[MRG] FIX: save-load split FIF round trip

[massich]

split save and reload a FIF file fails due to Annotations

Fixes #5856

[codecov]

Codecov Report

Merging #5857 into master will decrease coverage by 1.77%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #5857      +/-   ##
==========================================
- Coverage   89.23%   87.45%   -1.78%     
==========================================
  Files         417      417              
  Lines       75168    75176       +8     
  Branches    12376    12375       -1     
==========================================
- Hits        67075    65745    -1330     
- Misses       5215     6577    +1362     
+ Partials     2878     2854      -24

[larsoner]

It would be great if this could also fix #5908

[larsoner]

@massich it would be good to release soon, this should go in if at all possible so this is a high priority!

[lgtm-com]

This pull request introduces 1 alert when merging 5b35f1f into 017d156 - view on LGTM.com

new alerts:

• 1 for Unused import

---

Comment posted by LGTM.com

[lgtm-com]

This pull request introduces 2 alerts when merging e8609b8 into 14d0527 - view on LGTM.com

new alerts:

• 1 for Except block handles 'BaseException'
• 1 for Unused import

---

Comment posted by LGTM.com

[massich]

The current status solves #5856 and does not break any other tests.

The following snipped fails in master and passes in the PR.

import os.path as op
import numpy as np
from numpy.testing import assert_array_equal, assert_allclose

from mne.datasets import testing
from mne.io import read_raw_fif
from mne.utils import _TempDir
from mne.annotations import Annotations

testing_path = testing.data_path(download=False)
data_dir = op.join(testing_path, 'MEG', 'sample')
fif_fname = op.join(data_dir, 'sample_audvis_trunc_raw.fif')
tempdir = _TempDir()

raw_1 = read_raw_fif(fif_fname, preload=True)
annot = Annotations(np.arange(20), np.ones((20,)), 'test')
raw_1.set_annotations(annot)
split_fname = op.join(tempdir, 'split_raw.fif')
raw_1.save(split_fname, buffer_size_sec=1.0, split_size='10MB')
raw_2 = read_raw_fif(split_fname)
assert_allclose(raw_2.buffer_size_sec, 1., atol=1e-2)  # samp rate
assert_allclose(raw_1.annotations.onset, raw_2.annotations.onset)
assert_allclose(raw_1.annotations.duration, raw_2.annotations.duration,
                rtol=0.001 / raw_2.info['sfreq'])
assert_array_equal(raw_1.annotations.description,
                    raw_2.annotations.description)

[larsoner]

Probably worth an entry in whats_new.rst BUG section, otherwise +1 for merge, thanks @massich

[larsoner]

The following snipped fails in master and passes in the PR.

This is effectively captured by one of the modifications to the test files now, right? If not, please do add it because it's an important non-regression test.

[massich]

@larsoner yes it is. Actually, the snippet is just a snipped from the modified test.

[agramfort]

just add entry in what's new bug fixes.

I like fixes which are red lines :)

[larsoner]

Thanks @massich !