Three related problems with Drop Shipping with Anglo Saxon Accounting.

One has been broken since #20080.

Another is caused by the same code.

The third - a fix from #12687 - is being bypassed by current code.



Impacted versions:

11.0, and 10.0 for at least some of this

Steps to reproduce:

Set up a product with
- real time valuation
- standard price
- Anglo Saxon accounting
- drop shipping turned on
- invoicing on delivered quantities

Create a product with a standard price of $40.

Current behavior:

_If I create a sales order and choose to ship from existing stock, then the invoice created after delivery is correct, and it has the correct Anglo Saxon account moves._

- Dr COGS $40
- Cr Output $40

If I create a sales order and choose to drop ship, I can then go to the RFQ, and change the RFQ price to $45, then receive the product, and generate the Vendor Bill.  Everything is correct at this point.  When I go back to the Sales Order and create and validate the invoice, it has the incorrect Anglo Saxon account moves:

- Dr Output $45
- Cr COGS $45

Expected behavior:

The accounting should be the same on the invoice.  The value is wrong, and the debits and credits are reversed.

Also, there should be an additional journal:

- Dr Output $40
- Cr Input $40

Th 3 problems are:

1. It is getting a -ve price unit from _compute_average_price because the stock move is not an outgoing move, but a supplier -> customer move!
2. It is getting the average price from those moves and using it, even if the product is using standard price.
3. The extra move that #12687 created is no longer being generated as the account moves are being bypassed entirely for dropshipping.  Somewhere in the process, we need to move the value from stock_input to stock_output.  This may be a v11 problem only.

Video/Screenshot link (optional):


partner_id = (self.picking_id.partner_id and self.env['res.partner']._find_accounting_partner(self.picking_id.partner_id).id) or False
        debit_line_vals = {
            'name': self.name,
            'product_id': self.product_id.id,
            'quantity': qty,
            'product_uom_id': self.product_id.uom_id.id,
            'ref': self.picking_id.name,
            'partner_id': partner_id,
            'debit': debit_value if debit_value > 0 else 0,
            'credit': -debit_value if debit_value < 0 else 0,
            'account_id': debit_account_id,
        }
        credit_line_vals = {
            'name': self.name,
            'product_id': self.product_id.id,
            'quantity': qty,
            'product_uom_id': self.product_id.uom_id.id,
            'ref': self.picking_id.name,
            'partner_id': partner_id,
            'credit': credit_value if credit_value > 0 else 0,
            'debit': -credit_value if credit_value < 0 else 0,
            'account_id': credit_account_id,
        }
        res = [(0, 0, debit_line_vals), (0, 0, credit_line_vals)]
        if credit_value != debit_value:
            
            diff_amount = debit_value - credit_value
            price_diff_account = self.product_id.property_account_creditor_price_difference
            if not price_diff_account:
                price_diff_account = self.product_id.categ_id.property_account_creditor_price_difference_categ