fix(subgraph): Conditionally print @SpecifiedBy directive on scalars …

…correctly (backport #1463) (`version-0.x`) (#1465)

Co-authored-by: Angelo Moreira <angelo.moreira@gmail.com>

subgraph-js/CHANGELOG.md

@@ -5,6 +5,7 @@
 > The changes noted within this `vNEXT` section have not been released yet.  New PRs and commits which introduce changes should include an entry in this `vNEXT` section as part of their development.  When a release is being prepared, a new header will be (manually) created below and the appropriate changes within that release will be moved into the new section.
 
 - Print description text for the `schema` definition node, as allowed per the October 2021 edition of the GraphQL specification [PR #1442](https://github.com/apollographql/federation/pull/1442).
+- Make sure scalars don't print a `specifiedBy` directive unless specified in the subgraph. [PR #1465](https://github.com/apollographql/federation/pull/1465)
 
 ## v0.1.5
 

subgraph-js/src/__tests__/printSubgraphSchema.test.ts

@@ -1,6 +1,7 @@
 import { fixtures } from 'apollo-federation-integration-testsuite';
 import { buildSubgraphSchema } from '../buildSubgraphSchema';
 import { printSubgraphSchema } from '../printSubgraphSchema';
+import gql from 'graphql-tag';
 
 describe('printSubgraphSchema', () => {
   it('prints a subgraph correctly', () => {
@@ -77,6 +78,20 @@ describe('printSubgraphSchema', () => {
     `);
   });
 
+  it('prints a scalar without a directive correctly', () => {
+    const schema = gql`scalar JSON`;
+    const subgraphSchema = buildSubgraphSchema(schema);
+
+    expect(printSubgraphSchema(subgraphSchema)).toMatchInlineSnapshot(`
+      "scalar JSON
+
+      type Query {
+        _service: _Service!
+      }
+      "
+    `);
+  });
+
   it('prints reviews subgraph correctly', () => {
     const schema = buildSubgraphSchema(fixtures[5].typeDefs);
     expect(printSubgraphSchema(schema)).toMatchInlineSnapshot(`

subgraph-js/src/printSubgraphSchema.ts

@@ -373,7 +373,7 @@ function printSpecifiedByURL(scalar: GraphQLScalarType): string {
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   const value = (scalar as any).specifiedByUrl ?? scalar.specifiedByURL;
 
-  if (value === null) {
+  if (value == null) {
     return '';
   }
   const astValue = print({