Also validate against improper @inaccessible usage

docs/source/errors.md

@@ -53,11 +53,12 @@ If Apollo Gateway encounters an error, composition fails. This document lists co
 | `REQUIRES_FIELDS_MISSING_ON_BASE` | The `fields` argument of an entity field's `@requires` directive includes a field that is not defined in the entity's originating subgraph.`|
 | `REQUIRES_USED_ON_BASE` | An entity field is marked with `@requires` in the entity's originating subgraph, which is invalid. |
 
-## `@tag`
+## Non-federation directives
 
 | Code | Description |
 |---|---|
 | `TAG_USED_WITH_EXTERNAL` | Fields marked as `@external` cannot also have `@tag` usages.  |
+| `INACCESSIBLE_USED_WITH_EXTERNAL` | Fields marked as `@external` cannot also have `@inaccessible` usages.  |
 
 ## Custom directives
 

federation-js/src/composition/validate/preComposition/__tests__/tagOrInaccessibleUsedWithExternal.test.ts

@@ -0,0 +1,173 @@
+import { tagOrInaccessibleUsedWithExternal } from '..';
+import {
+  gql,
+  graphqlErrorSerializer,
+} from 'apollo-federation-integration-testsuite';
+
+expect.addSnapshotSerializer(graphqlErrorSerializer);
+
+describe('tagOrInaccessibleUsedWithExternal', () => {
+  describe('no errors', () => {
+    it('has no errors @external and @tag are used separately', () => {
+      const serviceA = {
+        typeDefs: gql`
+          type Query {
+            product: Product @tag(name: "prod")
+          }
+
+          extend type Product @key(fields: "sku") {
+            sku: String @external
+          }
+        `,
+        name: 'serviceA',
+      };
+
+      const errors = tagOrInaccessibleUsedWithExternal(serviceA);
+      expect(errors).toHaveLength(0);
+    });
+
+    it('has no errors @external and @inaccessible are used separately', () => {
+      const serviceA = {
+        typeDefs: gql`
+          type Query {
+            product: Product @inaccessible
+          }
+
+          extend type Product @key(fields: "sku") {
+            sku: String @external
+          }
+        `,
+        name: 'serviceA',
+      };
+
+      const errors = tagOrInaccessibleUsedWithExternal(serviceA);
+      expect(errors).toHaveLength(0);
+    });
+  });
+
+  describe('errors', () => {
+    it('errors when `@external` and `@tag` are used on the same field of an object extension', () => {
+      const serviceA = {
+        typeDefs: gql`
+          type Query {
+            product: Product @tag(name: "prod")
+          }
+
+          extend type Product @key(fields: "sku") {
+            sku: String @external @tag(name: "prod")
+          }
+        `,
+        name: 'serviceA',
+      };
+
+      const errors = tagOrInaccessibleUsedWithExternal(serviceA);
+      expect(errors).toMatchInlineSnapshot(`
+        Array [
+          Object {
+            "code": "TAG_USED_WITH_EXTERNAL",
+            "locations": Array [
+              Object {
+                "column": 25,
+                "line": 7,
+              },
+            ],
+            "message": "[serviceA] Product.sku -> Found illegal use of @tag directive. @tag directives cannot currently be used in tandem with an @external directive.",
+          },
+        ]
+      `);
+    });
+
+    it('errors when `@external` and `@tag` are used on the same field of an interface extension', () => {
+      const serviceA = {
+        typeDefs: gql`
+          type Query {
+            product: Product @tag(name: "prod")
+          }
+
+          extend interface Product @key(fields: "sku") {
+            sku: String @external @tag(name: "prod")
+          }
+        `,
+        name: 'serviceA',
+      };
+
+      const errors = tagOrInaccessibleUsedWithExternal(serviceA);
+      expect(errors).toMatchInlineSnapshot(`
+        Array [
+          Object {
+            "code": "TAG_USED_WITH_EXTERNAL",
+            "locations": Array [
+              Object {
+                "column": 25,
+                "line": 7,
+              },
+            ],
+            "message": "[serviceA] Product.sku -> Found illegal use of @tag directive. @tag directives cannot currently be used in tandem with an @external directive.",
+          },
+        ]
+      `);
+    });
+
+    it('errors when `@external` and `@inaccessible` are used on the same field of an object extension', () => {
+      const serviceA = {
+        typeDefs: gql`
+          type Query {
+            product: Product @tag(name: "prod")
+          }
+
+          extend type Product @key(fields: "sku") {
+            sku: String @external @inaccessible
+          }
+        `,
+        name: 'serviceA',
+      };
+
+      const errors = tagOrInaccessibleUsedWithExternal(serviceA);
+      expect(errors).toMatchInlineSnapshot(`
+        Array [
+          Object {
+            "code": "INACCESSIBLE_USED_WITH_EXTERNAL",
+            "locations": Array [
+              Object {
+                "column": 25,
+                "line": 7,
+              },
+            ],
+            "message": "[serviceA] Product.sku -> Found illegal use of @inaccessible directive. @inaccessible directives cannot currently be used in tandem with an @external directive.",
+          },
+        ]
+      `);
+    });
+
+    it('errors when `@external` and `@inaccessible` are used on the same field of an interface extension', () => {
+      const serviceA = {
+        typeDefs: gql`
+          type Query {
+            product: Product @tag(name: "prod")
+          }
+
+          extend interface Product @key(fields: "sku") {
+            sku: String @external @inaccessible
+          }
+        `,
+        name: 'serviceA',
+      };
+
+      const errors = tagOrInaccessibleUsedWithExternal(serviceA);
+      expect(errors).toMatchInlineSnapshot(`
+        Array [
+          Object {
+            "code": "INACCESSIBLE_USED_WITH_EXTERNAL",
+            "locations": Array [
+              Object {
+                "column": 25,
+                "line": 7,
+              },
+            ],
+            "message": "[serviceA] Product.sku -> Found illegal use of @inaccessible directive. @inaccessible directives cannot currently be used in tandem with an @external directive.",
+          },
+        ]
+      `);
+    });
+  });
+});

