Temporal fix for the empty file error
Override Request::duplicate so that it handles cases where input files are null
Fix indentation
Change test to tabs
Remove extra line
Format fixes
Simplify
Import class
Merge commit 'c55ddb2d1edc087f1c5564acd9dc02555083575d'
Merge remote-tracking branch 'upstream/master'
Merge pull request #6256 from eduard44/master

[5.0] Fix Broken File Upload When Submitting A Form Without Selecting A File