Support dev dependencies in virtual workspace roots (#5709)

## Summary

Closes https://github.com/astral-sh/uv/issues/5650.

crates/uv-distribution/src/lib.rs

@@ -2,7 +2,7 @@ pub use distribution_database::{DistributionDatabase, HttpArchivePointer, LocalA
 pub use download::LocalWheel;
 pub use error::Error;
 pub use index::{BuiltWheelIndex, RegistryWheelIndex};
-pub use metadata::{ArchiveMetadata, Metadata, RequiresDist, DEV_DEPENDENCIES};
+pub use metadata::{ArchiveMetadata, Metadata, RequiresDist};
 pub use reporter::Reporter;
 
 mod archive;

crates/uv-distribution/src/metadata/mod.rs

@@ -4,7 +4,7 @@ use std::path::Path;
 use thiserror::Error;
 
 use crate::metadata::lowering::LoweringError;
-pub use crate::metadata::requires_dist::{RequiresDist, DEV_DEPENDENCIES};
+pub use crate::metadata::requires_dist::RequiresDist;
 use pep440_rs::{Version, VersionSpecifiers};
 use pypi_types::{HashDigest, Metadata23};
 use uv_configuration::PreviewMode;

crates/uv-distribution/src/metadata/requires_dist.rs

@@ -1,22 +1,14 @@
 use std::collections::BTreeMap;
 use std::path::Path;
-use std::sync::LazyLock;
 
 use uv_configuration::PreviewMode;
-use uv_normalize::{ExtraName, GroupName, PackageName};
+use uv_normalize::{ExtraName, GroupName, PackageName, DEV_DEPENDENCIES};
 use uv_workspace::{DiscoveryOptions, ProjectWorkspace};
 
 use crate::metadata::lowering::lower_requirement;
 use crate::metadata::MetadataError;
 use crate::Metadata;
 
-/// The name of the global `dev-dependencies` group.
-///
-/// Internally, we model dependency groups as a generic concept; but externally, we only expose the
-/// `dev-dependencies` group.
-pub static DEV_DEPENDENCIES: LazyLock<GroupName> =
-    LazyLock::new(|| GroupName::new("dev".to_string()).unwrap());
-
 #[derive(Debug, Clone)]
 pub struct RequiresDist {
     pub name: PackageName,

crates/uv-normalize/src/group_name.rs

@@ -1,6 +1,7 @@
 use std::fmt;
 use std::fmt::{Display, Formatter};
 use std::str::FromStr;
+use std::sync::LazyLock;
 
 use serde::{Deserialize, Deserializer, Serialize};
 
@@ -51,3 +52,10 @@ impl AsRef<str> for GroupName {
         &self.0
     }
 }
+
+/// The name of the global `dev-dependencies` group.
+///
+/// Internally, we model dependency groups as a generic concept; but externally, we only expose the
+/// `dev-dependencies` group.
+pub static DEV_DEPENDENCIES: LazyLock<GroupName> =
+    LazyLock::new(|| GroupName::new("dev".to_string()).unwrap());

crates/uv-normalize/src/lib.rs

@@ -2,7 +2,7 @@ use std::error::Error;
 use std::fmt::{Display, Formatter};
 
 pub use extra_name::ExtraName;
-pub use group_name::GroupName;
+pub use group_name::{GroupName, DEV_DEPENDENCIES};
 pub use package_name::PackageName;
 
 mod extra_name;

crates/uv-resolver/src/lock.rs

@@ -420,6 +420,18 @@ impl Lock {
             }
         }
 
+        // Add any dependency groups that are exclusive to the workspace root (e.g., dev
+        // dependencies in virtual workspaces).
+        for group in dev {
+            for dependency in project.group(group) {
+                let root = self
+                    .find_by_name(dependency)
+                    .expect("found too many distributions matching root")
+                    .expect("could not find root");
+                queue.push_back((root, None));
+            }
+        }
+
         let mut map = BTreeMap::default();
         let mut hashes = BTreeMap::default();
         while let Some((dist, extra)) = queue.pop_front() {

crates/uv-workspace/src/workspace.rs

@@ -11,7 +11,7 @@ use tracing::{debug, trace, warn};
 use pep508_rs::{RequirementOrigin, VerbatimUrl};
 use pypi_types::{Requirement, RequirementSource};
 use uv_fs::{absolutize_path, normalize_path, relative_to, Simplified};
-use uv_normalize::PackageName;
+use uv_normalize::{GroupName, PackageName, DEV_DEPENDENCIES};
 use uv_warnings::warn_user;
 
 use crate::pyproject::{Project, PyProjectToml, Source, ToolUvWorkspace};
@@ -239,53 +239,94 @@ impl Workspace {
         }
     }
 
