fix(language_server): handle invalid root URI gracefully

crates/oxc_language_server/src/formatter/server_formatter.rs

@@ -21,9 +21,7 @@ use crate::{
 pub struct ServerFormatterBuilder;
 
 impl ServerFormatterBuilder {
-    /// # Panics
-    /// Panics if the root URI cannot be converted to a file path.
-    pub fn build(root_uri: &Uri, options: serde_json::Value) -> ServerFormatter {
+    pub fn build(root_uri: &Uri, options: serde_json::Value) -> Option<ServerFormatter> {
         let options = match serde_json::from_value::<LSPFormatOptions>(options) {
             Ok(opts) => opts,
             Err(err) => {
@@ -34,7 +32,7 @@ impl ServerFormatterBuilder {
             }
         };
 
-        let root_path = root_uri.to_file_path().unwrap();
+        let root_path = root_uri.to_file_path()?;
         let oxfmtrc = Self::get_config(&root_path, options.config_path.as_ref());
         let (format_options, oxfmt_options) = Self::get_options(oxfmtrc);
 
@@ -49,7 +47,7 @@ impl ServerFormatterBuilder {
                 }
             };
 
-        ServerFormatter::new(format_options, gitignore_glob)
+        Some(ServerFormatter::new(format_options, gitignore_glob))
     }
 }
 
@@ -62,8 +60,8 @@ impl ToolBuilder for ServerFormatterBuilder {
         capabilities.document_formatting_provider =
             Some(tower_lsp_server::ls_types::OneOf::Left(true));
     }
-    fn build_boxed(&self, root_uri: &Uri, options: serde_json::Value) -> Box<dyn Tool> {
-        Box::new(ServerFormatterBuilder::build(root_uri, options))
+    fn build_boxed(&self, root_uri: &Uri, options: serde_json::Value) -> Option<Box<dyn Tool>> {
+        ServerFormatterBuilder::build(root_uri, options).map(|f| Box::new(f) as Box<dyn Tool>)
     }
 }
 
@@ -162,8 +160,6 @@ impl Tool for ServerFormatter {
     fn name(&self) -> &'static str {
         "formatter"
     }
-    /// # Panics
-    /// Panics if the root URI cannot be converted to a file path.
     fn handle_configuration_change(
         &self,
         root_uri: &Uri,
@@ -196,7 +192,11 @@ impl Tool for ServerFormatter {
             return ToolRestartChanges { tool: None, watch_patterns: None };
         }
 
-        let new_formatter = ServerFormatterBuilder::build(root_uri, new_options_json.clone());
+        let Some(new_formatter) = ServerFormatterBuilder::build(root_uri, new_options_json.clone())
+        else {
+            warn!("Failed to build formatter: root URI cannot be converted to file path");
+            return ToolRestartChanges { tool: None, watch_patterns: None };
+        };
         let watch_patterns = new_formatter.get_watcher_patterns(new_options_json);
         ToolRestartChanges {
             tool: Some(Box::new(new_formatter)),
@@ -230,7 +230,10 @@ impl Tool for ServerFormatter {
     ) -> ToolRestartChanges {
         // TODO: Check if the changed file is actually a config file
 
-        let new_formatter = ServerFormatterBuilder::build(root_uri, options);
+        let Some(new_formatter) = ServerFormatterBuilder::build(root_uri, options) else {
+            warn!("Failed to build formatter: root URI cannot be converted to file path");
+            return ToolRestartChanges { tool: None, watch_patterns: None };
+        };
 