federation-js/src/composition/validate/preComposition/index.ts

@@ -4,4 +4,4 @@ export { keyFieldsMissingExternal } from './keyFieldsMissingExternal';
 export { reservedFieldUsed } from './reservedFieldUsed';
 export { duplicateEnumOrScalar } from './duplicateEnumOrScalar';
 export { duplicateEnumValue } from './duplicateEnumValue';
-export { tagUsedWithExternal } from './tagUsedWithExternal';
+export { tagOrInaccessibleUsedWithExternal } from './tagOrInaccessibleUsedWithExternal';

federation-js/src/composition/validate/preComposition/tagUsedWithExternal.ts → federation-js/src/composition/validate/preComposition/tagOrInaccessibleUsedWithExternal.ts

@@ -13,10 +13,11 @@ import {
 } from '../../utils';
 
 /**
- * There are no fields with both @tag and @external. We're only concerned with
- * the xTypeExtension nodes because @external is not allowed on base types.
+ * Ensure there are no fields with @external and _either_ @tag or @inaccessible.
+ * We're only concerned with the xTypeExtension nodes because @external is
+ * already disallowed on base types.
  */
-export const tagUsedWithExternal = ({
+export const tagOrInaccessibleUsedWithExternal = ({
   name: serviceName,
   typeDefs,
 }: ServiceDefinition) => {
@@ -28,14 +29,17 @@ export const tagUsedWithExternal = ({
   });
 
   function fieldsVisitor(
-    typeDefinition:
-      | ObjectTypeExtensionNode
-      | InterfaceTypeExtensionNode,
+    typeDefinition: ObjectTypeExtensionNode | InterfaceTypeExtensionNode,
   ) {
     if (!typeDefinition.fields) return;
     for (const fieldDefinition of typeDefinition.fields) {
       const tagDirectives = findDirectivesOnNode(fieldDefinition, 'tag');
       const hasTagDirective = tagDirectives.length > 0;
+      const inaccessibleDirectives = findDirectivesOnNode(
+        fieldDefinition,
+        'inaccessible',
+      );
+      const hasInaccessibleDirective = inaccessibleDirectives.length > 0;
       const hasExternalDirective =
         findDirectivesOnNode(fieldDefinition, 'external').length > 0;
       if (hasTagDirective && hasExternalDirective) {
@@ -52,6 +56,21 @@ export const tagUsedWithExternal = ({
           ),
         );
       }
+
+      if (hasInaccessibleDirective && hasExternalDirective) {
+        errors.push(
+          errorWithCode(
+            'INACCESSIBLE_USED_WITH_EXTERNAL',
+            logServiceAndType(
+              serviceName,
+              typeDefinition.name.value,
+              fieldDefinition.name.value,
+            ) +
+              `Found illegal use of @inaccessible directive. @inaccessible directives cannot currently be used in tandem with an @external directive.`,
+            inaccessibleDirectives,
+          ),
+        );
+      }
     }
   }