Message of custom validation won't be displayed

[Roluc]

Prerequisites

• I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• The issue still exists against the latest master branch of bootstrap-fileinput.
• This is not an usage question. I confirm having read the plugin documentation and demos.
• This is not a general programming / coding question. (Those should be directed to the webtips Q & A forum).
• I have attempted to find the simplest possible steps to reproduce the issue.
• I have included a failing test as a pull request (Optional).

Steps to reproduce the issue

1. Added custom validation to 'filebatchpreupload' event (validation not needed to reproduce issue)
   this.element.on('filebatchpreupload', function(event, data, previewId, index) {
   return {
   message: "too many files!"
   };
   });
2. As soon as the validation fails and uploads are cancelled, the issue happens on line 3140, saying 'self.ajaxAborted' is undefined.
3. As far as i debugged the code, i encountered that self.ajaxAborted will be overwritten by the 'fileenable' event raised some lines above:
   -> 3138: self.cancel();
   -> 3247: self.unlock();
   -> 3218: self.enable();
   -> 3325: self._raise('fileenabled');
   -> 990: self.ajaxAborted = e.result;
   Undefined will be written into self.ajaxAborted.

So on line 3140 there wont be a message accessible anymore.
self._showUploadError(self.ajaxAborted.message, data, 'filecustomerror');

Therefore the custom error message won't be displayed.

A possible solution could be:

• to move line 3138 after line 3140
  or
• instead of using self.ajaxAborted.message, use data.abortMessage as a parameter for _showUploadError.

Libraries

• jQuery version: 1.11.3
• bootstrap-fileinput version: 4.4.0

[kartik-v]

Thanks for detailing the issue. Will check and update.