Infinite import dur to incorrect $sheet_id check

When i discovered feeds_excel, I believed my task to import data was finished...
But i found a bug...

After configuring the feed_excel, i tried to import a simple file and the progress bar was stuck to 0%.

After long hours of debugging, i finally found the issue :

In the ExcelParser.inc, in the function parseItems, there is a if statement to check an offset :

original code :

<?php
        // Start off after the last element for known sheets.
        if ($sheet_id == $last_sheet_id) {
          $offset = $last_sheet_item + 1;
        }
        // Start off at 0 for new sheets.
        else {
          $offset = 0;
        }

?>

In fact, if i(ts the first run, the pointer is : ":" so $last_sheet_id id empty.
On the other side, $sheet_id is equals to 0.

"" == 0 means
false == false
so it returns true.

We have to check like this :

<?php
        // Start off after the last element for known sheets.
        if ($sheet_id === $last_sheet_id) {
          $offset = $last_sheet_item + 1;
        }
        // Start off at 0 for new sheets.
        else {
          $offset = 0;
        }

?>

Sorry for my report, it's my first. (also i'm french, damn...)
And i don't know yet how to work with GIT and making patches. (sorry)