debugger: Rework language association with the debuggers (#29945)

- Languages now define their preferred debuggers in `config.toml`.
- `LanguageRegistry` now exposes language config even for languages that
are not yet loaded. This necessitated extension registry changes (we now
deserialize config.toml of all language entries when loading new
extension index), but it should be backwards compatible with the old
format. /cc @maxdeviant

Release Notes:

- N/A

---------

Co-authored-by: Anthony Eid <hello@anthonyeid.me>
Co-authored-by: Remco Smits <djsmits12@gmail.com>
Co-authored-by: Anthony <anthony@zed.dev>

assets/settings/default.json

@@ -908,6 +908,8 @@
   "hard_tabs": false,
   // How many columns a tab should occupy.
   "tab_size": 4,
+  // What debuggers are preferred by default for all languages.
+  "debuggers": [],
   // Control what info is collected by Zed.
   "telemetry": {
     // Send debug info like crash reports.

crates/debugger_ui/src/debugger_panel.rs

@@ -621,20 +621,32 @@ impl DebugPanel {
                     move |_, window, cx| {
                         let weak_panel = weak_panel.clone();
                         let past_debug_definition = past_debug_definition.clone();
+                        let workspace = workspace.clone();
+                        window
+                            .spawn(cx, async move |cx| {
+                                let task_contexts = workspace
+                                    .update_in(cx, |workspace, window, cx| {
+                                        tasks_ui::task_contexts(workspace, window, cx)
+                                    })?
+                                    .await;
 
-                        let _ = workspace.update(cx, |this, cx| {
+                                workspace.update_in(cx, |this, window, cx| {
-                            let workspace = cx.weak_entity();
+                                    this.toggle_modal(window, cx, |window, cx| {
-                            this.toggle_modal(window, cx, |window, cx| {
+                                        NewSessionModal::new(
-                                NewSessionModal::new(
+                                            past_debug_definition,
-                                    past_debug_definition,
+                                            weak_panel,
-                                    weak_panel,
+                                            workspace.clone(),
-                                    workspace,
+                                            None,
-                                    None,
+                                            task_contexts,
-                                    window,
+                                            window,
-                                    cx,
+                                            cx,
-                                )
+                                        )
-                            });
+                                    });
-                        });
+                                })?;
+
+                                Result::<_, anyhow::Error>::Ok(())
+                            })
+                            .detach();
                     }
                 })
                 .tooltip({

crates/debugger_ui/src/debugger_ui.rs

@@ -153,16 +153,29 @@ pub fn init(cx: &mut App) {
                             let weak_panel = debug_panel.downgrade();
                             let weak_workspace = cx.weak_entity();
 
-                            workspace.toggle_modal(window, cx, |window, cx| {
+                            cx.spawn_in(window, async move |this, cx| {
-                                NewSessionModal::new(
+                                let task_contexts = this
-                                    debug_panel.read(cx).past_debug_definition.clone(),
+                                    .update_in(cx, |workspace, window, cx| {
-                                    weak_panel,
+                                        tasks_ui::task_contexts(workspace, window, cx)
-                                    weak_workspace,
+                                    })?
-                                    None,
+                                    .await;
-                                    window,
+                                this.update_in(cx, |workspace, window, cx| {
-                                    cx,
+                                    workspace.toggle_modal(window, cx, |window, cx| {
-                                )
+                                        NewSessionModal::new(
-                            });
+                                            debug_panel.read(cx).past_debug_definition.clone(),
+                                            weak_panel,
+                                            weak_workspace,
+                                            None,
+                                            task_contexts,
+                                            window,
+                                            cx,
+                                        )
+                                    });
+                                })?;
+
+                                Result::<_, anyhow::Error>::Ok(())
+                            })
+                            .detach();
                         }
                     },
                 )
@@ -172,16 +185,30 @@ pub fn init(cx: &mut App) {
                         let weak_workspace = cx.weak_entity();
                         let task_store = workspace.project().read(cx).task_store().clone();
 
-                        workspace.toggle_modal(window, cx, |window, cx| {
+                        cx.spawn_in(window, async move |this, cx| {
-                            NewSessionModal::new(
+                            let task_contexts = this
-                                debug_panel.read(cx).past_debug_definition.clone(),
+                                .update_in(cx, |workspace, window, cx| {
-                                weak_panel,
+                                    tasks_ui::task_contexts(workspace, window, cx)
-                                weak_workspace,
+                                })?
-                                Some(task_store),
+                                .await;
-                                window,
+
-                                cx,
+                            this.update_in(cx, |workspace, window, cx| {
-                            )
+                                workspace.toggle_modal(window, cx, |window, cx| {
-                        });
+                                    NewSessionModal::new(
+                                        debug_panel.read(cx).past_debug_definition.clone(),
+                                        weak_panel,
+                                        weak_workspace,
+                                        Some(task_store),
+                                        task_contexts,
+                                        window,
+                                        cx,
+                                    )
+                                });
+                            })?;
+
+                            anyhow::Ok(())
+                        })
+                        .detach()
                     }
                 });
         })

crates/debugger_ui/src/new_session_modal.rs

@@ -1,9 +1,12 @@
 use std::{
     borrow::Cow,
+    cmp::Reverse,
     ops::Not,
     path::{Path, PathBuf},
+    sync::Arc,
 };
 
