lsp: Identify language servers by their configuration (#35270)

- **WIP: reorganize dispositions**
- **Introduce a LocalToolchainStore trait and use it for LspAdapter
methods**

Closes #35782
Closes #27331

Release Notes:

- Python: Improved propagation of a selected virtual environment into
the LSP configuration. This should the make all language-related
features such as Go to definition or Find all references more reliable.

---------

Co-authored-by: Cole Miller <cole@zed.dev>
Co-authored-by: Lukas Wirth <lukas@zed.dev>

crates/editor/src/editor.rs

@@ -16022,23 +16022,11 @@ impl Editor {
         cx.spawn_in(window, async move |editor, cx| {
             let location_task = editor.update(cx, |_, cx| {
                 project.update(cx, |project, cx| {
-                    let language_server_name = project
+                    project.open_local_buffer_via_lsp(lsp_location.uri.clone(), server_id, cx)
-                        .language_server_statuses(cx)
-                        .find(|(id, _)| server_id == *id)
-                        .map(|(_, status)| status.name.clone());
-                    language_server_name.map(|language_server_name| {
-                        project.open_local_buffer_via_lsp(
-                            lsp_location.uri.clone(),
-                            server_id,
-                            language_server_name,
-                            cx,
-                        )
-                    })
                 })
             })?;
-            let location = match location_task {
+            let location = Some({
-                Some(task) => Some({
+                let target_buffer_handle = location_task.await.context("open local buffer")?;
-                    let target_buffer_handle = task.await.context("open local buffer")?;
                 let range = target_buffer_handle.read_with(cx, |target_buffer, _| {
                     let target_start = target_buffer
                         .clip_point_utf16(point_from_lsp(lsp_location.range.start), Bias::Left);
@@ -16051,9 +16039,7 @@ impl Editor {
                     buffer: target_buffer_handle,
                     range,
                 }
-                }),
+            });
-                None => None,
-            };
             Ok(location)
         })
     }

crates/extension_host/src/extension_host.rs

@@ -1275,6 +1275,7 @@ impl ExtensionStore {
                         queries,
                         context_provider,
                         toolchain_provider: None,
+                        manifest_name: None,
                     })
                 }),
             );

crates/extension_host/src/headless_host.rs

@@ -163,6 +163,7 @@ impl HeadlessExtensionStore {
                             queries: LanguageQueries::default(),
                             context_provider: None,
                             toolchain_provider: None,
+                            manifest_name: None,
                         })
                     }),
                 );

crates/extension_host/src/wasm_host/wit/since_v0_6_0.rs

@@ -938,7 +938,7 @@ impl ExtensionImports for WasmState {
                             binary: settings.binary.map(|binary| settings::CommandSettings {
                                 path: binary.path,
                                 arguments: binary.arguments,
-                                env: binary.env,
+                                env: binary.env.map(|env| env.into_iter().collect()),
                             }),
                             settings: settings.settings,
                             initialization_options: settings.initialization_options,

crates/language/src/buffer.rs

@@ -1571,6 +1571,7 @@ impl Buffer {
             diagnostics: diagnostics.iter().cloned().collect(),
             lamport_timestamp,
         };
+
         self.apply_diagnostic_update(server_id, diagnostics, lamport_timestamp, cx);
         self.send_operation(op, true, cx);
     }

crates/language/src/language.rs

@@ -44,6 +44,7 @@ use serde::{Deserialize, Deserializer, Serialize, Serializer, de};
 use serde_json::Value;
 use settings::WorktreeId;
 use smol::future::FutureExt as _;
+use std::num::NonZeroU32;
 use std::{
     any::Any,
     ffi::OsStr,
@@ -59,7 +60,6 @@ use std::{
         atomic::{AtomicU64, AtomicUsize, Ordering::SeqCst},
     },
 };
-use std::{num::NonZeroU32, sync::OnceLock};
 use syntax_map::{QueryCursorHandle, SyntaxSnapshot};
 use task::RunnableTag;
 pub use task_context::{ContextLocation, ContextProvider, RunnableRange};
@@ -67,7 +67,9 @@ pub use text_diff::{
     DiffOptions, apply_diff_patch, line_diff, text_diff, text_diff_with_options, unified_diff,
 };
 use theme::SyntaxTheme;
-pub use toolchain::{LanguageToolchainStore, Toolchain, ToolchainList, ToolchainLister};
+pub use toolchain::{
+    LanguageToolchainStore, LocalLanguageToolchainStore, Toolchain, ToolchainList, ToolchainLister,
+};
 use tree_sitter::{self, Query, QueryCursor, WasmStore, wasmtime};
 use util::serde::default_true;
 
@@ -165,7 +167,6 @@ pub struct CachedLspAdapter {
     pub adapter: Arc<dyn LspAdapter>,
     pub reinstall_attempt_count: AtomicU64,
     cached_binary: futures::lock::Mutex<Option<LanguageServerBinary>>,
-    manifest_name: OnceLock<Option<ManifestName>>,
 }
 
 impl Debug for CachedLspAdapter {
@@ -201,7 +202,6 @@ impl CachedLspAdapter {
             adapter,
             cached_binary: Default::default(),
             reinstall_attempt_count: AtomicU64::new(0),
-            manifest_name: Default::default(),
         })
     }
 
@@ -212,7 +212,7 @@ impl CachedLspAdapter {
     pub async fn get_language_server_command(
         self: Arc<Self>,
         delegate: Arc<dyn LspAdapterDelegate>,
-        toolchains: Arc<dyn LanguageToolchainStore>,
+        toolchains: Option<Toolchain>,
         binary_options: LanguageServerBinaryOptions,
         cx: &mut AsyncApp,
     ) -> Result<LanguageServerBinary> {
@@ -281,12 +281,6 @@ impl CachedLspAdapter {
             .cloned()
             .unwrap_or_else(|| language_name.lsp_id())
     }
-
-    pub fn manifest_name(&self) -> Option<ManifestName> {
-        self.manifest_name
-            .get_or_init(|| self.adapter.manifest_name())
-            .clone()
-    }
 }
 
 /// Determines what gets sent out as a workspace folders content
@@ -327,7 +321,7 @@ pub trait LspAdapter: 'static + Send + Sync {
     fn get_language_server_command<'a>(
         self: Arc<Self>,
         delegate: Arc<dyn LspAdapterDelegate>,
-        toolchains: Arc<dyn LanguageToolchainStore>,
+        toolchains: Option<Toolchain>,
         binary_options: LanguageServerBinaryOptions,
         mut cached_binary: futures::lock::MutexGuard<'a, Option<LanguageServerBinary>>,
         cx: &'a mut AsyncApp,
@@ -402,7 +396,7 @@ pub trait LspAdapter: 'static + Send + Sync {
     async fn check_if_user_installed(
         &self,
         _: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         None
@@ -535,7 +529,7 @@ pub trait LspAdapter: 'static + Send + Sync {
         self: Arc<Self>,
         _: &dyn Fs,
         _: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _cx: &mut AsyncApp,
     ) -> Result<Value> {
         Ok(serde_json::json!({}))
@@ -555,7 +549,6 @@ pub trait LspAdapter: 'static + Send + Sync {
         _target_language_server_id: LanguageServerName,
         _: &dyn Fs,
         _: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
         _cx: &mut AsyncApp,
     ) -> Result<Option<Value>> {
         Ok(None)
@@ -594,10 +587,6 @@ pub trait LspAdapter: 'static + Send + Sync {
         WorkspaceFoldersContent::SubprojectRoots
     }
 
-    fn manifest_name(&self) -> Option<ManifestName> {
-        None
-    }
-
     /// Method only implemented by the default JSON language server adapter.
     /// Used to provide dynamic reloading of the JSON schemas used to
     /// provide autocompletion and diagnostics in Zed setting and keybind
@@ -1108,6 +1097,7 @@ pub struct Language {
     pub(crate) grammar: Option<Arc<Grammar>>,
     pub(crate) context_provider: Option<Arc<dyn ContextProvider>>,
     pub(crate) toolchain: Option<Arc<dyn ToolchainLister>>,
+    pub(crate) manifest_name: Option<ManifestName>,
 }
 
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy)]
@@ -1318,6 +1308,7 @@ impl Language {
             }),
             context_provider: None,
             toolchain: None,
+            manifest_name: None,
         }
     }
 
