecutionResultFields(result) {
+ }
+ function orderSubsequentIncrementalExecutionResultFields(result) {
+     return {
++        ...result,
+         hasNext: result.hasNext,
+         incremental: orderIncrementalResultFields(result.incremental),
+         extensions: result.extensions,
+@@ -203,6 +205,7 @@ function orderSubsequentIncrementalExecutionResultFields(result) {
+ }
+ function orderIncrementalResultFields(incremental) {
+     return incremental?.map((i) => ({
++        ...i,
+         hasNext: i.hasNext,
+         errors: i.errors,
+         path: i.path,

tests/defer/build.gradle.kts

@@ -74,5 +74,12 @@ tasks.withType(AbstractTestTask::class.java) {
   } else {
     filter.setExcludePatterns("test.DeferWithRouterTest")
   }
-}
 
+  // Run the defer with Apollo Server tests only from a specific CI job
+  val runDeferWithApolloServerTests = System.getenv("DEFER_WITH_APOLLO_SERVER_TESTS").toBoolean()
+  if (runDeferWithApolloServerTests) {
+    filter.setIncludePatterns("test.DeferWithApolloServerTest")
+  } else {
+    filter.setExcludePatterns("test.DeferWithApolloServerTest")
+  }
+}

tests/defer/src/commonMain/graphql/base/operation.graphql

@@ -109,6 +109,15 @@ query CanDeferAFragmentThatIsAlsoNotDeferredDeferredFragmentIsFirstQuery {
   }
 }
 
+query DeferFragmentThatIsAlsoNotDeferredIsSkipped1Query {
+  computer(id: "Computer1") {
+    screen {
+      ...ScreenFields @defer
+      ...ScreenFields
+    }
+  }
+}
+
 query CanDeferAFragmentThatIsAlsoNotDeferredNotDeferredFragmentIsFirstQuery {
   computer(id: "Computer1") {
     screen {
@@ -118,6 +127,15 @@ query CanDeferAFragmentThatIsAlsoNotDeferredNotDeferredFragmentIsFirstQuery {
   }
 }
 
+query DeferFragmentThatIsAlsoNotDeferredIsSkipped2Query {
+  computer(id: "Computer1") {
+    screen {
+      ...ScreenFields
+      ...ScreenFields @defer
+    }
+  }
+}
+
 query HandlesErrorsThrownInDeferredFragmentsQuery {
   computer(id: "Computer1") {
     id