Normalize paths when lowering Git dependencies

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

@@ -315,11 +315,12 @@ impl LoweredRequirement {
                             })?;
 
                             let source = if let Some(git_member) = &git_member {
-                                // If the workspace comes from a git dependency, all workspace
-                                // members need to be git deps, too.
-                                let subdirectory =
-                                    uv_fs::relative_to(member.root(), git_member.fetch_root)
-                                        .expect("Workspace member must be relative");
+                                // If the workspace comes from a Git dependency, all workspace
+                                // members need to be Git dependencies, too.
+                                let subdirectory = uv_fs::normalize_path(
+                                    &uv_fs::relative_to(member.root(), git_member.fetch_root)
+                                        .expect("Workspace member must be relative"),
+                                );
                                 RequirementSource::Git {
                                     repository: git_member.git_source.git.repository().clone(),
                                     reference: git_member.git_source.git.reference().clone(),

crates/uv-resolver/src/resolver/urls.rs

@@ -191,11 +191,14 @@ impl Urls {
 fn same_resource(a: &ParsedUrl, b: &ParsedUrl, git: &GitResolver) -> bool {
     match (a, b) {
         (ParsedUrl::Archive(a), ParsedUrl::Archive(b)) => {
-            a.subdirectory == b.subdirectory
+            a.subdirectory.as_deref().map(uv_fs::normalize_path)
+                == b.subdirectory.as_deref().map(uv_fs::normalize_path)
                 && CanonicalUrl::new(&a.url) == CanonicalUrl::new(&b.url)
         }
         (ParsedUrl::Git(a), ParsedUrl::Git(b)) => {
-            a.subdirectory == b.subdirectory && git.same_ref(&a.url, &b.url)
+            a.subdirectory.as_deref().map(uv_fs::normalize_path)
+                == b.subdirectory.as_deref().map(uv_fs::normalize_path)
+                && git.same_ref(&a.url, &b.url)
         }
         (ParsedUrl::Path(a), ParsedUrl::Path(b)) => {
             a.install_path == b.install_path

crates/uv/tests/it/sync.rs

@@ -5319,6 +5319,97 @@ fn sync_git_repeated_member_dynamic_metadata() -> Result<()> {
     Ok(())
 }
 
+/// See: <https://github.com/astral-sh/uv/issues/8887>
+#[test]
+fn sync_git_repeated_member_backwards_path() -> Result<()> {
+    let context = TestContext::new("3.13");
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "foo"
+        version = "0.1.0"
+        requires-python = ">=3.13"
+        dependencies = ["package", "dependency"]
+        [tool.uv.sources]
+        package = { git = "https://github.com/astral-sh/uv-backwards-path-test", subdirectory = "root" }
+        dependency = { git = "https://github.com/astral-sh/uv-backwards-path-test", subdirectory = "dependency" }
+        "#,
+    )?;
+
+    uv_snapshot!(context.filters(), context.lock(), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 3 packages in [TIME]
+    "###);
+
+    let lock = context.read("uv.lock");
+
+    insta::with_settings!(
+        {
+            filters => context.filters(),
+        },
+        {
+            assert_snapshot!(
+                lock, @r###"
+            version = 1
+            requires-python = ">=3.13"
+
+            [options]
+            exclude-newer = "2024-03-25T00:00:00Z"
+
+            [[package]]
+            name = "dependency"
+            version = "0.1.0"
+            source = { git = "https://github.com/astral-sh/uv-backwards-path-test?subdirectory=dependency#4bcc7fcd2e548c2ab7ba6b97b1c4e3ababccc7a9" }
+
+            [[package]]
+            name = "foo"
+            version = "0.1.0"
+            source = { virtual = "." }
+            dependencies = [
+                { name = "dependency" },
+                { name = "package" },
+            ]
+
+            [package.metadata]
+            requires-dist = [
+                { name = "dependency", git = "https://github.com/astral-sh/uv-backwards-path-test?subdirectory=dependency" },
+                { name = "package", git = "https://github.com/astral-sh/uv-backwards-path-test?subdirectory=root" },
+            ]
+
+            [[package]]
+            name = "package"
+            version = "0.1.0"
+            source = { git = "https://github.com/astral-sh/uv-backwards-path-test?subdirectory=root#4bcc7fcd2e548c2ab7ba6b97b1c4e3ababccc7a9" }
+            dependencies = [
+                { name = "dependency" },
+            ]
+            "###
+            );
+        }
+    );
+
+    uv_snapshot!(context.filters(), context.sync(), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 3 packages in [TIME]
+    Prepared 2 packages in [TIME]
+    Installed 2 packages in [TIME]
+     + dependency==0.1.0 (from git+https://github.com/astral-sh/uv-backwards-path-test@4bcc7fcd2e548c2ab7ba6b97b1c4e3ababccc7a9#subdirectory=dependency)
+     + package==0.1.0 (from git+https://github.com/astral-sh/uv-backwards-path-test@4bcc7fcd2e548c2ab7ba6b97b1c4e3ababccc7a9#subdirectory=root)
+    "###);
+
+    Ok(())
+}
+
 /// The project itself is marked as an editable dependency, but under the wrong name. The project
 /// is a package.
 #[test]