Tax rounding: Allow to apply only for B2B (Z#23220106) (#5810)

* Tax rounding: Allow to apply only for B2B (Z#23220106)

Most effective in combination with #5807

* Update src/pretix/base/settings.py

Co-authored-by: Richard Schreiber <schreiber@pretix.eu>

---------

Co-authored-by: Richard Schreiber <schreiber@pretix.eu>

src/pretix/api/serializers/order.py

@@ -1743,6 +1743,7 @@ class OrderCreateSerializer(I18nAwareModelSerializer):
             rounding_mode = self.context["event"].settings.tax_rounding
         changed = apply_rounding(
             rounding_mode,
+            ia,
             self.context["event"].currency,
             [*pos_map.values(), *fees]
         )

src/pretix/base/services/cart.py

@@ -1639,7 +1639,7 @@ def get_fees(event, request, _total_ignored_=None, invoice_address=None, payment
         if fee.tax_rule and not fee.tax_rule.pk:
             fee.tax_rule = None  # TODO: deprecate
 
-    apply_rounding(event.settings.tax_rounding, event.currency, [*positions, *fees])
+    apply_rounding(event.settings.tax_rounding, invoice_address, event.currency, [*positions, *fees])
     total = sum([c.price for c in positions]) + sum([f.value for f in fees])
 
     if total != 0 and payments:
@@ -1679,7 +1679,7 @@ def get_fees(event, request, _total_ignored_=None, invoice_address=None, payment
                 fees.append(pf)
 
                 # Re-apply rounding as grand total has changed
-                apply_rounding(event.settings.tax_rounding, event.currency, [*positions, *fees])
+                apply_rounding(event.settings.tax_rounding, invoice_address, event.currency, [*positions, *fees])
                 total = sum([c.price for c in positions]) + sum([f.value for f in fees])
 
                 # Re-calculate to_pay as grand total has changed

src/pretix/base/services/orders.py

@@ -955,7 +955,7 @@ def _apply_rounding_and_fees(positions: List[CartPosition], payment_requests: Li
             fee.tax_rule = None  # TODO: deprecate
 
     # Apply rounding to get final total in case no payment fees will be added
-    apply_rounding(event.settings.tax_rounding, event.currency, [*positions, *fees])
+    apply_rounding(event.settings.tax_rounding, address, event.currency, [*positions, *fees])
     total = sum([c.price for c in positions]) + sum([f.value for f in fees])
 
     payments_assigned = Decimal("0.00")
@@ -982,7 +982,7 @@ def _apply_rounding_and_fees(positions: List[CartPosition], payment_requests: Li
             p['fee'] = pf
 
             # Re-apply rounding as grand total has changed
-            apply_rounding(event.settings.tax_rounding, event.currency, [*positions, *fees])
+            apply_rounding(event.settings.tax_rounding, address, event.currency, [*positions, *fees])
             total = sum([c.price for c in positions]) + sum([f.value for f in fees])
 
             # Re-calculate to_pay as grand total has changed
@@ -1610,6 +1610,7 @@ class OrderChangeManager:
     ChangeValidUntilOperation = namedtuple('ChangeValidUntilOperation', ('position', 'valid_until'))
     AddBlockOperation = namedtuple('AddBlockOperation', ('position', 'block_name', 'ignore_from_quota_while_blocked'))
     RemoveBlockOperation = namedtuple('RemoveBlockOperation', ('position', 'block_name', 'ignore_from_quota_while_blocked'))
+    ForceRecomputeOperation = namedtuple('ForceRecomputeOperation', tuple())
 
     class AddPositionResult:
         _position: Optional[OrderPosition]
@@ -1773,6 +1774,7 @@ class OrderChangeManager:
         positions = self.order.positions.select_related('item', 'item__tax_rule')
         ia = self._invoice_address
         tax_rules = self._current_tax_rules()
+        self._operations.append(self.ForceRecomputeOperation())
 
