Add the ability for extensions to provide language settings (#10296)

This PR adds the ability for extensions to provide certain language
settings via the language `config.toml`.

These settings are then merged in with the rest of the settings when the
language is loaded from the extension.

The language settings that are available are:

- `tab_size`
- `hard_tabs`
- `soft_wrap`

Additionally, for bundled languages we moved these settings out of the
`settings/default.json` and into their respective `config.toml`s .

For languages currently provided by extensions, we are leaving the
values in the `settings/default.json` temporarily until all released
versions of Zed are able to load these settings from the extension.

---

Along the way we ended up refactoring the `Settings::load` method
slightly, introducing a new `SettingsSources` struct to better convey
where the settings are being loaded from.

This makes it easier to load settings from specific locations/sets of
locations in an explicit way.

Release Notes:

- N/A

---------

Co-authored-by: Max <max@zed.dev>
Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>

crates/languages/src/deno.rs

@@ -2,12 +2,13 @@ use anyhow::{anyhow, bail, Context, Result};
 use async_trait::async_trait;
 use collections::HashMap;
 use futures::StreamExt;
+use gpui::AppContext;
 use language::{LanguageServerName, LspAdapter, LspAdapterDelegate};
 use lsp::{CodeActionKind, LanguageServerBinary};
 use schemars::JsonSchema;
 use serde_derive::{Deserialize, Serialize};
 use serde_json::json;
-use settings::Settings;
+use settings::{Settings, SettingsSources};
 use smol::{fs, fs::File};
 use std::{any::Any, env::consts, ffi::OsString, path::PathBuf, sync::Arc};
 use util::{
@@ -31,15 +32,8 @@ impl Settings for DenoSettings {
 
     type FileContent = DenoSettingsContent;
 
-    fn load(
-        default_value: &Self::FileContent,
-        user_values: &[&Self::FileContent],
-        _: &mut gpui::AppContext,
-    ) -> Result<Self>
-    where
-        Self: Sized,
-    {
-        Self::load_via_json_merge(default_value, user_values)
+    fn load(sources: SettingsSources<Self::FileContent>, _: &mut AppContext) -> Result<Self> {
+        sources.json_merge()
     }
 }
 

crates/languages/src/elixir.rs

@@ -1,14 +1,14 @@
 use anyhow::{anyhow, bail, Context, Result};
 use async_trait::async_trait;
 use futures::StreamExt;
-use gpui::{AsyncAppContext, Task};
+use gpui::{AppContext, AsyncAppContext, Task};
 pub use language::*;
 use lsp::{CompletionItemKind, LanguageServerBinary, SymbolKind};
 use project::project_settings::ProjectSettings;
 use schemars::JsonSchema;
 use serde_derive::{Deserialize, Serialize};
 use serde_json::Value;
-use settings::Settings;
+use settings::{Settings, SettingsSources};
 use smol::fs::{self, File};
 use std::{
     any::Any,
@@ -56,15 +56,8 @@ impl Settings for ElixirSettings {
 
     type FileContent = ElixirSettingsContent;
 
-    fn load(
-        default_value: &Self::FileContent,
-        user_values: &[&Self::FileContent],
-        _: &mut gpui::AppContext,
-    ) -> Result<Self>
-    where
-        Self: Sized,
-    {
-        Self::load_via_json_merge(default_value, user_values)
+    fn load(sources: SettingsSources<Self::FileContent>, _: &mut AppContext) -> Result<Self> {
+        sources.json_merge()
     }
 }
 

crates/languages/src/elixir/config.toml

@@ -10,6 +10,7 @@ brackets = [
     { start = "\"", end = "\"", close = true, newline = false, not_in = ["string", "comment"] },
     { start = "'", end = "'", close = true, newline = false, not_in = ["string", "comment"] },
 ]
+tab_size = 2
 scope_opt_in_language_servers = ["tailwindcss-language-server"]
 
