From 7ab994a71d0a787f627183ac01ea330b2ff6c98e Mon Sep 17 00:00:00 2001
From: Jason Wen <haibin.wen3@gmail.com>
Date: Mon, 24 Mar 2025 20:32:51 -0400
Subject: [PATCH] brake pedal release should not allow auto lane change (caught
 by test)

---
 .../controls/lib/auto_lane_change.py          |  6 ++---
 .../lib/tests/test_auto_lane_change.py        | 25 +++++++++++++++++++
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/sunnypilot/selfdrive/controls/lib/auto_lane_change.py b/sunnypilot/selfdrive/controls/lib/auto_lane_change.py
index f1aced5b92..dc86a2c9f1 100644
--- a/sunnypilot/selfdrive/controls/lib/auto_lane_change.py
+++ b/sunnypilot/selfdrive/controls/lib/auto_lane_change.py
@@ -44,7 +44,6 @@ class AutoLaneChangeController:
     self.prev_brake_pressed = False
     self.lane_change_delay = 0.0
     self._blindspot_detected = False
-    self._brake_pressed = False
     self.auto_lane_change_allowed = False
     self.read_params()
 
@@ -95,10 +94,11 @@ class AutoLaneChangeController:
 
   def update(self, blindspot_detected: bool, brake_pressed: bool) -> None:
     self._blindspot_detected = blindspot_detected
-    self._brake_pressed = brake_pressed
+
+    if brake_pressed and not self.prev_brake_pressed:
+      self.prev_brake_pressed = brake_pressed
 
     self.update_lane_change_timers()
     alc_allowed = self.update_allowed()
 
     self.auto_lane_change_allowed = alc_allowed
-    self.prev_brake_pressed = self._brake_pressed
diff --git a/sunnypilot/selfdrive/controls/lib/tests/test_auto_lane_change.py b/sunnypilot/selfdrive/controls/lib/tests/test_auto_lane_change.py
index 65b89097ec..1d342d85b0 100644
--- a/sunnypilot/selfdrive/controls/lib/tests/test_auto_lane_change.py
+++ b/sunnypilot/selfdrive/controls/lib/tests/test_auto_lane_change.py
@@ -94,6 +94,31 @@ class TestAutoLaneChangeController:
       assert self.alc.lane_change_wait_timer > self.alc.lane_change_delay
       assert self.alc.auto_lane_change_allowed
 
+  def test_brake_pressed_disables_auto_lane_change(self):
+    """Test that pressing the brake disables auto lane change."""
+    self.alc.reset()
+    # Setup NUDGELESS mode (which normally allows auto lane change)
+    self.alc.lane_change_bsm_delay = False
+    self.alc.lane_change_set_timer = AutoLaneChangeState.NUDGELESS
+
+    # Update with brake pressed for 1 second
+    num_updates = int(1.0 / DT_MDL)
+    for _ in range(num_updates):
+      self.alc.update(blindspot_detected=False, brake_pressed=True)
+
+    # Even though NUDGELESS mode, lane change should be disallowed due to brake pressed prior initiating lane change
+    assert not self.alc.auto_lane_change_allowed
+
+    # Check that prev_brake_pressed is saved
+    assert self.alc.prev_brake_pressed
+
+    # Even releasing brake shouldn't allow auto lane change
+    num_updates = int(1.0 / DT_MDL)
+    for _ in range(num_updates):
+      self.alc.update(blindspot_detected=False, brake_pressed=False)
+
+    assert not self.alc.auto_lane_change_allowed
+
   def test_blindspot_detected_with_bsm_delay(self):
     """Test behavior when blindspot is detected with BSM delay enabled."""
     self.alc.reset()