BUG: Fix bug with logging and n_jobs>1

README.rst

@@ -199,5 +199,5 @@ MNE-Python is **BSD-licensed** (BSD-3-Clause):
 .. |OpenSSF| image:: https://www.bestpractices.dev/projects/7783/badge
 .. _OpenSSF: https://www.bestpractices.dev/projects/7783
 
-.. |MNE| image:: https://mne.tools/stable/_static/mne_logo.svg
+.. |MNE| image:: https://mne.tools/dev/_static/mne_logo_gray.svg
 .. _MNE: https://mne.tools/dev/

doc/changes/devel.rst

@@ -57,6 +57,7 @@ Bugs
 - Fix bug with :func:`mne.channels.read_ch_adjacency` (:gh:`11608` by :newcontrib:`Ivan Zubarev`)
 - Fix bugs with saving splits for :class:`~mne.Epochs` (:gh:`11876` by `Dmitrii Altukhov`_)
 - Fix bug with multi-plot 3D rendering where only one plot was updated (:gh:`11896` by `Eric Larson`_)
+- Fix bug where ``verbose`` level was not respected inside parallel jobs (:gh:`12154` by `Eric Larson`_)
 - Fix bug where subject birthdays were not correctly read by :func:`mne.io.read_raw_snirf` (:gh:`11912` by `Eric Larson`_)
 - Fix bug with :func:`mne.chpi.compute_head_pos` for CTF data where digitization points were modified in-place, producing an incorrect result during a save-load round-trip (:gh:`11934` by `Eric Larson`_)
 - Fix bug where non-compliant stimulus data streams were not ignored by :func:`mne.io.read_raw_snirf` (:gh:`11915` by `Johann Benerradi`_)

mne/parallel.py

@@ -14,6 +14,7 @@
     _validate_type,
     get_config,
     logger,
+    use_log_level,
     verbose,
     warn,
 )
@@ -120,7 +121,12 @@ def parallel_func(
         logger.debug(f"Got {n_jobs} parallel jobs after requesting {n_jobs_orig}")
         if max_jobs is not None:
             n_jobs = min(n_jobs, max(_ensure_int(max_jobs, "max_jobs"), 1))
-        my_func = delayed(func)
+
+        def run_verbose(*args, verbose=logger.level, **kwargs):
+            with use_log_level(verbose=verbose):
+                return func(*args, **kwargs)
+
+        my_func = delayed(run_verbose)
 
     if total is not None:
 

mne/utils/tests/test_logging.py

@@ -1,3 +1,4 @@
+import logging
 import os
 import re
 import warnings
@@ -8,6 +9,7 @@
 
 from mne import Epochs, create_info, read_evokeds
 from mne.io import RawArray, read_raw_fif
+from mne.parallel import parallel_func
 from mne.utils import (
     _get_call_line,
     catch_logging,
@@ -252,3 +254,23 @@ def meth_2(self, verbose=None):
         o.meth_2(verbose=False)
     log = log.getvalue()
     assert log == ""
+
+
+@pytest.mark.parametrize("n_jobs", (1, 2))
+def test_verbose_threads(n_jobs):
+    """Test that our verbose level propagates to threads."""
+
+    def my_fun():
+        from mne.utils import logger
+
+        return logger.level
+
+    with use_log_level("info"):
+        assert logger.level == logging.INFO
+        with use_log_level("warning"):
+            assert logger.level == logging.WARNING
+            parallel, p_fun, got_jobs = parallel_func(my_fun, n_jobs=n_jobs)
+            assert got_jobs in (1, n_jobs)  # FORCE_SERIAL could be set
+            out = parallel(p_fun() for _ in range(5))
+            want_levels = [logging.WARNING] * 5
+            assert out == want_levels