Update BaseInputFilter
If value is required, it must be set in $this->data[].
If the value is set and it should not be empty, it must be invalid, even if not required.
Merge remote-tracking branch 'upstream/master'
BaseInputFilter fixed
Merge remote-tracking branch 'upstream/master'
Merge pull request #3983 from ossinkine/master

Update BaseInputFilter
Merge branch 'hotfix/3983'

Close #3983