         for pos in positions:
             tax_rule = tax_rules.get(pos.pk, pos.tax_rule)
@@ -2611,6 +2613,10 @@ class OrderChangeManager:
                         except BlockedTicketSecret.DoesNotExist:
                             pass
                 # todo: revoke list handling
+            elif isinstance(op, self.ForceRecomputeOperation):
+                self.order.log_action('pretix.event.order.changed.recomputed', user=self.user, auth=self.auth, data={})
+            else:
+                raise TypeError(f"Unknown operation {type(op)}")
 
         for p in secret_dirty:
             assign_ticket_secret(
@@ -2665,7 +2671,10 @@ class OrderChangeManager:
             fees.append(new_fee)
 
         changed_by_rounding = set(apply_rounding(
-            self.order.tax_rounding_mode, self.event.currency, [p for p in split_positions if not p.canceled] + fees
+            self.order.tax_rounding_mode,
+            self._invoice_address,
+            self.event.currency,
+            [p for p in split_positions if not p.canceled] + fees
         ))
         split_order.total = sum([p.price for p in split_positions if not p.canceled])
 
@@ -2687,7 +2696,10 @@ class OrderChangeManager:
                 fee.delete()
 
             changed_by_rounding |= set(apply_rounding(
-                self.order.tax_rounding_mode, self.event.currency, [p for p in split_positions if not p.canceled] + fees
+                self.order.tax_rounding_mode,
+                self._invoice_address,
+                self.event.currency,
+                [p for p in split_positions if not p.canceled] + fees
             ))
             split_order.total = sum([p.price for p in split_positions if not p.canceled]) + sum([f.value for f in fees])
 
@@ -2804,7 +2816,12 @@ class OrderChangeManager:
         if fee_changed:
             fees = list(self.order.fees.all())
 
-        changed = apply_rounding(self.order.tax_rounding_mode, self.order.event.currency, [*positions, *fees])
+        changed = apply_rounding(
+            self.order.tax_rounding_mode,
+            self._invoice_address,
+            self.order.event.currency,
+            [*positions, *fees]
+        )
         for l in changed:
             if isinstance(l, OrderPosition):
                 l.save(update_fields=[
@@ -3240,8 +3257,12 @@ def change_payment_provider(order: Order, payment_provider, amount=None, new_pay
 
     positions = list(order.positions.all())
     fees = list(order.fees.all())
+    try:
+        ia = order.invoice_address
+    except InvoiceAddress.DoesNotExist:
+        ia = None
     rounding_changed = set(apply_rounding(
-        order.tax_rounding_mode, order.event.currency, [*positions, *[f for f in fees if f.pk != fee.pk]]
+        order.tax_rounding_mode, ia, order.event.currency, [*positions, *[f for f in fees if f.pk != fee.pk]]
     ))
     total_without_fee = sum(c.price for c in positions) + sum(f.value for f in fees if f.pk != fee.pk)
     pending_sum_without_fee = max(Decimal("0.00"), total_without_fee - already_paid)
@@ -3266,7 +3287,7 @@ def change_payment_provider(order: Order, payment_provider, amount=None, new_pay
         fee = None
 
     rounding_changed |= set(apply_rounding(
-        order.tax_rounding_mode, order.event.currency, [*positions, *fees]
+        order.tax_rounding_mode, ia, order.event.currency, [*positions, *fees]
     ))
     for l in rounding_changed:
         if isinstance(l, OrderPosition):

src/pretix/base/services/pricing.py

@@ -211,7 +211,8 @@ def apply_discounts(event: Event, sales_channel: Union[str, SalesChannel],
     return [new_prices.get(idx, (p[3], None)) for idx, p in enumerate(positions)]
 
 
-def apply_rounding(rounding_mode: Literal["line", "sum_by_net", "sum_by_net_keep_gross"], currency: str,
+def apply_rounding(rounding_mode: Literal["line", "sum_by_net", "sum_by_net_only_business", "sum_by_net_keep_gross"],
+                   invoice_address: Optional[InvoiceAddress], currency: str,
                    lines: List[Union[OrderPosition, CartPosition, OrderFee]]) -> list:
     """
     Given a list of order positions / cart positions / order fees (may be mixed), applies the given rounding mode
@@ -226,11 +227,17 @@ def apply_rounding(rounding_mode: Literal["line", "sum_by_net", "sum_by_net_keep
     When rounding mode is set to ``"sum_by_net"``, the gross prices and tax values of the individual lines will be
     adjusted such that the per-taxrate/taxcode subtotal is rounded correctly. The net prices will stay constant.
 
