Avoid crash of SC2 if no templates are detected after clustering

src/spikeinterface/sorters/internal/spyking_circus2.py

@@ -382,7 +382,8 @@ def _run_from_folder(cls, sorter_output_folder, params, verbose):
                     sorting.save(folder=curation_folder)
                     # np.save(fitting_folder / "amplitudes", guessed_amplitudes)
 
-                sorting = final_cleaning_circus(recording_w, sorting, templates, **merging_params, **job_kwargs)
+                if sorting.get_non_empty_unit_ids().size > 0:
+                    sorting = final_cleaning_circus(recording_w, sorting, templates, **merging_params, **job_kwargs)
 
                 if verbose:
                     print(f"Kept {len(sorting.unit_ids)} units after final merging")

src/spikeinterface/sortingcomponents/matching/main.py

@@ -9,6 +9,14 @@
 from spikeinterface.core.job_tools import fix_job_kwargs
 from spikeinterface.core.node_pipeline import run_node_pipeline
 
+spike_dtype = [
+    ("sample_index", "int64"),
+    ("channel_index", "int64"),
+    ("cluster_index", "int64"),
+    ("amplitude", "float64"),
+    ("segment_index", "int64"),
+]
+
 
 def find_spikes_from_templates(
     recording, method="naive", method_kwargs={}, extra_outputs=False, verbose=False, **job_kwargs
@@ -46,6 +54,9 @@ def find_spikes_from_templates(
     method_class = matching_methods[method]
     node0 = method_class(recording, **method_kwargs)
     nodes = [node0]
+    assert "templates" in method_kwargs, "You must provide templates in method_kwargs"
+    if len(method_kwargs["templates"].unit_ids) == 0:
+        return np.zeros(0, dtype=spike_dtype)
 
     spikes = run_node_pipeline(
         recording,