@@ -1331,6 +1322,10 @@ impl Language {
         self
     }
 
+    pub fn with_manifest(mut self, name: Option<ManifestName>) -> Self {
+        self.manifest_name = name;
+        self
+    }
     pub fn with_queries(mut self, queries: LanguageQueries) -> Result<Self> {
         if let Some(query) = queries.highlights {
             self = self
@@ -1764,6 +1759,9 @@ impl Language {
     pub fn name(&self) -> LanguageName {
         self.config.name.clone()
     }
+    pub fn manifest(&self) -> Option<&ManifestName> {
+        self.manifest_name.as_ref()
+    }
 
     pub fn code_fence_block_name(&self) -> Arc<str> {
         self.config
@@ -2209,7 +2207,7 @@ impl LspAdapter for FakeLspAdapter {
     async fn check_if_user_installed(
         &self,
         _: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         Some(self.language_server_binary.clone())
@@ -2218,7 +2216,7 @@ impl LspAdapter for FakeLspAdapter {
     fn get_language_server_command<'a>(
         self: Arc<Self>,
         _: Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: LanguageServerBinaryOptions,
         _: futures::lock::MutexGuard<'a, Option<LanguageServerBinary>>,
         _: &'a mut AsyncApp,

crates/language/src/language_registry.rs

@@ -1,6 +1,6 @@
 use crate::{
     CachedLspAdapter, File, Language, LanguageConfig, LanguageId, LanguageMatcher,
-    LanguageServerName, LspAdapter, PLAIN_TEXT, ToolchainLister,
+    LanguageServerName, LspAdapter, ManifestName, PLAIN_TEXT, ToolchainLister,
     language_settings::{
         AllLanguageSettingsContent, LanguageSettingsContent, all_language_settings,
     },
@@ -172,6 +172,7 @@ pub struct AvailableLanguage {
     hidden: bool,
     load: Arc<dyn Fn() -> Result<LoadedLanguage> + 'static + Send + Sync>,
     loaded: bool,
+    manifest_name: Option<ManifestName>,
 }
 
 impl AvailableLanguage {
@@ -259,6 +260,7 @@ pub struct LoadedLanguage {
     pub queries: LanguageQueries,
     pub context_provider: Option<Arc<dyn ContextProvider>>,
     pub toolchain_provider: Option<Arc<dyn ToolchainLister>>,
+    pub manifest_name: Option<ManifestName>,
 }
 
 impl LanguageRegistry {
@@ -349,12 +351,14 @@ impl LanguageRegistry {
             config.grammar.clone(),
             config.matcher.clone(),
             config.hidden,
+            None,
             Arc::new(move || {
                 Ok(LoadedLanguage {
                     config: config.clone(),
                     queries: Default::default(),
                     toolchain_provider: None,
                     context_provider: None,
+                    manifest_name: None,
                 })
             }),
         )
@@ -487,6 +491,7 @@ impl LanguageRegistry {
         grammar_name: Option<Arc<str>>,
         matcher: LanguageMatcher,
         hidden: bool,
+        manifest_name: Option<ManifestName>,
         load: Arc<dyn Fn() -> Result<LoadedLanguage> + 'static + Send + Sync>,
     ) {
         let state = &mut *self.state.write();
@@ -496,6 +501,7 @@ impl LanguageRegistry {
                 existing_language.grammar = grammar_name;
                 existing_language.matcher = matcher;
                 existing_language.load = load;
+                existing_language.manifest_name = manifest_name;
                 return;
             }
         }
@@ -508,6 +514,7 @@ impl LanguageRegistry {
             load,
             hidden,
             loaded: false,
+            manifest_name,
         });
         state.version += 1;
         state.reload_count += 1;
@@ -575,6 +582,7 @@ impl LanguageRegistry {
             grammar: language.config.grammar.clone(),
             matcher: language.config.matcher.clone(),
             hidden: language.config.hidden,
+            manifest_name: None,
             load: Arc::new(|| Err(anyhow!("already loaded"))),
             loaded: true,
         });
@@ -914,10 +922,12 @@ impl LanguageRegistry {
                                 Language::new_with_id(id, loaded_language.config, grammar)
                                     .with_context_provider(loaded_language.context_provider)
                                     .with_toolchain_lister(loaded_language.toolchain_provider)
+                                    .with_manifest(loaded_language.manifest_name)
                                     .with_queries(loaded_language.queries)
                             } else {
                                 Ok(Language::new_with_id(id, loaded_language.config, None)
                                     .with_context_provider(loaded_language.context_provider)
+                                    .with_manifest(loaded_language.manifest_name)
                                     .with_toolchain_lister(loaded_language.toolchain_provider))
                             }
                         }

crates/language/src/manifest.rs

@@ -12,6 +12,12 @@ impl Borrow<SharedString> for ManifestName {
     }
 }
 
+impl Borrow<str> for ManifestName {
+    fn borrow(&self) -> &str {
+        &self.0
+    }
+}
+
 impl From<SharedString> for ManifestName {
     fn from(value: SharedString) -> Self {
         Self(value)

crates/language/src/toolchain.rs

@@ -17,7 +17,7 @@ use settings::WorktreeId;
 use crate::{LanguageName, ManifestName};
 
 /// Represents a single toolchain.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Eq)]
 pub struct Toolchain {
     /// User-facing label
     pub name: SharedString,
@@ -27,6 +27,14 @@ pub struct Toolchain {
     pub as_json: serde_json::Value,
 }
 
+impl std::hash::Hash for Toolchain {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.name.hash(state);
+        self.path.hash(state);
+        self.language_name.hash(state);
+    }
+}
+
 impl PartialEq for Toolchain {
     fn eq(&self, other: &Self) -> bool {
         // Do not use as_json for comparisons; it shouldn't impact equality, as it's not user-surfaced.
@@ -64,6 +72,29 @@ pub trait LanguageToolchainStore: Send + Sync + 'static {
     ) -> Option<Toolchain>;
 }
 
+pub trait LocalLanguageToolchainStore: Send + Sync + 'static {
+    fn active_toolchain(
+        self: Arc<Self>,
+        worktree_id: WorktreeId,
+        relative_path: &Arc<Path>,
+        language_name: LanguageName,
+        cx: &mut AsyncApp,
+    ) -> Option<Toolchain>;
+}
+
+#[async_trait(?Send )]
+impl<T: LocalLanguageToolchainStore> LanguageToolchainStore for T {
+    async fn active_toolchain(
+        self: Arc<Self>,
+        worktree_id: WorktreeId,
+        relative_path: Arc<Path>,
+        language_name: LanguageName,
+        cx: &mut AsyncApp,
+    ) -> Option<Toolchain> {
+        self.active_toolchain(worktree_id, &relative_path, language_name, cx)
+    }
+}
+
 type DefaultIndex = usize;
 #[derive(Default, Clone)]
 pub struct ToolchainList {

crates/language_extension/src/extension_lsp_adapter.rs

@@ -12,8 +12,8 @@ use fs::Fs;
 use futures::{Future, FutureExt, future::join_all};
 use gpui::{App, AppContext, AsyncApp, Task};
 use language::{
-    BinaryStatus, CodeLabel, HighlightId, Language, LanguageName, LanguageToolchainStore,
+    BinaryStatus, CodeLabel, HighlightId, Language, LanguageName, LspAdapter, LspAdapterDelegate,
-    LspAdapter, LspAdapterDelegate,
+    Toolchain,
 };
 use lsp::{
     CodeActionKind, LanguageServerBinary, LanguageServerBinaryOptions, LanguageServerName,
@@ -159,7 +159,7 @@ impl LspAdapter for ExtensionLspAdapter {
     fn get_language_server_command<'a>(
         self: Arc<Self>,
         delegate: Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: LanguageServerBinaryOptions,
         _: futures::lock::MutexGuard<'a, Option<LanguageServerBinary>>,
         _: &'a mut AsyncApp,
@@ -288,7 +288,7 @@ impl LspAdapter for ExtensionLspAdapter {
         self: Arc<Self>,
         _: &dyn Fs,
         delegate: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _cx: &mut AsyncApp,
     ) -> Result<Value> {
         let delegate = Arc::new(WorktreeDelegateAdapter(delegate.clone())) as _;
@@ -336,7 +336,7 @@ impl LspAdapter for ExtensionLspAdapter {
         target_language_server_id: LanguageServerName,
         _: &dyn Fs,
         delegate: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+
         _cx: &mut AsyncApp,
     ) -> Result<Option<serde_json::Value>> {
         let delegate = Arc::new(WorktreeDelegateAdapter(delegate.clone())) as _;

crates/language_extension/src/language_extension.rs

@@ -52,7 +52,7 @@ impl ExtensionLanguageProxy for LanguageServerRegistryProxy {
         load: Arc<dyn Fn() -> Result<LoadedLanguage> + Send + Sync + 'static>,
     ) {
         self.language_registry
-            .register_language(language, grammar, matcher, hidden, load);
+            .register_language(language, grammar, matcher, hidden, None, load);
     }
 
     fn remove_languages(

crates/languages/src/c.rs

@@ -28,7 +28,7 @@ impl super::LspAdapter for CLspAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         let path = delegate.which(Self::SERVER_NAME.as_ref()).await?;

crates/languages/src/css.rs

@@ -2,7 +2,7 @@ use anyhow::{Context as _, Result};
 use async_trait::async_trait;
 use futures::StreamExt;
 use gpui::AsyncApp;
-use language::{LanguageToolchainStore, LspAdapter, LspAdapterDelegate};
+use language::{LspAdapter, LspAdapterDelegate, Toolchain};
 use lsp::{LanguageServerBinary, LanguageServerName};
 use node_runtime::{NodeRuntime, VersionStrategy};
 use project::{Fs, lsp_store::language_server_settings};
@@ -43,7 +43,7 @@ impl LspAdapter for CssLspAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         let path = delegate
@@ -144,7 +144,7 @@ impl LspAdapter for CssLspAdapter {
         self: Arc<Self>,
         _: &dyn Fs,
         delegate: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         cx: &mut AsyncApp,
     ) -> Result<serde_json::Value> {
         let mut default_config = json!({

crates/languages/src/go.rs

@@ -75,7 +75,7 @@ impl super::LspAdapter for GoLspAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         let path = delegate.which(Self::SERVER_NAME.as_ref()).await?;

crates/languages/src/json.rs

@@ -8,8 +8,8 @@ use futures::StreamExt;
 use gpui::{App, AsyncApp, Task};
 use http_client::github::{GitHubLspBinaryVersion, latest_github_release};
 use language::{
-    ContextProvider, LanguageName, LanguageRegistry, LanguageToolchainStore, LocalFile as _,
+    ContextProvider, LanguageName, LanguageRegistry, LocalFile as _, LspAdapter,
-    LspAdapter, LspAdapterDelegate,
+    LspAdapterDelegate, Toolchain,
 };
 use lsp::{LanguageServerBinary, LanguageServerName};
 use node_runtime::{NodeRuntime, VersionStrategy};
@@ -303,7 +303,7 @@ impl LspAdapter for JsonLspAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         let path = delegate
@@ -404,7 +404,7 @@ impl LspAdapter for JsonLspAdapter {
         self: Arc<Self>,
         _: &dyn Fs,
         delegate: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         cx: &mut AsyncApp,
     ) -> Result<Value> {
         let mut config = self.get_or_init_workspace_config(cx).await?;
@@ -529,7 +529,7 @@ impl LspAdapter for NodeVersionAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         let path = delegate.which(Self::SERVER_NAME.as_ref()).await?;