-    :param rounding_mode: One of ``"line"``, ``"sum_by_net"``, or ``"sum_by_net_keep_gross"``.
+    :param rounding_mode: One of ``"line"``, ``"sum_by_net"``, ``"sum_by_net_only_business"``, or ``"sum_by_net_keep_gross"``.
+    :param invoice_address: The invoice address, or ``None``
     :param currency: Currency that will be used to determine rounding precision
     :param lines: List of order/cart contents
     :return: Collection of ``lines`` members that have been changed and may need to be persisted to the database.
     """
+    if rounding_mode == "sum_by_net_only_business":
+        if invoice_address and invoice_address.is_business:
+            rounding_mode = "sum_by_net"
+        else:
+            rounding_mode = "line"
 
     def _key(line):
         return (line.tax_rate, line.tax_code or "")

src/pretix/base/settings.py

@@ -81,6 +81,7 @@ from pretix.helpers.countries import CachedCountries, pycountry_add
 ROUNDING_MODES = (
     ('line', _('Compute taxes for every line individually')),
     ('sum_by_net', _('Compute taxes based on net total')),
+    ('sum_by_net_only_business', _('For business customers, compute taxes based on net total. For individuals, use line-based rounding')),
     ('sum_by_net_keep_gross', _('Compute taxes based on net total with stable gross prices')),
     # We could also have sum_by_gross, but we're not aware of any use-cases for it
 )

src/pretix/control/forms/event.py

@@ -867,6 +867,11 @@ class TaxSettingsForm(EventSettingsValidationMixin, SettingsForm):
                 "The gross price of some products may be changed to ensure correct rounding, while the net "
                 "prices will be kept as configured. This may cause the actual payment amount to differ."
             ),
+            "sum_by_net_only_business": _(
+                "Same as above, but only applied to business customers. Line-based rounding will be used for consumers. "
+                "Recommended when e-invoicing is only used for business customers and consumers do not receive "
+                "invoices. This can cause the payment amount to change when the invoice address is changed."
+            ),
             "sum_by_net_keep_gross": _(
                 "Recommended for e-invoicing when you primarily sell to consumers. "
                 "The gross or net price of some products may be changed automatically to ensure correct "

src/pretix/control/logdisplay.py

@@ -170,6 +170,12 @@ class OrderFeeAdded(OrderChangeLogEntryType):
     plain = _('A fee has been added')
 
 
+@log_entry_types.new()
+class OrderRecomputed(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.recomputed'
+    plain = _('Taxes and rounding have been recomputed')
+
+
 @log_entry_types.new()
 class OrderFeeChanged(OrderChangeLogEntryType):
     action_type = 'pretix.event.order.changed.feevalue'

src/pretix/presale/templates/pretixpresale/event/fragment_cart.html

@@ -493,7 +493,18 @@
         </div>
     {% endif %}
 </div>
-
+{% if cart.show_rounding_info %}
+    <div class="text-muted">
+        <small>
+            {% icon "info-circle" %}
+            {% blocktrans trimmed %}
+                Since you entered a business address, your price was computed from the
+                VAT-exclusive price. Due to rounding, this caused a small change to the
+                total price.
+            {% endblocktrans %}
+        </small>
+    </div>
+{% endif %}
 <div class="row">
     <div class="col-md-12">
     {% if not cart.is_ordered %}

src/pretix/presale/views/__init__.py

@@ -167,7 +167,7 @@ class CartMixin:
             fees = []
 
         if not order:
-            apply_rounding(self.request.event.settings.tax_rounding, self.request.event.currency, [*lcp, *fees])
+            apply_rounding(self.request.event.settings.tax_rounding, self.invoice_address, self.request.event.currency, [*lcp, *fees])
 
