Cargo: decouple crate from main Cargo.toml workspace #7525

phip1611 · 2025-11-27T15:19:37Z

This is my solution for #7524 which we discussed in todays Cloud Hypervisor office hour. I think it improves certain things:

TL;DR improvements

more fearless refactorings: cargo test|check|clippy now run on the whole workspace by default (without explicit --all/--workspace)
main Cargo.toml is not so overwhelming anymore
We got rid of a lot of repetitions in CI files (no more -D warnings all the time)
cleaned up technical debt of unused build.rs scripts

More info in ticket or commit message.

Steps

add new workspace member cloud-hypervisor
move ./src to new workspace member
move ./tests to new workspace member
move relevant parts from Cargo.toml to new workspace member

performance-metrics/Cargo.toml

vhost_user_block/Cargo.toml

phip1611 · 2025-11-27T16:51:00Z

From today's cloud hypervisor office meeting: Yes, it is a great improvement, we want to go that way (Rob)

phip1611 · 2025-11-28T08:06:40Z

ping @RuoqingHe - I needed to take special care for the riscv job: bc4a2bd

alyssais

Like the direction. :)

Cargo.toml

CONTRIBUTING.md

alyssais · 2025-12-05T12:39:29Z

test_infra/src/lib.rs

+    let target_cmd_path = format!("{target_artifact_dir}/{cmd}");
+
+    let full_path = workspace_root.join(&target_cmd_path);
+    String::from(full_path.to_str().unwrap())


Just a thought, not a blocker at all: I wonder if we could use e.g. env!("CARGO_BIN_EXE_cloud-hypervisor") and get rid of this function. It should at least work for the code in tests/, but I'm not sure if it would be set when the test_infra crate is built, so if not it would require the two other users of this function to be adjusted to take an executable path as a parameter passed by code in tests/.

This will also prevent some useless rebuilds. Using `--verbose` we can observe that the build.rs causes frequent useless rebuilds - having less is a good thing. They come from the dependency of `build.rs` to the local git repository. Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

TL;DR: cargo clippy|check|... now runs on whole workspace by default. ## Steps - add new workspace member `cloud-hypervisor` - move `./src` to new workspace member - move `./tests` to new workspace member - move relevant parts from Cargo.toml to new workspace member - kept necessary parts in main Cargo.toml, such as profile configurations ## About The main Cargo.toml historically mixes workspace and crate definitions for cloud-hypervisor and ch-remote. This makes it hard to read and requires `--workspace` to run cargo clippy or cargo test on all workspace members, which is counter-intuitive. This patch separates the workspace from the crate definition in the main Cargo.toml file. After this, cargo clippy, cargo test, etc., work on the whole workspace naturally, giving a smoother developer experience. The Cargo.toml without a package definition is also called a virtual workspace or virtual manifest by Cargo [0]. Backporting is not a concern: CHV no longer backports, but the affected files are rarely modified anyway. [0] https://doc.rust-lang.org/cargo/reference/workspaces.html#virtual-workspace Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

Unrelated but necessary to also always format code for all architectures and all features. Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

It is no longer needed to add `--all` (which is an alias for `--workspace`). The documentation says "Commands run in the workspace root will run against all workspace members by default" [0]. We however still need `--tests` as this activates the building of tests in `<crate>/tests` directories. [0] https://doc.rust-lang.org/cargo/reference/workspaces.html#virtual-workspace Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

`cargo rustc` is incompatible with virtual manifests, so the CI needs to use cargo build instead. However, passing `RUSTFLAGS="-D warnings"` via the environment would propagate to all dependencies, and some of them currently fail to build under ``-D warnings` due to issues like [0]: ``` error: creating a mutable reference to mutable static --> src/temp.rs:97:5 | 97 | DIRS.pop() | ^^^^^^^^^^ mutable reference to mutable static ``` To resolve this, apply ``-D warnings` only to the `cargo clippy` commands (which apply to our workspace only) and avoid enforcing it for the entire cargo build. [0]: https://github.com/cloud-hypervisor/cloud-hypervisor/actions/runs/19962283528/job/57245376263?pr=7525 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

This is the first commit of the cherry-pick from [0]. [0] cloud-hypervisor#7525 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

This is the last commit of the cherry-pick from [1]. `cargo rustc` is incompatible with virtual manifests, so the CI needs to use cargo build instead. However, passing `RUSTFLAGS="-D warnings"` via the environment would propagate to all dependencies, and some of them currently fail to build under ``-D warnings` due to issues like [0]: ``` error: creating a mutable reference to mutable static --> src/temp.rs:97:5 | 97 | DIRS.pop() | ^^^^^^^^^^ mutable reference to mutable static ``` To resolve this, apply ``-D warnings` only to the `cargo clippy` commands (which apply to our workspace only) and avoid enforcing it for the entire cargo build. [0]: https://github.com/cloud-hypervisor/cloud-hypervisor/actions/runs/19962283528/job/57245376263?pr=7525 [1]: cloud-hypervisor#7525 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

This is the first commit of the cherry-pick from [0]. [0] cloud-hypervisor#7525 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

This is the last commit of the cherry-pick from [1]. `cargo rustc` is incompatible with virtual manifests, so the CI needs to use cargo build instead. However, passing `RUSTFLAGS="-D warnings"` via the environment would propagate to all dependencies, and some of them currently fail to build under ``-D warnings` due to issues like [0]: ``` error: creating a mutable reference to mutable static --> src/temp.rs:97:5 | 97 | DIRS.pop() | ^^^^^^^^^^ mutable reference to mutable static ``` To resolve this, apply ``-D warnings` only to the `cargo clippy` commands (which apply to our workspace only) and avoid enforcing it for the entire cargo build. [0]: https://github.com/cloud-hypervisor/cloud-hypervisor/actions/runs/19962283528/job/57245376263?pr=7525 [1]: cloud-hypervisor#7525 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

