Avoid early-stop when no inpaint region

src/LanPaint/earlystop.py

@@ -104,9 +104,12 @@ class LanPaintEarlyStopper:
                 enabled_early_stop = False
             else:
                 inpaint_weight = (1 - latent_mask).to(dtype=torch.float32)
-                ring_weight = _boundary_weight(latent_mask, inpaint_weight)
-                if isinstance(model_options, dict):
-                    trace = model_options.get("lanpaint_semantic_trace")
+                if float(torch.sum(inpaint_weight).item()) < 1e-6:
+                    enabled_early_stop = False
+                else:
+                    ring_weight = _boundary_weight(latent_mask, inpaint_weight)
+                    if isinstance(model_options, dict):
+                        trace = model_options.get("lanpaint_semantic_trace")
 
         if not enabled_early_stop:
             return None
@@ -270,7 +273,7 @@ class LanPaintEarlyStopper:
                 dist = dist_inpaint
                 if self.ring_weight is not None:
                     dist_ring = _weighted_mse(x0_cur, x0_prev, self.ring_weight)
-                    dist = max(float(dist_inpaint), float(dist_ring))
+                    dist = max(dist_inpaint, dist_ring)
             else:
                 dist_inpaint = _weighted_mse(x_t_after, x_t_before, inpaint)
                 dist = dist_inpaint
@@ -287,8 +290,8 @@ class LanPaintEarlyStopper:
                     dist_drift = drift_inpaint
                     if self.ring_weight is not None:
                         drift_ring = _weighted_mse(x0_cur, self.x0_anchor, self.ring_weight)
-                        dist_drift = max(float(drift_inpaint), float(drift_ring))
-                    dist = max(float(dist), float(dist_drift))
+                        dist_drift = max(drift_inpaint, drift_ring)
+                    dist = max(dist, dist_drift)
             else:
                 self.x0_anchor = None
 

tests/test_lanpaint_semantic_stop.py

@@ -669,6 +669,45 @@ def test_default_semantic_stop_is_mask_normalized() -> None:
     assert calls["without_score"] == 0
 
 
+def test_semantic_stop_is_disabled_when_no_inpaint_region() -> None:
+    engine = LanPaintEngine(
+        _DummyModel(),
+        NSteps=10,
+        Friction=15.0,
+        Lambda=1.0,
+        Beta=1.0,
+        StepSize=0.2,
+    )
+
+    calls = {"langevin": 0, "with_score": 0, "without_score": 0}
+
+    def fake_langevin(x_t, score, mask, step_size, current_times, sigma_x=1, sigma_y=0, args=None):  # type: ignore[no-untyped-def]
+        calls["langevin"] += 1
+        if score is None:
+            calls["without_score"] += 1
+        else:
+            calls["with_score"] += 1
+        return x_t, args
+
+    engine.langevin_dynamics = fake_langevin  # type: ignore[method-assign]
+
+    model_options = {
+        "lanpaint_semantic_stop": {
+            "threshold": 1e-6,
+            "patience": 1,
+        }
+    }
+
+    x, latent_image, noise, sigma, latent_mask, _ = _inputs()
+    current_times = (sigma, torch.tensor([0.5]), torch.tensor([0.0]))
+    no_inpaint_mask = torch.ones_like(latent_mask)
+    engine(x, latent_image, noise, sigma, no_inpaint_mask, current_times, model_options=model_options, seed=0, n_steps=10)
+
+    assert calls["langevin"] == 10
+    assert calls["with_score"] == 10
+    assert calls["without_score"] == 0
+
+
 def test_semantic_stop_drift_guard_prevents_premature_stop() -> None:
     engine = LanPaintEngine(
         _DummyModel(),