Remove RelayFBPreloadedModules, error on overlapping modules

Reviewed By: davidaurelio

Differential Revision: D4779671

fbshipit-source-id: f2dfeb696baab457769c22ca7ab28972270e5fc0

packager/src/Bundler/Bundle.js

@@ -420,7 +420,7 @@ function createGroups(ramGroups: Array<string>, lazyModules) {
       // print a warning for each removed module
       const parentNames = parents.map(byId.get, byId);
       const lastName = parentNames.pop();
-      console.warn(
+      throw new Error(
         /* $FlowFixMe: this assumes the element exists. */
         `Module ${byId.get(moduleId)} belongs to groups ${
           parentNames.join(', ')}, and ${lastName

packager/src/Bundler/__tests__/Bundle-test.js

@@ -330,13 +330,10 @@ describe('Bundle', () => {
 
     it('omits modules that are contained by more than one group', () => {
       bundle = createBundle([fsLocation('React'), fsLocation('OtherFramework')]);
-      const {groups} = bundle.getUnbundle();
-      expect(groups).toEqual(new Map([
-        [idFor('React'),
-          new Set(['ReactFoo', 'ReactBar', 'cx'].map(idFor))],
-        [idFor('OtherFramework'),
-          new Set(['OtherFrameworkFoo', 'OtherFrameworkBar', 'crc32'].map(idFor))],
-      ]));
+      expect(() => {
+        const {groups} = bundle.getUnbundle(); //eslint-disable-line no-unused-vars
+      }).toThrow(new Error(`Module ${fsLocation('invariant')} belongs to groups ${fsLocation('React')}` +
+        `, and ${fsLocation('OtherFramework')}. Removing it from all groups.`));
     });
 
     it('ignores missing dependencies', () => {