         ToolRestartChanges {
             tool: Some(Box::new(new_formatter)),

crates/oxc_language_server/src/formatter/tester.rs

@@ -59,6 +59,7 @@ impl Tester<'_> {
             &Self::get_root_uri(self.relative_root_dir),
             self.options.clone(),
         )
+        .expect("test requires valid root URI")
     }
 
     pub fn get_root_uri(relative_root_dir: &str) -> Uri {

crates/oxc_language_server/src/linter/server_linter.rs

@@ -41,9 +41,12 @@ use crate::{
 pub struct ServerLinterBuilder;
 
 impl ServerLinterBuilder {
+    /// Build a new `ServerLinter` for the given root URI and options.
+    ///
     /// # Panics
-    /// Panics if the root URI cannot be converted to a file path.
-    pub fn build(root_uri: &Uri, options: serde_json::Value) -> ServerLinter {
+    ///
+    /// Panics if an empty `ConfigStoreBuilder` fails to build, which should never happen.
+    pub fn build(root_uri: &Uri, options: serde_json::Value) -> Option<ServerLinter> {
         let options = match serde_json::from_value::<LSPLintOptions>(options) {
             Ok(opts) => opts,
             Err(e) => {
@@ -53,7 +56,7 @@ impl ServerLinterBuilder {
                 LSPLintOptions::default()
             }
         };
-        let root_path = root_uri.to_file_path().unwrap();
+        let root_path = root_uri.to_file_path()?;
         let mut nested_ignore_patterns = Vec::new();
         let (nested_configs, mut extended_paths) =
             Self::create_nested_configs(&root_path, &options, &mut nested_ignore_patterns);
@@ -133,14 +136,14 @@ impl ServerLinterBuilder {
             },
         );
 
-        ServerLinter::new(
+        Some(ServerLinter::new(
             options.run,
             root_path.to_path_buf(),
             isolated_linter,
             LintIgnoreMatcher::new(&base_patterns, &root_path, nested_ignore_patterns),
             Self::create_ignore_glob(&root_path),
             extended_paths,
-        )
+        ))
     }
 }
 
@@ -213,8 +216,8 @@ impl ToolBuilder for ServerLinterBuilder {
             Some(DiagnosticServerCapabilities::Options(DiagnosticOptions::default()))
         };
     }
-    fn build_boxed(&self, root_uri: &Uri, options: serde_json::Value) -> Box<dyn Tool> {
-        Box::new(ServerLinterBuilder::build(root_uri, options))
+    fn build_boxed(&self, root_uri: &Uri, options: serde_json::Value) -> Option<Box<dyn Tool>> {
+        ServerLinterBuilder::build(root_uri, options).map(|l| Box::new(l) as Box<dyn Tool>)
     }
 }
 
@@ -324,8 +327,6 @@ impl Tool for ServerLinter {
         ToolShutdownChanges { uris_to_clear_diagnostics: Some(self.get_cached_uris()) }
     }
 
-    /// # Panics
-    /// Panics if the root URI cannot be converted to a file path.
     fn handle_configuration_change(
         &self,
         root_uri: &Uri,
@@ -357,7 +358,11 @@ impl Tool for ServerLinter {
         }
 
         // get the cached files before refreshing the linter, and revalidate them after
-        let new_linter = ServerLinterBuilder::build(root_uri, new_options_json.clone());
+        let Some(new_linter) = ServerLinterBuilder::build(root_uri, new_options_json.clone())
+        else {
+            warn!("Failed to build linter: root URI cannot be converted to file path");
+            return ToolRestartChanges { tool: None, watch_patterns: None };
+        };
 
         let patterns = {
             if old_option.config_path == new_options.config_path
@@ -412,7 +417,10 @@ impl Tool for ServerLinter {
         options: serde_json::Value,
     ) -> ToolRestartChanges {
         // TODO: Check if the changed file is actually a config file (including extended paths)
-        let new_linter = ServerLinterBuilder::build(root_uri, options);
+        let Some(new_linter) = ServerLinterBuilder::build(root_uri, options) else {
+            warn!("Failed to build linter: root URI cannot be converted to file path");
+            return ToolRestartChanges { tool: None, watch_patterns: None };
+        };
 