+use collections::{HashMap, HashSet};
 use dap::{
     DapRegistry, DebugRequest,
     adapters::{DebugAdapterName, DebugTaskDefinition},
@@ -15,10 +18,9 @@ use gpui::{
     Subscription, TextStyle, WeakEntity,
 };
 use picker::{Picker, PickerDelegate, highlighted_match_with_paths::HighlightedMatch};
-use project::{TaskSourceKind, task_store::TaskStore};
+use project::{TaskContexts, TaskSourceKind, task_store::TaskStore};
 use settings::Settings;
 use task::{DebugScenario, LaunchRequest};
-use tasks_ui::task_contexts;
 use theme::ThemeSettings;
 use ui::{
     ActiveTheme, Button, ButtonCommon, ButtonSize, CheckboxWithLabel, Clickable, Color, Context,
@@ -32,7 +34,6 @@ use workspace::{ModalView, Workspace};
 
 use crate::{attach_modal::AttachModal, debugger_panel::DebugPanel};
 
-#[derive(Clone)]
 pub(super) struct NewSessionModal {
     workspace: WeakEntity<Workspace>,
     debug_panel: WeakEntity<DebugPanel>,
@@ -41,6 +42,7 @@ pub(super) struct NewSessionModal {
     initialize_args: Option<serde_json::Value>,
     debugger: Option<DebugAdapterName>,
     last_selected_profile_name: Option<SharedString>,
+    task_contexts: Arc<TaskContexts>,
 }
 
 fn suggested_label(request: &DebugRequest, debugger: &str) -> SharedString {
@@ -67,6 +69,7 @@ impl NewSessionModal {
         debug_panel: WeakEntity<DebugPanel>,
         workspace: WeakEntity<Workspace>,
         task_store: Option<Entity<TaskStore>>,
+        task_contexts: TaskContexts,
         window: &mut Window,
         cx: &mut Context<Self>,
     ) -> Self {
@@ -105,6 +108,7 @@ impl NewSessionModal {
                 .unwrap_or(ToggleState::Unselected),
             last_selected_profile_name: None,
             initialize_args: None,
+            task_contexts: Arc::new(task_contexts),
         }
     }
 
@@ -145,22 +149,10 @@ impl NewSessionModal {
         };
 
         let debug_panel = self.debug_panel.clone();
-        let workspace = self.workspace.clone();
+        let task_contexts = self.task_contexts.clone();
         cx.spawn_in(window, async move |this, cx| {
-            let task_contexts = workspace
+            let task_context = task_contexts.active_context().cloned().unwrap_or_default();
-                .update_in(cx, |this, window, cx| task_contexts(this, window, cx))?
-                .await;
             let worktree_id = task_contexts.worktree();
-            let task_context = task_contexts
-                .active_item_context
-                .map(|(_, _, context)| context)
-                .or_else(|| {
-                    task_contexts
-                        .active_worktree_context
-                        .map(|(_, context)| context)
-                })
-                .unwrap_or_default();
-
             debug_panel.update_in(cx, |debug_panel, window, cx| {
                 debug_panel.start_session(config, task_context, None, worktree_id, window, cx)
             })?;
@@ -198,14 +190,27 @@ impl NewSessionModal {
         &self,
         window: &mut Window,
         cx: &mut Context<Self>,
-    ) -> ui::DropdownMenu {
+    ) -> Option<ui::DropdownMenu> {
         let workspace = self.workspace.clone();
+        let language_registry = self
+            .workspace
+            .update(cx, |this, _| this.app_state().languages.clone())
+            .ok()?;
         let weak = cx.weak_entity();
         let label = self
             .debugger
             .as_ref()
             .map(|d| d.0.clone())
             .unwrap_or_else(|| SELECT_DEBUGGER_LABEL.clone());
+        let active_buffer_language_name =
+            self.task_contexts
+                .active_item_context
+                .as_ref()
+                .and_then(|item| {
+                    item.1
+                        .as_ref()
+                        .and_then(|location| location.buffer.read(cx).language()?.name().into())
+                });
         DropdownMenu::new(
             "dap-adapter-picker",
             label,
@@ -224,17 +229,50 @@ impl NewSessionModal {
                     }
                 };
 
-                let available_adapters = workspace
+                let available_languages = language_registry.language_names();
+                let mut debugger_to_languages = HashMap::default();
+                for language in available_languages {
+                    let Some(language) =
+                        language_registry.available_language_for_name(language.as_str())
+                    else {
+                        continue;
+                    };
+
+                    language.config().debuggers.iter().for_each(|adapter| {
+                        debugger_to_languages
+                            .entry(adapter.clone())
+                            .or_insert_with(HashSet::default)
+                            .insert(language.name());
+                    });
+                }
+                let mut available_adapters = workspace
                     .update(cx, |_, cx| DapRegistry::global(cx).enumerate_adapters())
                     .ok()
                     .unwrap_or_default();
 
-                for adapter in available_adapters {
+                available_adapters.sort_by_key(|name| {
+                    let languages_for_debugger = debugger_to_languages.get(name.as_ref());
+                    let languages_count =
+                        languages_for_debugger.map_or(0, |languages| languages.len());
+                    let contains_language_of_active_buffer = languages_for_debugger
+                        .zip(active_buffer_language_name.as_ref())
+                        .map_or(false, |(languages, active_buffer_language)| {
+                            languages.contains(active_buffer_language)
+                        });
+
+                    (
+                        Reverse(contains_language_of_active_buffer),
+                        Reverse(languages_count),
+                    )
+                });
+
+                for adapter in available_adapters.into_iter() {
                     menu = menu.entry(adapter.0.clone(), None, setter_for_name(adapter.clone()));
                 }
                 menu
             }),
         )
+        .into()
     }
 
