Allow uv sync --package without copying member pyproject.toml (#6943

)

## Summary

Closes #6935.

crates/uv-resolver/src/lock/mod.rs

@@ -35,7 +35,7 @@ use uv_fs::{relative_to, PortablePath, PortablePathBuf};
 use uv_git::{GitReference, GitSha, RepositoryReference, ResolvedRepositoryReference};
 use uv_normalize::{ExtraName, GroupName, PackageName};
 use uv_types::BuildContext;
-use uv_workspace::{VirtualProject, Workspace};
+use uv_workspace::{InstallTarget, Workspace};
 
 pub use crate::lock::requirements_txt::RequirementsTxtExport;
 pub use crate::lock::tree::TreeDisplay;
@@ -426,7 +426,7 @@ impl Lock {
     /// Convert the [`Lock`] to a [`Resolution`] using the given marker environment, tags, and root.
     pub fn to_resolution(
         &self,
-        project: &VirtualProject,
+        project: InstallTarget<'_>,
         marker_env: &ResolverMarkerEnvironment,
         tags: &Tags,
         extras: &ExtrasSpecification,
@@ -439,8 +439,12 @@ impl Lock {
         for root_name in project.packages() {
             let root = self
                 .find_by_name(root_name)
-                .expect("found too many packages matching root")
-                .expect("could not find root");
+                .map_err(|_| LockErrorKind::MultipleRootPackages {
+                    name: root_name.clone(),
+                })?
+                .ok_or_else(|| LockErrorKind::MissingRootPackage {
+                    name: root_name.clone(),
+                })?;
 
             // Add the base package.
             queue.push_back((root, None));
@@ -466,10 +470,15 @@ impl Lock {
         for group in dev {
             for dependency in project.group(group) {
                 if dependency.marker.evaluate(marker_env, &[]) {
+                    let root_name = &dependency.name;
                     let root = self
-                        .find_by_markers(&dependency.name, marker_env)
-                        .expect("found too many packages matching root")
-                        .expect("could not find root");
+                        .find_by_markers(root_name, marker_env)
+                        .map_err(|_| LockErrorKind::MultipleRootPackages {
+                            name: root_name.clone(),
+                        })?
+                        .ok_or_else(|| LockErrorKind::MissingRootPackage {
+                            name: root_name.clone(),
+                        })?;
 
                     // Add the base package.
                     queue.push_back((root, None));
@@ -3605,6 +3614,19 @@ enum LockErrorKind {
     /// An error that occurs when converting a URL to a path
     #[error("failed to convert URL to path")]
     UrlToPath,
+    /// An error that occurs when multiple packages with the same
+    /// name were found when identifying the root packages.
+    #[error("found multiple packages matching `{name}`")]
+    MultipleRootPackages {
+        /// The ID of the package.
+        name: PackageName,
+    },
+    /// An error that occurs when a root package can't be found.
+    #[error("could not find root package `{name}`")]
+    MissingRootPackage {
+        /// The ID of the package.
+        name: PackageName,
+    },
 }
 
 /// An error that occurs when a source string could not be parsed.

crates/uv-workspace/src/lib.rs

@@ -1,6 +1,6 @@
 pub use workspace::{
-    check_nested_workspaces, DiscoveryOptions, MemberDiscovery, ProjectWorkspace, VirtualProject,
-    Workspace, WorkspaceError, WorkspaceMember,
+    check_nested_workspaces, DiscoveryOptions, InstallTarget, MemberDiscovery, ProjectWorkspace,
+    VirtualProject, Workspace, WorkspaceError, WorkspaceMember,
 };
 
 pub mod pyproject;

