FIX: account for potential .{integer}_meg4 extensions in CTF format

CITATION.cff

@@ -171,6 +171,10 @@ authors:
       family-names: Guetschel
       orcid: 'https://orcid.org/0000-0002-8933-7640'
       affiliation: 'Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands'
+    - given-names: Mara
+      family-names: Wolter
+      orcid: 'https://orcid.org/0000-0002-6785-9886'
+      affiliation: 'Centre for Integrative Neuroscience, Tübingen, Germany'
     - given-names: Alexandre
       family-names: Gramfort
       affiliation: 'Université Paris-Saclay, Inria, CEA, Palaiseau, France'

doc/whats_new.rst

@@ -59,6 +59,8 @@ Detailed list of changes
 
 - The datatype in the dataframe returned by :func:`mne_bids.stats.count_events` is now
   ``pandas.Int64Dtype`` instead of ``float64``, by `Eric Larson`_ (:gh:`1227`)
+- The :func:`mne_bids.copyfiles.copyfile_ctf` now accounts for files with ``.{integer}_meg4`` extension, instead of only .meg4, 
+  when renaming the files of a .ds folder, by `Mara Wolter`_ (:gh:`1230`)
 
 ⚕️ Code health
 ^^^^^^^^^^^^^^

mne_bids/copyfiles.py

@@ -158,10 +158,15 @@ def copyfile_ctf(src, dest):
         ".hist",
         ".infods",
         ".bak",
-        "meg4",
+        ".meg4",
         ".newds",
         ".res4",
     )
+
+    # Consider CTF files that are split having consecutively numbered extensions
+    extra_ctf_file_types = tuple(f".{i}_meg4" for i in range(1, 21))  # cap at 20 is arbitrary
+    file_types += extra_ctf_file_types
+
     # Rename files in dest with the name of the dest directory
     fnames = [f for f in os.listdir(dest) if f.endswith(file_types)]
     bids_folder_name = op.splitext(op.split(dest)[-1])[0]