Treat workspace members with an intermediate pyproject.toml as standalone

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

@@ -53,10 +53,22 @@ impl LoweredRequirement {
         editable: bool,
         credentials_cache: &'data CredentialsCache,
     ) -> impl Iterator<Item = Result<Self, LoweringError>> + use<'data> + 'data {
+        // Handle the case where a `pyproject.toml` sits between a member and its workspace root.
+        // This unintentionally supported case regressed when adding workspace caching, which
+        // memorizes which projects are workspace members without traversing upwards, ignoring the
+        // `pyproject.toml` in the middle. Before caching, workspace discovery for this project
+        // starting from the project itself would terminate at the intermediate `pyroject.toml` and
+        // treat it as standalone project, which this hack restores.
+        // <https://github.com/astral-sh/uv/issues/19916>
+        let treat_as_standalone_project =
+            has_intermediate_pyproject(workspace.install_path(), project_dir);
+
         // Identify the source from the `tool.uv.sources` table.
         let (sources, origin) = if let Some(source) = project_sources.get(&requirement.name) {
             (Some(source), RequirementOrigin::Project)
-        } else if let Some(source) = workspace.sources().get(&requirement.name) {
+        } else if !treat_as_standalone_project
+            && let Some(source) = workspace.sources().get(&requirement.name)
+        {
             (Some(source), RequirementOrigin::Workspace)
         } else {
             (None, RequirementOrigin::Project)
@@ -86,7 +98,7 @@ impl LoweredRequirement {
         });
 
         // If you use a package that's part of the workspace...
-        if workspace.packages().contains_key(&requirement.name) {
+        if !treat_as_standalone_project && workspace.packages().contains_key(&requirement.name) {
             // And it's not a recursive self-inclusion (extras that activate other extras), e.g.
             // `framework[machine_learning]` depends on `framework[cuda]`.
             if project_name.is_none_or(|project_name| *project_name != requirement.name) {
@@ -566,6 +578,24 @@ impl LoweredRequirement {
     }
 }
 
+/// Returns `true` when a `pyproject.toml` sits between the member project directory and the
+/// workspace root.
+fn has_intermediate_pyproject(workspace_root: &Path, project_dir: &Path) -> bool {
+    if project_dir == workspace_root {
+        return false;
+    }
+
+    let Ok(_) = project_dir.strip_prefix(workspace_root) else {
+        return false;
+    };
+
+    project_dir
+        .ancestors()
+        .skip(1)
+        .take_while(|ancestor| *ancestor != workspace_root)
+        .any(|ancestor| ancestor.join("pyproject.toml").is_file())
+}
+
 /// An error parsing and merging `tool.uv.sources` with
 /// `project.{dependencies,optional-dependencies}`.
 #[derive(Debug, Error)]

crates/uv/tests/lock/lock.rs

@@ -10228,6 +10228,180 @@ fn lock_no_workspace_source() -> Result<()> {
     Ok(())
 }
 
+/// Lock a project-valued workspace root nested below another project.
+#[test]
+fn lock_no_workspace_source_nested_project() -> Result<()> {
+    let context = uv_test::test_context!("3.12");
+
+    let parent = context.temp_dir.child("parent");
+    parent.child("pyproject.toml").write_str(
+        r#"
+        [project]
+        name = "parent"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = []
+        "#,
+    )?;
+
+    let workspace = parent.child("workspace");
+    workspace.child("pyproject.toml").write_str(
+        r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["child"]
+
+        [tool.uv.workspace]
+        members = ["child"]
+        "#,
+    )?;
+
+    let child = workspace.child("child");
+    fs_err::create_dir_all(&child)?;
+    child.child("pyproject.toml").write_str(
+        r#"
+        [project]
+        name = "child"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = []
+
+        [build-system]
+        requires = ["uv_build>=0.7,<10000"]
+        build-backend = "uv_build"
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.lock().current_dir(&workspace), @"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+
+    ----- stderr -----
+    Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
+      × Failed to build `project @ file://[TEMP_DIR]/parent/workspace`
+      ├─▶ Failed to parse entry: `child`
+      ╰─▶ `child` is included as a workspace member, but is missing an entry in `tool.uv.sources` (e.g., `child = { workspace = true }`)
+    ");
+
+    Ok(())
+}
+
+/// Regression test for <https://github.com/astral-sh/uv/issues/19916>.
+///
+/// Lock a workspace with a member that also supports standalone installation via platform-specific
+/// path sources.
+#[test]
+fn lock_workspace_member_with_standalone_path_source() -> Result<()> {
+    let context = uv_test::test_context!("3.12");
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [tool.uv.workspace]
+        members = ["root/app", "root/lib"]
+
+        [tool.uv.sources]
+        lib = { workspace = true }
+        "#,
+    )?;
+
+    let root = context.temp_dir.child("root");
+    root.child("pyproject.toml").write_str(
+        r#"
+        [project]
+        name = "root"
+        version = "0.1.0"
+
+        [tool.uv.sources]
+        lib = { path = "lib" }
+        "#,
+    )?;
+
+    root.child("app").child("pyproject.toml").write_str(
+        r#"
+        [project]
+        name = "app"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["lib"]
+
+        [tool.uv.sources]
+        lib = [
+            { path = "../lib", editable = true, marker = "sys_platform == 'darwin'" },
+            { path = "../lib", editable = true, marker = "sys_platform != 'darwin'" },
+        ]
+        "#,
+    )?;
+
+    root.child("lib").child("pyproject.toml").write_str(
+        r#"
+        [project]
+        name = "lib"
+        version = "0.1.0"
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.lock(), @"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 2 packages in [TIME]
+    ");
+
+    let lock = context.read("uv.lock");
+
+    insta::with_settings!({
+        filters => context.filters(),
+    }, {
+        assert_snapshot!(
+            lock, @r#"
+        version = 1
+        revision = 3
+        requires-python = ">=3.12"
+        resolution-markers = [
+            "sys_platform == 'darwin'",
+            "sys_platform != 'darwin'",
+        ]
+
+        [options]
+        exclude-newer = "2024-03-25T00:00:00Z"
+
+        [manifest]
+        members = [
+            "app",
+            "lib",
+        ]
+
+        [[package]]
+        name = "app"
+        version = "0.1.0"
+        source = { virtual = "root/app" }
+        dependencies = [
+            { name = "lib" },
+        ]
+
+        [package.metadata]
+        requires-dist = [
+            { name = "lib", marker = "sys_platform != 'darwin'", editable = "root/lib" },
+            { name = "lib", marker = "sys_platform == 'darwin'", editable = "root/lib" },
+        ]
+
+        [[package]]
+        name = "lib"
+        version = "0.1.0"
+        source = { editable = "root/lib" }
+        "#
+        );
+    });
+
+    Ok(())
+}
+
 /// Lock a workspace with a member that's a peer to the root.
 #[test]
 fn lock_peer_member() -> Result<()> {