Bug 245732

When using a WKDownload to download a file, the download will succeed and calls -[WKDownloadDelegate downloadDidFinish:] before the download is actually written to file. Consider the following delegate method - (void)downloadDidFinish:(WKDownload *)download API_AVAILABLE(ios(15.0)) { BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:self.downloadPath.absoluteString]; UIAlertController* alertController = [UIAlertController alertControllerWithTitle:@"Download Succeeded" message:[NSString stringWithFormat:@Exists = %u", fileExists] preferredStyle:UIAlertControllerStyleAlert]; UIAlertAction* dismiss = [UIAlertAction actionWithTitle:@"Dismiss" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) { BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:self.downloadPath.path]; NSLog(@"%u",fileExists); }]; [alertController addAction:dismiss]; if(NSThread.isMainThread) { [self.webViewController presentViewController:alertController animated:NO completion:nil]; } else { dispatch_async(dispatch_get_main_queue(), ^{ [self.webViewController presentViewController:alertController animated:NO completion:nil]; }); } } Upon a successful download the alert will be presented with "Exists = false" however once the dismiss is pressed we have logged "true". The file will exist after the call but not before. The delegate should be called AFTER the file has been created so that the delegate can respond to the file be downloaded.