crates/uv-workspace/src/workspace.rs

@@ -1219,7 +1219,7 @@ fn is_included_in_workspace(
     Ok(false)
 }
 
-/// A project that can be synced.
+/// A project that can be discovered.
 ///
 /// The project could be a package within a workspace, a real workspace root, or a (legacy)
 /// non-project workspace root, which can define its own dev dependencies.
@@ -1311,13 +1311,13 @@ impl VirtualProject {
     #[must_use]
     pub fn with_pyproject_toml(self, pyproject_toml: PyProjectToml) -> Option<Self> {
         match self {
-            VirtualProject::Project(project) => Some(VirtualProject::Project(
-                project.with_pyproject_toml(pyproject_toml)?,
-            )),
-            VirtualProject::NonProject(workspace) => {
+            Self::Project(project) => {
+                Some(Self::Project(project.with_pyproject_toml(pyproject_toml)?))
+            }
+            Self::NonProject(workspace) => {
                 // If this is a non-project workspace root, then by definition the root isn't a
                 // member, so we can just update the top-level `pyproject.toml`.
-                Some(VirtualProject::NonProject(Workspace {
+                Some(Self::NonProject(Workspace {
                     pyproject_toml,
                     ..workspace.clone()
                 }))
@@ -1328,38 +1328,77 @@ impl VirtualProject {
     /// Return the root of the project.
     pub fn root(&self) -> &Path {
         match self {
-            VirtualProject::Project(project) => project.project_root(),
-            VirtualProject::NonProject(workspace) => workspace.install_path(),
+            Self::Project(project) => project.project_root(),
+            Self::NonProject(workspace) => workspace.install_path(),
         }
     }
 
     /// Return the [`PyProjectToml`] of the project.
     pub fn pyproject_toml(&self) -> &PyProjectToml {
         match self {
-            VirtualProject::Project(project) => project.current_project().pyproject_toml(),
-            VirtualProject::NonProject(workspace) => &workspace.pyproject_toml,
+            Self::Project(project) => project.current_project().pyproject_toml(),
+            Self::NonProject(workspace) => &workspace.pyproject_toml,
         }
     }
 
     /// Return the [`Workspace`] of the project.
     pub fn workspace(&self) -> &Workspace {
         match self {
-            VirtualProject::Project(project) => project.workspace(),
-            VirtualProject::NonProject(workspace) => workspace,
+            Self::Project(project) => project.workspace(),
+            Self::NonProject(workspace) => workspace,
+        }
+    }
+
+    /// Return the [`PackageName`] of the project, if available.
+    pub fn project_name(&self) -> Option<&PackageName> {
+        match self {
+            VirtualProject::Project(project) => Some(project.project_name()),
+            VirtualProject::NonProject(_) => None,
         }
     }
 
-    /// Return the [`PackageName`] of the project.
+    /// Returns `true` if the project is a virtual workspace root.
+    pub fn is_non_project(&self) -> bool {
+        matches!(self, VirtualProject::NonProject(_))
+    }
+}
+
+/// A target that can be installed.
+#[derive(Debug, Clone, Copy)]
+pub enum InstallTarget<'env> {
+    /// A project (which could be a workspace root or member).
+    Project(&'env ProjectWorkspace),
+    /// A (legacy) non-project workspace root.
+    NonProject(&'env Workspace),
+    /// A frozen member within a [`Workspace`].
+    FrozenMember(&'env Workspace, &'env PackageName),
+}
+
+impl<'env> InstallTarget<'env> {
+    /// Create an [`InstallTarget`] for a frozen member within a workspace.
+    pub fn frozen_member(project: &'env VirtualProject, package_name: &'env PackageName) -> Self {
+        Self::FrozenMember(project.workspace(), package_name)
+    }
+
+    /// Return the [`Workspace`] of the target.
+    pub fn workspace(&self) -> &Workspace {
+        match self {
+            Self::Project(project) => project.workspace(),
+            Self::NonProject(workspace) => workspace,
+            Self::FrozenMember(workspace, _) => workspace,
+        }
+    }
+
+    /// Return the [`PackageName`] of the target.
     pub fn packages(&self) -> impl Iterator<Item = &PackageName> {
         match self {
-            VirtualProject::Project(project) => {
-                Either::Left(std::iter::once(project.project_name()))
-            }
-            VirtualProject::NonProject(workspace) => Either::Right(workspace.packages().keys()),
+            Self::Project(project) => Either::Left(std::iter::once(project.project_name())),
+            Self::NonProject(workspace) => Either::Right(workspace.packages().keys()),
+            Self::FrozenMember(_, package_name) => Either::Left(std::iter::once(*package_name)),
         }
     }
 
-    /// Return the [`VirtualProject`] dependencies for the given group name.
+    /// Return the [`InstallTarget`] 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
@@ -1369,11 +1408,11 @@ impl VirtualProject {
         name: &GroupName,
     ) -> impl Iterator<Item = &pep508_rs::Requirement<VerbatimParsedUrl>> {
         match self {
-            VirtualProject::Project(_) => {
+            Self::Project(_) | Self::FrozenMember(..) => {
                 // For projects, dev dependencies are attached to the members.
                 Either::Left(std::iter::empty())
             }
-            VirtualProject::NonProject(workspace) => {
+            Self::NonProject(workspace) => {
                 // For non-projects, we might have dev dependencies that are attached to the
                 // workspace root (which isn't a member).
                 if name == &*DEV_DEPENDENCIES {
@@ -1395,17 +1434,22 @@ impl VirtualProject {
         }
     }
 
