Backport PR #13341 on branch maint/1.10 (BUG: Fix bug with reading old reports) (#13344)

Co-authored-by: Eric Larson <larson.eric.d@gmail.com>

Author: meeseeksmachine

doc/changes/devel/13341.bugfix.rst

@@ -0,0 +1 @@
+Fix bug with :func:`mne.open_report` not working with old saved files, by `Eric Larson`_.

mne/report/report.py

@@ -714,12 +714,11 @@ def open_report(fname, **params):
         # Check **params with the loaded report
         read_hdf5, _ = _import_h5io_funcs()
         state = read_hdf5(fname, title="mnepython")
+        for param, default in _backward_compat_map.items():
+            state.setdefault(param, default)
         for param in params:
             if param not in state:
-                if param in _backward_compat_map:
-                    state[param] = _backward_compat_map[param]
-                else:
-                    raise ValueError(f"The loaded report has no attribute {param}")
+                raise ValueError(f"The loaded report has no attribute {param}")
             if params[param] != state[param]:
                 raise ValueError(
                     f"Attribute '{param}' of loaded report ({params[param]}) does not "

mne/report/tests/test_report.py

@@ -1172,6 +1172,21 @@ def test_report_tweaks(tmp_path, monkeypatch):
     assert img.shape == (2000, 2000, 3)  # figure.figsize * figure.dpi
 
 
+def test_report_backward_compat(tmp_path):
+    """Ensure our options are still backward compatible."""
+    h5io = pytest.importorskip("h5io")
+    fname = tmp_path / "report.h5"
+    r = Report()
+    r.img_max_width = 600
+    r.save(fname)
+    h = h5io.read_hdf5(fname, title="mnepython")
+    assert h["img_max_width"] == 600
+    del h["img_max_width"]
+    h5io.write_hdf5(fname, h, title="mnepython", overwrite=True)
+    with open_report(fname) as r2:
+        assert r2.img_max_width == 850
+
+
 @pytest.mark.slowtest  # 30 s on Azure
 @testing.requires_testing_data
 def test_manual_report_3d(tmp_path, renderer):