From 91e58dcd1b438120e3268f8fa5864bdb1ff3a81f Mon Sep 17 00:00:00 2001
From: Raphael Michel <michel@pretix.eu>
Date: Thu, 17 Sep 2026 10:53:38 +0200
Subject: [PATCH] Fix precision issue

---
 src/pretix/base/templatetags/money.py | 13 +++++++++++++
 src/tests/base/test_templatetag.py    |  8 ++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/pretix/base/templatetags/money.py b/src/pretix/base/templatetags/money.py
index 477943d433..91880ac7e5 100644
--- a/src/pretix/base/templatetags/money.py
+++ b/src/pretix/base/templatetags/money.py
@@ -49,6 +49,13 @@ def money_filter(value: Optional[Decimal | float | int | str], arg='', hide_curr
         raise ValueError("No currency passed.")
     arg = arg.upper()
 
+    if value.normalize().as_tuple().exponent < -9:
+        # Heuristic: It's unlikely we'll ever see values of less than 0.000000001 in any currency. Therefore, if we
+        # do see them, we very likely deal with a floating point error. This happens mostly in dev mode when computations
+        # are made in SQLite, which uses REAL precision, but it can also happen when we naively pass a float from Python
+        # land to this filter (even though it should not happen).
+        value = value.quantize(Decimal('1e-9'), ROUND_HALF_UP).normalize()
+
     currency_places = settings.CURRENCY_PLACES.get(arg, 2)
     required_places = -value.normalize().as_tuple().exponent
     render_places = max(currency_places, required_places)
@@ -108,6 +115,12 @@ def tax_rate_format(number: Optional[Decimal | float | int | str]):
         number = Decimal('0.00')
     if not isinstance(number, Decimal):
         raise TypeError("Invalid data type passed to tax rate format filter: %r" % type(number))
+    if number.normalize().as_tuple().exponent < -9:
+        # Heuristic: It's unlikely we'll ever see values of less than 0.000000001 in any currency. Therefore, if we
+        # do see them, we very likely deal with a floating point error. This happens mostly in dev mode when computations
+        # are made in SQLite, which uses REAL precision, but it can also happen when we naively pass a float from Python
+        # land to this filter (even though it should not happen).
+        number = number.quantize(Decimal('1e-9'), ROUND_HALF_UP).normalize()
     return mark_safe(
         formats.number_format(
             number,
diff --git a/src/tests/base/test_templatetag.py b/src/tests/base/test_templatetag.py
index a4b5cd3ef0..c7e71bb869 100644
--- a/src/tests/base/test_templatetag.py
+++ b/src/tests/base/test_templatetag.py
@@ -60,7 +60,9 @@ def test_urlreplace_replace_parameter():
     "locale,amount,currency,expected",
     [
         ("en", None, "USD", "$0.00"),
+        ("en", "", "USD", ""),
         ("en", 1000000, "USD", "$1,000,000.00"),
+        ("en", 2.23, "USD", "$2.23"),
         ("en", Decimal("1000.00"), "USD", "$1,000.00"),
         ("de", Decimal("1.23"), "EUR", "1,23" + NBSP + "€"),
         ("de", Decimal("1000.00"), "EUR", "1.000,00" + NBSP + "€"),
@@ -74,6 +76,7 @@ def test_urlreplace_replace_parameter():
 
         # deal with precision that is higher than the currency
         ("de", Decimal("1.234"), "EUR", "1,234" + NBSP + "€"),
+        ("de", 1.234, "EUR", "1,234" + NBSP + "€"),
         ("de", Decimal("1.2340"), "EUR", "1,234" + NBSP + "€"),
         ("de", Decimal("1.2300"), "EUR", "1,23" + NBSP + "€"),
         ("de", Decimal("1023.1"), "JPY", "1.023,10" + NBSP + "¥"),
@@ -118,6 +121,11 @@ def test_money_filter_hidecurrency(locale, amount, currency, expected):
         ("en", Decimal("2.50"), "2.5"),
         ("en", Decimal("4.3e7"), "43000000"),
         ("en", Decimal("2.2340"), "2.234"),
+        ("en", "2.23", "2.23"),
+        ("en", 2.23, "2.23"),
+        ("en", 2, "2"),
+        ("en", "", ""),
+        ("en", None, "0"),
     ]
 )
 def test_tax_rate_format(locale, rate, expected):