crates/languages/src/lib.rs

@@ -1,6 +1,6 @@
 use anyhow::Context as _;
 use feature_flags::{FeatureFlag, FeatureFlagAppExt as _};
-use gpui::{App, UpdateGlobal};
+use gpui::{App, SharedString, UpdateGlobal};
 use node_runtime::NodeRuntime;
 use python::PyprojectTomlManifestProvider;
 use rust::CargoManifestProvider;
@@ -177,11 +177,13 @@ pub fn init(languages: Arc<LanguageRegistry>, node: NodeRuntime, cx: &mut App) {
             adapters: vec![python_lsp_adapter.clone(), py_lsp_adapter.clone()],
             context: Some(python_context_provider),
             toolchain: Some(python_toolchain_provider),
+            manifest_name: Some(SharedString::new_static("pyproject.toml").into()),
         },
         LanguageInfo {
             name: "rust",
             adapters: vec![rust_lsp_adapter],
             context: Some(rust_context_provider),
+            manifest_name: Some(SharedString::new_static("Cargo.toml").into()),
             ..Default::default()
         },
         LanguageInfo {
@@ -234,6 +236,7 @@ pub fn init(languages: Arc<LanguageRegistry>, node: NodeRuntime, cx: &mut App) {
             registration.adapters,
             registration.context,
             registration.toolchain,
+            registration.manifest_name,
         );
     }
 
@@ -340,7 +343,7 @@ pub fn init(languages: Arc<LanguageRegistry>, node: NodeRuntime, cx: &mut App) {
         Arc::from(PyprojectTomlManifestProvider),
     ];
     for provider in manifest_providers {
-        project::ManifestProviders::global(cx).register(provider);
+        project::ManifestProvidersStore::global(cx).register(provider);
     }
 }
 
@@ -350,6 +353,7 @@ struct LanguageInfo {
     adapters: Vec<Arc<dyn LspAdapter>>,
     context: Option<Arc<dyn ContextProvider>>,
     toolchain: Option<Arc<dyn ToolchainLister>>,
+    manifest_name: Option<ManifestName>,
 }
 
 fn register_language(
@@ -358,6 +362,7 @@ fn register_language(
     adapters: Vec<Arc<dyn LspAdapter>>,
     context: Option<Arc<dyn ContextProvider>>,
     toolchain: Option<Arc<dyn ToolchainLister>>,
+    manifest_name: Option<ManifestName>,
 ) {
     let config = load_config(name);
     for adapter in adapters {
@@ -368,12 +373,14 @@ fn register_language(
         config.grammar.clone(),
         config.matcher.clone(),
         config.hidden,
+        manifest_name.clone(),
         Arc::new(move || {
             Ok(LoadedLanguage {
                 config: config.clone(),
                 queries: load_queries(name),
                 context_provider: context.clone(),
                 toolchain_provider: toolchain.clone(),
+                manifest_name: manifest_name.clone(),
             })
         }),
     );

crates/languages/src/python.rs

@@ -127,7 +127,7 @@ impl LspAdapter for PythonLspAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         if let Some(pyright_bin) = delegate.which("pyright-langserver".as_ref()).await {
@@ -319,17 +319,9 @@ impl LspAdapter for PythonLspAdapter {
         self: Arc<Self>,
         _: &dyn Fs,
         adapter: &Arc<dyn LspAdapterDelegate>,
-        toolchains: Arc<dyn LanguageToolchainStore>,
+        toolchain: Option<Toolchain>,
         cx: &mut AsyncApp,
     ) -> Result<Value> {
-        let toolchain = toolchains
-            .active_toolchain(
-                adapter.worktree_id(),
-                Arc::from("".as_ref()),
-                LanguageName::new("Python"),
-                cx,
-            )
-            .await;
         cx.update(move |cx| {
             let mut user_settings =
                 language_server_settings(adapter.as_ref(), &Self::SERVER_NAME, cx)
@@ -397,9 +389,7 @@ impl LspAdapter for PythonLspAdapter {
             user_settings
         })
     }
-    fn manifest_name(&self) -> Option<ManifestName> {
+
-        Some(SharedString::new_static("pyproject.toml").into())
-    }
     fn workspace_folders_content(&self) -> WorkspaceFoldersContent {
         WorkspaceFoldersContent::WorktreeRoot
     }
@@ -1046,8 +1036,8 @@ impl LspAdapter for PyLspAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        toolchains: Arc<dyn LanguageToolchainStore>,
+        toolchain: Option<Toolchain>,
-        cx: &AsyncApp,
+        _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         if let Some(pylsp_bin) = delegate.which(Self::SERVER_NAME.as_ref()).await {
             let env = delegate.shell_env().await;
@@ -1057,14 +1047,7 @@ impl LspAdapter for PyLspAdapter {
                 arguments: vec![],
             })
         } else {
-            let venv = toolchains
+            let venv = toolchain?;
-                .active_toolchain(
-                    delegate.worktree_id(),
-                    Arc::from("".as_ref()),
-                    LanguageName::new("Python"),
-                    &mut cx.clone(),
-                )
-                .await?;
             let pylsp_path = Path::new(venv.path.as_ref()).parent()?.join("pylsp");
             pylsp_path.exists().then(|| LanguageServerBinary {
                 path: venv.path.to_string().into(),
@@ -1211,17 +1194,9 @@ impl LspAdapter for PyLspAdapter {
         self: Arc<Self>,
         _: &dyn Fs,
         adapter: &Arc<dyn LspAdapterDelegate>,
-        toolchains: Arc<dyn LanguageToolchainStore>,
+        toolchain: Option<Toolchain>,
         cx: &mut AsyncApp,
     ) -> Result<Value> {
-        let toolchain = toolchains
-            .active_toolchain(
-                adapter.worktree_id(),
-                Arc::from("".as_ref()),
-                LanguageName::new("Python"),
-                cx,
-            )
-            .await;
         cx.update(move |cx| {
             let mut user_settings =
                 language_server_settings(adapter.as_ref(), &Self::SERVER_NAME, cx)
@@ -1282,9 +1257,6 @@ impl LspAdapter for PyLspAdapter {
             user_settings
         })
     }
-    fn manifest_name(&self) -> Option<ManifestName> {
-        Some(SharedString::new_static("pyproject.toml").into())
-    }
     fn workspace_folders_content(&self) -> WorkspaceFoldersContent {
         WorkspaceFoldersContent::WorktreeRoot
     }
@@ -1377,8 +1349,8 @@ impl LspAdapter for BasedPyrightLspAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        toolchains: Arc<dyn LanguageToolchainStore>,
+        toolchain: Option<Toolchain>,
-        cx: &AsyncApp,
+        _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         if let Some(bin) = delegate.which(Self::BINARY_NAME.as_ref()).await {
             let env = delegate.shell_env().await;
@@ -1388,15 +1360,7 @@ impl LspAdapter for BasedPyrightLspAdapter {
                 arguments: vec!["--stdio".into()],
             })
         } else {
-            let venv = toolchains
+            let path = Path::new(toolchain?.path.as_ref())
-                .active_toolchain(
-                    delegate.worktree_id(),
-                    Arc::from("".as_ref()),
-                    LanguageName::new("Python"),
-                    &mut cx.clone(),
-                )
-                .await?;
-            let path = Path::new(venv.path.as_ref())
                 .parent()?
                 .join(Self::BINARY_NAME);
             path.exists().then(|| LanguageServerBinary {
@@ -1543,17 +1507,9 @@ impl LspAdapter for BasedPyrightLspAdapter {
         self: Arc<Self>,
         _: &dyn Fs,
         adapter: &Arc<dyn LspAdapterDelegate>,
-        toolchains: Arc<dyn LanguageToolchainStore>,
+        toolchain: Option<Toolchain>,
         cx: &mut AsyncApp,
     ) -> Result<Value> {
-        let toolchain = toolchains
-            .active_toolchain(
-                adapter.worktree_id(),
-                Arc::from("".as_ref()),
-                LanguageName::new("Python"),
-                cx,
-            )
-            .await;
         cx.update(move |cx| {
             let mut user_settings =
                 language_server_settings(adapter.as_ref(), &Self::SERVER_NAME, cx)
@@ -1622,10 +1578,6 @@ impl LspAdapter for BasedPyrightLspAdapter {
         })
     }
 
-    fn manifest_name(&self) -> Option<ManifestName> {
-        Some(SharedString::new_static("pyproject.toml").into())
-    }
-
     fn workspace_folders_content(&self) -> WorkspaceFoldersContent {
         WorkspaceFoldersContent::WorktreeRoot
     }

crates/languages/src/rust.rs

@@ -109,14 +109,10 @@ impl LspAdapter for RustLspAdapter {
         SERVER_NAME.clone()
     }
 
