Allow the use of extend interface when merging schemas (#703)

* allow the use of extend interface when merging schemas. Fixes #699 * update changelog * backwards compatibility for interface extension tests * still extend the type for older versions
ardatan · Apr 5, 2018 · 01e23fc · 01e23fc
1 parent 2bb9b0c
commit 01e23fc
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,10 +2,9 @@
 
 ### vNEXT
 
+* Allow `extend interface` definitions in merged schemas [PR #703](https://github.com/apollographql/graphql-tools/pull/703)
 * Fix typo in schema-directive.md deprecated example[PR #706](https://github.com/apollographql/graphql-tools/pull/706)
-
 * Fix timezone bug in test for @date directive [PR #686](https://github.com/apollographql/graphql-tools/pull/686)
-
 * Expose `defaultMergedResolver` from stitching [PR #685](https://github.com/apollographql/graphql-tools/pull/685)
 
 ### v2.23.0

diff --git a/src/schemaGenerator.ts b/src/schemaGenerator.ts
@@ -241,12 +241,14 @@ function buildSchemaFromTypeDefinitions(
 // TODO fix types https://github.com/apollographql/graphql-tools/issues/542
 const oldTypeExtensionDefinitionKind = 'TypeExtensionDefinition';
 const newExtensionDefinitionKind = 'ObjectTypeExtension';
+const interfaceExtensionDefinitionKind = 'InterfaceTypeExtension';
 
 export function extractExtensionDefinitions(ast: DocumentNode) {
   const extensionDefs = ast.definitions.filter(
     (def: DefinitionNode) =>
       def.kind === oldTypeExtensionDefinitionKind ||
-      (def.kind as any) === newExtensionDefinitionKind,
+      (def.kind as any) === newExtensionDefinitionKind ||
+      (def.kind as any) === interfaceExtensionDefinitionKind,
   );
 
   return Object.assign({}, ast, {

diff --git a/src/test/testMergeSchemas.ts b/src/test/testMergeSchemas.ts
@@ -174,6 +174,26 @@ const loneExtend = `
   }
 `;
 
+
+let interfaceExtensionTest = `
+  # No-op for older versions since this feature does not yet exist
+  extend type DownloadableProduct {
+    filesize: Int
+  }
+`;
+
+if (['^0.11', '^0.12'].indexOf(process.env.GRAPHQL_VERSION) === -1) {
+  interfaceExtensionTest = `
+    extend interface Downloadable {
+      filesize: Int
+    }
+
+    extend type DownloadableProduct {
+      filesize: Int
+    }
+  `;
+}
+
 if (process.env.GRAPHQL_VERSION === '^0.11') {
   scalarTest = `
     # Description of TestScalar.
@@ -289,6 +309,7 @@ testCombinations.forEach(async combination => {
           bookingSchema,
           productSchema,
           scalarTest,
+          interfaceExtensionTest,
           enumSchema,
           linkSchema,
           loneExtend,
@@ -328,6 +349,11 @@ testCombinations.forEach(async combination => {
               },
             },
           },
+          DownloadableProduct: {
+            filesize() {
+              return 1024;
+            }
+          },
           LinkType: {
             property: {
               resolve(parent, args, context, info) {
@@ -2272,6 +2298,41 @@ fragment BookingFragment on Booking {
         });
       });
 
+      if (['^0.11', '^0.12'].indexOf(process.env.GRAPHQL_VERSION) === -1) {
+        it('interface extensions', async () => {
+          const result = await graphql(
+            mergedSchema,
+            `
+              query {
+                products {
+                  id
+                  __typename
+                  ... on Downloadable {
+                    filesize
+                  }
+                }
+              }
+            `,
+          );
+
+          expect(result).to.deep.equal({
+            data: {
+              products: [
+                {
+                  id: 'pd1',
+                  __typename: 'SimpleProduct',
+                },
+                {
+                  id: 'pd2',
+                  __typename: 'DownloadableProduct',
+                  filesize: 1024
+                },
+              ]
+            }
+          });
+        });
+      }
+
       it('arbitrary transforms that return interfaces', async () => {
         const result = await graphql(
           mergedSchema,