fix: Make internal Sentry flags non-enumerable in fill util

Author: kamilogorek

packages/utils/src/object.ts

@@ -62,9 +62,28 @@ export function fill(source: { [key: string]: any }, name: string, replacement:
   }
   const original = source[name] as () => any;
   const wrapped = replacement(original) as SentryWrappedFunction;
-  wrapped.__sentry__ = true;
-  wrapped.__sentry_original__ = original;
-  wrapped.__sentry_wrapped__ = wrapped;
+
+  // Make sure it's a function first, as we need to attach an empty prototype for `defineProperties` to work
+  // otherwise it'll throw "TypeError: Object.defineProperties called on non-object"
+  // tslint:disable-next-line:strict-type-predicates
+  if (typeof wrapped === 'function') {
+    wrapped.prototype = {};
+    Object.defineProperties(wrapped, {
+      __sentry__: {
+        enumerable: false,
+        value: true,
+      },
+      __sentry_original__: {
+        enumerable: false,
+        value: original,
+      },
+      __sentry_wrapped__: {
+        enumerable: false,
+        value: wrapped,
+      },
+    });
+  }
+
   source[name] = wrapped;
 }
 

packages/utils/test/object.test.ts

@@ -207,6 +207,25 @@ describe('fill()', () => {
     expect(replacement).toBeCalled();
     expect.assertions(3);
   });
+
+  test('internal flags shouldnt be enumerable', () => {
+    const source = {
+      foo: (): number => 42,
+    };
+    const name = 'foo';
+    const replacement = cb => cb;
+
+    fill(source, name, replacement);
+
+    // Shouldn't show up in iteration
+    expect(Object.keys(replacement)).not.toContain('__sentry__');
+    expect(Object.keys(replacement)).not.toContain('__sentry_original__');
+    expect(Object.keys(replacement)).not.toContain('__sentry_wrapped__');
+    // But should be accessible directly
+    expect(source.foo.__sentry__).toBe(true);
+    expect(source.foo.__sentry_original__).toBe(source.foo);
+    expect(source.foo.__sentry_wrapped__).toBe(source.foo);
+  });
 });
 
 describe('urlEncode()', () => {