This is the first commit of the cherry-pick from [0]. [0] cloud-hypervisor#7525 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

This is the last commit of the cherry-pick from [1]. `cargo rustc` is incompatible with virtual manifests, so the CI needs to use cargo build instead. However, passing `RUSTFLAGS="-D warnings"` via the environment would propagate to all dependencies, and some of them currently fail to build under ``-D warnings` due to issues like [0]: ``` error: creating a mutable reference to mutable static --> src/temp.rs:97:5 | 97 | DIRS.pop() | ^^^^^^^^^^ mutable reference to mutable static ``` To resolve this, apply ``-D warnings` only to the `cargo clippy` commands (which apply to our workspace only) and avoid enforcing it for the entire cargo build. [0]: https://github.com/cloud-hypervisor/cloud-hypervisor/actions/runs/19962283528/job/57245376263?pr=7525 [1]: cloud-hypervisor#7525 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

Since PR #7525 (Dec 2025)[0], Cloud Hypervisor uses a virtual Cargo manifest and the main package was moved to the `./cloud-hypervisor` subdirectory. This change is effective since v50. As our v49-based CHV version backported these changes already, we need to adapt the Nix build of CHV. [0] cloud-hypervisor/cloud-hypervisor#7525

Since PR #7525 (Dec 2025)[0], Cloud Hypervisor uses a virtual Cargo manifest and the main package was moved to the `./cloud-hypervisor` subdirectory. This change is effective since v50. As our v49-based CHV version backported these changes already, we need to adapt the Nix build of CHV. [0] cloud-hypervisor/cloud-hypervisor#7525 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

Since PR #7525 (Dec 2025)[0], Cloud Hypervisor uses a virtual Cargo manifest and the main package was moved to the `./cloud-hypervisor` subdirectory. This change is effective since v50. Since we updated our Cloud Hypervisor to v50 [1], we need to adjust that here. [0] cloud-hypervisor/cloud-hypervisor#7525 [1] cyberus-technology/cloud-hypervisor#60 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

Since PR #7525 (Dec 2025)[0], Cloud Hypervisor uses a virtual Cargo manifest and the main package was moved to the `./cloud-hypervisor` subdirectory. This change is effective since v50, which we just upgraded to [1]. [0] cloud-hypervisor/cloud-hypervisor#7525 [1] cyberus-technology/cloud-hypervisor#60 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

Since PR #7525 (Dec 2025)[0], Cloud Hypervisor uses a virtual Cargo manifest and the main package was moved to the `./cloud-hypervisor` subdirectory. This change is effective since v50, which we just upgraded our Cloud Hypervisor patchset to [1]. [0] cloud-hypervisor/cloud-hypervisor#7525 [1] cyberus-technology/cloud-hypervisor#60 Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

phip1611 force-pushed the workspace branch from 38c1f3e to 4032601 Compare November 27, 2025 15:25

phip1611 commented Nov 27, 2025

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phip1611 force-pushed the workspace branch from a6d02b9 to 272f8aa Compare November 27, 2025 15:45

phip1611 force-pushed the workspace branch 2 times, most recently from 4d0b9d2 to 544c9ab Compare November 27, 2025 18:48

phip1611 marked this pull request as ready for review November 27, 2025 18:48

phip1611 requested a review from a team as a code owner November 27, 2025 18:48

phip1611 force-pushed the workspace branch from 544c9ab to 23eeab4 Compare November 27, 2025 18:56

phip1611 mentioned this pull request Nov 27, 2025

Code Quality: Lints, Developer Experience & Technical Debt [Tracking Issue] #7489

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phip1611 force-pushed the workspace branch 5 times, most recently from 378de4b to 0259156 Compare November 28, 2025 08:05

phip1611 force-pushed the workspace branch 4 times, most recently from 796c055 to bc4a2bd Compare November 28, 2025 08:15

phip1611 self-assigned this Dec 2, 2025

phip1611 force-pushed the workspace branch from bc4a2bd to b8f4a50 Compare December 4, 2025 12:33

alyssais reviewed Dec 4, 2025

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phip1611 force-pushed the workspace branch 5 times, most recently from 7615b35 to cc3bd62 Compare December 5, 2025 12:00

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phip1611 added 6 commits December 8, 2025 15:43

test_infra: Adapt to workspace + make code more robust

76c2631

Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

docs: adjust contributing.md: fix missing --all

d294c73

Unrelated but necessary to also always format code for all architectures and all features. Signed-off-by: Philipp Schuster <[email protected]> On-behalf-of: SAP [email protected]

phip1611 force-pushed the workspace branch from d1cb0a9 to 249e7fa Compare December 8, 2025 14:43

phip1611 mentioned this pull request Dec 8, 2025

[DON'T MERGE] gardenlinux-v49 cyberus-technology/cloud-hypervisor#40

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rbradford added this pull request to the merge queue Dec 9, 2025

Merged via the queue into cloud-hypervisor:main with commit 0be7d1b Dec 9, 2025
48 of 49 checks passed

phip1611 deleted the workspace branch December 9, 2025 19:22

phip1611 mentioned this pull request Dec 17, 2025

flake/chv: bump cloud-hypervisor-src + adapt to new crate structure cyberus-technology/libvirt-tests#95

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