Add details what to do if sourceURLForBridge return nil

React/Base/RCTBridgeDelegate.h

@@ -19,6 +19,8 @@
  * this should be an absolute URL, e.g. `http://localhost:8081/index.ios.bundle`.
  * When running from a locally bundled JS file, this should be a `file://` url
  * pointing to a path inside the app resources, e.g. `file://.../main.jsbundle`.
+ * If you return nil you need to implement loadSourceForBridge:onProgress:onComplete:
+ * or loadSourceForBridge:withBlock: instead
  */
 - (NSURL *)sourceURLForBridge:(RCTBridge *)bridge;
 

React/Executors/RCTJSCExecutor.mm

@@ -668,7 +668,6 @@ - (void)executeApplicationScript:(NSData *)script
                       onComplete:(RCTJavaScriptCompleteBlock)onComplete
 {
   RCTAssertParam(script);
-  RCTAssertParam(sourceURL);
 
   NSError *loadError;
   TaggedScript taggedScript = loadTaggedScript(script, sourceURL,
@@ -717,6 +716,7 @@ static TaggedScript loadTaggedScript(NSData *script,
   NSData *loadedScript = NULL;
   switch (tag) {
     case facebook::react::ScriptTag::RAMBundle:
+      RCTAssertParam(sourceURL);
       [performanceLogger markStartForTag:RCTPLRAMBundleLoad];
 
       loadedScript = loadRAMBundle(sourceURL, error, randomAccessBundle);