path_info: check for and resolve symlink

Cargo.toml

@@ -16,15 +16,14 @@ futures = "0.3.31"
 nix-compat = { git = "https://github.com/tvlfyi/tvix.git", version = "0.1.0" }
 regex = "1.11.1"
 reqwest = "0.12.15"
-serde = { version = "1.0.219", features = [ "derive" ]}
+serde = { version = "1.0.219", features = ["derive"] }
 serde_json = "1.0.140"
 sha2 = "0.10.8"
-tokio = { version = "1.44.1", features = [ "full", "tracing", "parking_lot" ]}
+tokio = { version = "1.44.1", features = ["full", "tracing", "parking_lot"] }
 tracing = "0.1.41"
-url = { version = "2.5.4", features = [ "serde" ]}
+url = { version = "2.5.4", features = ["serde"] }
 cxx = "1.0"
 console-subscriber = "0.4.1"
-tempfile = "3.19.1"
 tokio-util = { version = "0.7.15", features = ["io"] }
 bytes = "1.10.1"
 object_store = { version = "0.12.0", features = ["aws"] }
@@ -35,3 +34,6 @@ humansize = "2.1.3"
 [build-dependencies]
 cxx-build = "1.0"
 pkg-config = "0.3.32"
+
+[dev-dependencies]
+tempfile = "3.19.1"

src/path_info.rs

@@ -28,6 +28,14 @@ impl PathInfo {
         let derivation = match drv.extension() {
             Some(ext) if ext == "drv" => drv.as_os_str().as_encoded_bytes(),
             _ => {
+                let drv = {
+                    // resolve symlink
+                    if drv.is_symlink() {
+                        &drv.canonicalize()?
+                    } else {
+                        drv
+                    }
+                };
                 &Command::new("nix")
                     .arg("path-info")
                     .arg("--derivation")

tests/path_info.rs

@@ -1,6 +1,8 @@
 use nixcp::path_info::PathInfo;
 use std::path::PathBuf;
 
+use tempfile::TempDir;
+
 use crate::common::{HELLO, HELLO_DRV, HELLO_PATH};
 
 mod common;
@@ -25,6 +27,23 @@ async fn path_info_from_path() {
     assert_eq!(path_info.path.to_string(), HELLO_DRV);
 }
 
+#[tokio::test]
+async fn path_info_symlink() {
+    let ctx = common::context();
+
+    let temp_path = TempDir::new().unwrap();
+    let link_path = temp_path.path().join("result");
+
+    // symlink at ./result (like `nix build`)
+    std::os::unix::fs::symlink(HELLO_PATH, &link_path).unwrap();
+
+    // should resolve symlink
+    let path_info = PathInfo::from_derivation(&link_path, &ctx.store)
+        .await
+        .expect("get pathinfo from package");
+    assert_eq!(path_info.path.to_string(), HELLO_DRV);
+}
+
 #[tokio::test]
 async fn closure() {
     let ctx = common::context();