     fn debug_config_drop_down_menu(
@@ -591,7 +629,9 @@ impl Render for NewSessionModal {
                             ),
                     )
                     .justify_between()
-                    .child(self.adapter_drop_down_menu(window, cx))
+                    .when(!matches!(self.mode, NewSessionMode::Scenario(_)), |this| {
+                        this.children(self.adapter_drop_down_menu(window, cx))
+                    })
                     .border_color(cx.theme().colors().border_variant)
                     .border_b_1(),
             )

crates/editor/src/editor.rs

@@ -5206,12 +5206,22 @@ impl Editor {
                                     let dap_store = project.read(cx).dap_store();
                                     let mut scenarios = vec![];
                                     let resolved_tasks = resolved_tasks.as_ref()?;
-                                    let debug_adapter: SharedString = buffer
+                                    let buffer = buffer.read(cx);
-                                        .read(cx)
+                                    let language = buffer.language()?;
-                                        .language()?
+                                    let file = buffer.file();
-                                        .context_provider()?
+                                    let debug_adapter =
-                                        .debug_adapter()?
+                                        language_settings(language.name().into(), file, cx)
-                                        .into();
+                                            .debuggers
+                                            .first()
+                                            .map(SharedString::from)
+                                            .or_else(|| {
+                                                language
+                                                    .config()
+                                                    .debuggers
+                                                    .first()
+                                                    .map(SharedString::from)
+                                            })?;
+
                                     dap_store.update(cx, |this, cx| {
                                         for (_, task) in &resolved_tasks.templates {
                                             if let Some(scenario) = this

crates/extension/src/extension_host_proxy.rs

@@ -4,7 +4,7 @@ use std::sync::Arc;
 use anyhow::Result;
 use fs::Fs;
 use gpui::{App, Global, ReadGlobal, SharedString, Task};
-use language::{BinaryStatus, LanguageMatcher, LanguageName, LoadedLanguage};
+use language::{BinaryStatus, LanguageConfig, LanguageName, LoadedLanguage};
 use lsp::LanguageServerName;
 use parking_lot::RwLock;
 
@@ -224,10 +224,7 @@ impl ExtensionGrammarProxy for ExtensionHostProxy {
 pub trait ExtensionLanguageProxy: Send + Sync + 'static {
     fn register_language(
         &self,
-        language: LanguageName,
+        config: LanguageConfig,
-        grammar: Option<Arc<str>>,
-        matcher: LanguageMatcher,
-        hidden: bool,
         load: Arc<dyn Fn() -> Result<LoadedLanguage> + Send + Sync + 'static>,
     );
 
@@ -241,17 +238,14 @@ pub trait ExtensionLanguageProxy: Send + Sync + 'static {
 impl ExtensionLanguageProxy for ExtensionHostProxy {
     fn register_language(
         &self,
-        language: LanguageName,
+        language: LanguageConfig,
-        grammar: Option<Arc<str>>,
-        matcher: LanguageMatcher,
-        hidden: bool,
         load: Arc<dyn Fn() -> Result<LoadedLanguage> + Send + Sync + 'static>,
     ) {
         let Some(proxy) = self.language_proxy.read().clone() else {
             return;
         };
 
-        proxy.register_language(language, grammar, matcher, hidden, load)
+        proxy.register_language(language, load)
     }
 
     fn remove_languages(

crates/extension_host/src/extension_host.rs

@@ -34,8 +34,7 @@ use gpui::{
 };
 use http_client::{AsyncBody, HttpClient, HttpClientWithUrl};
 use language::{
-    LanguageConfig, LanguageMatcher, LanguageName, LanguageQueries, LoadedLanguage,
+    LanguageConfig, LanguageName, LanguageQueries, LoadedLanguage, QUERY_FILENAME_PREFIXES, Rope,
-    QUERY_FILENAME_PREFIXES, Rope,
 };
 use node_runtime::NodeRuntime;
 use project::ContextProviderWithTasks;
@@ -140,7 +139,7 @@ struct GlobalExtensionStore(Entity<ExtensionStore>);
 
 impl Global for GlobalExtensionStore {}
 
-#[derive(Debug, Deserialize, Serialize, Default, PartialEq, Eq)]
+#[derive(Deserialize, Serialize, Default)]
 pub struct ExtensionIndex {
     pub extensions: BTreeMap<Arc<str>, ExtensionIndexEntry>,
     pub themes: BTreeMap<Arc<str>, ExtensionIndexThemeEntry>,
@@ -167,13 +166,12 @@ pub struct ExtensionIndexIconThemeEntry {
     pub path: PathBuf,
 }
 
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Debug, Deserialize, Serialize)]
+#[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct ExtensionIndexLanguageEntry {
     pub extension: Arc<str>,
     pub path: PathBuf,
-    pub matcher: LanguageMatcher,
+    #[serde(skip)]
-    pub hidden: bool,
+    pub config: LanguageConfig,
-    pub grammar: Option<Arc<str>>,
 }
 
 actions!(zed, [ReloadExtensions]);
@@ -1015,7 +1013,7 @@ impl ExtensionStore {
     /// added to the manifest, or whose files have changed on disk.
     fn extensions_updated(
         &mut self,
-        new_index: ExtensionIndex,
+        mut new_index: ExtensionIndex,
         cx: &mut Context<Self>,
     ) -> Task<()> {
         let old_index = &self.extension_index;
@@ -1143,11 +1141,6 @@ impl ExtensionStore {
         self.proxy
             .remove_languages(&languages_to_remove, &grammars_to_remove);
 
