From e96354a6dd00d8362bb33388ca0466cef9517e08 Mon Sep 17 00:00:00 2001
From: Zsolt Dollenstein <zsol.zsol@gmail.com>
Date: Wed, 12 Nov 2025 17:10:15 +0000
Subject: [PATCH] Always attach linehaul data (#16705)

---
 crates/uv-client/src/base_client.rs           |  8 +++----
 crates/uv-client/src/linehaul.rs              | 14 +++++------
 .../uv-client/tests/it/user_agent_version.rs  | 24 +++++++++++++++++--
 3 files changed, 32 insertions(+), 14 deletions(-)

diff --git a/crates/uv-client/src/base_client.rs b/crates/uv-client/src/base_client.rs
index a834e5e75..97192dcd8 100644
--- a/crates/uv-client/src/base_client.rs
+++ b/crates/uv-client/src/base_client.rs
@@ -358,11 +358,9 @@ impl<'a> BaseClientBuilder<'a> {
         let mut user_agent_string = format!("uv/{}", version());
 
         // Add linehaul metadata.
-        if let Some(markers) = self.markers {
-            let linehaul = LineHaul::new(markers, self.platform);
-            if let Ok(output) = serde_json::to_string(&linehaul) {
-                let _ = write!(user_agent_string, " {output}");
-            }
+        let linehaul = LineHaul::new(self.markers, self.platform);
+        if let Ok(output) = serde_json::to_string(&linehaul) {
+            let _ = write!(user_agent_string, " {output}");
         }
 
         // Check for the presence of an `SSL_CERT_FILE`.
diff --git a/crates/uv-client/src/linehaul.rs b/crates/uv-client/src/linehaul.rs
index 8d159152d..4eea4f755 100644
--- a/crates/uv-client/src/linehaul.rs
+++ b/crates/uv-client/src/linehaul.rs
@@ -63,7 +63,7 @@ pub struct LineHaul {
 impl LineHaul {
     /// Initializes Linehaul information based on PEP 508 markers.
     #[instrument(name = "linehaul", skip_all)]
-    pub fn new(markers: &MarkerEnvironment, platform: Option<&Platform>) -> Self {
+    pub fn new(markers: Option<&MarkerEnvironment>, platform: Option<&Platform>) -> Self {
         // https://github.com/pypa/pip/blob/24.0/src/pip/_internal/network/session.py#L87
         let looks_like_ci = [
             EnvVars::BUILD_BUILDID,
@@ -124,17 +124,17 @@ impl LineHaul {
                 name: Some("uv".to_string()),
                 version: Some(version().to_string()),
             }),
-            python: Some(markers.python_full_version().version.to_string()),
+            python: markers.map(|markers| markers.python_full_version().version.to_string()),
             implementation: Option::from(Implementation {
-                name: Some(markers.platform_python_implementation().to_string()),
-                version: Some(markers.python_full_version().version.to_string()),
+                name: markers.map(|markers| markers.platform_python_implementation().to_string()),
+                version: markers.map(|markers| markers.python_full_version().version.to_string()),
             }),
             distro,
             system: Option::from(System {
-                name: Some(markers.platform_system().to_string()),
-                release: Some(markers.platform_release().to_string()),
+                name: markers.map(|markers| markers.platform_system().to_string()),
+                release: markers.map(|markers| markers.platform_release().to_string()),
             }),
-            cpu: Some(markers.platform_machine().to_string()),
+            cpu: markers.map(|markers| markers.platform_machine().to_string()),
             // Should probably always be None in uv.
             openssl_version: None,
             // Should probably always be None in uv.
diff --git a/crates/uv-client/tests/it/user_agent_version.rs b/crates/uv-client/tests/it/user_agent_version.rs
index bc3e7deef..5c4a1e80c 100644
--- a/crates/uv-client/tests/it/user_agent_version.rs
+++ b/crates/uv-client/tests/it/user_agent_version.rs
@@ -70,8 +70,28 @@ async fn test_user_agent_has_version() -> Result<()> {
     // Check User Agent
     let body = res.text().await?;
 
-    // Verify body matches regex
-    assert_eq!(body, format!("uv/{}", version()));
+    let (uv_version, uv_linehaul) = body
+        .split_once(' ')
+        .expect("Failed to split User-Agent header");
+
+    // Deserializing Linehaul
+    let linehaul: LineHaul = serde_json::from_str(uv_linehaul)?;
+
+    // Assert linehaul user agent
+    let filters = vec![(version(), "[VERSION]")];
+    with_settings!({
+        filters => filters
+    }, {
+        // Assert uv version
+        assert_snapshot!(uv_version, @"uv/[VERSION]");
+        // Assert linehaul json
+        assert_json_snapshot!(&linehaul.installer, @r#"
+        {
+          "name": "uv",
+          "version": "[VERSION]"
+        }
+        "#);
+    });
 
     // Wait for the server task to complete, to be a good citizen.
     server_task.await?;