Require an angular turn for redirect touches, not speed alone.

Speed-only redirects let teammate fly-bys (e.g. #15→#8 on 08fd33) complete a
pass before the real interceptor settles; require a deflection angle so the
turnover attributes to #3.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: AlexBodner

sports/common/possession.py

@@ -562,6 +562,23 @@ def _ball_touch_path_metrics(
     return angle_deg, speed_ratio
 
 
+def _redirect_signature(
+    angle_deg: float,
+    speed_ratio: float,
+    *,
+    min_angle_deg: float,
+    min_speed_ratio: float,
+) -> bool:
+    """True when path change looks like a kick, not a speed blip on a fly-by.
+
+    Speed alone is not enough: a ball skimming a teammate mid-pass can briefly
+    change measured speed without a real deflection. Require an angular turn.
+    """
+    return min_angle_deg <= angle_deg <= 135.0 or (
+        speed_ratio >= min_speed_ratio and angle_deg >= min_angle_deg
+    )
+
+
 def ball_redirected_at_touch(
     frames_by_idx: dict[int, sv.Detections],
     touch_frame: int,
@@ -583,9 +600,11 @@ def ball_redirected_at_touch(
     if metrics is None:
         return False
     angle_deg, speed_ratio = metrics
-    return (
-        speed_ratio >= min_speed_ratio
-        or (min_angle_deg <= angle_deg <= 135.0)
+    return _redirect_signature(
+        angle_deg,
+        speed_ratio,
+        min_angle_deg=min_angle_deg,
+        min_speed_ratio=min_speed_ratio,
     )
 
 
@@ -640,16 +659,15 @@ def redirect_overrides_transit_flyby(
     if (
         release_gap_frames is not None
         and release_gap_frames >= config.gravity_flyby_min_release_gap_frames
+        and speed_ratio > 4.0
     ):
-        if speed_ratio > 4.0:
-            return False
-        return (
-            min_angle <= angle_deg <= 135.0
-            or (speed_ratio >= min_ratio and angle_deg >= min_angle)
-        )
-    return (
-        speed_ratio >= min_ratio
-        or (min_angle <= angle_deg <= 135.0)
+        # Teleport / sparse-detection speed spike during a long flight.
+        return False
+    return _redirect_signature(
+        angle_deg,
+        speed_ratio,
+        min_angle_deg=min_angle,
+        min_speed_ratio=min_ratio,
     )
 
 

tests/test_flyby_turnover.py

@@ -83,6 +83,50 @@ def test_flyby_teammate_does_not_steal_opponent_turnover():
     )
 
 
+def test_speed_only_path_blip_is_not_a_redirect():
+    """A speed change without an angular turn must not count as a kick/redirect.
+
+    Regression for false #15→#8 on 08fd33: teammate skim had speed_ratio≈2.4 and
+    angle≈11°, which the old speed-only rule treated as a redirect and completed
+    a pass before opponent #3 secured the ball.
+    """
+    from sports.common.possession import (
+        ball_redirected_at_touch,
+        redirect_overrides_transit_flyby,
+        TouchValidationConfig,
+    )
+
+    # Straight-ish flight with a mid-path deceleration (speed blip, tiny angle).
+    ball_path = (
+        [(100.0 + 25 * i, 200.0) for i in range(6)]
+        + [(250.0, 202.0), (255.0, 203.0), (260.0, 204.0)]  # slower, ~tiny bend
+        + [(280.0 + 25 * i, 205.0) for i in range(6)]
+    )
+    frames_by_idx = {
+        i: _frame(players=[(8, 0, (255.0, 220.0))], ball=ball)
+        for i, ball in enumerate(ball_path, 1)
+    }
+    touch = 8  # around the deceleration
+    assert ball_redirected_at_touch(
+        frames_by_idx,
+        touch,
+        lookback=5,
+        lookahead=5,
+        min_angle_deg=28.0,
+        min_speed_ratio=1.35,
+        min_segment_px=10.0,
+    ) is False
+    assert (
+        redirect_overrides_transit_flyby(
+            frames_by_idx,
+            touch,
+            config=TouchValidationConfig(),
+            release_gap_frames=None,
+        )
+        is False
+    )
+
+
 def test_fast_flyby_still_turnovers_to_interceptor():
     """Default transit speed: ball flying past #6 still yields #15→#3 turnover."""
     ball_path = (