-        let languages_to_add = new_index
-            .languages
-            .iter()
-            .filter(|(_, entry)| extensions_to_load.contains(&entry.extension))
-            .collect::<Vec<_>>();
         let mut grammars_to_add = Vec::new();
         let mut themes_to_add = Vec::new();
         let mut icon_themes_to_add = Vec::new();
@@ -1189,39 +1182,7 @@ impl ExtensionStore {
 
         self.proxy.register_grammars(grammars_to_add);
 
-        for (language_name, language) in languages_to_add {
+        let installed_dir = self.installed_dir.clone();
-            let mut language_path = self.installed_dir.clone();
-            language_path.extend([
-                Path::new(language.extension.as_ref()),
-                language.path.as_path(),
-            ]);
-            self.proxy.register_language(
-                language_name.clone(),
-                language.grammar.clone(),
-                language.matcher.clone(),
-                language.hidden,
-                Arc::new(move || {
-                    let config = std::fs::read_to_string(language_path.join("config.toml"))?;
-                    let config: LanguageConfig = ::toml::from_str(&config)?;
-                    let queries = load_plugin_queries(&language_path);
-                    let context_provider =
-                        std::fs::read_to_string(language_path.join("tasks.json"))
-                            .ok()
-                            .and_then(|contents| {
-                                let definitions =
-                                    serde_json_lenient::from_str(&contents).log_err()?;
-                                Some(Arc::new(ContextProviderWithTasks::new(definitions)) as Arc<_>)
-                            });
-
-                    Ok(LoadedLanguage {
-                        config,
-                        queries,
-                        context_provider,
-                        toolchain_provider: None,
-                    })
-                }),
-            );
-        }
 
         let fs = self.fs.clone();
         let wasm_host = self.wasm_host.clone();
@@ -1232,11 +1193,59 @@ impl ExtensionStore {
             .filter_map(|name| new_index.extensions.get(name).cloned())
             .collect::<Vec<_>>();
 
-        self.extension_index = new_index;
-        cx.notify();
-        cx.emit(Event::ExtensionsUpdated);
-
         cx.spawn(async move |this, cx| {
+            let languages_to_add = new_index
+                .languages
+                .iter_mut()
+                .filter(|(_, entry)| extensions_to_load.contains(&entry.extension))
+                .collect::<Vec<_>>();
+            for (_, language) in languages_to_add {
+                let mut language_path = installed_dir.clone();
+                language_path.extend([
+                    Path::new(language.extension.as_ref()),
+                    language.path.as_path(),
+                ]);
+                let Some(config) = fs.load(&language_path.join("config.toml")).await.ok() else {
+                    log::error!("Could not load config.toml in {:?}", language_path);
+                    continue;
+                };
+                let Some(config) = ::toml::from_str::<LanguageConfig>(&config).ok() else {
+                    log::error!(
+                        "Could not parse language config.toml in {:?}",
+                        language_path
+                    );
+                    continue;
+                };
+                language.config = config.clone();
+                proxy.register_language(
+                    language.config.clone(),
+                    Arc::new(move || {
+                        let queries = load_plugin_queries(&language_path);
+                        let context_provider =
+                            std::fs::read_to_string(language_path.join("tasks.json"))
+                                .ok()
+                                .and_then(|contents| {
+                                    let definitions =
+                                        serde_json_lenient::from_str(&contents).log_err()?;
+                                    Some(Arc::new(ContextProviderWithTasks::new(definitions))
+                                        as Arc<_>)
+                                });
+
+                        Ok(LoadedLanguage {
+                            config: config.clone(),
+                            queries,
+                            context_provider,
+                            toolchain_provider: None,
+                        })
+                    }),
+                );
+            }
+            this.update(cx, |this, cx| {
+                this.extension_index = new_index;
+                cx.notify();
+                cx.emit(Event::ExtensionsUpdated);
+            })
+            .ok();
             cx.background_spawn({
                 let fs = fs.clone();
                 async move {
@@ -1439,9 +1448,7 @@ impl ExtensionStore {
                     ExtensionIndexLanguageEntry {
                         extension: extension_id.clone(),
                         path: relative_path,
-                        matcher: config.matcher,
+                        config,
-                        hidden: config.hidden,
-                        grammar: config.grammar,
                     },
                 );
             }