-    /// Return the [`PackageName`] of the project, if available.
+    /// Return the [`PackageName`] of the target, if available.
     pub fn project_name(&self) -> Option<&PackageName> {
         match self {
-            VirtualProject::Project(project) => Some(project.project_name()),
-            VirtualProject::NonProject(_) => None,
+            Self::Project(project) => Some(project.project_name()),
+            Self::NonProject(_) => None,
+            Self::FrozenMember(_, package_name) => Some(package_name),
         }
     }
+}
 
-    /// Returns `true` if the project is a virtual workspace root.
-    pub fn is_non_project(&self) -> bool {
-        matches!(self, VirtualProject::NonProject(_))
+impl<'env> From<&'env VirtualProject> for InstallTarget<'env> {
+    fn from(project: &'env VirtualProject) -> Self {
+        match project {
+            VirtualProject::Project(project) => Self::Project(project),
+            VirtualProject::NonProject(workspace) => Self::NonProject(workspace),
+        }
     }
 }
 

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

@@ -30,7 +30,7 @@ use uv_types::{BuildIsolation, HashStrategy};
 use uv_warnings::warn_user_once;
 use uv_workspace::pyproject::{DependencyType, Source, SourceError};
 use uv_workspace::pyproject_mut::{ArrayEdit, DependencyTarget, PyProjectTomlMut};
-use uv_workspace::{DiscoveryOptions, VirtualProject, Workspace};
+use uv_workspace::{DiscoveryOptions, InstallTarget, VirtualProject, Workspace};
 
 use crate::commands::pip::loggers::{
     DefaultInstallLogger, DefaultResolveLogger, SummaryResolveLogger,
@@ -668,7 +668,7 @@ pub(crate) async fn add(
     let install_options = InstallOptions::default();
 
     if let Err(err) = project::sync::do_sync(
-        &project,
+        InstallTarget::from(&project),
         &venv,
         &lock,
         &extras,

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

@@ -13,7 +13,7 @@ use uv_scripts::Pep723Script;
 use uv_warnings::{warn_user, warn_user_once};
 use uv_workspace::pyproject::DependencyType;
 use uv_workspace::pyproject_mut::{DependencyTarget, PyProjectTomlMut};
-use uv_workspace::{DiscoveryOptions, VirtualProject, Workspace};
+use uv_workspace::{DiscoveryOptions, InstallTarget, VirtualProject, Workspace};
 
 use crate::commands::pip::loggers::{DefaultInstallLogger, DefaultResolveLogger};
 use crate::commands::pip::operations::Modifications;
@@ -196,7 +196,7 @@ pub(crate) async fn remove(
     let state = SharedState::default();
 
     project::sync::do_sync(
-        &project,
+        InstallTarget::from(&project),
         &venv,
         &lock,
         &extras,

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

@@ -26,7 +26,7 @@ use uv_python::{
 use uv_requirements::{RequirementsSource, RequirementsSpecification};
 use uv_scripts::Pep723Script;
 use uv_warnings::warn_user;
-use uv_workspace::{DiscoveryOptions, VirtualProject, Workspace, WorkspaceError};
+use uv_workspace::{DiscoveryOptions, InstallTarget, VirtualProject, Workspace, WorkspaceError};
 
 use crate::commands::pip::loggers::{
     DefaultInstallLogger, DefaultResolveLogger, SummaryInstallLogger, SummaryResolveLogger,
@@ -432,7 +432,7 @@ pub(crate) async fn run(
                     uv_resolver::ResolveError::NoSolution(err),
                 ))) => {
                     let report = miette::Report::msg(format!("{err}")).context(err.header());
-                    anstream::eprint!("{report:?}");
+                    eprint!("{report:?}");
                     return Ok(ExitStatus::Failure);
                 }
                 Err(err) => return Err(err.into()),
@@ -441,7 +441,7 @@ pub(crate) async fn run(
             let install_options = InstallOptions::default();
 
             project::sync::do_sync(
-                &project,
+                InstallTarget::from(&project),
                 &venv,
                 result.lock(),
                 &extras,