-    fn manifest_name(&self) -> Option<ManifestName> {
-        Some(SharedString::new_static("Cargo.toml").into())
-    }
-
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         let path = delegate.which("rust-analyzer".as_ref()).await?;

crates/languages/src/tailwind.rs

@@ -3,7 +3,7 @@ use async_trait::async_trait;
 use collections::HashMap;
 use futures::StreamExt;
 use gpui::AsyncApp;
-use language::{LanguageName, LanguageToolchainStore, LspAdapter, LspAdapterDelegate};
+use language::{LanguageName, LspAdapter, LspAdapterDelegate, Toolchain};
 use lsp::{LanguageServerBinary, LanguageServerName};
 use node_runtime::{NodeRuntime, VersionStrategy};
 use project::{Fs, lsp_store::language_server_settings};
@@ -50,7 +50,7 @@ impl LspAdapter for TailwindLspAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         let path = delegate.which(Self::SERVER_NAME.as_ref()).await?;
@@ -155,7 +155,7 @@ impl LspAdapter for TailwindLspAdapter {
         self: Arc<Self>,
         _: &dyn Fs,
         delegate: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         cx: &mut AsyncApp,
     ) -> Result<Value> {
         let mut tailwind_user_settings = cx.update(|cx| {

crates/languages/src/typescript.rs

@@ -7,7 +7,7 @@ use gpui::{App, AppContext, AsyncApp, Task};
 use http_client::github::{AssetKind, GitHubLspBinaryVersion, build_asset_url};
 use language::{
     ContextLocation, ContextProvider, File, LanguageName, LanguageToolchainStore, LspAdapter,
-    LspAdapterDelegate,
+    LspAdapterDelegate, Toolchain,
 };
 use lsp::{CodeActionKind, LanguageServerBinary, LanguageServerName};
 use node_runtime::{NodeRuntime, VersionStrategy};
@@ -722,7 +722,7 @@ impl LspAdapter for TypeScriptLspAdapter {
         self: Arc<Self>,
         _: &dyn Fs,
         delegate: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         cx: &mut AsyncApp,
     ) -> Result<Value> {
         let override_options = cx.update(|cx| {
@@ -822,7 +822,7 @@ impl LspAdapter for EsLintLspAdapter {
         self: Arc<Self>,
         _: &dyn Fs,
         delegate: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         cx: &mut AsyncApp,
     ) -> Result<Value> {
         let workspace_root = delegate.worktree_root_path();

crates/languages/src/vtsls.rs

@@ -2,7 +2,7 @@ use anyhow::Result;
 use async_trait::async_trait;
 use collections::HashMap;
 use gpui::AsyncApp;
-use language::{LanguageName, LanguageToolchainStore, LspAdapter, LspAdapterDelegate};
+use language::{LanguageName, LspAdapter, LspAdapterDelegate, Toolchain};
 use lsp::{CodeActionKind, LanguageServerBinary, LanguageServerName};
 use node_runtime::{NodeRuntime, VersionStrategy};
 use project::{Fs, lsp_store::language_server_settings};
@@ -86,7 +86,7 @@ impl LspAdapter for VtslsLspAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         let env = delegate.shell_env().await;
@@ -211,7 +211,7 @@ impl LspAdapter for VtslsLspAdapter {
         self: Arc<Self>,
         fs: &dyn Fs,
         delegate: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         cx: &mut AsyncApp,
     ) -> Result<Value> {
         let tsdk_path = Self::tsdk_path(fs, delegate).await;

crates/languages/src/yaml.rs

@@ -2,9 +2,7 @@ use anyhow::{Context as _, Result};
 use async_trait::async_trait;
 use futures::StreamExt;
 use gpui::AsyncApp;
-use language::{
+use language::{LspAdapter, LspAdapterDelegate, Toolchain, language_settings::AllLanguageSettings};
-    LanguageToolchainStore, LspAdapter, LspAdapterDelegate, language_settings::AllLanguageSettings,
-};
 use lsp::{LanguageServerBinary, LanguageServerName};
 use node_runtime::{NodeRuntime, VersionStrategy};
 use project::{Fs, lsp_store::language_server_settings};
@@ -57,7 +55,7 @@ impl LspAdapter for YamlLspAdapter {
     async fn check_if_user_installed(
         &self,
         delegate: &dyn LspAdapterDelegate,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         _: &AsyncApp,
     ) -> Option<LanguageServerBinary> {
         let path = delegate.which(Self::SERVER_NAME.as_ref()).await?;
@@ -135,7 +133,7 @@ impl LspAdapter for YamlLspAdapter {
         self: Arc<Self>,
         _: &dyn Fs,
         delegate: &Arc<dyn LspAdapterDelegate>,
-        _: Arc<dyn LanguageToolchainStore>,
+        _: Option<Toolchain>,
         cx: &mut AsyncApp,
     ) -> Result<Value> {
         let location = SettingsLocation {

crates/project/src/lsp_command.rs

@@ -500,13 +500,12 @@ impl LspCommand for PerformRename {
         mut cx: AsyncApp,
     ) -> Result<ProjectTransaction> {
         if let Some(edit) = message {
-            let (lsp_adapter, lsp_server) =
+            let (_, lsp_server) =
                 language_server_for_buffer(&lsp_store, &buffer, server_id, &mut cx)?;
             LocalLspStore::deserialize_workspace_edit(
                 lsp_store,
                 edit,
                 self.push_to_history,
-                lsp_adapter,
                 lsp_server,
                 &mut cx,
             )
@@ -1116,18 +1115,12 @@ pub async fn location_links_from_lsp(
         }
     }
 
-    let (lsp_adapter, language_server) =
+    let (_, language_server) = language_server_for_buffer(&lsp_store, &buffer, server_id, &mut cx)?;
-        language_server_for_buffer(&lsp_store, &buffer, server_id, &mut cx)?;
     let mut definitions = Vec::new();
     for (origin_range, target_uri, target_range) in unresolved_links {
         let target_buffer_handle = lsp_store
             .update(&mut cx, |this, cx| {
-                this.open_local_buffer_via_lsp(
+                this.open_local_buffer_via_lsp(target_uri, language_server.server_id(), cx)
-                    target_uri,
-                    language_server.server_id(),
-                    lsp_adapter.name.clone(),
-                    cx,
-                )
             })?
             .await?;
 
@@ -1172,8 +1165,7 @@ pub async fn location_link_from_lsp(
     server_id: LanguageServerId,
     cx: &mut AsyncApp,
 ) -> Result<LocationLink> {
-    let (lsp_adapter, language_server) =
+    let (_, language_server) = language_server_for_buffer(&lsp_store, &buffer, server_id, cx)?;
-        language_server_for_buffer(&lsp_store, &buffer, server_id, cx)?;
 
     let (origin_range, target_uri, target_range) = (
         link.origin_selection_range,
@@ -1183,12 +1175,7 @@ pub async fn location_link_from_lsp(
 
     let target_buffer_handle = lsp_store
         .update(cx, |lsp_store, cx| {
-            lsp_store.open_local_buffer_via_lsp(
+            lsp_store.open_local_buffer_via_lsp(target_uri, language_server.server_id(), cx)
-                target_uri,
-                language_server.server_id(),
-                lsp_adapter.name.clone(),
-                cx,
-            )
         })?
         .await?;
 
@@ -1326,7 +1313,7 @@ impl LspCommand for GetReferences {
         mut cx: AsyncApp,
     ) -> Result<Vec<Location>> {
         let mut references = Vec::new();
-        let (lsp_adapter, language_server) =
+        let (_, language_server) =
             language_server_for_buffer(&lsp_store, &buffer, server_id, &mut cx)?;
 
         if let Some(locations) = locations {
@@ -1336,7 +1323,6 @@ impl LspCommand for GetReferences {
                         lsp_store.open_local_buffer_via_lsp(
                             lsp_location.uri,
                             language_server.server_id(),
-                            lsp_adapter.name.clone(),
                             cx,
                         )
                     })?

crates/project/src/manifest_tree.rs

@@ -7,18 +7,12 @@ mod manifest_store;
 mod path_trie;
 mod server_tree;
 
-use std::{
+use std::{borrow::Borrow, collections::hash_map::Entry, ops::ControlFlow, path::Path, sync::Arc};
-    borrow::Borrow,
-    collections::{BTreeMap, hash_map::Entry},
-    ops::ControlFlow,
-    path::Path,
-    sync::Arc,
-};
 
 use collections::HashMap;
-use gpui::{App, AppContext as _, Context, Entity, EventEmitter, Subscription};
+use gpui::{App, AppContext as _, Context, Entity, Subscription};
 use language::{ManifestDelegate, ManifestName, ManifestQuery};
-pub use manifest_store::ManifestProviders;
+pub use manifest_store::ManifestProvidersStore;
 use path_trie::{LabelPresence, RootPathTrie, TriePath};
 use settings::{SettingsStore, WorktreeId};
 use worktree::{Event as WorktreeEvent, Snapshot, Worktree};
@@ -28,9 +22,7 @@ use crate::{
     worktree_store::{WorktreeStore, WorktreeStoreEvent},
 };
 
-pub(crate) use server_tree::{
+pub(crate) use server_tree::{LanguageServerTree, LanguageServerTreeNode, LaunchDisposition};
-    AdapterQuery, LanguageServerTree, LanguageServerTreeNode, LaunchDisposition,
-};
 
 struct WorktreeRoots {
     roots: RootPathTrie<ManifestName>,
@@ -81,14 +73,6 @@ pub struct ManifestTree {
     _subscriptions: [Subscription; 2],
 }
 