crates/extension_host/src/extension_store_test.rs

@@ -10,7 +10,7 @@ use fs::{FakeFs, Fs, RealFs};
 use futures::{AsyncReadExt, StreamExt, io::BufReader};
 use gpui::{AppContext as _, SemanticVersion, SharedString, TestAppContext};
 use http_client::{FakeHttpClient, Response};
-use language::{BinaryStatus, LanguageMatcher, LanguageRegistry};
+use language::{BinaryStatus, LanguageConfig, LanguageMatcher, LanguageRegistry};
 use lsp::LanguageServerName;
 use node_runtime::NodeRuntime;
 use parking_lot::Mutex;
@@ -206,11 +206,14 @@ async fn test_extension_store(cx: &mut TestAppContext) {
                 ExtensionIndexLanguageEntry {
                     extension: "zed-ruby".into(),
                     path: "languages/erb".into(),
-                    grammar: Some("embedded_template".into()),
+                    config: LanguageConfig {
-                    hidden: false,
+                        grammar: Some("embedded_template".into()),
-                    matcher: LanguageMatcher {
+                        hidden: false,
-                        path_suffixes: vec!["erb".into()],
+                        matcher: LanguageMatcher {
-                        first_line_pattern: None,
+                            path_suffixes: vec!["erb".into()],
+                            first_line_pattern: None,
+                        },
+                        ..Default::default()
                     },
                 },
             ),
@@ -219,11 +222,14 @@ async fn test_extension_store(cx: &mut TestAppContext) {
                 ExtensionIndexLanguageEntry {
                     extension: "zed-ruby".into(),
                     path: "languages/ruby".into(),
-                    grammar: Some("ruby".into()),
+                    config: LanguageConfig {
-                    hidden: false,
+                        grammar: Some("ruby".into()),
-                    matcher: LanguageMatcher {
+                        hidden: false,
-                        path_suffixes: vec!["rb".into()],
+                        matcher: LanguageMatcher {
-                        first_line_pattern: None,
+                            path_suffixes: vec!["rb".into()],
+                            first_line_pattern: None,
+                        },
+                        ..Default::default()
                     },
                 },
             ),
@@ -290,7 +296,24 @@ async fn test_extension_store(cx: &mut TestAppContext) {
     store.read_with(cx, |store, _| {
         let index = &store.extension_index;
         assert_eq!(index.extensions, expected_index.extensions);
-        assert_eq!(index.languages, expected_index.languages);
+
+        for ((actual_key, actual_language), (expected_key, expected_language)) in
+            index.languages.iter().zip(expected_index.languages.iter())
+        {
+            assert_eq!(actual_key, expected_key);
+            assert_eq!(
+                actual_language.config.grammar,
+                expected_language.config.grammar
+            );
+            assert_eq!(
+                actual_language.config.matcher,
+                expected_language.config.matcher
+            );
+            assert_eq!(
+                actual_language.config.hidden,
+                expected_language.config.hidden
+            );
+        }
         assert_eq!(index.themes, expected_index.themes);
 
         assert_eq!(
@@ -377,8 +400,26 @@ async fn test_extension_store(cx: &mut TestAppContext) {
     cx.executor().advance_clock(RELOAD_DEBOUNCE_DURATION);
     store.read_with(cx, |store, _| {
         let index = &store.extension_index;
+
+        for ((actual_key, actual_language), (expected_key, expected_language)) in
+            index.languages.iter().zip(expected_index.languages.iter())
+        {
+            assert_eq!(actual_key, expected_key);
+            assert_eq!(
+                actual_language.config.grammar,
+                expected_language.config.grammar
+            );
+            assert_eq!(
+                actual_language.config.matcher,
+                expected_language.config.matcher
+            );
+            assert_eq!(
+                actual_language.config.hidden,
+                expected_language.config.hidden
+            );
+        }
+
         assert_eq!(index.extensions, expected_index.extensions);
-        assert_eq!(index.languages, expected_index.languages);
         assert_eq!(index.themes, expected_index.themes);
 
         assert_eq!(
@@ -415,7 +456,34 @@ async fn test_extension_store(cx: &mut TestAppContext) {
 
     cx.executor().run_until_parked();
     store.read_with(cx, |store, _| {
-        assert_eq!(store.extension_index, expected_index);
+        assert_eq!(store.extension_index.extensions, expected_index.extensions);
+        assert_eq!(store.extension_index.themes, expected_index.themes);
+        assert_eq!(
+            store.extension_index.icon_themes,
+            expected_index.icon_themes
+        );
+
+        for ((actual_key, actual_language), (expected_key, expected_language)) in store
+            .extension_index
+            .languages
+            .iter()
+            .zip(expected_index.languages.iter())
+        {
+            assert_eq!(actual_key, expected_key);
+            assert_eq!(
+                actual_language.config.grammar,
+                expected_language.config.grammar
+            );
+            assert_eq!(
+                actual_language.config.matcher,
+                expected_language.config.matcher
+            );
+            assert_eq!(
+                actual_language.config.hidden,
+                expected_language.config.hidden
+            );
+        }
+
         assert_eq!(
             language_registry.language_names(),
             ["ERB", "Plain Text", "Ruby"]
@@ -452,7 +520,34 @@ async fn test_extension_store(cx: &mut TestAppContext) {
     expected_index.languages.remove("ERB");
 
     store.read_with(cx, |store, _| {
-        assert_eq!(store.extension_index, expected_index);
+        assert_eq!(store.extension_index.extensions, expected_index.extensions);
+        assert_eq!(store.extension_index.themes, expected_index.themes);
+        assert_eq!(
+            store.extension_index.icon_themes,
+            expected_index.icon_themes
+        );
+
+        for ((actual_key, actual_language), (expected_key, expected_language)) in store
+            .extension_index
+            .languages
+            .iter()
+            .zip(expected_index.languages.iter())
+        {
+            assert_eq!(actual_key, expected_key);
+            assert_eq!(
+                actual_language.config.grammar,
+                expected_language.config.grammar
+            );
+            assert_eq!(
+                actual_language.config.matcher,
+                expected_language.config.matcher
+            );
+            assert_eq!(
+                actual_language.config.hidden,
+                expected_language.config.hidden
+            );
+        }
+
         assert_eq!(language_registry.language_names(), ["Plain Text"]);
         assert_eq!(language_registry.grammar_names(), []);
     });

crates/extension_host/src/headless_host.rs

@@ -149,10 +149,7 @@ impl HeadlessExtensionStore {
                 config.grammar = None;
 
                 this.proxy.register_language(
-                    config.name.clone(),
+                    config.clone(),
-                    None,
-                    config.matcher.clone(),
-                    config.hidden,
                     Arc::new(move || {
                         Ok(LoadedLanguage {
                             config: config.clone(),

crates/language/src/language.rs

@@ -26,7 +26,7 @@ pub use crate::language_settings::EditPredictionsMode;
 use crate::language_settings::SoftWrap;
 use anyhow::{Context as _, Result, anyhow};
 use async_trait::async_trait;
-use collections::{HashMap, HashSet};
+use collections::{HashMap, HashSet, IndexSet};
 use fs::Fs;
 use futures::Future;
 use gpui::{App, AsyncApp, Entity, SharedString, Task};
@@ -666,7 +666,7 @@ pub struct CodeLabel {
     pub filter_range: Range<usize>,
 }
 
