Avoid trailing slash when deserializing from lockfile (#9848)

## Summary

Very tricky problem whereby `workspace_root.join(path)` returns the
workspace root with a trailing slash if `path` is empty... This caused
us to accidentally _include_ excluded members during workspace
discovery, since (e.g.) `packages/seeds` doesn't match
`packages/seeds/`.

Closes
https://github.com/astral-sh/uv/issues/9832#issuecomment-2539121761.

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

@@ -1682,10 +1682,11 @@ impl Package {
                     Source::Path(path) => {
                         let filename: WheelFilename =
                             self.wheels[best_wheel_index].filename.clone();
+                        let install_path = absolute_path(workspace_root, path)?;
                         let path_dist = PathBuiltDist {
                             filename,
-                            url: verbatim_url(workspace_root.join(path), &self.id)?,
-                            install_path: workspace_root.join(path),
+                            url: verbatim_url(&install_path, &self.id)?,
+                            install_path: absolute_path(workspace_root, path)?,
                         };
                         let built_dist = BuiltDist::Path(path_dist);
                         Ok(Dist::Built(built_dist))
@@ -1780,40 +1781,44 @@ impl Package {
                 let DistExtension::Source(ext) = DistExtension::from_path(path)? else {
                     return Ok(None);
                 };
+                let install_path = absolute_path(workspace_root, path)?;
                 let path_dist = PathSourceDist {
                     name: self.id.name.clone(),
                     version: Some(self.id.version.clone()),
-                    url: verbatim_url(workspace_root.join(path), &self.id)?,
-                    install_path: workspace_root.join(path),
+                    url: verbatim_url(&install_path, &self.id)?,
+                    install_path,
                     ext,
                 };
                 uv_distribution_types::SourceDist::Path(path_dist)
             }
             Source::Directory(path) => {
+                let install_path = absolute_path(workspace_root, path)?;
                 let dir_dist = DirectorySourceDist {
                     name: self.id.name.clone(),
-                    url: verbatim_url(workspace_root.join(path), &self.id)?,
-                    install_path: workspace_root.join(path),
+                    url: verbatim_url(&install_path, &self.id)?,
+                    install_path,
                     editable: false,
                     r#virtual: false,
                 };
                 uv_distribution_types::SourceDist::Directory(dir_dist)
             }
             Source::Editable(path) => {
+                let install_path = absolute_path(workspace_root, path)?;
                 let dir_dist = DirectorySourceDist {
                     name: self.id.name.clone(),
-                    url: verbatim_url(workspace_root.join(path), &self.id)?,
-                    install_path: workspace_root.join(path),
+                    url: verbatim_url(&install_path, &self.id)?,
+                    install_path,
                     editable: true,
                     r#virtual: false,
                 };
                 uv_distribution_types::SourceDist::Directory(dir_dist)
             }
             Source::Virtual(path) => {
+                let install_path = absolute_path(workspace_root, path)?;
                 let dir_dist = DirectorySourceDist {
                     name: self.id.name.clone(),
-                    url: verbatim_url(workspace_root.join(path), &self.id)?,
-                    install_path: workspace_root.join(path),
+                    url: verbatim_url(&install_path, &self.id)?,
+                    install_path,
                     editable: false,
                     r#virtual: true,
                 };
@@ -2181,15 +2186,21 @@ impl Package {
 }
 
 /// Attempts to construct a `VerbatimUrl` from the given `Path`.
-fn verbatim_url(path: PathBuf, id: &PackageId) -> Result<VerbatimUrl, LockError> {
+fn verbatim_url(path: &Path, id: &PackageId) -> Result<VerbatimUrl, LockError> {
     let url = VerbatimUrl::from_absolute_path(path).map_err(|err| LockErrorKind::VerbatimUrl {
         id: id.clone(),
         err,
     })?;
-
     Ok(url)
 }
 
+/// Attempts to construct an absolute path from the given `Path`.
+fn absolute_path(workspace_root: &Path, path: &Path) -> Result<PathBuf, LockError> {
+    let path = uv_fs::normalize_absolute_path(&workspace_root.join(path))
+        .map_err(LockErrorKind::AbsolutePath)?;
+    Ok(path)
+}
+
 #[derive(Clone, Debug, serde::Deserialize)]
 #[serde(rename_all = "kebab-case")]
 struct PackageWire {
@@ -4059,6 +4070,13 @@ enum LockErrorKind {
         #[source]
         std::io::Error,
     ),
+    /// An error that occurs when converting a lockfile path from relative to absolute.
+    #[error("Could not compute absolute path from workspace root and lockfile path")]
+    AbsolutePath(
+        /// The inner error we forward.
+        #[source]
+        std::io::Error,
+    ),
     /// An error that occurs when an ambiguous `package.dependency` is
     /// missing a `version` field.
     #[error(

crates/uv/tests/it/lock.rs

@@ -6242,6 +6242,111 @@ fn lock_exclusion() -> Result<()> {
     Ok(())
 }
 
+/// See: <https://github.com/astral-sh/uv/issues/9832#issuecomment-2539121761>
+#[test]
+fn lock_relative_lock_deserialization() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "project"
+        requires-python = ">=3.12"
+        dependencies = ["member"]
+        dynamic = ["version"]
+
+        [tool.uv.sources]
+        member = { workspace = true }
+
+        [tool.uv.workspace]
+        members = ["packages/*"]
+        exclude = ["packages/child"]
+
+        [build-system]
+        requires = ["setuptools>=42"]
+        build-backend = "setuptools.build_meta"
+        "#,
+    )?;
+
+    let packages = context.temp_dir.child("packages");
+
+    let member = packages.child("member");
+    member.child("pyproject.toml").write_str(
+        r#"
+        [project]
+        name = "member"
+        requires-python = ">=3.12"
+        dependencies = []
+        dynamic = ["version"]
+
+        [build-system]
+        requires = ["setuptools>=42"]
+        build-backend = "setuptools.build_meta"
+        "#,
+    )?;
+
+    let child = packages.child("child");
+    child.child("pyproject.toml").write_str(
+        r#"
+        [project]
+        name = "child"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["member"]
+
+        [build-system]
+        requires = ["setuptools>=42"]
+        build-backend = "setuptools.build_meta"
+
+        [tool.uv.sources]
+        member = { workspace = true }
+        "#,
+    )?;
+
+    // Add an arbitrary lockfile, to ensure that we attempt to validate it, which is necessary to
+    // trigger the bug.
+    child.child("uv.lock").write_str(
+        r#"
+        version = 1
+        requires-python = ">=3.12"
+
+        [options]
+        exclude-newer = "2024-03-25T00:00:00Z"
+
+        [[package]]
+        name = "child"
+        version = "0.1.0"
+        source = { editable = "." }
+        dependencies = [
+            { name = "project" },
+        ]
+
+        [package.metadata]
+        requires-dist = [{ name = "project", directory = "../" }]
+
+        [[package]]
+        name = "project"
+        version = "0.1.0"
+        source = { directory = "../" }
+    "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.lock().current_dir(&child), @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+    error: Failed to generate package metadata for `child==0.1.0 @ editable+.`
+      Caused by: Failed to parse entry: `member`
+      Caused by: `member` references a workspace in `tool.uv.sources` (e.g., `member = { workspace = true }`), but is not a workspace member
+    "###);
+
+    Ok(())
+}
+
 /// Lock a workspace member with a non-workspace source.
 #[test]
 fn lock_non_workspace_source() -> Result<()> {