-#[derive(PartialEq)]
-pub(crate) enum ManifestTreeEvent {
-    WorktreeRemoved(WorktreeId),
-    Cleared,
-}
-
-impl EventEmitter<ManifestTreeEvent> for ManifestTree {}
-
 impl ManifestTree {
     pub fn new(worktree_store: Entity<WorktreeStore>, cx: &mut App) -> Entity<Self> {
         cx.new(|cx| Self {
@@ -101,30 +85,28 @@ impl ManifestTree {
                             worktree_roots.roots = RootPathTrie::new();
                         })
                     }
-                    cx.emit(ManifestTreeEvent::Cleared);
                 }),
             ],
             worktree_store,
         })
     }
+
     pub(crate) fn root_for_path(
         &mut self,
-        ProjectPath { worktree_id, path }: ProjectPath,
+        ProjectPath { worktree_id, path }: &ProjectPath,
-        manifests: &mut dyn Iterator<Item = ManifestName>,
+        manifest_name: &ManifestName,
-        delegate: Arc<dyn ManifestDelegate>,
+        delegate: &Arc<dyn ManifestDelegate>,
         cx: &mut App,
-    ) -> BTreeMap<ManifestName, ProjectPath> {
+    ) -> Option<ProjectPath> {
-        debug_assert_eq!(delegate.worktree_id(), worktree_id);
+        debug_assert_eq!(delegate.worktree_id(), *worktree_id);
-        let mut roots = BTreeMap::from_iter(
+        let (mut marked_path, mut current_presence) = (None, LabelPresence::KnownAbsent);
-            manifests.map(|manifest| (manifest, (None, LabelPresence::KnownAbsent))),
+        let worktree_roots = match self.root_points.entry(*worktree_id) {
-        );
-        let worktree_roots = match self.root_points.entry(worktree_id) {
             Entry::Occupied(occupied_entry) => occupied_entry.get().clone(),
             Entry::Vacant(vacant_entry) => {
                 let Some(worktree) = self
                     .worktree_store
                     .read(cx)
-                    .worktree_for_id(worktree_id, cx)
+                    .worktree_for_id(*worktree_id, cx)
                 else {
                     return Default::default();
                 };
@@ -133,16 +115,16 @@ impl ManifestTree {
             }
         };
 
-        let key = TriePath::from(&*path);
+        let key = TriePath::from(&**path);
         worktree_roots.read_with(cx, |this, _| {
             this.roots.walk(&key, &mut |path, labels| {
                 for (label, presence) in labels {
-                    if let Some((marked_path, current_presence)) = roots.get_mut(label) {
+                    if label == manifest_name {
-                        if *current_presence > *presence {
+                        if current_presence > *presence {
                             debug_assert!(false, "RootPathTrie precondition violation; while walking the tree label presence is only allowed to increase");
                         }
-                        *marked_path = Some(ProjectPath {worktree_id, path: path.clone()});
+                        marked_path = Some(ProjectPath {worktree_id: *worktree_id, path: path.clone()});
-                        *current_presence = *presence;
+                        current_presence = *presence;
                     }
 
                 }
@@ -150,12 +132,9 @@ impl ManifestTree {
             });
         });
 
-        for (manifest_name, (root_path, presence)) in &mut roots {
+        if current_presence == LabelPresence::KnownAbsent {
-            if *presence == LabelPresence::Present {
+            // Some part of the path is unexplored.
-                continue;
+            let depth = marked_path
-            }
-
-            let depth = root_path
                 .as_ref()
                 .map(|root_path| {
                     path.strip_prefix(&root_path.path)
@@ -165,13 +144,10 @@ impl ManifestTree {
                 })
                 .unwrap_or_else(|| path.components().count() + 1);
 
-            if depth > 0 {
+            if depth > 0
-                let Some(provider) = ManifestProviders::global(cx).get(manifest_name.borrow())
+                && let Some(provider) =
-                else {
+                    ManifestProvidersStore::global(cx).get(manifest_name.borrow())
-                    log::warn!("Manifest provider `{}` not found", manifest_name.as_ref());
+            {
-                    continue;
-                };
-
                 let root = provider.search(ManifestQuery {
                     path: path.clone(),
                     depth,
@@ -182,9 +158,9 @@ impl ManifestTree {
                         let root = TriePath::from(&*known_root);
                         this.roots
                             .insert(&root, manifest_name.clone(), LabelPresence::Present);
-                        *presence = LabelPresence::Present;
+                        current_presence = LabelPresence::Present;
-                        *root_path = Some(ProjectPath {
+                        marked_path = Some(ProjectPath {
-                            worktree_id,
+                            worktree_id: *worktree_id,
                             path: known_root,
                         });
                     }),
@@ -195,25 +171,35 @@ impl ManifestTree {
                 }
             }
         }
-
+        marked_path.filter(|_| current_presence.eq(&LabelPresence::Present))
-        roots
-            .into_iter()
-            .filter_map(|(k, (path, presence))| {
-                let path = path?;
-                presence.eq(&LabelPresence::Present).then(|| (k, path))
-            })
-            .collect()
     }
+
+    pub(crate) fn root_for_path_or_worktree_root(
+        &mut self,
+        project_path: &ProjectPath,
+        manifest_name: Option<&ManifestName>,
+        delegate: &Arc<dyn ManifestDelegate>,
+        cx: &mut App,
+    ) -> ProjectPath {
+        let worktree_id = project_path.worktree_id;
+        // Backwards-compat: Fill in any adapters for which we did not detect the root as having the project root at the root of a worktree.
+        manifest_name
+            .and_then(|manifest_name| self.root_for_path(project_path, manifest_name, delegate, cx))
+            .unwrap_or_else(|| ProjectPath {
+                worktree_id,
+                path: Arc::from(Path::new("")),
+            })
+    }
+
     fn on_worktree_store_event(
         &mut self,
         _: Entity<WorktreeStore>,
         evt: &WorktreeStoreEvent,
-        cx: &mut Context<Self>,
+        _: &mut Context<Self>,
     ) {
         match evt {
             WorktreeStoreEvent::WorktreeRemoved(_, worktree_id) => {
                 self.root_points.remove(&worktree_id);
-                cx.emit(ManifestTreeEvent::WorktreeRemoved(*worktree_id));
             }
             _ => {}
         }
@@ -223,6 +209,7 @@ impl ManifestTree {
 pub(crate) struct ManifestQueryDelegate {
     worktree: Snapshot,
 }
+
 impl ManifestQueryDelegate {
     pub fn new(worktree: Snapshot) -> Self {
         Self { worktree }

crates/project/src/manifest_tree/manifest_store.rs

@@ -1,4 +1,4 @@
-use collections::HashMap;
+use collections::{HashMap, HashSet};
 use gpui::{App, Global, SharedString};
 use parking_lot::RwLock;
 use std::{ops::Deref, sync::Arc};
@@ -11,13 +11,13 @@ struct ManifestProvidersState {
 }
 
 #[derive(Clone, Default)]
-pub struct ManifestProviders(Arc<RwLock<ManifestProvidersState>>);
+pub struct ManifestProvidersStore(Arc<RwLock<ManifestProvidersState>>);
 
 #[derive(Default)]
-struct GlobalManifestProvider(ManifestProviders);
+struct GlobalManifestProvider(ManifestProvidersStore);
 
 impl Deref for GlobalManifestProvider {
-    type Target = ManifestProviders;
+    type Target = ManifestProvidersStore;
 
     fn deref(&self) -> &Self::Target {
         &self.0
@@ -26,7 +26,7 @@ impl Deref for GlobalManifestProvider {
 
 impl Global for GlobalManifestProvider {}
 
-impl ManifestProviders {
+impl ManifestProvidersStore {
     /// Returns the global [`ManifestStore`].
     ///
     /// Inserts a default [`ManifestStore`] if one does not yet exist.
@@ -45,4 +45,7 @@ impl ManifestProviders {
     pub(super) fn get(&self, name: &SharedString) -> Option<Arc<dyn ManifestProvider>> {
         self.0.read().providers.get(name).cloned()
     }
+    pub(crate) fn manifest_file_names(&self) -> HashSet<ManifestName> {
+        self.0.read().providers.keys().cloned().collect()
+    }
 }

crates/project/src/manifest_tree/server_tree.rs

@@ -4,8 +4,7 @@
 //!
 //! ## RPC
 //! LSP Tree is transparent to RPC peers; when clients ask host to spawn a new language server, the host will perform LSP Tree lookup for provided path; it may decide
-//! to reuse existing language server. The client maintains it's own LSP Tree that is a subset of host LSP Tree. Done this way, the client does not need to
+//! to reuse existing language server.
-//! ask about suitable language server for each path it interacts with; it can resolve most of the queries locally.
 
 use std::{
     collections::{BTreeMap, BTreeSet},
@@ -14,20 +13,23 @@ use std::{
 };
 
 use collections::IndexMap;
-use gpui::{App, AppContext as _, Entity, Subscription};
+use gpui::{App, Entity};
 use language::{
-    CachedLspAdapter, LanguageName, LanguageRegistry, ManifestDelegate,
+    CachedLspAdapter, LanguageName, LanguageRegistry, ManifestDelegate, ManifestName, Toolchain,
     language_settings::AllLanguageSettings,
 };
 use lsp::LanguageServerName;
 use settings::{Settings, SettingsLocation, WorktreeId};
 use std::sync::OnceLock;
 
-use crate::{LanguageServerId, ProjectPath, project_settings::LspSettings};
+use crate::{
+    LanguageServerId, ProjectPath, project_settings::LspSettings,
+    toolchain_store::LocalToolchainStore,
+};
 
-use super::{ManifestTree, ManifestTreeEvent};
+use super::ManifestTree;
 