-#[derive(Clone, Deserialize, JsonSchema)]
+#[derive(Clone, Deserialize, JsonSchema, Serialize, Debug)]
 pub struct LanguageConfig {
     /// Human-readable name of the language.
     pub name: LanguageName,
@@ -690,12 +690,20 @@ pub struct LanguageConfig {
     pub auto_indent_on_paste: Option<bool>,
     /// A regex that is used to determine whether the indentation level should be
     /// increased in the following line.
-    #[serde(default, deserialize_with = "deserialize_regex")]
+    #[serde(
+        default,
+        deserialize_with = "deserialize_regex",
+        serialize_with = "serialize_regex"
+    )]
     #[schemars(schema_with = "regex_json_schema")]
     pub increase_indent_pattern: Option<Regex>,
     /// A regex that is used to determine whether the indentation level should be
     /// decreased in the following line.
-    #[serde(default, deserialize_with = "deserialize_regex")]
+    #[serde(
+        default,
+        deserialize_with = "deserialize_regex",
+        serialize_with = "serialize_regex"
+    )]
     #[schemars(schema_with = "regex_json_schema")]
     pub decrease_indent_pattern: Option<Regex>,
     /// A list of characters that trigger the automatic insertion of a closing
@@ -748,6 +756,9 @@ pub struct LanguageConfig {
     /// A list of characters that Zed should treat as word characters for completion queries.
     #[serde(default)]
     pub completion_query_characters: HashSet<char>,
+    /// A list of preferred debuggers for this language.
+    #[serde(default)]
+    pub debuggers: IndexSet<String>,
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize, Default, JsonSchema)]
@@ -766,7 +777,7 @@ pub struct LanguageMatcher {
 }
 
 /// The configuration for JSX tag auto-closing.
-#[derive(Clone, Deserialize, JsonSchema)]
+#[derive(Clone, Deserialize, JsonSchema, Serialize, Debug)]
 pub struct JsxTagAutoCloseConfig {
     /// The name of the node for a opening tag
     pub open_tag_node_name: String,
@@ -807,7 +818,7 @@ pub struct LanguageScope {
     override_id: Option<u32>,
 }
 
-#[derive(Clone, Deserialize, Default, Debug, JsonSchema)]
+#[derive(Clone, Deserialize, Default, Debug, JsonSchema, Serialize)]
 pub struct LanguageConfigOverride {
     #[serde(default)]
     pub line_comments: Override<Vec<Arc<str>>>,
@@ -872,6 +883,7 @@ impl Default for LanguageConfig {
             hidden: false,
             jsx_tag_auto_close: None,
             completion_query_characters: Default::default(),
+            debuggers: Default::default(),
         }
     }
 }
@@ -932,7 +944,7 @@ pub struct FakeLspAdapter {
 ///
 /// This struct includes settings for defining which pairs of characters are considered brackets and
 /// also specifies any language-specific scopes where these pairs should be ignored for bracket matching purposes.
-#[derive(Clone, Debug, Default, JsonSchema)]
+#[derive(Clone, Debug, Default, JsonSchema, Serialize)]
 pub struct BracketPairConfig {
     /// A list of character pairs that should be treated as brackets in the context of a given language.
     pub pairs: Vec<BracketPair>,
@@ -982,7 +994,7 @@ impl<'de> Deserialize<'de> for BracketPairConfig {
 
 /// Describes a single bracket pair and how an editor should react to e.g. inserting
 /// an opening bracket or to a newline character insertion in between `start` and `end` characters.
-#[derive(Clone, Debug, Default, Deserialize, PartialEq, JsonSchema)]
+#[derive(Clone, Debug, Default, Deserialize, PartialEq, JsonSchema, Serialize)]
 pub struct BracketPair {
     /// Starting substring for a bracket.
     pub start: String,

crates/language/src/language_registry.rs

@@ -145,24 +145,24 @@ pub enum BinaryStatus {
 #[derive(Clone)]
 pub struct AvailableLanguage {
     id: LanguageId,
-    name: LanguageName,
+    config: LanguageConfig,
-    grammar: Option<Arc<str>>,
-    matcher: LanguageMatcher,
-    hidden: bool,
     load: Arc<dyn Fn() -> Result<LoadedLanguage> + 'static + Send + Sync>,
     loaded: bool,
 }
 
 impl AvailableLanguage {
     pub fn name(&self) -> LanguageName {
-        self.name.clone()
+        self.config.name.clone()
     }
 
     pub fn matcher(&self) -> &LanguageMatcher {
-        &self.matcher
+        &self.config.matcher
     }
     pub fn hidden(&self) -> bool {
-        self.hidden
+        self.config.hidden
+    }
+    pub fn config(&self) -> &LanguageConfig {
+        &self.config
     }
 }
 
