improve Python environment activation (#118)

crates/djls-server/Cargo.toml

@@ -16,3 +16,6 @@ tokio = { workspace = true }
 tower-lsp-server = { workspace = true }
 
 percent-encoding = "2.3"
+
+[build-dependencies]
+pyo3-build-config = { workspace = true, features = ["resolve-config"] }

crates/djls-server/build.rs

@@ -0,0 +1,45 @@
+/// Build script to configure linking against the Python library.
+///
+/// This script is necessary when the crate's code, particularly tests
+/// that interact with the Python interpreter via `pyo3` (e.g., using
+/// `Python::with_gil`, importing modules, calling Python functions),
+/// needs symbols from the Python C API at link time.
+///
+/// It uses `pyo3-build-config` to detect the Python installation and
+/// prints the required `cargo:rustc-link-search` and `cargo:rustc-link-lib`
+/// directives to Cargo, enabling the linker to find and link against the
+/// appropriate Python library (e.g., libpythonX.Y.so).
+///
+/// It also adds an RPATH linker argument on Unix-like systems so the
+/// resulting test executable can find the Python library at runtime.
+///
+/// Note: Each crate whose test target requires Python linking needs its
+/// own `build.rs` with this logic.
+fn main() {
+    println!("cargo:rerun-if-changed=build.rs");
+
+    // Set up #[cfg] flags first (useful for conditional compilation)
+    pyo3_build_config::use_pyo3_cfgs();
+
+    // Get the Python interpreter configuration directly
+    let config = pyo3_build_config::get();
+
+    // Add the library search path if available
+    if let Some(lib_dir) = &config.lib_dir {
+        println!("cargo:rustc-link-search=native={}", lib_dir);
+
+        // Add RPATH linker argument for Unix-like systems (Linux, macOS)
+        // This helps the test executable find the Python library at runtime.
+        #[cfg(not(windows))]
+        println!("cargo:rustc-link-arg=-Wl,-rpath,{}", lib_dir);
+    } else {
+        println!("cargo:warning=Python library directory not found in config.");
+    }
+
+    // Add the library link directive if available
+    if let Some(lib_name) = &config.lib_name {
+        println!("cargo:rustc-link-lib=dylib={}", lib_name);
+    } else {
+        println!("cargo:warning=Python library name not found in config.");
+    }
+}

crates/djls-server/src/workspace.rs

@@ -29,13 +29,12 @@ fn uri_to_pathbuf(uri: &Uri) -> Option<PathBuf> {
 
     // Decode the percent-encoded path string
     let decoded_path_cow = percent_decode_str(encoded_path_str).decode_utf8_lossy();
-    let path_str = decoded_path_cow.as_ref();
 
+    #[cfg(unix)]
+    let path_str = decoded_path_cow.as_ref();
     #[cfg(windows)]
-    let path_str = {
-        // Remove leading '/' for paths like /C:/...
-        path_str.strip_prefix('/').unwrap_or(path_str)
-    };
+    // Remove leading '/' for paths like /C:/...
+    let path_str = path_str.strip_prefix('/').unwrap_or(path_str);
 
     Some(PathBuf::from(path_str))
 }