Add --no-deps option to avoid running on path dependencies in workspaces

[ebroto]

Since rust-lang/cargo#8758 has hit nightly, this allows us to address the second bullet point and the concern related to --fix in the RUSTC_WORKSPACE_WRAPPER tracking issue.

As a reminder stabilizing that env var will solve #4612 (Clippy not running after cargo check in stable) and would allow to stabilize the --fix option in Clippy.

changelog: Add --no-deps option to avoid running on path dependencies in workspaces

Fixes #3025

[rust-highfive]

r? @Manishearth

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[ehuss]

Thanks for moving this forward!

One more thing, I think when running cargo clippy --fix it should also probably imply --no-deps as well, since it can cause problems with how fix works. I'm not sure how easy that would be to wire in, or if it would have any problems, though.

[Manishearth]

@bors r+

[bors]

📌 Commit 5f51eed has been approved by Manishearth

[bors]

⌛ Testing commit 5f51eed with merge 5139104...

[ebroto]

Oops I think @ehuss comment is relevant, should I open a followup?

[bors]

☀️ Try build successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Build commit: 5139104 (5139104ada0b418dcd596e11ad3f3ff9aa9fa136)

[ebroto]

Sorry to everyone involved for the delay in making this move forward, I didn't have much free time lately and wanted to give priority to some pending reviews.

@flip1995 I've addressed your concern, code is much clearer now, thanks!

@ehuss now --fix implies --no-deps. Thanks for your suggestion!

Regarding the RUSTC_WORKSPACE_WRAPPER tracking issue, I have prepared another PR to make Clippy use RUSTFLAGS for their own arguments so changing those results in a rebuild instead of reusing cached results. It removes a hack (CLIPPY_HACKERY) to add another one, but I think it's better to solve the usability problem. We can solve that in the future (maybe by making cargo take into account another env var to invalidate cached results).

After that, I'm not sure if there would be something else missing to stabilize RUSTC_WORKSPACE_WRAPPER. Maybe the ccache issue, not sure if that would be a blocker? I would be happy to work on that if it is :)

[flip1995]

r=me. Don't know if other people want to take a look before merging.

[ebroto]

I will go ahead and @bors r=flip1995 this. We can always add further changes in a follow-up :)

[bors]

📌 Commit 952b731 has been approved by flip1995

[bors]

⌛ Testing commit 952b731 with merge a2d9925...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: flip1995
Pushing a2d9925 to master...

[mleonhard]

This is super useful. Thank you!