@@ -326,10 +326,7 @@ impl LanguageRegistry {
     #[cfg(any(feature = "test-support", test))]
     pub fn register_test_language(&self, config: LanguageConfig) {
         self.register_language(
-            config.name.clone(),
+            config.clone(),
-            config.grammar.clone(),
-            config.matcher.clone(),
-            config.hidden,
             Arc::new(move || {
                 Ok(LoadedLanguage {
                     config: config.clone(),
@@ -488,18 +485,14 @@ impl LanguageRegistry {
     /// Adds a language to the registry, which can be loaded if needed.
     pub fn register_language(
         &self,
-        name: LanguageName,
+        config: LanguageConfig,
-        grammar_name: Option<Arc<str>>,
-        matcher: LanguageMatcher,
-        hidden: bool,
         load: Arc<dyn Fn() -> Result<LoadedLanguage> + 'static + Send + Sync>,
     ) {
         let state = &mut *self.state.write();
 
         for existing_language in &mut state.available_languages {
-            if existing_language.name == name {
+            if existing_language.config.name == config.name {
-                existing_language.grammar = grammar_name;
+                existing_language.config = config;
-                existing_language.matcher = matcher;
                 existing_language.load = load;
                 return;
             }
@@ -507,11 +500,8 @@ impl LanguageRegistry {
 
         state.available_languages.push(AvailableLanguage {
             id: LanguageId::new(),
-            name,
+            config,
-            grammar: grammar_name,
-            matcher,
             load,
-            hidden,
             loaded: false,
         });
         state.version += 1;
@@ -557,7 +547,7 @@ impl LanguageRegistry {
         let mut result = state
             .available_languages
             .iter()
-            .filter_map(|l| l.loaded.not().then_some(l.name.to_string()))
+            .filter_map(|l| l.loaded.not().then_some(l.config.name.to_string()))
             .chain(state.languages.iter().map(|l| l.config.name.to_string()))
             .collect::<Vec<_>>();
         result.sort_unstable_by_key(|language_name| language_name.to_lowercase());
@@ -576,10 +566,7 @@ impl LanguageRegistry {
         let mut state = self.state.write();
         state.available_languages.push(AvailableLanguage {
             id: language.id,
-            name: language.name(),
+            config: language.config.clone(),
-            grammar: language.config.grammar.clone(),
-            matcher: language.config.matcher.clone(),
-            hidden: language.config.hidden,
             load: Arc::new(|| Err(anyhow!("already loaded"))),
             loaded: true,
         });
@@ -648,7 +635,7 @@ impl LanguageRegistry {
         state
             .available_languages
             .iter()
-            .find(|l| l.name.0.as_ref() == name)
+            .find(|l| l.config.name.0.as_ref() == name)
             .cloned()
     }
 
@@ -765,8 +752,11 @@ impl LanguageRegistry {
                 let current_match_type = best_language_match
                     .as_ref()
                     .map_or(LanguageMatchPrecedence::default(), |(_, score)| *score);
-                let language_score =
+                let language_score = callback(
-                    callback(&language.name, &language.matcher, current_match_type);
+                    &language.config.name,
+                    &language.config.matcher,
+                    current_match_type,
+                );
                 debug_assert!(
                     language_score.is_none_or(|new_score| new_score > current_match_type),
                     "Matching callback should only return a better match than the current one"
@@ -814,7 +804,7 @@ impl LanguageRegistry {
                 let this = self.clone();
 
                 let id = language.id;
-                let name = language.name.clone();
+                let name = language.config.name.clone();
                 let language_load = language.load.clone();
 
                 self.executor
@@ -1130,7 +1120,7 @@ impl LanguageRegistryState {
         self.languages
             .retain(|language| !languages_to_remove.contains(&language.name()));
         self.available_languages
-            .retain(|language| !languages_to_remove.contains(&language.name));
+            .retain(|language| !languages_to_remove.contains(&language.config.name));
         self.grammars
             .retain(|name, _| !grammars_to_remove.contains(name));
         self.version += 1;

crates/language/src/language_settings.rs

@@ -153,6 +153,8 @@ pub struct LanguageSettings {
     pub show_completion_documentation: bool,
     /// Completion settings for this language.
     pub completions: CompletionSettings,
+    /// Preferred debuggers for this language.
+    pub debuggers: Vec<String>,
 }
 
 impl LanguageSettings {
@@ -551,6 +553,10 @@ pub struct LanguageSettingsContent {
     pub show_completion_documentation: Option<bool>,
     /// Controls how completions are processed for this language.
     pub completions: Option<CompletionSettings>,
+    /// Preferred debuggers for this language.
+    ///
+    /// Default: []
+    pub debuggers: Option<Vec<String>>,
 }
 
 /// The behavior of `editor::Rewrap`.

crates/language/src/task_context.rs

@@ -47,7 +47,4 @@ pub trait ContextProvider: Send + Sync {
     fn lsp_task_source(&self) -> Option<LanguageServerName> {
         None
     }
-
-    /// Default debug adapter for a given language.
-    fn debug_adapter(&self) -> Option<String>;
 }

crates/language_extension/src/language_extension.rs

@@ -5,7 +5,7 @@ use std::sync::Arc;
 
 use anyhow::Result;
 use extension::{ExtensionGrammarProxy, ExtensionHostProxy, ExtensionLanguageProxy};
-use language::{LanguageMatcher, LanguageName, LanguageRegistry, LoadedLanguage};
+use language::{LanguageConfig, LanguageName, LanguageRegistry, LoadedLanguage};
 
