Invoice/EventListener/AbstractInvoiceLineListener.php
public function onDelete(ResourceEventInterface $event)
    {
        $line = $this->getInvoiceLineFromEvent($event);

        $this->stockUnitAssigner->detachInvoiceLine($line);

        // Get invoice from change set if null
        if (null === $invoice = $line->getInvoice()) {
            $invoice = $this->persistenceHelper->getChangeSet($line, 'invoice')[0];
        }

        $this->scheduleInvoiceContentChangeEvent($invoice);
    }
public function onDelete(ResourceEventInterface $event)
    {
        $line = $this->getInvoiceLineFromEvent($event);

        $this->stockUnitAssigner->detachInvoiceLine($line);

        // Get invoice from change set if null
        if (null === $invoice = $line->getInvoice()) {
            $invoice = $this->persistenceHelper->getChangeSet($line, 'invoice')[0];
        }

        $this->scheduleInvoiceContentChangeEvent($invoice);
    }
Delete event handler.

@param ResourceEventInterface $event