-#[derive(Debug, Default)]
+#[derive(Clone, Debug, Default)]
 pub(crate) struct ServersForWorktree {
     pub(crate) roots: BTreeMap<
         Arc<Path>,
@@ -39,7 +41,7 @@ pub struct LanguageServerTree {
     manifest_tree: Entity<ManifestTree>,
     pub(crate) instances: BTreeMap<WorktreeId, ServersForWorktree>,
     languages: Arc<LanguageRegistry>,
-    _subscriptions: Subscription,
+    toolchains: Entity<LocalToolchainStore>,
 }
 
 /// A node in language server tree represents either:
@@ -49,22 +51,15 @@ pub struct LanguageServerTree {
 pub struct LanguageServerTreeNode(Weak<InnerTreeNode>);
 
 /// Describes a request to launch a language server.
-#[derive(Debug)]
+#[derive(Clone, Debug)]
-pub(crate) struct LaunchDisposition<'a> {
+pub(crate) struct LaunchDisposition {
-    pub(crate) server_name: &'a LanguageServerName,
+    pub(crate) server_name: LanguageServerName,
+    /// Path to the root directory of a subproject.
     pub(crate) path: ProjectPath,
     pub(crate) settings: Arc<LspSettings>,
+    pub(crate) toolchain: Option<Toolchain>,
 }
 
-impl<'a> From<&'a InnerTreeNode> for LaunchDisposition<'a> {
-    fn from(value: &'a InnerTreeNode) -> Self {
-        LaunchDisposition {
-            server_name: &value.name,
-            path: value.path.clone(),
-            settings: value.settings.clone(),
-        }
-    }
-}
 impl LanguageServerTreeNode {
     /// Returns a language server ID for this node if there is one.
     /// Returns None if this node has not been initialized yet or it is no longer in the tree.
@@ -76,19 +71,17 @@ impl LanguageServerTreeNode {
     /// May return None if the node no longer belongs to the server tree it was created in.
     pub(crate) fn server_id_or_init(
         &self,
-        init: impl FnOnce(LaunchDisposition) -> LanguageServerId,
+        init: impl FnOnce(&Arc<LaunchDisposition>) -> LanguageServerId,
     ) -> Option<LanguageServerId> {
         let this = self.0.upgrade()?;
-        Some(
+        Some(*this.id.get_or_init(|| init(&this.disposition)))
-            *this
-                .id
-                .get_or_init(|| init(LaunchDisposition::from(&*this))),
-        )
     }
 
     /// Returns a language server name as the language server adapter would return.
     pub fn name(&self) -> Option<LanguageServerName> {
-        self.0.upgrade().map(|node| node.name.clone())
+        self.0
+            .upgrade()
+            .map(|node| node.disposition.server_name.clone())
     }
 }
 
@@ -101,126 +94,79 @@ impl From<Weak<InnerTreeNode>> for LanguageServerTreeNode {
 #[derive(Debug)]
 pub struct InnerTreeNode {
     id: OnceLock<LanguageServerId>,
-    name: LanguageServerName,
+    disposition: Arc<LaunchDisposition>,
-    path: ProjectPath,
-    settings: Arc<LspSettings>,
 }
 
 impl InnerTreeNode {
     fn new(
-        name: LanguageServerName,
+        server_name: LanguageServerName,
         path: ProjectPath,
-        settings: impl Into<Arc<LspSettings>>,
+        settings: LspSettings,
+        toolchain: Option<Toolchain>,
     ) -> Self {
         InnerTreeNode {
             id: Default::default(),
-            name,
+            disposition: Arc::new(LaunchDisposition {
+                server_name,
                 path,
                 settings: settings.into(),
+                toolchain,
+            }),
         }
     }
 }
 
-/// Determines how the list of adapters to query should be constructed.
-pub(crate) enum AdapterQuery<'a> {
-    /// Search for roots of all adapters associated with a given language name.
-    /// Layman: Look for all project roots along the queried path that have any
-    /// language server associated with this language running.
-    Language(&'a LanguageName),
-    /// Search for roots of adapter with a given name.
-    /// Layman: Look for all project roots along the queried path that have this server running.
-    Adapter(&'a LanguageServerName),
-}
-
 impl LanguageServerTree {
     pub(crate) fn new(
         manifest_tree: Entity<ManifestTree>,
         languages: Arc<LanguageRegistry>,
-        cx: &mut App,
+        toolchains: Entity<LocalToolchainStore>,
-    ) -> Entity<Self> {
+    ) -> Self {
-        cx.new(|cx| Self {
+        Self {
-            _subscriptions: cx.subscribe(&manifest_tree, |_: &mut Self, _, event, _| {
-                if event == &ManifestTreeEvent::Cleared {}
-            }),
             manifest_tree,
             instances: Default::default(),
-
             languages,
-        })
+            toolchains,
+        }
+    }
+
+    /// Get all initialized language server IDs for a given path.
+    pub(crate) fn get<'a>(
+        &'a self,
+        path: ProjectPath,
+        language_name: LanguageName,
+        manifest_name: Option<&ManifestName>,
+        delegate: &Arc<dyn ManifestDelegate>,
+        cx: &mut App,
+    ) -> impl Iterator<Item = LanguageServerId> + 'a {
+        let manifest_location = self.manifest_location_for_path(&path, manifest_name, delegate, cx);
+        let adapters = self.adapters_for_language(&manifest_location, &language_name, cx);
+        self.get_with_adapters(manifest_location, adapters)
     }
 
     /// Get all language server root points for a given path and language; the language servers might already be initialized at a given path.
-    pub(crate) fn get<'a>(
+    pub(crate) fn walk<'a>(
         &'a mut self,
         path: ProjectPath,
-        query: AdapterQuery<'_>,
+        language_name: LanguageName,
-        delegate: Arc<dyn ManifestDelegate>,
+        manifest_name: Option<&ManifestName>,
-        cx: &mut App,
+        delegate: &Arc<dyn ManifestDelegate>,
+        cx: &'a mut App,
     ) -> impl Iterator<Item = LanguageServerTreeNode> + 'a {
-        let settings_location = SettingsLocation {
+        let manifest_location = self.manifest_location_for_path(&path, manifest_name, delegate, cx);
-            worktree_id: path.worktree_id,
+        let adapters = self.adapters_for_language(&manifest_location, &language_name, cx);
-            path: &path.path,
+        self.init_with_adapters(manifest_location, language_name, adapters, cx)
-        };
-        let adapters = match query {
-            AdapterQuery::Language(language_name) => {
-                self.adapters_for_language(settings_location, language_name, cx)
-            }
-            AdapterQuery::Adapter(language_server_name) => {
-                IndexMap::from_iter(self.adapter_for_name(language_server_name).map(|adapter| {
-                    (
-                        adapter.name(),
-                        (LspSettings::default(), BTreeSet::new(), adapter),
-                    )
-                }))
-            }
-        };
-        self.get_with_adapters(path, adapters, delegate, cx)
     }
 
-    fn get_with_adapters<'a>(
+    fn init_with_adapters<'a>(
         &'a mut self,
-        path: ProjectPath,
+        root_path: ProjectPath,
-        adapters: IndexMap<
+        language_name: LanguageName,
-            LanguageServerName,
+        adapters: IndexMap<LanguageServerName, (LspSettings, Arc<CachedLspAdapter>)>,
-            (LspSettings, BTreeSet<LanguageName>, Arc<CachedLspAdapter>),
+        cx: &'a App,
-        >,
-        delegate: Arc<dyn ManifestDelegate>,
-        cx: &mut App,
     ) -> impl Iterator<Item = LanguageServerTreeNode> + 'a {
-        let worktree_id = path.worktree_id;
+        adapters.into_iter().map(move |(_, (settings, adapter))| {
-
+            let root_path = root_path.clone();
-        let mut manifest_to_adapters = BTreeMap::default();
-        for (_, _, adapter) in adapters.values() {
-            if let Some(manifest_name) = adapter.manifest_name() {
-                manifest_to_adapters
-                    .entry(manifest_name)
-                    .or_insert_with(Vec::default)
-                    .push(adapter.clone());
-            }
-        }
-
-        let roots = self.manifest_tree.update(cx, |this, cx| {
-            this.root_for_path(
-                path,
-                &mut manifest_to_adapters.keys().cloned(),
-                delegate,
-                cx,
-            )
-        });
-        let root_path = std::cell::LazyCell::new(move || ProjectPath {
-            worktree_id,
-            path: Arc::from("".as_ref()),
-        });
-        adapters
-            .into_iter()
-            .map(move |(_, (settings, new_languages, adapter))| {
-                // Backwards-compat: Fill in any adapters for which we did not detect the root as having the project root at the root of a worktree.
-                let root_path = adapter
-                    .manifest_name()
-                    .and_then(|name| roots.get(&name))
-                    .cloned()
-                    .unwrap_or_else(|| root_path.clone());
-
             let inner_node = self
                 .instances
                 .entry(root_path.worktree_id)
@@ -230,31 +176,67 @@ impl LanguageServerTree {
                 .or_default()
                 .entry(adapter.name());
             let (node, languages) = inner_node.or_insert_with(|| {
+                let toolchain = self.toolchains.read(cx).active_toolchain(
+                    root_path.worktree_id,
+                    &root_path.path,
+                    language_name.clone(),
+                );
                 (
                     Arc::new(InnerTreeNode::new(
                         adapter.name(),
                         root_path.clone(),
                         settings.clone(),
+                        toolchain,
                     )),
                     Default::default(),
                 )
             });
-                languages.extend(new_languages.iter().cloned());
+            languages.insert(language_name.clone());
             Arc::downgrade(&node).into()
         })
     }
 
