MRG: Don't overwrite Report.fname upon saving (#9998) (#10066)

* Don't overwrite Report.fname upon saving

* Add changelog entry

* Fix pickling

Co-authored-by: Richard Höchenberger <richard.hoechenberger@gmail.com>

doc/changes/0.24.inc

@@ -45,6 +45,8 @@ Version 0.24.1 (2021-12-01)
 
 - Fix automatic channel type detection from channel labels in :func:`mne.io.read_raw_edf` and :func:`mne.io.read_raw_bdf` (and disable this functionality from :func:`mne.io.read_raw_gdf`) (:gh:`10058` by `Clemens Brunner`_)
 
+- When opening a saved report and saving it to a different filename again, don't change ``Report.fname`` to avoid a regression when using :func:`~mne.open_report` as a context manager (:gh:`9998` by `Marijn van Vliet`_)
+
 .. _changes_0_24_0:
 
 Version 0.24.0 (2021-11-03)

mne/report/report.py

@@ -741,7 +741,8 @@ def _get_state_params():
         return (
             'baseline', 'cov_fname', 'include', '_content', 'image_format',
             'info_fname', '_dom_id', 'raw_psd', 'projs',
-            'subjects_dir', 'subject', 'title', 'data_path', 'lang', 'verbose'
+            'subjects_dir', 'subject', 'title', 'data_path', 'lang', 'verbose',
+            'fname'
         )
 
     def _get_dom_id(self):
@@ -2843,7 +2844,8 @@ def save(self, fname=None, open_browser=True, overwrite=False,
         if open_browser and not is_hdf5 and not building_doc:
             webbrowser.open_new_tab('file://' + fname)
 
-        self.fname = fname
+        if self.fname is None:
+            self.fname = fname
         return fname
 
     def __enter__(self):