Add --warn-unreachable flag to mypy as a optional flag

[gopidesupavan]

We are planing another activity after mypy bump, to see if any unreachable code warns and fix them. This pr helps to this #53395 to enable community unreachable argument and fix if any real issues

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[gopidesupavan]

Will announce this activity after thie merge

[jscheffl]

Looks OK for me. But options are growing. Does it maybe makes sense to consolidate the ENV to "SHOW_WARNINGS" only and apply the env to both parameters?

Besides this the ENV is only known if you read the source, would it be preferrable to add an arg to CLI entry point? Or is it an in-official entry as actually target is to call indirectly via pre-commit only? We could also make a pre-commit manual stage out of it, then it might be easier to find?

Not blocking comments, just ideas.

[gopidesupavan]

Looks OK for me. But options are growing. Does it maybe makes sense to consolidate the ENV to "SHOW_WARNINGS" only and apply the env to both parameters?

Besides this the ENV is only known if you read the source, would it be preferrable to add an arg to CLI entry point? Or is it an in-official entry as actually target is to call indirectly via pre-commit only? We could also make a pre-commit manual stage out of it, then it might be easier to find?

Not blocking comments, just ideas.

Make sense :), i will get it into separate PR..

[github-actions]

Backport successfully created: v3-0-test

Status	Branch	Result
✅	v3-0-test