Respect `-e` flags in `uv add` (#16882)

## Summary

Closes https://github.com/astral-sh/uv/issues/16872.

crates/uv-workspace/src/pyproject.rs

@@ -1697,9 +1697,25 @@ impl Source {
                     return Ok(None);
                 }
             }
-            RequirementSource::Path { install_path, .. }
-            | RequirementSource::Directory { install_path, .. } => Self::Path {
-                editable,
+            RequirementSource::Path { install_path, .. } => Self::Path {
+                editable: None,
+                package: None,
+                path: PortablePathBuf::from(
+                    relative_to(&install_path, root)
+                        .or_else(|_| std::path::absolute(&install_path))
+                        .map_err(SourceError::Absolute)?
+                        .into_boxed_path(),
+                ),
+                marker: MarkerTree::TRUE,
+                extra: None,
+                group: None,
+            },
+            RequirementSource::Directory {
+                install_path,
+                editable: is_editable,
+                ..
+            } => Self::Path {
+                editable: editable.or(is_editable),
                 package: None,
                 path: PortablePathBuf::from(
                     relative_to(&install_path, root)

crates/uv/tests/it/edit.rs

@@ -5379,6 +5379,223 @@ fn add_requirements_file() -> Result<()> {
     Ok(())
 }
 
+/// Add a path dependency from a requirements file, respecting the lack of a `-e` flag.
+#[test]
+fn add_requirements_file_non_editable() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(indoc! {r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = []
+    "#})?;
+
+    // Create a peer package.
+    let child = context.temp_dir.child("packages").child("child");
+    child.child("pyproject.toml").write_str(indoc! {r#"
+        [project]
+        name = "child"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+
+        [build-system]
+        requires = ["hatchling"]
+        build-backend = "hatchling.build"
+    "#})?;
+    child
+        .child("src")
+        .child("child")
+        .child("__init__.py")
+        .touch()?;
+
+    // Without `-e`, the package should not be listed as editable.
+    let requirements_txt = context.temp_dir.child("requirements.txt");
+    requirements_txt.write_str("./packages/child")?;
+
+    uv_snapshot!(context.filters(), context.add().arg("-r").arg("requirements.txt").arg("--no-workspace"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 2 packages in [TIME]
+    Prepared 1 package in [TIME]
+    Installed 1 package in [TIME]
+     + child==0.1.0 (from file://[TEMP_DIR]/packages/child)
+    ");
+
+    let pyproject_toml_content = context.read("pyproject.toml");
+
+    insta::with_settings!({
+        filters => context.filters(),
+    }, {
+        assert_snapshot!(
+            pyproject_toml_content, @r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = [
+            "child",
+        ]
+
+        [tool.uv.sources]
+        child = { path = "packages/child" }
+        "#
+        );
+    });
+
+    Ok(())
+}
+
+/// Add a path dependency from a requirements file, respecting `-e` for editable.
+#[test]
+fn add_requirements_file_editable() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(indoc! {r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = []
+    "#})?;
+
+    // Create a peer package.
+    let child = context.temp_dir.child("packages").child("child");
+    child.child("pyproject.toml").write_str(indoc! {r#"
+        [project]
+        name = "child"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+
+        [build-system]
+        requires = ["hatchling"]
+        build-backend = "hatchling.build"
+    "#})?;
+    child
+        .child("src")
+        .child("child")
+        .child("__init__.py")
+        .touch()?;
+
+    // With `-e`, the package should be listed as editable.
+    let requirements_txt = context.temp_dir.child("requirements.txt");
+    requirements_txt.write_str("-e ./packages/child")?;
+
+    uv_snapshot!(context.filters(), context.add().arg("-r").arg("requirements.txt").arg("--no-workspace"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 2 packages in [TIME]
+    Prepared 1 package in [TIME]
+    Installed 1 package in [TIME]
+     + child==0.1.0 (from file://[TEMP_DIR]/packages/child)
+    ");
+
+    let pyproject_toml_content = context.read("pyproject.toml");
+
+    insta::with_settings!({
+        filters => context.filters(),
+    }, {
+        assert_snapshot!(
+            pyproject_toml_content, @r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = [
+            "child",
+        ]
+
+        [tool.uv.sources]
+        child = { path = "packages/child", editable = true }
+        "#
+        );
+    });
+
+    Ok(())
+}
+
+/// Add a path dependency from a requirements file, overriding the `-e` flag.
+#[test]
+fn add_requirements_file_editable_override() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(indoc! {r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = []
+    "#})?;
+
+    // Create a peer package.
+    let child = context.temp_dir.child("packages").child("child");
+    child.child("pyproject.toml").write_str(indoc! {r#"
+        [project]
+        name = "child"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+
+        [build-system]
+        requires = ["hatchling"]
+        build-backend = "hatchling.build"
+    "#})?;
+    child
+        .child("src")
+        .child("child")
+        .child("__init__.py")
+        .touch()?;
+
+    // With `-e`, the package should be listed as editable, but the `--no-editable` flag should
+    // override it.
+    let requirements_txt = context.temp_dir.child("requirements.txt");
+    requirements_txt.write_str("-e ./packages/child")?;
+
+    uv_snapshot!(context.filters(), context.add().arg("-r").arg("requirements.txt").arg("--no-workspace").arg("--no-editable"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 2 packages in [TIME]
+    Prepared 1 package in [TIME]
+    Installed 1 package in [TIME]
+     + child==0.1.0 (from file://[TEMP_DIR]/packages/child)
+    ");
+
+    let pyproject_toml_content = context.read("pyproject.toml");
+
+    insta::with_settings!({
+        filters => context.filters(),
+    }, {
+        assert_snapshot!(
+            pyproject_toml_content, @r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = [
+            "child",
+        ]
+
+        [tool.uv.sources]
+        child = { path = "packages/child", editable = false }
+        "#
+        );
+    });
+
+    Ok(())
+}
+
 /// Add requirements from a file with a marker flag.
 ///
 /// We test that: