[IMP] account_invoice_tax: refactor tax override to use a Json field

Replace the old relational model approach with a lightweight
`tax_override_data = fields.Json(copy=False)` on `account.move`.
The field stores manually-set amounts keyed by tax id (string) with the
structure `{"<tax_id>": {"amount": float, "rate": float}}`.

Overrides are **only** persisted for fixed-amount taxes; percentage-based
taxes are always recomputed automatically and are never stored here.

Author: maq-adhoc

account_invoice_tax/__init__.py

@@ -1,2 +1,3 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 from . import wizards
+from . import models

account_invoice_tax/__manifest__.py

@@ -1,6 +1,6 @@
 {
     "name": "Account Invoice Tax",
-    "version": "18.0.1.0.0",
+    "version": "18.0.1.1.0",
     "author": "ADHOC SA",
     "category": "Localization",
     "depends": [

account_invoice_tax/models/__init__.py

@@ -0,0 +1,2 @@
+from . import account_move
+from . import account_tax

account_invoice_tax/models/account_move.py

@@ -0,0 +1,148 @@
+from contextlib import contextmanager
+
+from odoo import fields, models
+
+
+class AccountMove(models.Model):
+    _inherit = "account.move"
+
+    # Stores manually-overridden tax amounts keyed by tax id (as string).
+    # Structure: { "<tax_id>": {"amount": float, "amount_company_currency": float} }
+    # Only fixed-amount taxes are stored here; percentage taxes are always
+    # recomputed automatically.
+    tax_override_data = fields.Json(
+        copy=False,
+    )
+
+    def sync_tax_override_from_tax_totals(self):
+        """Rebuild ``tax_override_data`` from the current ``tax_totals`` widget value.
+
+        Iterates every tax group in ``tax_totals`` and, for each fixed-amount
+        tax found, stores the displayed amounts as an override so they survive
+        future recomputations.
+
+        ``tax_totals`` structure (relevant fields)::
+
+            {
+                "subtotals": [{
+                    "tax_groups": [{
+                        "involved_tax_ids": [<tax_id>, ...],
+                        "tax_amount":          <float>,   # company currency
+                        "tax_amount_currency": <float>,   # invoice currency
+                    }, ...]
+                }, ...]
+            }
+
+        ``amount`` (invoice-currency) → ``tax_amount_currency`` when the
+        invoice is in a foreign currency, otherwise ``tax_amount``.
+        ``amount_company_currency`` → ``tax_amount`` (always company currency),
+        or 0.0 when the invoice is in company currency (field unused in that
+        case, see ``_apply_tax_overrides``).
+        """
+        for rec in self:
+            tax_totals = rec.tax_totals
+            if not tax_totals:
+                continue
+
+            is_company_currency = rec.currency_id == rec.company_currency_id
+            new_overrides = {}
+
+            for subtotal in tax_totals.get("subtotals", []):
+                for tax_group in subtotal.get("tax_groups", []):
+                    tax_amount = tax_group.get("tax_amount", 0.0)
+                    tax_amount_currency = tax_group.get("tax_amount_currency", 0.0)
+
+                    for tax_id in tax_group.get("involved_tax_ids", []):
+                        tax = rec.env["account.tax"].browse(tax_id)
+                        if not tax.exists() or tax.amount_type != "fixed":
+                            continue
+
+                        if is_company_currency:
+                            amount = tax_amount
+                            amount_cc = 0.0
+                        else:
+                            amount = tax_amount_currency
+                            amount_cc = tax_amount
+
+                        new_overrides[str(tax_id)] = {
+                            "amount": amount,
+                            "amount_company_currency": amount_cc,
+                        }
+
+            rec.tax_override_data = new_overrides or False
+
+    # ------------------------------------------------------------------
+    # Tax-totals widget: inject override amounts so the widget reflects
+    # the manually-set values instead of the recomputed ones.
+    # ------------------------------------------------------------------
+
+    def _compute_tax_totals(self):
+        for move in self:
+            overrides = move.tax_override_data or {}
+            if not overrides:
+                super(AccountMove, move)._compute_tax_totals()
+                continue
+
+            tax_context = {
+                "tax_context": {
+                    int(tax_id): {
+                        "fixed_amount": (vals["amount"]),
+                        "rate": (move.invoice_currency_rate or 1.0),
+                    }
+                    for tax_id, vals in overrides.items()
+                },
+            }
+            super(AccountMove, move.with_context(**tax_context))._compute_tax_totals()
+
+    # ------------------------------------------------------------------
+    # Re-apply overrides after every tax-line recomputation so that the
+    # amounts set through the wizard survive any subsequent edits on the
+    # invoice lines.
+    # ------------------------------------------------------------------
+
+    @contextmanager
+    def _sync_tax_lines(self, container):
+        """Restore manually-set tax amounts after the core recomputes tax lines."""
+        with super()._sync_tax_lines(container):
+            yield
+        for move in container.get("records", self):
+            move._apply_tax_overrides()
+
+    def _apply_tax_overrides(self):
+        """Re-write values from ``tax_override_data`` onto the matching tax lines.
+
+        Only overrides for fixed-amount taxes are applied; percentage-based
+        taxes must always reflect their recomputed values.
+        """
+        overrides = self.tax_override_data or {}
+        if not overrides:
+            return
+
+        move_currency = self.currency_id
+        company_currency = self.company_currency_id
+        not_company_currency = move_currency and move_currency != company_currency
+        for line in self.line_ids.filtered(lambda l: l.tax_line_id and str(l.tax_line_id.id) in overrides):
+            vals = overrides[str(line.tax_line_id.id)]
+            rate = line.move_id.invoice_currency_rate or 1.0
+            amount = vals.get("amount", 0.0)
+            amount_cc = amount / rate
+            debit = credit = debit_cc = credit_cc = 0.0
+            if self.move_type in ("in_invoice", "in_receipt"):
+                if amount > 0:
+                    debit, debit_cc = amount, amount_cc
+                elif amount < 0:
+                    credit, credit_cc = -amount, -amount_cc
+            else:
+                if amount > 0:
+                    credit, credit_cc = amount, amount_cc
+                elif amount < 0:
+                    debit, debit_cc = -amount, -amount_cc
+
+            line_vals = {
+                "debit": debit_cc if not_company_currency else debit,
+                "credit": credit_cc if not_company_currency else credit,
+                "balance": ((amount_cc if not_company_currency else amount) * (1 if debit or debit_cc else -1)),
+            }
+            if not_company_currency and amount:
+                line_vals["amount_currency"] = amount
+            line.write(line_vals)