-    fn adapter_for_name(&self, name: &LanguageServerName) -> Option<Arc<CachedLspAdapter>> {
+    fn get_with_adapters<'a>(
-        self.languages.adapter_for_name(name)
+        &'a self,
+        root_path: ProjectPath,
+        adapters: IndexMap<LanguageServerName, (LspSettings, Arc<CachedLspAdapter>)>,
+    ) -> impl Iterator<Item = LanguageServerId> + 'a {
+        adapters.into_iter().filter_map(move |(_, (_, adapter))| {
+            let root_path = root_path.clone();
+            let inner_node = self
+                .instances
+                .get(&root_path.worktree_id)?
+                .roots
+                .get(&root_path.path)?
+                .get(&adapter.name())?;
+            inner_node.0.id.get().copied()
+        })
+    }
+
+    fn manifest_location_for_path(
+        &self,
+        path: &ProjectPath,
+        manifest_name: Option<&ManifestName>,
+        delegate: &Arc<dyn ManifestDelegate>,
+        cx: &mut App,
+    ) -> ProjectPath {
+        // Find out what the root location of our subproject is.
+        // That's where we'll look for language settings (that include a set of language servers).
+        self.manifest_tree.update(cx, |this, cx| {
+            this.root_for_path_or_worktree_root(path, manifest_name, delegate, cx)
+        })
     }
 
     fn adapters_for_language(
         &self,
-        settings_location: SettingsLocation,
+        manifest_location: &ProjectPath,
         language_name: &LanguageName,
         cx: &App,
-    ) -> IndexMap<LanguageServerName, (LspSettings, BTreeSet<LanguageName>, Arc<CachedLspAdapter>)>
+    ) -> IndexMap<LanguageServerName, (LspSettings, Arc<CachedLspAdapter>)> {
-    {
+        let settings_location = SettingsLocation {
+            worktree_id: manifest_location.worktree_id,
+            path: &manifest_location.path,
+        };
         let settings = AllLanguageSettings::get(Some(settings_location), cx).language(
             Some(settings_location),
             Some(language_name),
@@ -295,14 +277,7 @@ impl LanguageServerTree {
                 )
                 .cloned()
                 .unwrap_or_default();
-                Some((
+                Some((adapter.name(), (adapter_settings, adapter)))
-                    adapter.name(),
-                    (
-                        adapter_settings,
-                        BTreeSet::from_iter([language_name.clone()]),
-                        adapter,
-                    ),
-                ))
             })
             .collect::<IndexMap<_, _>>();
         // After starting all the language servers, reorder them to reflect the desired order
@@ -315,17 +290,23 @@ impl LanguageServerTree {
             &language_name,
             adapters_with_settings
                 .values()
-                .map(|(_, _, adapter)| adapter.clone())
+                .map(|(_, adapter)| adapter.clone())
                 .collect(),
         );
 
         adapters_with_settings
     }
 
-    // Rebasing a tree:
+    /// Server Tree is built up incrementally via queries for distinct paths of the worktree.
-    // - Clears it out
+    /// Results of these queries have to be invalidated when data used to build the tree changes.
-    // - Provides you with the indirect access to the old tree while you're reinitializing a new one (by querying it).
+    ///
-    pub(crate) fn rebase(&mut self) -> ServerTreeRebase<'_> {
+    /// The environment of a server tree is a set of all user settings.
+    /// Rebasing a tree means invalidating it and building up a new one while reusing the old tree where applicable.
+    /// We want to reuse the old tree in order to preserve as many of the running language servers as possible.
+    /// E.g. if the user disables one of their language servers for Python, we don't want to shut down any language servers unaffected by this settings change.
+    ///
+    /// Thus, [`ServerTreeRebase`] mimics the interface of a [`ServerTree`], except that it tries to find a matching language server in the old tree before handing out an uninitialized node.
+    pub(crate) fn rebase(&mut self) -> ServerTreeRebase {
         ServerTreeRebase::new(self)
     }
 
@@ -354,16 +335,16 @@ impl LanguageServerTree {
             .roots
             .entry(Arc::from(Path::new("")))
             .or_default()
-            .entry(node.name.clone())
+            .entry(node.disposition.server_name.clone())
             .or_insert_with(|| (node, BTreeSet::new()))
             .1
             .insert(language_name);
     }
 }
 
-pub(crate) struct ServerTreeRebase<'a> {
+pub(crate) struct ServerTreeRebase {
     old_contents: BTreeMap<WorktreeId, ServersForWorktree>,
-    new_tree: &'a mut LanguageServerTree,
+    new_tree: LanguageServerTree,
     /// All server IDs seen in the old tree.
     all_server_ids: BTreeMap<LanguageServerId, LanguageServerName>,
     /// Server IDs we've preserved for a new iteration of the tree. `all_server_ids - rebased_server_ids` is the
@@ -371,9 +352,9 @@ pub(crate) struct ServerTreeRebase<'a> {
     rebased_server_ids: BTreeSet<LanguageServerId>,
 }
 
-impl<'tree> ServerTreeRebase<'tree> {
+impl ServerTreeRebase {
-    fn new(new_tree: &'tree mut LanguageServerTree) -> Self {
+    fn new(old_tree: &LanguageServerTree) -> Self {
-        let old_contents = std::mem::take(&mut new_tree.instances);
+        let old_contents = old_tree.instances.clone();
         let all_server_ids = old_contents
             .values()
             .flat_map(|nodes| {
@@ -384,69 +365,68 @@ impl<'tree> ServerTreeRebase<'tree> {
                             .id
                             .get()
                             .copied()
-                            .map(|id| (id, server.0.name.clone()))
+                            .map(|id| (id, server.0.disposition.server_name.clone()))
                     })
                 })
             })
             .collect();
+        let new_tree = LanguageServerTree::new(
+            old_tree.manifest_tree.clone(),
+            old_tree.languages.clone(),
+            old_tree.toolchains.clone(),
+        );
         Self {
             old_contents,
-            new_tree,
             all_server_ids,
+            new_tree,
             rebased_server_ids: BTreeSet::new(),
         }
     }
 
-    pub(crate) fn get<'a>(
+    pub(crate) fn walk<'a>(
         &'a mut self,
         path: ProjectPath,
-        query: AdapterQuery<'_>,
+        language_name: LanguageName,
+        manifest_name: Option<&ManifestName>,
         delegate: Arc<dyn ManifestDelegate>,
-        cx: &mut App,
+        cx: &'a mut App,
     ) -> impl Iterator<Item = LanguageServerTreeNode> + 'a {
-        let settings_location = SettingsLocation {
+        let manifest =
-            worktree_id: path.worktree_id,
-            path: &path.path,
-        };
-        let adapters = match query {
-            AdapterQuery::Language(language_name) => {
             self.new_tree
-                    .adapters_for_language(settings_location, language_name, cx)
+                .manifest_location_for_path(&path, manifest_name, &delegate, cx);
-            }
+        let adapters = self
-            AdapterQuery::Adapter(language_server_name) => {
+            .new_tree
-                IndexMap::from_iter(self.new_tree.adapter_for_name(language_server_name).map(
+            .adapters_for_language(&manifest, &language_name, cx);
-                    |adapter| {
-                        (
-                            adapter.name(),
-                            (LspSettings::default(), BTreeSet::new(), adapter),
-                        )
-                    },
-                ))
-            }
-        };
 
         self.new_tree
-            .get_with_adapters(path, adapters, delegate, cx)
+            .init_with_adapters(manifest, language_name, adapters, cx)
             .filter_map(|node| {
                 // Inspect result of the query and initialize it ourselves before
                 // handing it off to the caller.
-                let disposition = node.0.upgrade()?;
+                let live_node = node.0.upgrade()?;
 
-                if disposition.id.get().is_some() {
+                if live_node.id.get().is_some() {
                     return Some(node);
                 }
+                let disposition = &live_node.disposition;
                 let Some((existing_node, _)) = self
                     .old_contents
                     .get(&disposition.path.worktree_id)
                     .and_then(|worktree_nodes| worktree_nodes.roots.get(&disposition.path.path))
-                    .and_then(|roots| roots.get(&disposition.name))
+                    .and_then(|roots| roots.get(&disposition.server_name))
-                    .filter(|(old_node, _)| disposition.settings == old_node.settings)
+                    .filter(|(old_node, _)| {
+                        (&disposition.toolchain, &disposition.settings)
+                            == (
+                                &old_node.disposition.toolchain,
+                                &old_node.disposition.settings,
+                            )
+                    })
                 else {
                     return Some(node);
                 };
                 if let Some(existing_id) = existing_node.id.get() {
                     self.rebased_server_ids.insert(*existing_id);
-                    disposition.id.set(*existing_id).ok();
+                    live_node.id.set(*existing_id).ok();
                 }
 
