Linting

[TomNicholas]

@jhamman I think there's a small problem with the pre-commit tools interacting with one another - my cmd line output is given below but no files are changed for me to commit. I've already run pre-commit run --all-files a few times to get to this point (those changes are what is committed in this PR), but now this happens every time. I think this means that black and isort are undoing each others changes to datatree/datatree.py? If I delete isort from the pre-commit-config.yaml then black passes.

(py38-mamba) tom@pop-os:~/Documents/Work/Code/datatree$ pre-commit run --all-files
Trim Trailing Whitespace.................................................Passed
Fix End of Files.........................................................Passed
Check Yaml...............................................................Passed
isort....................................................................Failed
- hook id: isort
- files were modified by this hook
Fixing /home/tom/Documents/Work/Code/datatree/datatree/datatree.py
black....................................................................Failed
- hook id: black
- files were modified by this hook
reformatted datatree/datatree.py
All done! ✨ 🍰 ✨
1 file reformatted, 8 files left unchanged.
blackdoc.................................................................Passed
flake8...................................................................Failed
- hook id: flake8
- exit code: 1
datatree/tests/test_dataset_api.py:166:80: E501 line too long (87 > 79 characters)
...

(py38-mamba) tom@pop-os:~/Documents/Work/Code/datatree$ git status
On branch linting
Your branch is up to date with 'origin/linting'.
Changes not staged for commit:
(use "git add <file>..." to update what will be committed)
(use "git restore <file>..." to discard changes in working directory)
modified: .pre-commit-config.yaml
Untracked files:
(use "git add <file>..." to include in what will be committed)
.idea/
datafiles/
datatree/accessors.py
design_notes.md
setup.cfg
no changes added to commit (use "git add" and/or "git commit -a")

(there are more flake8 and mypy suggestions/warnings later but I'll try and deal with them afterwards)

[jhamman]

@TomNicholas - try merging #22 into your linting branch and running pre-commit over all the files again.

[TomNicholas]

@jhamman that works nicely, thanks!

[jhamman]

Nice! The remaining failure seems to be related to mypy. We could turn that off for now, or you can make those fixes here.

[TomNicholas]

The remaining failure seems to be related to mypy. We could turn that off for now, or you can make those fixes here.

Yes - I'm currently trying to fix the mypy failures, but I don't understand a lot of them. What I think we could do is turn off mypy for now in the CI and open a separate PR to discuss changes needed to make mypy pass locally.

[jhamman]

Great. Just comment out the my-py section in the pre-commit-config and you should be good to go.