account_invoice_tax/models/account_tax.py

@@ -0,0 +1,41 @@
+from odoo import api, models
+
+
+class AccountTax(models.Model):
+    _inherit = "account.tax"
+
+    @api.model
+    def _get_tax_totals_summary(self, base_lines, currency, company, cash_rounding=None):
+        res = super()._get_tax_totals_summary(base_lines, currency, company, cash_rounding=cash_rounding)
+        # ``tax_context`` is injected by AccountMove._compute_tax_totals when
+        # there are active tax overrides.  Structure:
+        #   { tax_id (int): {'fixed_amount': float, 'rate': float}, ... }
+        tax_context = self.env.context.get("tax_context")
+        if not tax_context:
+            return res
+
+        for tax_group in res.get("subtotals", [{}])[0].get("tax_groups", []):
+            for involved_tax_id in tax_group.get("involved_tax_ids", []):
+                override = tax_context.get(involved_tax_id)
+                if not override:
+                    continue
+                new_amount = override.get("fixed_amount", 0.0)
+                rate = override.get("rate", 1.0)
+                original_amount = tax_group.get("tax_amount", 0.0)
+                original_currency_amount = tax_group.get("tax_amount_currency", 0.0)
+                if not new_amount or new_amount == original_currency_amount:
+                    continue
+                diff = new_amount - original_currency_amount
+                currency_diff = new_amount / rate - original_amount
+                tax_group.update(
+                    {
+                        "tax_amount": new_amount / rate,
+                        "tax_amount_currency": new_amount,
+                    }
+                )
+                res["tax_amount"] += diff
+                res["total_amount"] += diff
+                res["tax_amount_currency"] += currency_diff
+                res["total_amount_currency"] += currency_diff
+
+        return res

