Steps to reproduce:
1. Install eCommerce and Subscriptions.
2. Create a 21% Excluded tax.
3. Create a subscription product with a price of 45 with 21% tax and enable "Accept One-Time" in the Recurring Prices tab.
4. Publish the product on the website under the Sales tab.
5. Create a pricelist for 6 months recurring with two lines:
 - If min quantity is 0, then 0% discount
 - If min quantity is 2, then 5% discount
6. Set "Display Product Prices" to "Tax Included" in the Settings.
7. Open the product on the website, select the 6-month plan, and increase quantity to 2.

Issue:
The discount percentage displayed on the website shows 4% instead of the configured 5%.

Why this happens:
In `_get_additionnal_combination_info`, the discount is reverse-calculated from the tax-included price vs the tax-included sales price. When the 21% tax is included to both prices, it introduces a floating-point precision loss (4.9954..%), which floor() then truncates to 4%.

Fix:
When the pricelist rule uses 'percentage' discount, read `percent_price` directly from the pricing rule instead of reverse-calculating from tax-adjusted prices, as it represents the exact discount percentage the merchant configured with no floating-point involvement.

opw-6224735

Forward-Port-Of: odoo/enterprise#121654

`sync_participants` calls `action_set_unlink` on every participant whose record is no longer in the campaign domain, and `action_set_unlink` writes "Record deleted" on each scheduled trace. The removed bucket also contains records that still exist but no longer match the campaign filter, so the cancelled trace dialog shows "Record deleted" even when the record was only filtered out.

In `sync_participants`, the to_remove participants are split between those whose record still exists in the database (filtered out by the campaign domain) and those whose record was actually deleted. `action_set_unlink` accepts an optional `trace_message` argument, defaulting to "Record deleted", and the filtered-out batch passes "Record no longer matches campaign filter" so the cancelled trace dialog reflects the real cause.

Steps to reproduce:
1. Install Marketing Automation and CRM.
2. Open Marketing Automation, create a campaign on Lead with filter Stage = New.
3. Add a begin activity to the workflow.
4. Open CRM, create a Lead in the New stage.
5. Back in the campaign, click Generate Participants.
6. In the CRM pipeline, drag the Lead from New to Qualified.
7. Back in the campaign, click Generate Participants again.
8. Open the Participants smart button, click the participant for the moved Lead.
9. Click the cancelled activity in the workflow timeline.

=> The activity dialog shows "Error message: Record deleted" although the Lead still exists.

Ticket [link](https://www.odoo.com/odoo/project/49/tasks/6251264)
opw-6251264

Forward-Port-Of: odoo/enterprise#118692

Currently, an error occurs when a user removes the payslip date.

**Steps to Reproduce:**

 - Install `l10n_hk_hr_payroll` with demo data.
 - Switch to the `Hong Kong` company.
 - Go to `Payroll` > `Payslips` > `Payslips`.
 - Create a `payslip` and remove the `start` or `end` period.

**Error 1:**
`TypeError: unsupported operand type(s) for +: 'bool' and 'relativedelta'`

**Error2:**
`AttributeError: 'bool' object has no attribute 'month'`

When a user removes the start or end date of a payslip, the system computes the Average Daily Wage. 
Based on the payslip dates, it finds the previous year's payslips [1]. If the start or end date is not set, 
it raises an error [2].
For the second error, when computing whether to include EOY pay, it compares the company's EOY 
pay date with the end date's month. If the end date is not set, accessing its month raises an error [3].

This commit ensures that when retrieving previous-year payslips, if the start or end date is not set, 
it returns an empty payslip recordset. It also ensures that when computing whether to include EOY 
pay, if the end date is not set, `include_eoy_pay` is set to `False`.

