From e137c888a116b517d9696d2ce979e1bc52af4431 Mon Sep 17 00:00:00 2001
From: Sander van Grieken <sander@outrightsolutions.nl>
Date: Wed, 26 Nov 2025 16:33:44 +0100
Subject: [PATCH] qeconfig: fix btc amount regex, add msat regex property, add
 regex tests

---
 electrum/gui/qml/qeconfig.py | 14 +++++--
 tests/test_qml_qeconfig.py   | 72 ++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 3 deletions(-)

diff --git a/electrum/gui/qml/qeconfig.py b/electrum/gui/qml/qeconfig.py
index 979565e5e..349f87365 100644
--- a/electrum/gui/qml/qeconfig.py
+++ b/electrum/gui/qml/qeconfig.py
@@ -94,14 +94,22 @@ class QEConfig(AuthMixin, QObject):
 
     @pyqtProperty('QRegularExpression', notify=baseUnitChanged)
     def btcAmountRegex(self):
+        return self._btcAmountRegex()
+
+    @pyqtProperty('QRegularExpression', notify=baseUnitChanged)
+    def btcAmountRegexMsat(self):
+        return self._btcAmountRegex(3)
+
+    def _btcAmountRegex(self, extra_precision: int = 0):
         decimal_point = base_unit_name_to_decimal_point(self.config.get_base_unit())
         max_digits_before_dp = (
             len(str(TOTAL_COIN_SUPPLY_LIMIT_IN_BTC))
             + (base_unit_name_to_decimal_point("BTC") - decimal_point))
-        exp = '[0-9]{0,%d}' % max_digits_before_dp
+        exp = '^[0-9]{0,%d}' % max_digits_before_dp
+        decimal_point += extra_precision
         if decimal_point > 0:
-            exp += '\\.'
-            exp += '[0-9]{0,%d}' % decimal_point
+            exp += '(\\.[0-9]{0,%d})?' % decimal_point
+        exp += '$'
         return QRegularExpression(exp)
 
     thousandsSeparatorChanged = pyqtSignal()
diff --git a/tests/test_qml_qeconfig.py b/tests/test_qml_qeconfig.py
index d76c54338..f58956b73 100644
--- a/tests/test_qml_qeconfig.py
+++ b/tests/test_qml_qeconfig.py
@@ -1,7 +1,11 @@
+from typing import TYPE_CHECKING
 from electrum import SimpleConfig
 from electrum.gui.qml.qeconfig import QEConfig
 from tests.qt_util import QETestCase, qt_test
 
+if TYPE_CHECKING:
+    from PyQt6.QtCore import QRegularExpression
+
 
 class TestConfig(QETestCase):
     @classmethod
@@ -64,3 +68,71 @@ class TestConfig(QETestCase):
         self.assertFalse(qa.isEmpty)
         self.assertEqual(qa.satsInt, 1)
         self.assertEqual(qa.msatsInt, 1001)
+
+    @qt_test
+    def test_btc_amount_regexes(self):
+        self.q.config.BTC_AMOUNTS_DECIMAL_POINT = 8
+
+        a: 'QRegularExpression' = self.q.btcAmountRegex
+        b: 'QRegularExpression' = self.q.btcAmountRegexMsat
+
+        self.assertTrue(a.isValid())
+        self.assertTrue(b.isValid())
+
+        self.assertTrue(a.match('1').hasMatch())
+        self.assertTrue(a.match('1.').hasMatch())
+        self.assertTrue(a.match('1.00000000').hasMatch())
+        self.assertFalse(a.match('1.000000000').hasMatch())
+        self.assertTrue(a.match('21000000').hasMatch())
+        self.assertFalse(a.match('121000000').hasMatch())
+
+        self.assertTrue(b.match('1').hasMatch())
+        self.assertTrue(b.match('1.').hasMatch())
+        self.assertTrue(b.match('1.00000000').hasMatch())
+        self.assertTrue(b.match('1.00000000000').hasMatch())
+        self.assertFalse(b.match('1.000000000000').hasMatch())
+        self.assertTrue(b.match('21000000').hasMatch())
+        self.assertFalse(b.match('121000000').hasMatch())
+
+        self.q.config.BTC_AMOUNTS_DECIMAL_POINT = 5
+
+        a: 'QRegularExpression' = self.q.btcAmountRegex
+        b: 'QRegularExpression' = self.q.btcAmountRegexMsat
+
+        self.assertTrue(a.isValid())
+        self.assertTrue(b.isValid())
+
+        self.assertTrue(a.match('1').hasMatch())
+        self.assertTrue(a.match('1.').hasMatch())
+        self.assertTrue(a.match('1.00000').hasMatch())
+        self.assertFalse(a.match('1.000000').hasMatch())
+        self.assertTrue(a.match('21000000000').hasMatch())
+        self.assertFalse(a.match('121000000000').hasMatch())
+
+        self.assertTrue(b.match('1').hasMatch())
+        self.assertTrue(b.match('1.').hasMatch())
+        self.assertTrue(b.match('1.0000000').hasMatch())
+        self.assertTrue(b.match('1.00000000').hasMatch())
+        self.assertFalse(b.match('1.000000000000').hasMatch())
+        self.assertTrue(b.match('21000000000').hasMatch())
+        self.assertFalse(b.match('121000000000').hasMatch())
+
+        self.q.config.BTC_AMOUNTS_DECIMAL_POINT = 0
+
+        a: 'QRegularExpression' = self.q.btcAmountRegex
+        b: 'QRegularExpression' = self.q.btcAmountRegexMsat
+
+        self.assertTrue(a.isValid())
+        self.assertTrue(b.isValid())
+
+        self.assertTrue(a.match('1').hasMatch())
+        self.assertFalse(a.match('1.').hasMatch())
+        self.assertTrue(a.match('2100000000000000').hasMatch())
+        self.assertFalse(a.match('12100000000000000').hasMatch())
+
+        self.assertTrue(b.match('1').hasMatch())
+        self.assertTrue(b.match('1.').hasMatch())
+        self.assertTrue(b.match('1.000').hasMatch())
+        self.assertFalse(b.match('1.0000').hasMatch())
+        self.assertTrue(b.match('2100000000000000').hasMatch())
+        self.assertFalse(b.match('12100000000000000').hasMatch())