GraphQLError: Fixed originalError.extensions overriding extensions argument to constructor

src/error/GraphQLError.js

@@ -102,11 +102,12 @@ export class GraphQLError extends Error {
 
     this.path = path ?? undefined;
 
-    this.extensions = extensions ?? {};
-
     const originalExtensions = originalError?.extensions;
-    if (isObjectLike(originalExtensions)) {
+
+    if (extensions == null && isObjectLike(originalExtensions)) {
       this.extensions = { ...originalExtensions };
+    } else {
+      this.extensions = extensions ?? {};
     }
 
     // By being enumerable, JSON.stringify will include bellow properties in the resulting output.

src/error/__tests__/GraphQLError-test.js

@@ -122,6 +122,66 @@ describe('GraphQLError', () => {
     });
   });
 
+  it('defaults to original error extension only if extensions argument is not passed', () => {
+    class ErrorWithExtensions extends Error {
+      extensions: mixed;
+
+      constructor(message: string) {
+        super(message);
+        this.extensions = { original: 'extensions' };
+      }
+    }
+
+    const original = new ErrorWithExtensions('original');
+    const inheritedExtensions = new GraphQLError(
+      'InheritedExtensions',
+      undefined,
+      undefined,
+      undefined,
+      undefined,
+      original,
+      undefined,
+    );
+
+    expect(inheritedExtensions).to.deep.include({
+      message: 'InheritedExtensions',
+      originalError: original,
+      extensions: { original: 'extensions' },
+    });
+
+    const ownExtensions = new GraphQLError(
+      'OwnExtensions',
+      undefined,
+      undefined,
+      undefined,
+      undefined,
+      original,
+      { own: 'extensions' },
+    );
+
+    expect(ownExtensions).to.deep.include({
+      message: 'OwnExtensions',
+      originalError: original,
+      extensions: { own: 'extensions' },
+    });
+
+    const ownEmptyExtensions = new GraphQLError(
+      'OwnEmptyExtensions',
+      undefined,
+      undefined,
+      undefined,
+      undefined,
+      original,
+      {},
+    );
+
+    expect(ownEmptyExtensions).to.deep.include({
+      message: 'OwnEmptyExtensions',
+      originalError: original,
+      extensions: {},
+    });
+  });
+
   it('serializes to include all standard fields', () => {
     const eShort = new GraphQLError('msg');
     expect(JSON.stringify(eShort, null, 2) + '\n').to.equal(dedent`