fix(metric): honor torch.device context manager when setting default device

CHANGELOG.md

@@ -36,6 +36,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed malformed LaTeX in `CLIPScore` and `HausdorffDistance` docstring math so it renders correctly ([#3427](https://github.com/Lightning-AI/torchmetrics/pull/3427))
 
 
+- Fixed `Metric` ignoring an active `torch.device` context manager on torch 2.3-2.7 ([#3448](https://github.com/Lightning-AI/torchmetrics/pull/3448))
+
+
 ---
 
 ## [1.9.0] - 2026-03-05

src/torchmetrics/metric.py

@@ -39,7 +39,7 @@
 )
 from torchmetrics.utilities.distributed import gather_all_tensors
 from torchmetrics.utilities.exceptions import TorchMetricsUserError
-from torchmetrics.utilities.imports import _TORCH_GREATER_EQUAL_2_1, _TORCH_GREATER_EQUAL_2_3
+from torchmetrics.utilities.imports import _TORCH_GREATER_EQUAL_2_1, _TORCH_GREATER_EQUAL_2_8
 from torchmetrics.utilities.plot import _AX_TYPE, _PLOT_OUT_TYPE, plot_single_or_multi_val
 from torchmetrics.utilities.prints import rank_zero_warn
 
@@ -113,7 +113,8 @@ def __init__(
         torch._C._log_api_usage_once(f"torchmetrics.metric.{self.__class__.__name__}")
         # magic patch for `RuntimeError: DataLoader worker (pid(s) 104) exited unexpectedly`
         self._TORCH_GREATER_EQUAL_2_1 = bool(_TORCH_GREATER_EQUAL_2_1)
-        self._device = torch.get_default_device() if _TORCH_GREATER_EQUAL_2_3 else torch.empty(0).device
+        # before 2.8, `get_default_device` only tracked `set_default_device`, not an active `torch.device` context
+        self._device = torch.get_default_device() if _TORCH_GREATER_EQUAL_2_8 else torch.empty(0).device
         self._dtype = torch.get_default_dtype()
 
         self.compute_on_cpu = kwargs.pop("compute_on_cpu", False)

src/torchmetrics/utilities/imports.py

@@ -23,6 +23,7 @@
 _TORCH_GREATER_EQUAL_2_2 = RequirementCache("torch>=2.2.0")
 _TORCH_GREATER_EQUAL_2_3 = RequirementCache("torch>=2.3.0")
 _TORCH_GREATER_EQUAL_2_5 = RequirementCache("torch>=2.5.0")
+_TORCH_GREATER_EQUAL_2_8 = RequirementCache("torch>=2.8.0")
 _TORCH_LESS_THAN_2_6 = RequirementCache("torch<2.6.0")
 _TORCHMETRICS_GREATER_EQUAL_1_6 = RequirementCache("torchmetrics>=1.7.0")
 

tests/unittests/bases/test_metric.py

@@ -30,6 +30,7 @@
 from torchmetrics.clustering import AdjustedRandScore
 from torchmetrics.image import StructuralSimilarityIndexMeasure
 from torchmetrics.regression import PearsonCorrCoef, R2Score
+from torchmetrics.utilities.imports import _TORCH_GREATER_EQUAL_2_8
 from unittests._helpers import seed_all
 from unittests._helpers.testers import DummyListMetric, DummyMetric, DummyMetricMultiOutput, DummyMetricSum
 
@@ -333,6 +334,22 @@ def test_device_and_dtype_transfer(tmpdir):
     torch.set_default_dtype(default_dtype)
 
 
+@pytest.mark.parametrize(
+    "use_get_default_device",
+    [
+        pytest.param(True, marks=pytest.mark.skipif(not _TORCH_GREATER_EQUAL_2_8, reason="requires torch>=2.8")),
+        False,
+    ],
+)
+def test_device_from_device_context_manager(monkeypatch, use_get_default_device):
+    """Test that a metric picks up the device from an active `torch.device` context manager, on both version paths."""
+    monkeypatch.setattr("torchmetrics.metric._TORCH_GREATER_EQUAL_2_8", use_get_default_device)
+    with torch.device("meta"):
+        metric = DummyMetricSum()
+    assert metric.device == torch.device("meta")
+    assert metric.x.device == torch.device("meta")
+
+
 def test_disable_of_normal_dtype_methods():
     """Check that the default dtype changing methods does nothing."""
     metric = DummyMetricSum()