In odoo/odoo#112978, it missed the case when 0 is entered (and no
Counted Quantity already set).
On inventory adjustments, when Counted Quantity is 0 and then press
"enter" or "tab", the difference will always set to 0. The compute
function for inventory_diff_quantity is not triggered in this
situation. We manually update the value in this case to trigger the
compute function.
opw-3177578
closesodoo/odoo#115252
X-original-commit: b4b90ff5702d18cc17d74d04e12e3cf11e205e9f
Signed-off-by: Tiffany Chang <tic@odoo.com>