fix(lsp): run a server chosen from a Node.js installation on that Node

A language server path set to a script in a Node.js installation's bin
directory (nvm's bin/tsc or bin/npx) runs through #!/usr/bin/env node, which
found the project's Node.js interpreter or whatever node came first on the
IDE's PATH. TypeScript 7's tsc is an extensionless ES module that Node 20.9
refuses (ERR_UNKNOWN_FILE_EXTENSION), so tsc --lsp crashed although the
chosen installation runs Node 26. That installation's bin directory now
comes first on the server's PATH.

crates/ide-sdk/src/apply.rs

@@ -957,10 +957,15 @@ pub fn resolve_run_command(config: &mut RunConfig, root: &Path, s: &Settings) {
 }
 
 pub fn configure_server(cfg: &mut LanguageServerConfig, root: &Path, server_root: &Path, s: &Settings) {
+    let mut path_dirs: Vec<PathBuf> = Vec::new();
     if let Some(custom) = tool_command(root, s, &cfg.command) {
+        // An executable chosen from a Node.js installation (`~/.nvm/versions/node/v26/bin/tsc`,
+        // its `npx`) runs on that Node: its `#!/usr/bin/env node` finds the `node` beside it.
+        if let Some(bin) = custom.parent().filter(|bin| bin.join(exe("node")).is_file()) {
+            path_dirs.push(bin.to_path_buf());
+        }
         cfg.command = custom.to_string_lossy().into_owned();
     }
-    let mut path_dirs: Vec<PathBuf> = Vec::new();
     let name = cfg.name.clone();
     let name = name.as_str();
 

crates/ide-sdk/src/tests.rs

@@ -1325,6 +1325,40 @@ fn custom_tool_path_replaces_the_command() {
     assert_eq!(cfg.command, "zls");
 }
 
+/// A server picked from a Node.js installation (nvm's `bin/tsc`, `bin/npx`) is a
+/// `#!/usr/bin/env node` script: it runs on that installation's Node, ahead of the
+/// project's Node.js interpreter.
+#[test]
+fn a_server_chosen_from_a_node_installation_runs_on_that_node() {
+    let tmp = tempfile::tempdir().unwrap();
+    let v26 = tmp.path().join("nvm/versions/node/v26.4.0/bin");
+    let v20 = tmp.path().join("node20/bin");
+    for dir in [&v26, &v20] {
+        std::fs::create_dir_all(dir).unwrap();
+        std::fs::write(dir.join(exe("node")), "").unwrap();
+    }
+    std::fs::write(v26.join("tsc"), "#!/usr/bin/env node\n").unwrap();
+    let mut s = Settings::default();
+    s.languages.node.interpreter = v20.join(exe("node")).to_string_lossy().into_owned();
+    s.tools.insert(
+        "typescript-language-server".into(),
+        ide_core::settings::ToolSettings { path: v26.join("tsc").to_string_lossy().into_owned() },
+    );
+    let mut cfg = server("typescript-language-server");
+    configure_server(&mut cfg, tmp.path(), tmp.path(), &s);
+    let path: Vec<std::path::PathBuf> = std::env::split_paths(&cfg.env["PATH"]).collect();
+    assert_eq!(path[..2], [v26.clone(), v20.clone()]);
+
+    // Elsewhere, the project's Node.js interpreter comes first.
+    s.tools.insert(
+        "typescript-language-server".into(),
+        ide_core::settings::ToolSettings { path: tmp.path().join("tools/tsc").to_string_lossy().into_owned() },
+    );
+    let mut cfg = server("typescript-language-server");
+    configure_server(&mut cfg, tmp.path(), tmp.path(), &s);
+    assert_eq!(std::env::split_paths(&cfg.env["PATH"]).next(), Some(v20));
+}
+
 #[test]
 fn the_godot_setting_applies_to_server_debugger_and_run_configurations() {
     let tmp = tempfile::tempdir().unwrap();