 pub fn init(
     extension_host_proxy: Arc<ExtensionHostProxy>,
@@ -31,14 +31,10 @@ impl ExtensionGrammarProxy for LanguageServerRegistryProxy {
 impl ExtensionLanguageProxy for LanguageServerRegistryProxy {
     fn register_language(
         &self,
-        language: LanguageName,
+        language: LanguageConfig,
-        grammar: Option<Arc<str>>,
-        matcher: LanguageMatcher,
-        hidden: bool,
         load: Arc<dyn Fn() -> Result<LoadedLanguage> + Send + Sync + 'static>,
     ) {
-        self.language_registry
+        self.language_registry.register_language(language, load);
-            .register_language(language, grammar, matcher, hidden, load);
     }
 
     fn remove_languages(

crates/languages/src/c/config.toml

@@ -11,3 +11,4 @@ brackets = [
     { start = "'", end = "'", close = true, newline = false, not_in = ["string", "comment"] },
     { start = "/*", end = " */", close = true, newline = false, not_in = ["string", "comment"] },
 ]
+debuggers = ["CodeLLDB", "GDB"]

crates/languages/src/cpp/config.toml

@@ -11,3 +11,4 @@ brackets = [
     { start = "'", end = "'", close = true, newline = false, not_in = ["string", "comment"] },
     { start = "/*", end = " */", close = true, newline = false, not_in = ["string", "comment"] },
 ]
+debuggers = ["CodeLLDB", "GDB"]

crates/languages/src/go.rs

@@ -630,10 +630,6 @@ impl ContextProvider for GoContextProvider {
             },
         ]))
     }
-
-    fn debug_adapter(&self) -> Option<String> {
-        Some("Delve".into())
-    }
 }
 
 fn extract_subtest_name(input: &str) -> Option<String> {

crates/languages/src/go/config.toml

@@ -14,3 +14,4 @@ brackets = [
 ]
 tab_size = 4
 hard_tabs = true
+debuggers = ["Delve"]

crates/languages/src/javascript/config.toml

@@ -19,6 +19,7 @@ word_characters = ["$", "#"]
 tab_size = 2
 scope_opt_in_language_servers = ["tailwindcss-language-server", "emmet-language-server"]
 prettier_parser_name = "babel"
+debuggers = ["JavaScript"]
 
 [jsx_tag_auto_close]
 open_tag_node_name = "jsx_opening_element"

crates/languages/src/lib.rs

@@ -325,10 +325,7 @@ fn register_language(
         languages.register_lsp_adapter(config.name.clone(), adapter);
     }
     languages.register_language(
-        config.name.clone(),
+        config.clone(),
-        config.grammar.clone(),
-        config.matcher.clone(),
-        config.hidden,
         Arc::new(move || {
             Ok(LoadedLanguage {
                 config: config.clone(),

crates/languages/src/python.rs

@@ -474,10 +474,6 @@ impl ContextProvider for PythonContextProvider {
 
         Some(TaskTemplates(tasks))
     }
-
-    fn debug_adapter(&self) -> Option<String> {
-        Some("Debugpy".into())
-    }
 }
 
 fn selected_test_runner(location: Option<&Arc<dyn language::File>>, cx: &App) -> TestRunner {

crates/languages/src/python/config.toml

@@ -29,3 +29,4 @@ brackets = [
 auto_indent_using_last_non_empty_line = false
 increase_indent_pattern = "^[^#].*:\\s*$"
 decrease_indent_pattern = "^\\s*(else|elif|except|finally)\\b.*:"
+debuggers = ["Debugpy"]

crates/languages/src/rust.rs

@@ -803,10 +803,6 @@ impl ContextProvider for RustContextProvider {
     fn lsp_task_source(&self) -> Option<LanguageServerName> {
         Some(SERVER_NAME)
     }
-
-    fn debug_adapter(&self) -> Option<String> {
-        Some("CodeLLDB".to_owned())
-    }
 }
 
 /// Part of the data structure of Cargo metadata

crates/languages/src/rust/config.toml

@@ -15,3 +15,4 @@ brackets = [
     { start = "/*", end = " */", close = true, newline = false, not_in = ["string", "comment"] },
 ]
 collapsed_placeholder = " /* ... */ "
+debuggers = ["CodeLLDB", "GDB"]

crates/languages/src/tsx/config.toml

@@ -17,6 +17,7 @@ word_characters = ["#", "$"]
 scope_opt_in_language_servers = ["tailwindcss-language-server", "emmet-language-server"]
 prettier_parser_name = "typescript"
 tab_size = 2
+debuggers = ["JavaScript"]
 
 [jsx_tag_auto_close]
 open_tag_node_name = "jsx_opening_element"

crates/languages/src/typescript/config.toml

@@ -17,6 +17,7 @@ brackets = [
 word_characters = ["#", "$"]
 prettier_parser_name = "typescript"
 tab_size = 2
+debuggers = ["JavaScript"]
 
 [overrides.string]
 completion_query_characters = ["."]

crates/project/src/task_inventory.rs

@@ -808,10 +808,6 @@ impl ContextProvider for BasicContextProvider {
 
         Task::ready(Ok(task_variables))
     }
-
-    fn debug_adapter(&self) -> Option<String> {
-        None
-    }
 }
 
 /// A ContextProvider that doesn't provide any task variables on it's own, though it has some associated tasks.
@@ -835,10 +831,6 @@ impl ContextProvider for ContextProviderWithTasks {
     ) -> Option<TaskTemplates> {
         Some(self.templates.clone())
     }
-
-    fn debug_adapter(&self) -> Option<String> {
-        None
-    }
 }
 
 #[cfg(test)]