[1]: https://github.com/odoo/enterprise/blob/ec8a009794863090351d91650aff727e6fbeab7e/l10n_hk_hr_payroll/models/hr_payslip.py#L124

[2]- https://github.com/odoo/enterprise/blob/ec8a009794863090351d91650aff727e6fbeab7e/l10n_hk_hr_payroll/models/hr_payslip.py#L209-L215

[3]- https://github.com/odoo/enterprise/blob/ec8a009794863090351d91650aff727e6fbeab7e/l10n_hk_hr_payroll/models/hr_payslip.py#L141

Forward-Port-Of: odoo/enterprise#123135
Forward-Port-Of: odoo/enterprise#120586

The avatar card tour asserts the systray activity counter, which only counts activities whose state is today or overdue. The test scheduled its activities without an explicit deadline, so activity_schedule fell back to context_today on the class environment, whose superuser has tz Europe/Brussels with demo data. When the test runs between 22:00 and 00:00 UTC, that deadline is tomorrow from a UTC point of view. The state of an activity is however computed in the timezone of its assigned user, and hr_user is created without one, falling back to the server date (UTC). Its activities were therefore planned instead of today, the counter stayed empty and the tour timed out. The admin iteration kept passing because demo data gives admin the same Brussels timezone as the environment that computed the deadline, which is why only half the runs failed (both occurrences at 23:56 and 23:31 UTC).

Schedule the activities with a deadline one week in the past instead: an old deadline is overdue in every timezone, whatever timezone the scheduling environment or the assigned user has, making the counter deterministic at any time of the day.

https://runbot.odoo.com/odoo/error/941407

Forward-Port-Of: odoo/odoo#274679

# How to reproduce
- Install the Website module
- Install another module that has atleast one model with one html field,
sanitize=Flase or sanitize_form=False and groups
- Remove the field's group from the current user
- Enable dev mode
- Go to Settings > Technical > Database Structure > Models
- Pick any model (e.g. sale.order.line)
- Add a field to that model & Save
- Delete the added field & Save

> Note : Significantly harder to reproduce since :
https://github.com/odoo/odoo/commit/9a336bbb94b0a4266d84f7554c024c3abd2d1e7c
I am not sure a field as mentionned in the steps exists

# The problem
An access error is raised for the module wich access rights were
removed, even if the module is not linked in any way with the picked
model

# Cause of the issue
Deleting the field will endup calling the `unlink()` method of
`BaseModel` on the `ir.model.fields` record. This function triggers all
`@api.delete` methods defined on the model :
https://github.com/odoo/odoo/blob/5538132d9d14c4cc5031fc50ac0388ad2ab0fc92/odoo/models.py#L4548-L4552

This will call the this method :
https://github.com/odoo/odoo/blob/5538132d9d14c4cc5031fc50ac0388ad2ab0fc92/addons/website/models/website_form.py#L153-L154

That was introduced by :
https://github.com/odoo/odoo/commit/c0a827519844ec43537e4487f6abe358bb82ba9a

Which prevents a field from being deleted if it is actively used in any
website form. But this method does a search on every model return by
`_get_html_fields` which may contains models that are not accessible by
the user, so we get an access error.

# Proposed solution
Since `_check_if_used_in_website_form` should perform the same
independently from the user, we can do the search in sudo

opw-6231951

---
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Forward-Port-Of: odoo/odoo#274332
Forward-Port-Of: odoo/odoo#265781

**Problem:**
When scheduling a message using an email template with custom attachments, those attachments will not have their `res_model` and `res_id` updated to relate to the scheduled message record. This can lead to access errors.

**Cause:**
When composing a message using an email template with attachments, those attachments are created with their `res_model` and `res_id` values corresponding to the mail composer record. However, when scheduling a message, only attachments with no `res_id` value (or a value of 0) are updated to correspond to the scheduled message record. https://github.com/odoo/odoo/blob/77b180e8251fb8019e0034e1c2f485fd2c34ea4e/addons/mail/wizard/mail_compose_message.py#L1198-L1201
https://github.com/odoo/odoo/blob/30ca89b9e0d3c43d019167ec2de816c263f4bb92/addons/mail/models/mail_scheduled_message.py#L86

**Purpose:**
Modify the `mail.scheduled.message` override of `create` to not require an attachment have no `res_id` value to be properly updated.

**Steps to Reproduce in Runbot:**
1. Add an attachment to an email template.
2. Open a mail composer using that email template, then schedule the message for later.
3. Attempt to view the scheduled message with a different user.

More specific example flow:
1. Add an attachment to the Sales: Send Quotation email template.
2. Create a Quotation and send it with the Send by Email button, selecting Send Later instead of Send.
3. Attempt to view the Quotation with a different user.

opw-6293587

Forward-Port-Of: odoo/odoo#272261