-    /// Returns the set of requirements that include all packages in the workspace.
-    pub fn members_as_requirements(&self) -> Vec<Requirement> {
-        self.packages
+    pub fn is_virtual(&self) -> bool {
+        !self
+            .packages
             .values()
-            .filter_map(|member| {
-                let project = member.pyproject_toml.project.as_ref()?;
-                // Extract the extras available in the project.
-                let extras = project
-                    .optional_dependencies
-                    .as_ref()
-                    .map(|optional_dependencies| {
-                        // It's a `BTreeMap` so the keys are sorted.
-                        optional_dependencies
-                            .iter()
-                            .filter_map(|(name, dependencies)| {
-                                if dependencies.is_empty() {
-                                    None
-                                } else {
-                                    Some(name)
-                                }
-                            })
-                            .cloned()
-                            .collect::<Vec<_>>()
-                    })
-                    .unwrap_or_default();
+            .any(|member| *member.root() == self.install_path)
+    }
 
-                let url = VerbatimUrl::from_path(&member.root)
-                    .expect("path is valid URL")
-                    .with_given(member.root.to_string_lossy());
-                Some(Requirement {
-                    name: project.name.clone(),
-                    extras,
-                    marker: None,
-                    source: RequirementSource::Directory {
-                        install_path: member.root.clone(),
-                        lock_path: member
-                            .root
-                            .strip_prefix(&self.install_path)
-                            .expect("Project must be below workspace root")
-                            .to_path_buf(),
-                        editable: true,
-                        url,
-                    },
-                    origin: None,
+    /// Returns the set of requirements that include all packages in the workspace.
+    pub fn members_requirements(&self) -> impl Iterator<Item = Requirement> + '_ {
+        self.packages.values().filter_map(|member| {
+            let project = member.pyproject_toml.project.as_ref()?;
+            // Extract the extras available in the project.
+            let extras = project
+                .optional_dependencies
+                .as_ref()
+                .map(|optional_dependencies| {
+                    // It's a `BTreeMap` so the keys are sorted.
+                    optional_dependencies
+                        .iter()
+                        .filter_map(|(name, dependencies)| {
+                            if dependencies.is_empty() {
+                                None
+                            } else {
+                                Some(name)
+                            }
+                        })
+                        .cloned()
+                        .collect::<Vec<_>>()
                 })
+                .unwrap_or_default();
+
+            let url = VerbatimUrl::from_path(&member.root)
+                .expect("path is valid URL")
+                .with_given(member.root.to_string_lossy());
+            Some(Requirement {
+                name: project.name.clone(),
+                extras,
+                marker: None,
+                source: RequirementSource::Directory {
+                    install_path: member.root.clone(),
+                    lock_path: member
+                        .root
+                        .strip_prefix(&self.install_path)
+                        .expect("Project must be below workspace root")
+                        .to_path_buf(),
+                    editable: true,
+                    url,
+                },
+                origin: None,
             })
-            .collect()
+        })
+    }
+
+    /// Returns any requirements that are exclusive to the workspace root, i.e., not included in
+    /// any of the workspace members.
+    ///
+    /// For virtual workspaces, returns the dev dependencies in the workspace root, which are
+    /// the only dependencies that are not part of the workspace members.
+    ///
+    /// For non-virtual workspaces, returns an empty list.
+    pub fn root_requirements(&self) -> impl Iterator<Item = Requirement> + '_ {
+        if self
+            .packages
+            .values()
+            .any(|member| *member.root() == self.install_path)
+        {
+            // If the workspace is non-virtual, the root is a member, so we don't need to include
+            // any root-only requirements.
+            Either::Left(std::iter::empty())
+        } else {
+            // Otherwise, return the dev dependencies in the workspace root.
+            Either::Right(
+                self.pyproject_toml
+                    .tool
+                    .as_ref()
+                    .and_then(|tool| tool.uv.as_ref())
+                    .and_then(|uv| uv.dev_dependencies.as_ref())
+                    .into_iter()
+                    .flatten()
+                    .map(|requirement| {
+                        Requirement::from(
+                            requirement
+                                .clone()
+                                .with_origin(RequirementOrigin::Workspace),
+                        )
+                    }),
+            )
+        }
     }
 
     /// Returns the set of overrides for the workspace.
@@ -1255,6 +1296,39 @@ impl VirtualProject {
         }
     }
 