         ToolRestartChanges {
             tool: Some(Box::new(new_linter)),

crates/oxc_language_server/src/linter/tester.rs

@@ -188,6 +188,7 @@ impl Tester<'_> {
             &Self::get_root_uri(self.relative_root_dir),
             self.options.clone(),
         )
+        .expect("test requires valid root URI")
     }
 
     pub fn get_root_uri(relative_root_dir: &str) -> Uri {

crates/oxc_language_server/src/tests.rs

@@ -13,8 +13,8 @@ use crate::{Tool, ToolBuilder, ToolRestartChanges, backend::Backend, tool::Diagn
 pub struct FakeToolBuilder;
 
 impl ToolBuilder for FakeToolBuilder {
-    fn build_boxed(&self, _root_uri: &Uri, _options: serde_json::Value) -> Box<dyn Tool> {
-        Box::new(FakeTool)
+    fn build_boxed(&self, _root_uri: &Uri, _options: serde_json::Value) -> Option<Box<dyn Tool>> {
+        Some(Box::new(FakeTool))
     }
 }
 
@@ -59,7 +59,7 @@ impl Tool for FakeTool {
     ) -> ToolRestartChanges {
         if new_options_json.as_u64() == Some(1) || new_options_json.as_u64() == Some(3) {
             return ToolRestartChanges {
-                tool: Some(FakeToolBuilder.build_boxed(root_uri, new_options_json)),
+                tool: FakeToolBuilder.build_boxed(root_uri, new_options_json),
                 watch_patterns: None,
             };
         }
@@ -90,7 +90,7 @@ impl Tool for FakeTool {
     ) -> ToolRestartChanges {
         if changed_uri.as_str().ends_with("tool.config") {
             return ToolRestartChanges {
-                tool: Some(FakeToolBuilder.build_boxed(root_uri, options)),
+                tool: FakeToolBuilder.build_boxed(root_uri, options),
                 watch_patterns: None,
             };
         }

crates/oxc_language_server/src/tool.rs

@@ -18,7 +18,8 @@ pub trait ToolBuilder: Send + Sync {
     }
 
     /// Build a boxed instance of the tool for the given root URI and options.
-    fn build_boxed(&self, root_uri: &Uri, options: serde_json::Value) -> Box<dyn Tool>;
+    /// Returns `None` if the tool cannot be built for the given root URI and options.
+    fn build_boxed(&self, root_uri: &Uri, options: serde_json::Value) -> Option<Box<dyn Tool>>;
 }
 
 pub type DiagnosticResult = Vec<(Uri, Vec<Diagnostic>)>;

crates/oxc_language_server/src/worker.rs

@@ -48,21 +48,23 @@ impl WorkspaceWorker {
     /// e.g. root URI: file:///path/to/root
     ///      responsible for: file:///path/to/root/file.js
     ///      not responsible for: file:///path/to/other/file.js
-    ///
-    /// # Panics
-    /// Panics if the root URI cannot be converted to a file path.
     pub fn is_responsible_for_uri(&self, uri: &Uri) -> bool {
-        if let Some(path) = uri.to_file_path() {
-            return path.starts_with(self.root_uri.to_file_path().unwrap());
-        }
-        false
+        let Some(path) = uri.to_file_path() else {
+            return false;
+        };
+        let Some(root_path) = self.root_uri.to_file_path() else {
+            return false;
+        };
+        path.starts_with(root_path)
     }
 
     /// Start all programs (linter, formatter) for the worker.
     /// This should be called after the client has sent the workspace configuration.
     pub async fn start_worker(&self, options: serde_json::Value, tools: &[Box<dyn ToolBuilder>]) {
-        *self.tools.write().await =
-            tools.iter().map(|tool| tool.build_boxed(&self.root_uri, options.clone())).collect();
+        *self.tools.write().await = tools
+            .iter()
+            .filter_map(|tool| tool.build_boxed(&self.root_uri, options.clone()))
+            .collect();
 
         *self.options.lock().await = Some(options);
     }
@@ -428,6 +430,9 @@ mod tests {
             !worker
                 .is_responsible_for_uri(&Uri::from_str("file:///path/to/other/file.js").unwrap())
         );
+        assert!(!worker.is_responsible_for_uri(
+            &Uri::from_str("file:///path/to/root_second/file.js").unwrap()
+        ));
     }
 
     #[tokio::test]