                 Some(node)
@@ -454,11 +434,19 @@ impl<'tree> ServerTreeRebase<'tree> {
     }
 
     /// Returns IDs of servers that are no longer referenced (and can be shut down).
-    pub(crate) fn finish(self) -> BTreeMap<LanguageServerId, LanguageServerName> {
+    pub(crate) fn finish(
+        self,
+    ) -> (
+        LanguageServerTree,
+        BTreeMap<LanguageServerId, LanguageServerName>,
+    ) {
+        (
+            self.new_tree,
             self.all_server_ids
                 .into_iter()
                 .filter(|(id, _)| !self.rebased_server_ids.contains(id))
-            .collect()
+                .collect(),
+        )
     }
 
     pub(crate) fn server_tree(&mut self) -> &mut LanguageServerTree {

crates/project/src/project.rs

@@ -84,7 +84,7 @@ use lsp::{
 };
 use lsp_command::*;
 use lsp_store::{CompletionDocumentation, LspFormatTarget, OpenLspBufferHandle};
-pub use manifest_tree::ManifestProviders;
+pub use manifest_tree::ManifestProvidersStore;
 use node_runtime::NodeRuntime;
 use parking_lot::Mutex;
 pub use prettier_store::PrettierStore;
@@ -1115,7 +1115,11 @@ impl Project {
                     buffer_store.clone(),
                     worktree_store.clone(),
                     prettier_store.clone(),
-                    toolchain_store.clone(),
+                    toolchain_store
+                        .read(cx)
+                        .as_local_store()
+                        .expect("Toolchain store to be local")
+                        .clone(),
                     environment.clone(),
                     manifest_tree,
                     languages.clone(),
@@ -1260,7 +1264,6 @@ impl Project {
                 LspStore::new_remote(
                     buffer_store.clone(),
                     worktree_store.clone(),
-                    Some(toolchain_store.clone()),
                     languages.clone(),
                     ssh_proto.clone(),
                     SSH_PROJECT_ID,
@@ -1485,7 +1488,6 @@ impl Project {
             let mut lsp_store = LspStore::new_remote(
                 buffer_store.clone(),
                 worktree_store.clone(),
-                None,
                 languages.clone(),
                 client.clone().into(),
                 remote_id,
@@ -3596,16 +3598,10 @@ impl Project {
         &mut self,
         abs_path: lsp::Url,
         language_server_id: LanguageServerId,
-        language_server_name: LanguageServerName,
         cx: &mut Context<Self>,
     ) -> Task<Result<Entity<Buffer>>> {
         self.lsp_store.update(cx, |lsp_store, cx| {
-            lsp_store.open_local_buffer_via_lsp(
+            lsp_store.open_local_buffer_via_lsp(abs_path, language_server_id, cx)
-                abs_path,
-                language_server_id,
-                language_server_name,
-                cx,
-            )
         })
     }
 

crates/project/src/project_settings.rs

@@ -22,6 +22,7 @@ use settings::{
     SettingsStore, parse_json_with_comments, watch_config_file,
 };
 use std::{
+    collections::BTreeMap,
     path::{Path, PathBuf},
     sync::Arc,
     time::Duration,
@@ -518,16 +519,15 @@ impl Default for InlineBlameSettings {
     }
 }
 
-#[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema, Hash)]
 pub struct BinarySettings {
     pub path: Option<String>,
     pub arguments: Option<Vec<String>>,
-    // this can't be an FxHashMap because the extension APIs require the default SipHash
+    pub env: Option<BTreeMap<String, String>>,
-    pub env: Option<std::collections::HashMap<String, String>>,
     pub ignore_system_version: Option<bool>,
 }
 
-#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema, Hash)]
 #[serde(rename_all = "snake_case")]
 pub struct LspSettings {
     pub binary: Option<BinarySettings>,

crates/project/src/project_tests.rs

@@ -1099,9 +1099,9 @@ async fn test_reporting_fs_changes_to_language_servers(cx: &mut gpui::TestAppCon
     let prev_read_dir_count = fs.read_dir_call_count();
 
     let fake_server = fake_servers.next().await.unwrap();
-    let (server_id, server_name) = lsp_store.read_with(cx, |lsp_store, _| {
+    let server_id = lsp_store.read_with(cx, |lsp_store, _| {
-        let (id, status) = lsp_store.language_server_statuses().next().unwrap();
+        let (id, _) = lsp_store.language_server_statuses().next().unwrap();
-        (id, status.name.clone())
+        id
     });
 
     // Simulate jumping to a definition in a dependency outside of the worktree.
@@ -1110,7 +1110,6 @@ async fn test_reporting_fs_changes_to_language_servers(cx: &mut gpui::TestAppCon
             project.open_local_buffer_via_lsp(
                 lsp::Url::from_file_path(path!("/the-registry/dep1/src/dep1.rs")).unwrap(),
                 server_id,
-                server_name.clone(),
                 cx,
             )
         })

crates/project/src/toolchain_store.rs

@@ -11,7 +11,10 @@ use collections::BTreeMap;
 use gpui::{
     App, AppContext as _, AsyncApp, Context, Entity, EventEmitter, Subscription, Task, WeakEntity,
 };
-use language::{LanguageName, LanguageRegistry, LanguageToolchainStore, Toolchain, ToolchainList};
+use language::{
+    LanguageName, LanguageRegistry, LanguageToolchainStore, ManifestDelegate, Toolchain,
+    ToolchainList,
+};
 use rpc::{
     AnyProtoClient, TypedEnvelope,
     proto::{self, FromProto, ToProto},
@@ -104,9 +107,11 @@ impl ToolchainStore {
         cx: &App,
     ) -> Task<Option<Toolchain>> {
         match &self.0 {
-            ToolchainStoreInner::Local(local, _) => {
+            ToolchainStoreInner::Local(local, _) => Task::ready(local.read(cx).active_toolchain(
-                local.read(cx).active_toolchain(path, language_name, cx)
+                path.worktree_id,
-            }
+                &path.path,
+                language_name,
+            )),
             ToolchainStoreInner::Remote(remote) => {
                 remote.read(cx).active_toolchain(path, language_name, cx)
             }
@@ -232,9 +237,15 @@ impl ToolchainStore {
             ToolchainStoreInner::Remote(remote) => Arc::new(RemoteStore(remote.downgrade())),
         }
     }
+    pub fn as_local_store(&self) -> Option<&Entity<LocalToolchainStore>> {
+        match &self.0 {
+            ToolchainStoreInner::Local(local, _) => Some(local),
+            ToolchainStoreInner::Remote(_) => None,
+        }
+    }
 }
 
-struct LocalToolchainStore {
+pub struct LocalToolchainStore {
     languages: Arc<LanguageRegistry>,
     worktree_store: Entity<WorktreeStore>,
     project_environment: Entity<ProjectEnvironment>,
@@ -243,20 +254,19 @@ struct LocalToolchainStore {
 }
 
 #[async_trait(?Send)]
-impl language::LanguageToolchainStore for LocalStore {
+impl language::LocalLanguageToolchainStore for LocalStore {
-    async fn active_toolchain(
+    fn active_toolchain(
         self: Arc<Self>,
         worktree_id: WorktreeId,
-        path: Arc<Path>,
+        path: &Arc<Path>,
         language_name: LanguageName,
         cx: &mut AsyncApp,
     ) -> Option<Toolchain> {
         self.0
-            .update(cx, |this, cx| {
+            .update(cx, |this, _| {
-                this.active_toolchain(ProjectPath { worktree_id, path }, language_name, cx)
+                this.active_toolchain(worktree_id, path, language_name)
             })
             .ok()?
-            .await
     }
 }
 
@@ -279,19 +289,18 @@ impl language::LanguageToolchainStore for RemoteStore {
 }
 
 pub struct EmptyToolchainStore;
-#[async_trait(?Send)]
+impl language::LocalLanguageToolchainStore for EmptyToolchainStore {
-impl language::LanguageToolchainStore for EmptyToolchainStore {
+    fn active_toolchain(
-    async fn active_toolchain(
         self: Arc<Self>,
         _: WorktreeId,
-        _: Arc<Path>,
+        _: &Arc<Path>,
         _: LanguageName,
         _: &mut AsyncApp,
     ) -> Option<Toolchain> {
         None
     }
 }
-struct LocalStore(WeakEntity<LocalToolchainStore>);
+pub(crate) struct LocalStore(WeakEntity<LocalToolchainStore>);
 struct RemoteStore(WeakEntity<RemoteToolchainStore>);
 
 #[derive(Clone)]
@@ -349,17 +358,13 @@ impl LocalToolchainStore {
                 .flatten()?;
             let worktree_id = snapshot.id();
             let worktree_root = snapshot.abs_path().to_path_buf();
+            let delegate =
+                Arc::from(ManifestQueryDelegate::new(snapshot)) as Arc<dyn ManifestDelegate>;
             let relative_path = manifest_tree
                 .update(cx, |this, cx| {
-                    this.root_for_path(
+                    this.root_for_path(&path, &manifest_name, &delegate, cx)
-                        path,
-                        &mut std::iter::once(manifest_name.clone()),
-                        Arc::new(ManifestQueryDelegate::new(snapshot)),
-                        cx,
-                    )
                 })
                 .ok()?
-                .remove(&manifest_name)
                 .unwrap_or_else(|| ProjectPath {
                     path: Arc::from(Path::new("")),
                     worktree_id,
@@ -394,21 +399,20 @@ impl LocalToolchainStore {
     }
     pub(crate) fn active_toolchain(
         &self,
-        path: ProjectPath,
+        worktree_id: WorktreeId,
+        relative_path: &Arc<Path>,
         language_name: LanguageName,
-        _: &App,
+    ) -> Option<Toolchain> {
-    ) -> Task<Option<Toolchain>> {
+        let ancestors = relative_path.ancestors();
-        let ancestors = path.path.ancestors();
+
-        Task::ready(
         self.active_toolchains
-                .get(&(path.worktree_id, language_name))
+            .get(&(worktree_id, language_name))
             .and_then(|paths| {
                 ancestors
                     .into_iter()
                     .find_map(|root_path| paths.get(root_path))
             })
-                .cloned(),
+            .cloned()
-        )
     }
 }
 struct RemoteToolchainStore {

crates/remote_server/src/headless_project.rs

@@ -171,7 +171,11 @@ impl HeadlessProject {
                 buffer_store.clone(),
                 worktree_store.clone(),
                 prettier_store.clone(),
-                toolchain_store.clone(),
+                toolchain_store
+                    .read(cx)
+                    .as_local_store()
+                    .expect("Toolchain store to be local")
+                    .clone(),
                 environment,
                 manifest_tree,
                 languages.clone(),