Opening a project of a workspace checks the whole workspace

[Ten0]

I have a workspace which contains a large number of crates.

Say I need to do the following, in that order:

• Update lib L
• Fix crate A to new interface of lib L
• Fix crate B to new interface of lib L

(A and B do not depend on each other)

When I try to completely update crate A, I can't see warnings and in general I get errors from project B, which I haven't fixed yet. This is due to rust-analyzer watching the whole workspace, even though I have only opened the root of A, and the Cargo.toml at the root of my folder is that of A.

I would expect that the current behaviour only happens when I open my workspace folder, and that when I open a single project it doesn't try to build the whole workspace, allowing me to completely fix a crate before moving to the next.

This would also have other benefits:

• Performance: my workspace being very large, I rarely work on all projects at once so I would gain time and space by not building all of it
• Feature flags testing: a global cargo check does not behave the same way as individual checks: when running a workspace check, all feature flags required in any crate of the workspace are enabled for every crate of the workspace, while when running a crate check, only the flags required for that specific crate are enabled.

[Ten0]

#2792 may be another solution to the first part (though I'm not sure how it would behave with the warnings), but it doesn't do anything for the "other benefits".

[matklad]

The current workaround is to set checOnSave.overrideCommand to a cargo command which checks only a specific package.

[Ten0]

What's the original command and how should I set it so that it checks in the root of my project ? (I wouldn't want to remove any other important parameters)

[matklad]

Original one is cargo check --workspace --message-format=json

[Ten0]

I tried setting:

{
	"rust-analyzer.checkOnSave.overrideCommand": [
		"cargo",
		"check",
		"--message-format=json"
	]
}

and it seems to still check the whole workspace. :(

[matklad]

That’s the base command, yeah, you need to add -p some-package no top of it to narrow it to a single package

[Ten0]

Oh that's awful, I'd have to change everytime I open a project :(

[Ten0]

I'm trying to make this work with extraArgs but I can't seem to do so (while it does work with https://github.com/rust-analyzer/rust-analyzer/issues/3975#issuecomment-615272400):

{
	"rust-analyzer.checkOnSave.extraArgs": [
		"-p",
		"some_crate",
	],
	"rust-analyzer.cargo.allFeatures": true
}

seems to still check the whole workspace.

[ellbur]

That’s the base command, yeah, you need to add -p some-package no top of it to narrow it to a single package

So maybe a wrapper script to infer the current project and add the -p? I'm going to give that a try.

[ellbur]

So maybe a wrapper script to infer the current project and add the -p? I'm going to give that a try.

Alas, I can find no way to detect the package since the cwd is the workspace...