+    /// Return the [`VirtualProject`] dependencies for the given group name.
+    ///
+    /// Returns dependencies that apply to the workspace root, but not any of its members. As such,
+    /// only returns a non-empty iterator for virtual workspaces, which can include dev dependencies
+    /// on the virtual root.
+    pub fn group(&self, name: &GroupName) -> impl Iterator<Item = &PackageName> {
+        match self {
+            VirtualProject::Project(_) => {
+                // For non-virtual projects, dev dependencies are attached to the members.
+                Either::Left(std::iter::empty())
+            }
+            VirtualProject::Virtual(workspace) => {
+                // For virtual projects, we might have dev dependencies that are attached to the
+                // workspace root (which isn't a member).
+                if name == &*DEV_DEPENDENCIES {
+                    Either::Right(
+                        workspace
+                            .pyproject_toml
+                            .tool
+                            .as_ref()
+                            .and_then(|tool| tool.uv.as_ref())
+                            .and_then(|uv| uv.dev_dependencies.as_ref())
+                            .map(|dev| dev.iter().map(|req| &req.name))
+                            .into_iter()
+                            .flatten(),
+                    )
+                } else {
+                    Either::Left(std::iter::empty())
+                }
+            }
+        }
+    }
+
     /// Return the [`PackageName`] of the project, if it's not a virtual workspace.
     pub fn project_name(&self) -> Option<&PackageName> {
         match self {

crates/uv/src/commands/project/lock.rs

@@ -15,10 +15,9 @@ use uv_cache::Cache;
 use uv_client::{Connectivity, FlatIndexClient, RegistryClientBuilder};
 use uv_configuration::{Concurrency, ExtrasSpecification, PreviewMode, Reinstall, SetupPyStrategy};
 use uv_dispatch::BuildDispatch;
-use uv_distribution::DEV_DEPENDENCIES;
 use uv_fs::CWD;
 use uv_git::ResolvedRepositoryReference;
-use uv_normalize::PackageName;
+use uv_normalize::{PackageName, DEV_DEPENDENCIES};
 use uv_python::{Interpreter, PythonFetch, PythonPreference, PythonRequest};
 use uv_requirements::upgrade::{read_lock_requirements, LockedRequirements};
 use uv_resolver::{
@@ -228,8 +227,8 @@ async fn do_lock(
 
     // When locking, include the project itself (as editable).
     let requirements = workspace
-        .members_as_requirements()
-        .into_iter()
+        .members_requirements()
+        .chain(workspace.root_requirements())
         .map(UnresolvedRequirementSpecification::from)
         .collect::<Vec<_>>();
     let overrides = workspace

crates/uv/src/commands/project/sync.rs

@@ -7,10 +7,9 @@ use uv_configuration::{
     Concurrency, ExtrasSpecification, HashCheckingMode, PreviewMode, SetupPyStrategy,
 };
 use uv_dispatch::BuildDispatch;
-use uv_distribution::DEV_DEPENDENCIES;
 use uv_fs::CWD;
 use uv_installer::SitePackages;
-use uv_normalize::PackageName;
+use uv_normalize::{PackageName, DEV_DEPENDENCIES};
 use uv_python::{PythonEnvironment, PythonFetch, PythonPreference, PythonRequest};
 use uv_resolver::{FlatIndex, Lock};
 use uv_types::{BuildIsolation, HashStrategy};

crates/uv/tests/sync.rs

@@ -360,3 +360,79 @@ fn mixed_requires_python() -> Result<()> {
 
     Ok(())
 }
+
+/// Sync development dependencies in a virtual workspace root.
+#[test]
+fn virtual_workspace_dev_dependencies() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [tool.uv]
+        dev-dependencies = ["anyio>3"]
+
+        [tool.uv.workspace]
+        members = ["child"]
+        "#,
+    )?;
+
+    let src = context.temp_dir.child("src").child("albatross");
+    src.create_dir_all()?;
+
+    let init = src.child("__init__.py");
+    init.touch()?;
+
+    let child = context.temp_dir.child("child");
+    fs_err::create_dir_all(&child)?;
+
+    let pyproject_toml = child.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "child"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["iniconfig>1"]
+        "#,
+    )?;
+
+    let src = child.child("src").child("albatross");
+    src.create_dir_all()?;
+
+    let init = src.child("__init__.py");
+    init.touch()?;
+
+    // Syncing with `--no-dev` should omit `anyio`.
+    uv_snapshot!(context.filters(), context.sync().arg("--no-dev"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    warning: `uv sync` is experimental and may change without warning
+    Resolved 5 packages in [TIME]
+    Prepared 2 packages in [TIME]
+    Installed 2 packages in [TIME]
+     + child==0.1.0 (from file://[TEMP_DIR]/child)
+     + iniconfig==2.0.0
+    "###);
+
+    // Syncing without `--no-dev` should include `anyio`.
+    uv_snapshot!(context.filters(), context.sync(), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    warning: `uv sync` is experimental and may change without warning
+    Resolved 5 packages in [TIME]
+    Prepared 3 packages in [TIME]
+    Installed 3 packages in [TIME]
+     + anyio==4.3.0
+     + idna==3.6
+     + sniffio==1.3.1
+    "###);
+
+    Ok(())
+}