MAINT: Add nibabel as a required dependency

[larsoner]

Just the start of a proof-of-concept for #11564, in addition to the lines I removed already in #11557. Would still need:

• ~50 instances of @requires_nibabel to be removed
• Revert nibabel part of MAINT: Temporary regression workaround #11566

[drammock]

I think after discussion with @agramfort @britta-wstnr @larsoner and myself today, it was agreed to abandon this idea, closing as not planned. Rationale is that adding core deps can be burdensome for users in a tightly managed environment (they may need permission from IT to get nibabel added, for example).

[larsoner]

Indeed I'll open another PR soon to add more requires_nibabel to our code

[jasmainak]

we discovered this in HNN. Looks like nibabel is a core dependency now but it's not reflected in the setup.py: https://github.com/mne-tools/mne-python/blob/main/requirements_base.txt

[larsoner]

Can you give a traceback? We ended up not making it a core dependency

[jasmainak]

here you go: jonescompneurolab/hnn-core#649 (comment)

should we be installing nibabel in our CIs separately?

[larsoner]

Yes, nibabel is an optional dependency not a core one, so you have to install it separately. PR welcome to change the wording of the error message to say something about it being optional and to consider installing it

mne-python/mne/utils/check.py

Line 159 in 079c868

raise ImportError(f"The {lib} package{extra} is required to {what}, " f"{why}")