Fix root of uv tree when --package is used with circular dependencies (#15908)

Closes #15907

Best viewed with
https://github.com/astral-sh/uv/pull/15908/files?diff=unified&w=1

When `--package` is used, just use those as the roots rather than
calculating them. I'm not sure if there will be undesirable
side-effects, but it's the naive solution.

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

@@ -362,40 +362,58 @@ impl<'env> TreeDisplay<'env> {
 
         // Compute the list of roots.
         let roots = {
-            let mut edges = vec![];
+            // If specific packages were requested, use them as roots.
+            if !packages.is_empty() {
+                let mut roots = graph
+                    .node_indices()
+                    .filter(|index| {
+                        let Node::Package(package_id) = graph[*index] else {
+                            return false;
+                        };
+                        packages.contains(&package_id.name)
+                    })
+                    .collect::<Vec<_>>();
 
-            // Remove any cycles.
+                // Sort the roots.
-            let feedback_set: Vec<EdgeIndex> = petgraph::algo::greedy_feedback_arc_set(&graph)
+                roots.sort_by_key(|index| &graph[*index]);
-                .map(|e| e.id())
+
-                .collect();
+                roots
-            for edge_id in feedback_set {
+            } else {
-                if let Some((source, target)) = graph.edge_endpoints(edge_id) {
+                let mut edges = vec![];
-                    if let Some(weight) = graph.remove_edge(edge_id) {
+
-                        edges.push((source, target, weight));
+                // Remove any cycles.
+                let feedback_set: Vec<EdgeIndex> = petgraph::algo::greedy_feedback_arc_set(&graph)
+                    .map(|e| e.id())
+                    .collect();
+                for edge_id in feedback_set {
+                    if let Some((source, target)) = graph.edge_endpoints(edge_id) {
+                        if let Some(weight) = graph.remove_edge(edge_id) {
+                            edges.push((source, target, weight));
+                        }
                     }
                 }
+
+                // Find the root nodes: nodes with no incoming edges, or only an edge from the proxy.
+                let mut roots = graph
+                    .node_indices()
+                    .filter(|index| {
+                        graph
+                            .edges_directed(*index, Direction::Incoming)
+                            .next()
+                            .is_none()
+                    })
+                    .collect::<Vec<_>>();
+
+                // Sort the roots.
+                roots.sort_by_key(|index| &graph[*index]);
+
+                // Re-add the removed edges.
+                for (source, target, weight) in edges {
+                    graph.add_edge(source, target, weight);
+                }
+
+                roots
             }
-
-            // Find the root nodes: nodes with no incoming edges, or only an edge from the proxy.
-            let mut roots = graph
-                .node_indices()
-                .filter(|index| {
-                    graph
-                        .edges_directed(*index, Direction::Incoming)
-                        .next()
-                        .is_none()
-                })
-                .collect::<Vec<_>>();
-
-            // Sort the roots.
-            roots.sort_by_key(|index| &graph[*index]);
-
-            // Re-add the removed edges.
-            for (source, target, weight) in edges {
-                graph.add_edge(source, target, weight);
-            }
-
-            roots
         };
 
         Self {

crates/uv/tests/it/tree.rs

@@ -1703,3 +1703,99 @@ fn show_sizes() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn workspace_circular_dependencies() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    // Create workspace root
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [tool.uv.workspace]
+        members = ["packages/*"]
+    "#,
+    )?;
+
+    // Create package-a that depends on package-b
+    let package_a_dir = context.temp_dir.child("packages").child("package-a");
+    package_a_dir.create_dir_all()?;
+    let package_a_pyproject = package_a_dir.child("pyproject.toml");
+    package_a_pyproject.write_str(
+        r#"
+        [project]
+        name = "package-a"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["package-b"]
+
+        [tool.uv.sources]
+        package-b = { workspace = true }
+    "#,
+    )?;
+
+    // Create package-b that depends on package-a (circular dependency)
+    let package_b_dir = context.temp_dir.child("packages").child("package-b");
+    package_b_dir.create_dir_all()?;
+    let package_b_pyproject = package_b_dir.child("pyproject.toml");
+    package_b_pyproject.write_str(
+        r#"
+        [project]
+        name = "package-b"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["package-a"]
+
+        [tool.uv.sources]
+        package-a = { workspace = true }
+    "#,
+    )?;
+
+    // Test that package-a is at the root when requested
+    uv_snapshot!(context.filters(), context.tree().arg("--package").arg("package-a"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    package-a v0.1.0
+    └── package-b v0.1.0
+        └── package-a v0.1.0 (*)
+    (*) Package tree already displayed
+
+    ----- stderr -----
+    Resolved 2 packages in [TIME]
+    "###
+    );
+
+    // Test that package-b is at the root when requested
+    uv_snapshot!(context.filters(), context.tree().arg("--package").arg("package-b"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    package-b v0.1.0
+    └── package-a v0.1.0
+        └── package-b v0.1.0 (*)
+    (*) Package tree already displayed
+
+    ----- stderr -----
+    Resolved 2 packages in [TIME]
+    "###
+    );
+
+    // Test that both packages are shown as roots when both are requested
+    uv_snapshot!(context.filters(), context.tree().arg("--package").arg("package-a").arg("--package").arg("package-b"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    package-a v0.1.0
+    └── package-b v0.1.0
+        └── package-a v0.1.0 (*)
+    package-b v0.1.0 (*)
+    (*) Package tree already displayed
+
+    ----- stderr -----
+    Resolved 2 packages in [TIME]
+    "###
+    );
+
+    Ok(())
+}