[CI] Try introducing isort.

[rkooo567]

It is WIP, and Idk if committers agree on introducing this feature yet.

Seems like vllm oss has sorting rule that's implicit. This PR tries introducing isort to format.sh.

This PR only touches small # of files to avoid huge merge conflict.

FIX #xxxx (link existing issues this PR will resolve)

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[simon-mo]

Overall I'm in favor. But I think ruff already does this we just need to remove the ignore astral-sh/ruff#8926 (comment)

[zhuohan123]

This is great! I'm thinking about having this for a long time.

[rkooo567]

@simon-mo I can also use ruff if that's what you prefer, so plz lmk.

isort policy

The default ordering;

FUTURE,STDLIB,THIRDPARTY,FIRSTPARTY,LOCALFOLDER

Also it prioritizes regular import over from import. I believe this is exact same policy as vllm, but please review ^ @simon-mo @zhuohan123

Merge plan

In terms of sorting all files, I will do incrementally to avoid merge conflict.

CI

@simon-mo do Can you point me which file I have to modify to introduce sorting check in the CI?

[zhuohan123]

I think enabling ruff formatter is a big change and will probably not be done in the near future. Having isort as a temp fix is better.

[zhuohan123]

Also the order looks good to me!

[simon-mo]

Checkout .github folder for workflows for lint.

[rkooo567]

@simon-mo can you take a look? I included this to a part of ruff btw (instead of adding a new step)

[rkooo567]

Looks like I need to make every file to pass isort to pass ruff.

Let's merge this PR without ruff check. And then in the next PR, I am going to apply isort on all files + add ruff check to CI. And then let's merge fast before merge conflict happes?

[simon-mo]

Can you clarify the relationship here? I would assume once you enable the ruff check, isort is no longer needed. Supposedly developers can just run ruff --check fix to sort the imports

[rkooo567]

ah my wording was confusing. Sorry about that. More concretely;

• I added isort . --check-only to the end of ruff.yaml (so it will be included in the ci). See c4681b0
• this fail because not every file is sorted yet.
• So my proposal is to merge this PR, and I make another PR to sort every file. And add isort . --check-only to ruff.yaml

Alternatively, we can only check diff, but when I tried this, it somehow didin't work

[simon-mo]

Thanks for clarifying. My question is that, instead of using isort executable, can we just use ruff executable by uncomment this line

vllm/pyproject.toml

Lines 29 to 30 in e90fc21

	# isort
	# "I",

[rkooo567]

@simon-mo let me try that out!

[zhuohan123]

Thanks for introducing this! Please let us know when this is ready to be merged. I personally also feel that we can apply isort to all files in this PR.

[rkooo567]

@simon-mo @zhuohan123

• Tried ruff, and it doesn't support use_parentheses, so I just sticked to isort.
• All files are isorted.
• Isort running is added to the workflow (ruff workflow)