Check unused imports

[JaewonHur]

Add scripts/check-unused-imports.sh which checks the unused imports in modified swift source files.
Good to be used before making a pull request after modifying or creating lots of swift source files.

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Motivation and Context

Developers can check and refine unused imports using this script, before making a PR.

Testing

• Tested locally
• Added/updated tests
• Added/updated docs

[JaewonHur]

Not sure it's a good approach.

[jglogan]

For the pre-commit hook I added a separate swift-format config file for format-only checking. Could we use swift format in lint mode to do this, and then perhaps it's just a matter of adjusting the existing lint rule file?

swift-fmt-check:
	@echo Applying the standard code formatting...
	@$(SWIFT) format lint --recursive --strict --configuration .swift-format-nolint $(SWIFT_SRC)

[saehejkang]

Thoughts on updating the make fmt command to run this script? Maybe even the possibility of it making the formatting changes, ie. actually remove the unused imports?

[JaewonHur]

Hi @saehejkang I'm not sure it might be merged to make fmt :)
It requires rebuilding the project with verbose flag, which is quite slow.