php HTTP File Upload variables are not always readable

Question

In PHP (Version 5.4.39-0+deb7u2) I upload files. This went smooth for about 3 years, until today.

After hours of testing I noticed that the $_FILES['Filedata']['name'] array is not readable when:

• the filename is written by a Mac OSX system when the PATHINFO_EXTENSION is '.jpg'
• files written as '.JPG' have no problems.
• when the filename contains '-_' (eg 20151126-_HG634163.JPG)
• files written on PC containing .jpg, .JPG, -_, ... are working perfect

Below the code that worked perfect until this morning. There were no server-changes. Both Chrome and Safari gave the same results. The $this->file_name variable is stored in a DB to prevent doubles.

        if (!empty($_FILES)) {
        $tempFile = $_FILES['Filedata']['tmp_name'];
        $ext = pathinfo($_FILES['Filedata']['name'], PATHINFO_EXTENSION);
        $this->file_name = $_FILES['Filedata']['name'];
        $fileTypes = array('jpg','JPG','jpeg'); // File extensions
        $this->new_filename = $_POST['i']."_".date(YmdHis).$i."_".sha1($this->file)."_".rand(0, 1000)."_".rand(0, 1000).".JPG";
        $this->new_file = $this->targetFile."/".$this->new_filename;

        if (in_array($ext,$fileTypes)) {
        move_uploaded_file($tempFile,$this->new_file);
        } else {
        $this->upload_error = 1;
        }
        }