[FIX][16.0][contract] Fix issue on last_date_invoice contract line

[MTantin]

Module

contract

Describe the bug

On multiline reccuring contract, the contract line last_date_invoice field is correct on the first line and is shift by 1 period time on the others lines (verified in database). This issue generate visible bug only when #START keywork is used in line note.

To Reproduce

1. Generate a reccuring contract with a product and a line note using #START and #END keywords
2. Generate invoices for this contract
3. The first invoice will be OK but the next invoices will be shift in line note (for example "from 2024-10-01 to 2024-09-30" on september invoice)

Expected behavior
Have correct date in #START and #END keywords of line notes

Correction

The bug came from _update_recurring_next_date method. This method is using next_period_date_end field to fill last_date_invoiced field but last_date_invoiced is used to recompute recurring_next_date of contract and impact next_period_date_end. So the first line is correctly edited but the next line use the new recurring_next_date and it create a shift for the next lines.

I keep the older mechanism of _update_recurring_next_date without invoicing_date and i've add a new mechanism with a specified invoicing_date to use the actual invoicing date.

[remi-filament]

Thanks @MTantin for taking care of this issue. One of my customer experiences the same having a section and then a product line.
However, as far as I can tell, the problem is not only on date_end but also on next invoice date.

Please find below the output of generating the 3 next invoices for a contract post-paid every year starting on the 12th of Feb 2023, both on runboat without your fix and with your fix :
Without your fix :

--> we miss one invoice in 2025

First invoice (in 2024) lines are correct :

On second invoice (in 2026) end dates are correct but start dates are different on every line :

On third invoice (in 2027), the 2 first lines are correct, the start_date on the 3rd is not :

With your fix :

--> Invoices are generated only every 2 years (missing 1 in 2025, one in 2027)

However, dates on lines are correct every time :

So it is better on lines, but there is still an issue on both last_date_invoiced and recurring_next_date and therefore on next invoice to be generated.

[MTantin]

@remi-filament Yeah, i noticed some bugs coming from my fix over the different tests of the addon.
I have something else more important to do in the month but i will try to investigate more and fix this in october.