account_invoice_tax/wizards/account_invoice_tax.py

@@ -34,24 +34,15 @@ def default_get(self, fields):
 
     def action_update_tax(self):
         move = self.move_id
-        fixed_taxes_bu = {
-            line.tax_line_id: {
-                "amount_currency": line.amount_currency,
-                "debit": line.debit,
-                "credit": line.credit,
-            }
-            for line in self.move_id.line_ids.filtered(
-                lambda x: x.tax_repartition_line_id.tax_id.amount_type == "fixed"
-            )
-        }
 
         active_tax = self.tax_line_ids.mapped("tax_id")
         origin_tax = self.move_id.line_ids.filtered(lambda x: x.tax_line_id).mapped("tax_repartition_line_id.tax_id")
         to_remove_tax = origin_tax - active_tax
         to_add_tax = active_tax - origin_tax
+
         container = {"records": move, "self": move}
 
-        # change tax list
+        # --- 1. Update tax list on invoice lines ---
         with move.with_context(check_move_validity=False)._check_balanced(container):
             with move._sync_dynamic_lines(container):
                 if to_remove_tax:
@@ -63,29 +54,36 @@ def action_update_tax(self):
                         {"tax_ids": [Command.link(tax_id.id) for tax_id in to_add_tax]}
                     )
 
-        # set amount in the new created tax line. En este momento si queda balanceado y se ajusta la linea AP/AR
-        container = {"records": move}
+        # --- 2. Persist overrides in the JSON field so they survive recomputations ---
+        self._save_overrides()
 
-        if move.move_type == "in_invoice":
-            sign = 1
-        else:  # For refund
-            sign = -1
+        # --- 3. Apply overrides to the current tax lines ---
+        container = {"records": move}
         with move._check_balanced(container):
             with move._sync_dynamic_lines(container):
-                # restauramos todos los valores de impuestos fixed que se habrian recomputado
-                # restaured = []
-                for tax_line in move.line_ids.filtered(
-                    lambda x: x.tax_repartition_line_id.tax_id in fixed_taxes_bu
-                    and x.tax_repartition_line_id.tax_id.amount_type == "fixed"
-                ):
-                    tax_line.write(fixed_taxes_bu.get(tax_line.tax_line_id))
-                for tax_line_id in self.tax_line_ids:
-                    # seteamos valor al impuesto segun lo que puso en el wizard
-                    line_with_tax = move.line_ids.filtered(lambda x: x.tax_line_id == tax_line_id.tax_id)
-                    line_with_tax.write({"amount_currency": tax_line_id.amount * sign})
+                move._apply_tax_overrides()
+
+    def _save_overrides(self):
+        """Write wizard line amounts into ``tax_override_data`` on the move.
+
+        Only fixed-amount taxes are persisted as overrides.  Percentage-based
+        taxes are always recomputed automatically, so any stale entry for them
+        is removed.
+        """
+        new_overrides = {}
+        move = self.move_id
+        for wizard_line in self.tax_line_ids.filtered(lambda l: l.tax_id.amount_type == "fixed"):
+            new_overrides[str(wizard_line.tax_id.id)] = {
+                "amount": wizard_line.amount,
+                "rate": self.move_id.invoice_currency_rate or 1.0,
+            }
+
+        # Previous overrides are fully replaced – entries not present in
+        # new_overrides (removed taxes or percentage-based taxes) are dropped.
+        move.tax_override_data = new_overrides or False
 
     def add_tax_and_new(self):
-        self.add_tax()
+        self.action_update_tax()
         return {
             "type": "ir.actions.act_window",
             "name": _("Edit tax lines"),