Bug Report

Problem

I have a window.onerror err capture. In both cordova-ios 4.5.5 and 5.0.0 I get the following errors reported sometimes on load. I've been unable to reproduce on test devices or in ios simulator. It has a few different modules listed too (see below). cordova-android on the same install does not display similar issues. I am using https://github.com/mzealey/cordova-plugin-ionic-webview as replacement webview. I am including cordova_plugins.js but as this is a transient issue and I cannot see any obvious reason from the code why it would hit an error I don't know that this would be useful. Can you suggest anything to help debug this further?

  error_message: Error: Module cordova-plugin-background-download.BackgroundDownloader does not exist.
  frames:
    - addEntry()@http://localhost:8080/XXX.app/www/cordova.js:1255:24
    - clobbers()@http://localhost:8080/XXX.app/www/cordova.js:1265:13
    - onScriptLoadingComplete()@http://localhost:8080/XXX.app/www/cordova.js:1903:38
    - scriptLoadedCallback()@http://localhost:8080/XXX.app/www/cordova.js:1936:36

User agents reporting this are:

 Mozilla/5.0 (iPad; CPU OS 10_3_3 like Mac OS X) AppleWebKit/603.3.8 (KHTML, like Gecko) Mobile/14G60
 Mozilla/5.0 (iPad; CPU OS 11_4_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15G77
 Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_3 like Mac OS X) AppleWebKit/603.3.8 (KHTML, like Gecko) Mobile/14G60
 Mozilla/5.0 (iPhone; CPU iPhone OS 11_4_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15G77
 Mozilla/5.0 (iPhone; CPU iPhone OS 12_1_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/16C101
 Mozilla/5.0 (iPhone; CPU iPhone OS 12_1_4 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/16D57

Errors, always with same stack trace are variously (but usually the first):

 Error: Module cordova-plugin-background-download.BackgroundDownloader does not exist.
 Error: Module cordova-plugin-file.Entry does not exist.
 Error: Module cordova-plugin-file.Flags does not exist.
 Error: Module cordova-plugin-file.LocalFileSystem does not exist.
 Error: Module cordova-plugin-inappbrowser.inappbrowser does not exist.
 Error: Module cordova-plugin-statusbar.statusbar does not exist.

Checklist

[x] I searched for existing GitHub issues
[x] I updated all Cordova tooling to most recent version
[x] I included all the necessary information above

Mar 03 '19 18:03 mzealey

Anybody have any ideas for this?

Mar 29 '19 06:03 mzealey

Same problem here, no idea what is happening but my project is randomly failing (sometimes it show this error, but in general it works as expected, which makes it very hard to debug). I have different plugins in my project, so my trace is a little bit different, but it seems to be the same root problem. I couldn't find why it happens, but as you say it never occur in Android, so it seems to be an iOS related problem.

In my experience, I think it could be related with background app status (it seems to happen more frequently when you come from background after some time), or when application launchs another application (for example, if you receive a notification and launch safari url before application is completely loaded).

Jun 24 '19 16:06 mellinas314

@mellinas314 have you actually been able to see this on devices you control? Does it cause an issue with the code/app, or is it actually a harmless warning?

Jun 24 '19 17:06 mzealey

I can't reproduce this issue in my devices; only see it in my remote reporting tool; and I don't have any idea about how to reproduce the issue. In my case, it seems that (when this error happens) it is broking completely the application, as some users reports that it never starts and keeps in a white screen.

Jun 26 '19 09:06 mellinas314

Same here. I use Sentry to capture errors and see the same thing also, randomly occurring. From what I can see only occurs on IOS. It is also random on which plugin it complains about.