short-circuit corrmap when appropriate

drammock · drammock · commit 6011f5800cd2 · 2022-09-22T14:48:27.000-05:00
diff --git a/mne/preprocessing/ica.py b/mne/preprocessing/ica.py
@@ -2831,6 +2831,11 @@ def corrmap(icas, template, threshold="auto", label=None, ch_type="eeg", *,
                          "montage. Consider interpolating bad channels before "
                          "running ICA.")
 
+    if label is None and not plot:
+        warn('Nothing to do: when label=None and plot=False, corrmap() '
+             'returns None and the inputs are unchanged.', UserWarning)
+        return
+
     threshold_extra = ''
     if threshold == 'auto':
         threshold = np.arange(60, 95, dtype=np.float64) / 100.