         total = sum([c.price for c in lcp]) + sum([f.value for f in fees])
         net_total = sum(p.price - p.tax_value for p in lcp) + sum([f.net_value for f in fees])
@@ -264,6 +264,11 @@ class CartMixin:
             'max_expiry_extend': max_expiry_extend,
             'is_ordered': bool(order),
             'itemcount': sum(c.count for c in positions if not c.addon_to),
+            'show_rounding_info': (
+                self.request.event.settings.tax_rounding == "sum_by_net_only_business" and
+                not self.request.event.settings.display_net_prices and
+                sum(c.price_includes_rounding_correction for c in positions) + sum(f.price_includes_rounding_correction for f in fees)
+            ),
             'itemvarsums': itemvarsums,
             'current_selected_payments': [
                 p for p in self.current_selected_payments(lcp, fees, self.invoice_address)
@@ -275,7 +280,7 @@ class CartMixin:
         raw_payments = copy.deepcopy(self.cart_session.get('payments', []))
         fees = [f for f in fees if f.fee_type != OrderFee.FEE_TYPE_PAYMENT]  # we re-compute these here
 
-        apply_rounding(self.request.event.settings.tax_rounding, self.request.event.currency, [*positions, *fees])
+        apply_rounding(self.request.event.settings.tax_rounding, invoice_address, self.request.event.currency, [*positions, *fees])
         total = sum([c.price for c in positions]) + sum([f.value for f in fees])
 
         payments = []
@@ -329,7 +334,7 @@ class CartMixin:
                 fees.append(pf)
 
                 # Re-apply rounding as grand total has changed
-                apply_rounding(self.request.event.settings.tax_rounding, self.request.event.currency, [*positions, *fees])
+                apply_rounding(self.request.event.settings.tax_rounding, invoice_address, self.request.event.currency, [*positions, *fees])
                 total = sum([c.price for c in positions]) + sum([f.value for f in fees])
 
                 # Re-calculate to_pay as grand total has changed

src/tests/base/test_pricing_rounding.py

@@ -43,7 +43,7 @@ def _validate_sample_lines(sample_lines, rounding_mode):
         (line.tax_value_includes_rounding_correction, line.price_includes_rounding_correction)
         for line in sample_lines
     ]
-    changed = apply_rounding(rounding_mode, "EUR", sample_lines)
+    changed = apply_rounding(rounding_mode, None, "EUR", sample_lines)
     for line, original in zip(sample_lines, corrections):
         if (line.tax_value_includes_rounding_correction, line.price_includes_rounding_correction) != original:
             assert line in changed
@@ -108,7 +108,7 @@ def test_revert_net_rounding_to_single_line(sample_lines):
         tax_rate=Decimal("19.00"),
         tax_code="S",
     )
-    apply_rounding("sum_by_net", "EUR", [l])
+    apply_rounding("sum_by_net", None, "EUR", [l])
     assert l.price == Decimal("100.00")
     assert l.price_includes_rounding_correction == Decimal("0.00")
     assert l.tax_value == Decimal("15.97")
@@ -126,7 +126,7 @@ def test_revert_net_keep_gross_rounding_to_single_line(sample_lines):
         tax_rate=Decimal("19.00"),
         tax_code="S",
     )
-    apply_rounding("sum_by_net_keep_gross", "EUR", [l])
+    apply_rounding("sum_by_net_keep_gross", None, "EUR", [l])
     assert l.price == Decimal("100.00")
     assert l.price_includes_rounding_correction == Decimal("0.00")
     assert l.tax_value == Decimal("15.97")
@@ -144,7 +144,7 @@ def test_rounding_of_impossible_gross_price(rounding_mode):
         price=Decimal("23.00"),
     )
     l._calculate_tax(tax_rule=TaxRule(rate=Decimal("7.00")), invoice_address=InvoiceAddress())
-    apply_rounding(rounding_mode, "EUR", [l])
+    apply_rounding(rounding_mode, None, "EUR", [l])
     assert l.price == Decimal("23.01")
     assert l.price_includes_rounding_correction == Decimal("0.01")
     assert l.tax_value == Decimal("1.51")
@@ -164,12 +164,12 @@ def test_round_down():
     assert sum(l.tax_value for l in lines) == Decimal("79.85")
     assert sum(l.price - l.tax_value for l in lines) == Decimal("420.15")
 
