Save dtype in phase_shift kwargs

src/spikeinterface/preprocessing/phase_shift.py

@@ -65,7 +65,12 @@ def __init__(self, recording, margin_ms=40.0, inter_sample_shift=None, dtype=Non
         # for dumpability
         if inter_sample_shift is not None:
             inter_sample_shift = list(inter_sample_shift)
-        self._kwargs = dict(recording=recording, margin_ms=float(margin_ms), inter_sample_shift=inter_sample_shift)
+        self._kwargs = dict(
+            recording=recording,
+            margin_ms=float(margin_ms),
+            inter_sample_shift=inter_sample_shift,
+            dtype=np.dtype(dtype).str,
+        )
 
 
 class PhaseShiftRecordingSegment(BasePreprocessorSegment):

src/spikeinterface/preprocessing/tests/test_phase_shift.py

@@ -1,5 +1,6 @@
 import numpy as np
-from spikeinterface import NumpyRecording
+from spikeinterface import NumpyRecording, load
+from spikeinterface.core.testing import check_recordings_equal
 
 from spikeinterface.preprocessing import phase_shift
 
@@ -112,5 +113,16 @@ def signal(time):
     np.testing.assert_allclose(shifted_traces[interior], expected[interior], atol=1e-3)
 
 
+def test_phase_shift_dtype_survives_reload():
+    traces, sampling_frequency, inter_sample_shift = create_shifted_channel()
+    recording = NumpyRecording([traces.astype("int16")], sampling_frequency)
+    recording.set_property("inter_sample_shift", inter_sample_shift)
+
+    shifted = phase_shift(recording, dtype="float32")
+    reloaded = load(shifted.to_dict())
+
+    check_recordings_equal(shifted, reloaded, return_in_uV=False)
+
+
 if __name__ == "__main__":
     test_phase_shift()