Handle spread fragments for the required fields

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ### vNEXT
 
-- _Nothing yet!_
+- Handle spread fragments for the required fields. [PR #300](https://github.com/apollographql/eslint-plugin-graphql/pull/300) by [Arnav Mishra](https://github.com/arnmishra).
 
 ### v4.0.0
 

src/customGraphQLValidationRules.js

@@ -18,6 +18,12 @@ function getFieldWasRequestedOnNode(node, field) {
   });
 }
 
+function getNodeHasSpreadFragment(node) {
+  return node.selectionSet.selections.some(n => {
+    return n.kind === "FragmentSpread"
+  });
+}
+
 function fieldAvailableOnType(type, field) {
   if (!type) {
     return false;
@@ -38,6 +44,12 @@ export function RequiredFields(context, options) {
         const type = context.getType();
 
         if (fieldAvailableOnType(type, field)) {
+          // If there is a spread fragment, that spread fragment will already be checked for every field.
+          const nodeHasSpreadFragment = getNodeHasSpreadFragment(node);
+          if (nodeHasSpreadFragment) {
+            return
+          }
+
           const fieldWasRequested = getFieldWasRequestedOnNode(node, field);
           if (!fieldWasRequested) {
             context.reportError(
@@ -58,6 +70,12 @@ export function RequiredFields(context, options) {
         const type = context.getType();
 
         if (fieldAvailableOnType(type, field)) {
+          // If there is a spread fragment, that spread fragment will already be checked for every field.
+          const nodeHasSpreadFragment = getNodeHasSpreadFragment(node);
+          if (nodeHasSpreadFragment) {
+            return
+          }
+
           // First, check the selection set on this inline fragment
           if (node.selectionSet && getFieldWasRequestedOnNode(node, field)) {
             return true;
@@ -118,6 +136,12 @@ export function RequiredFields(context, options) {
 
       requiredFields.forEach(field => {
         if (fieldAvailableOnType(def.type, field)) {
+          // If there is a spread fragment, that spread fragment will already be checked for every field.
+          const nodeHasSpreadFragment = getNodeHasSpreadFragment(node);
+          if (nodeHasSpreadFragment) {
+            return
+          }
+
           const fieldWasRequested = getFieldWasRequestedOnNode(node, field);
           if (!fieldWasRequested) {
             context.reportError(

test/validationRules/required-fields.js

@@ -18,6 +18,7 @@ const requiredFieldsTestCases = {
     "const x = gql`fragment Foo on FooBar { id, hello, foo }`",
     "const x = gql`fragment Id on Node { id ... on NodeA { fieldA } }`",
     "const x = gql`query { nodes { id ... on NodeA { fieldA } } }`",
+    "const x = gql`query { greetings { hello ...GreetingsFragment} }`"
   ],
   fail: [
     {
@@ -48,15 +49,6 @@ const requiredFieldsTestCases = {
         }
       ]
     },
-    {
-      code: 'const x = gql`query { greetings { hello ...GreetingsFragment} }`',
-      errors: [
-        {
-          message: `'id' field required on 'greetings'`,
-          type: 'TaggedTemplateExpression',
-        },
-      ],
-    },
     {
       code: 'const x = gql`fragment Name on Greetings { hello }`',
       errors: [