fix(eeg): tighten is_valid_epoch signature; reject non-numeric dtype + -inf

src/pipelines/eeg_pipeline.py

@@ -19,12 +19,12 @@ from src.core.logger import get_logger
 logger = get_logger(__name__)
 
 
-def is_valid_epoch(epoch: object) -> bool:
-    """Return True iff `epoch` is a non-empty 2-D float array with no NaN/inf.
+def is_valid_epoch(epoch: np.ndarray | None) -> bool:
+    """Return True iff `epoch` is a non-empty 2-D numeric array with no NaN/inf.
 
-    Used to drop corrupted segments before feature extraction. Defensive
-    against the full set of garbage we expect from real recordings: lists,
-    None, NaN/inf samples, zero-sized arrays.
+    The annotation is the *expected* input class; the implementation defensively
+    rejects any other garbage (lists, scalars, string dtypes, zero-sized arrays)
+    without raising — matching the BBB pipeline's `is_valid_smiles` pattern.
     """
     if not isinstance(epoch, np.ndarray):
         return False
@@ -32,6 +32,8 @@ def is_valid_epoch(epoch: object) -> bool:
         return False
     if epoch.size == 0:
         return False
+    if not np.issubdtype(epoch.dtype, np.number):
+        return False
     if not np.all(np.isfinite(epoch)):
         return False
     return True

tests/pipelines/test_eeg_pipeline.py

@@ -30,6 +30,8 @@ class TestIsValidEpoch:
         epoch = np.zeros((4, 256))
         epoch[1, 5] = np.inf
         assert is_valid_epoch(epoch) is False
+        epoch[1, 5] = -np.inf
+        assert is_valid_epoch(epoch) is False
 
     def test_rejects_empty(self) -> None:
         assert is_valid_epoch(np.zeros((0, 256))) is False
@@ -38,3 +40,8 @@ class TestIsValidEpoch:
     def test_rejects_non_array(self) -> None:
         assert is_valid_epoch([[1, 2, 3]]) is False
         assert is_valid_epoch(None) is False
+
+    def test_rejects_non_numeric_dtype(self) -> None:
+        """String / object dtype arrays must be rejected without raising."""
+        epoch = np.array([["a", "b"], ["c", "d"]])
+        assert is_valid_epoch(epoch) is False