Fix when writing to directory that contains "tsv" in its name

doc/whats_new.rst

@@ -69,6 +69,7 @@ Bug fixes
 - :func:`mne_bids.write_raw_bids` now works across data types with ``overwrite=True``, by `Alexandre Gramfort`_ (:gh:`791`)
 - :func:`mne_bids.read_raw_bids` didn't always replace all traces of the measurement date and time stored in the raw data with the date found in `*_scans.tsv`, by `Richard Höchenberger`_ (:gh:`812`, :gh:`815`)
 - :func:`mne_bids.read_raw_bids` crashed when the (optional) ``acq_time`` column was missing in ``*_scans.tsv``, by `Alexandre Gramfort`_ (:gh:`814`)
+- :func:`mne_bids.write_raw_bids` doesn't crash anymore if the designated output directory contains the string ``"tsv"``, by `Richard Höchenberger`_ (:gh:`833`)
 
 :doc:`Find out what was new in previous releases <whats_new_previous_releases>`
 

mne_bids/tests/test_write.py

@@ -2806,3 +2806,18 @@ def test_write_associated_emptyroom(_bids_validate, tmpdir):
             .as_posix()  # make test work on Windows, too
             .endswith(meg_json_data['AssociatedEmptyRoom']))
     assert meg_json_data['AssociatedEmptyRoom'].startswith('/')
+
+
+@pytest.mark.parametrize(
+    'dir_name', ('tsv_test', 'json_test')
+)
+def test_write_raw_special_paths(tmpdir, dir_name):
+    """Test writing to locations containing strings with special meaning."""
+    data_path = testing.data_path()
+    raw_fname = op.join(data_path, 'MEG', 'sample',
+                        'sample_audvis_trunc_raw.fif')
+    raw = _read_raw_fif(raw_fname)
+
+    root = Path(tmpdir) / dir_name
+    bids_path = _bids_path.copy().update(root=root)
+    write_raw_bids(raw=raw, bids_path=bids_path)

mne_bids/write.py

@@ -1345,8 +1345,8 @@ def write_raw_bids(raw, bids_path, events_data=None,
     # For the remaining files, we can use BIDSPath to alter.
     readme_fname = op.join(bids_path.root, 'README')
     participants_tsv_fname = op.join(bids_path.root, 'participants.tsv')
-    participants_json_fname = participants_tsv_fname.replace('tsv',
-                                                             'json')
+    participants_json_fname = participants_tsv_fname.replace('.tsv',
+                                                             '.json')
 
     sidecar_path = bids_path.copy().update(suffix=bids_path.datatype,
                                            extension='.json')