Don't store age, sex, handedness for empty-room in participants.tsv (#…

…935)

doc/whats_new.rst

@@ -56,6 +56,9 @@ Bug fixes
 
 - :func:`mne_bids.make_report` now correctly handles `participant.tsv` files that only contain a `participant_id` column, by `Simon Kern`_ (:gh:`912`)
 
+- :func:`mne_bids.write_raw_bids` doesn't store age, handedness, and sex in `participants.tsv` anymore for empty-room recordings, by `Richard Höchenberger`_ (:gh:`935`)
+
+
 :doc:`Find out what was new in previous releases <whats_new_previous_releases>`
 
 .. include:: authors.rst

mne_bids/tests/test_write.py

@@ -161,9 +161,12 @@ def test_write_participants(_bids_validate, tmp_path):
     # add fake participants data
     raw.set_meas_date(datetime(year=1994, month=1, day=26,
                                tzinfo=timezone.utc))
-    raw.info['subject_info'] = {'his_id': subject_id2,
-                                'birthday': (1993, 1, 26),
-                                'sex': 1, 'hand': 2}
+    raw.info['subject_info'] = {
+        'his_id': subject_id2,
+        'birthday': (1993, 1, 26),
+        'sex': 1,
+        'hand': 2
+    }
 
     bids_path = _bids_path.copy().update(root=tmp_path)
     write_raw_bids(raw, bids_path)
@@ -222,7 +225,6 @@ def test_write_participants(_bids_validate, tmp_path):
 
     # if overwrite is False, then nothing should change from the above
     with pytest.raises(FileExistsError, match='already exists'):
-        raw.info['subject_info'] = None
         write_raw_bids(raw, bids_path, overwrite=False)
     data = _from_tsv(participants_tsv)
     with open(participants_json_fpath, 'r', encoding='utf-8') as fin:
@@ -233,6 +235,19 @@ def test_write_participants(_bids_validate, tmp_path):
     # in addition assert the original ordering of the new overwritten file
     assert list(data.keys()) == orig_key_order
 
+    # For empty-room data, all fields except participant_id should be 'n/a'
+    assert raw.info['subject_info']  # Ensure the following test makes sense!
+    bids_path_er = bids_path.copy().update(
+        subject='emptyroom', task='noise',
+        session=raw.info['meas_date'].strftime('%Y%m%d')
+    )
+    write_raw_bids(raw=raw, bids_path=bids_path_er, verbose=False)
+    participants_tsv = _from_tsv(participants_tsv)
+    idx = participants_tsv['participant_id'].index('sub-emptyroom')
+    assert participants_tsv['hand'][idx] == 'n/a'
+    assert participants_tsv['sex'][idx] == 'n/a'
+    assert participants_tsv['age'][idx] == 'n/a'
+
 
 def test_write_correct_inputs():
     """Test that inputs of write_raw_bids is correct."""

mne_bids/write.py

@@ -303,14 +303,11 @@ def _participants_tsv(raw, subject_id, fname, overwrite=False):
         False, an error will be raised.
 
     """
-    subject_id = 'sub-' + subject_id
-    data = OrderedDict(participant_id=[subject_id])
-
     subject_age = "n/a"
     sex = "n/a"
     hand = 'n/a'
     subject_info = raw.info.get('subject_info', None)
-    if subject_info is not None:
+    if subject_id != 'emptyroom' and subject_info is not None:
         # add sex
         sex = _map_options(what='sex', key=subject_info.get('sex', 0),
                            fro='mne', to='bids')
@@ -336,6 +333,8 @@ def _participants_tsv(raw, subject_id, fname, overwrite=False):
         else:
             subject_age = "n/a"
 
+    subject_id = 'sub-' + subject_id
+    data = OrderedDict(participant_id=[subject_id])
     data.update({'age': [subject_age], 'sex': [sex], 'hand': [hand]})
 
     if os.path.exists(fname):
@@ -1533,8 +1532,10 @@ def write_raw_bids(raw, bids_path, events_data=None, event_id=None,
     _readme(bids_path.datatype, readme_fname, False)
 
     # save all participants meta data
-    _participants_tsv(raw, bids_path.subject, participants_tsv_fname,
-                      overwrite)
+    _participants_tsv(
+        raw=raw, subject_id=bids_path.subject, fname=participants_tsv_fname,
+        overwrite=overwrite
+    )
     _participants_json(participants_json_fname, True)
 
     # for MEG, we only write coordinate system