-    apply_rounding("sum_by_net", "EUR", lines)
+    apply_rounding("sum_by_net", None, "EUR", lines)
     assert sum(l.price for l in lines) == Decimal("499.98")
     assert sum(l.tax_value for l in lines) == Decimal("79.83")
     assert sum(l.price - l.tax_value for l in lines) == Decimal("420.15")
 
-    apply_rounding("sum_by_net_keep_gross", "EUR", lines)
+    apply_rounding("sum_by_net_keep_gross", None, "EUR", lines)
     assert sum(l.price for l in lines) == Decimal("500.00")
     assert sum(l.tax_value for l in lines) == Decimal("79.83")
     assert sum(l.price - l.tax_value for l in lines) == Decimal("420.17")
@@ -187,12 +187,12 @@ def test_round_up():
     assert sum(l.tax_value for l in lines) == Decimal("79.80")
     assert sum(l.price - l.tax_value for l in lines) == Decimal("420.10")
 
-    apply_rounding("sum_by_net", "EUR", lines)
+    apply_rounding("sum_by_net", None, "EUR", lines)
     assert sum(l.price for l in lines) == Decimal("499.92")
     assert sum(l.tax_value for l in lines) == Decimal("79.82")
     assert sum(l.price - l.tax_value for l in lines) == Decimal("420.10")
 
-    apply_rounding("sum_by_net_keep_gross", "EUR", lines)
+    apply_rounding("sum_by_net_keep_gross", None, "EUR", lines)
     assert sum(l.price for l in lines) == Decimal("499.90")
     assert sum(l.tax_value for l in lines) == Decimal("79.82")
     assert sum(l.price - l.tax_value for l in lines) == Decimal("420.08")
@@ -210,12 +210,12 @@ def test_round_currency_without_decimals():
     assert sum(l.tax_value for l in lines) == Decimal("7980.00")
     assert sum(l.price - l.tax_value for l in lines) == Decimal("42010.00")
 
-    apply_rounding("sum_by_net", "JPY", lines)
+    apply_rounding("sum_by_net", None, "JPY", lines)
     assert sum(l.price for l in lines) == Decimal("49992.00")
     assert sum(l.tax_value for l in lines) == Decimal("7982.00")
     assert sum(l.price - l.tax_value for l in lines) == Decimal("42010.00")
 
-    apply_rounding("sum_by_net_keep_gross", "JPY", lines)
+    apply_rounding("sum_by_net_keep_gross", None, "JPY", lines)
     assert sum(l.price for l in lines) == Decimal("49990.00")
     assert sum(l.tax_value for l in lines) == Decimal("7982.00")
     assert sum(l.price - l.tax_value for l in lines) == Decimal("42008.00")
@@ -235,7 +235,7 @@ def test_do_not_touch_free(rounding_mode):
         price=Decimal("23.00"),
     )
     l2._calculate_tax(tax_rule=TaxRule(rate=Decimal("7.00")), invoice_address=InvoiceAddress())
-    apply_rounding(rounding_mode, "EUR", [l1, l2])
+    apply_rounding(rounding_mode, None, "EUR", [l1, l2])
     assert l2.price == Decimal("23.01")
     assert l2.price_includes_rounding_correction == Decimal("0.01")
     assert l2.tax_value == Decimal("1.51")
@@ -245,3 +245,20 @@ def test_do_not_touch_free(rounding_mode):
     assert l1.price_includes_rounding_correction == Decimal("0.00")
     assert l1.tax_value == Decimal("0.00")
     assert l1.tax_value_includes_rounding_correction == Decimal("0.00")
+
+
+@pytest.mark.django_db
+def test_only_business():
+    lines = [OrderPosition(
+        price=Decimal("100.00"),
+        tax_value=Decimal("15.97"),
+        tax_rate=Decimal("19.00"),
+        tax_code="S",
+    ) for _ in range(5)]
+    assert sum(l.price for l in lines) == Decimal("500.00")
+
+    apply_rounding("sum_by_net_only_business", None, "EUR", lines)
+    assert sum(l.price for l in lines) == Decimal("500.00")
+
+    apply_rounding("sum_by_net_only_business", InvoiceAddress(is_business=True), "EUR", lines)
+    assert sum(l.price for l in lines) == Decimal("499.98")