Adding logger.debug message when lalsim waveform longer than bilby's.

bilby/gw/source.py

@@ -383,8 +383,10 @@ def _base_lal_cbc_fd_waveform(
     h_cross = np.zeros_like(frequency_array, dtype=np.complex)
 
     if len(hplus.data.data) > len(frequency_array):
-        # lalsim waveform arrays can be padded with zeros up to
-        # a power of two length which can be greater than our length.
+        logger.debug("LALsim waveform longer than bilby's `frequency_array`" +
+                    "({} vs {}), ".format(len(hplus.data.data), len(frequency_array)) +
+                    "probably because padded with zeros up to the next power of two length." +
+                    " Truncating lalsim array.")
         h_plus = hplus.data.data[:len(h_plus)]
         h_cross = hcross.data.data[:len(h_cross)]