[FIX] stock_available_mrp: increment potencial_qty to immediately_usable_qty instead of replacing it

[ACheung-FactorLibre]

When no potential quantities are available, the immediate usable quantity should not be set to zero. Instead, the potential quantity should be added to the immediate usable quantity, rather than replacing it. This ensures that the stock calculation reflects both values accurately, rather than incorrectly disregarding the potential quantity.

[aitoreizmendi]

LGTM

[serCliff]

As I could verify, the value now is correct because it takes the stock on hand of the warehouse plus the potential to calculate the stock on hand (additionally, the system uses the outgoing and incoming stock to get the final value).

I will explain it with an example:

Important: In my configuration, the available to promise excludes incoming stock image

I have a product (5019) which has a BoM (bunch of materials) to produce 240 units. and it has enough stock to produce only one BoM, exactly 240 units. of the final product

As we can see, the Available to Promise (Disponible para prometer) was calculated taking stock on hand - outgoing + potential

The expected result is:

The result is:

LGTM

[serCliff]

More info: #32 (comment)

[OCA-git-bot]

This PR has the approved label and has been created more than 5 days ago. It should therefore be ready to merge by a maintainer (or a PSC member if the concerned addon has no declared maintainer). 🤖

[ACheung-FactorLibre]

Hi @rousseldenis @leemannd,

Could you please review this?

Thank you