 [overrides.string]

crates/languages/src/go/config.toml

@@ -11,3 +11,5 @@ brackets = [
     { start = "'", end = "'", close = true, newline = false, not_in = ["comment", "string"] },
     { start = "/*", end = " */", close = true, newline = false, not_in = ["comment", "string"] },
 ]
+tab_size = 4
+hard_tabs = true

crates/languages/src/javascript/config.toml

@@ -15,6 +15,7 @@ brackets = [
     { start = "/*", end = " */", close = true, newline = false, not_in = ["comment", "string"] },
 ]
 word_characters = ["$", "#"]
+tab_size = 2
 scope_opt_in_language_servers = ["tailwindcss-language-server"]
 prettier_parser_name = "babel"
 

crates/languages/src/json/config.toml

@@ -9,3 +9,4 @@ brackets = [
     { start = "\"", end = "\"", close = true, newline = false, not_in = ["string"] },
 ]
 prettier_parser_name = "json"
+tab_size = 2

crates/languages/src/lib.rs

@@ -1,11 +1,12 @@
 use anyhow::Context;
-use gpui::AppContext;
+use gpui::{AppContext, BorrowAppContext};
 pub use language::*;
 use node_runtime::NodeRuntime;
 use rust_embed::RustEmbed;
-use settings::Settings;
+use settings::{Settings, SettingsStore};
+use smol::stream::StreamExt;
 use std::{str, sync::Arc};
-use util::asset_str;
+use util::{asset_str, ResultExt};
 
 use crate::{elixir::elixir_task_context, rust::RustContextProvider};
 
@@ -327,6 +328,27 @@ pub fn init(
         "Svelte".into(),
         Arc::new(tailwind::TailwindLspAdapter::new(node_runtime.clone())),
     );
+
+    let mut subscription = languages.subscribe();
+    let mut prev_language_settings = languages.language_settings();
+
+    cx.spawn(|cx| async move {
+        while subscription.next().await.is_some() {
+            let language_settings = languages.language_settings();
+            if language_settings != prev_language_settings {
+                cx.update(|cx| {
+                    cx.update_global(|settings: &mut SettingsStore, cx| {
+                        settings
+                            .set_extension_settings(language_settings.clone(), cx)
+                            .log_err();
+                    });
+                })?;
+                prev_language_settings = language_settings;
+            }
+        }
+        anyhow::Ok(())
+    })
+    .detach();
 }
 
 #[cfg(any(test, feature = "test-support"))]

crates/languages/src/markdown/config.toml

@@ -12,3 +12,6 @@ brackets = [
     { start = "`", end = "`", close = false, newline = false },
 ]
 prettier_parser_name = "markdown"
+
+tab_size = 2
+soft_wrap = "preferred_line_length"

crates/languages/src/ocaml-interface/config.toml

@@ -10,3 +10,4 @@ brackets = [
   { start = "[", end = "]", close = true, newline = true },
   { start = "(", end = ")", close = true, newline = true }
 ]
+tab_size = 2

crates/languages/src/ocaml/config.toml

@@ -11,3 +11,4 @@ brackets = [
   { start = "(", end = ")", close = true, newline = true },
   { start = "\"", end = "\"", close = true, newline = false, not_in = ["string"] }
 ]
+tab_size = 2

crates/languages/src/terraform/config.toml

@@ -12,3 +12,4 @@ brackets = [
     { start = "'", end = "'", close = true, newline = false, not_in = ["comment", "string"] },
     { start = "/*", end = " */", close = true, newline = false, not_in = ["comment", "string"] },
 ]
+tab_size = 2

crates/languages/src/tsx/config.toml

@@ -16,6 +16,7 @@ brackets = [
 word_characters = ["#", "$"]
 scope_opt_in_language_servers = ["tailwindcss-language-server"]
 prettier_parser_name = "typescript"
+tab_size = 2
 
 [overrides.element]
 line_comments = { remove = true }

crates/languages/src/typescript/config.toml

@@ -15,3 +15,4 @@ brackets = [
 ]
 word_characters = ["#", "$"]
 prettier_parser_name = "typescript"
+tab_size = 2

crates/languages/src/yaml/config.toml

@@ -11,3 +11,4 @@ brackets = [
 
 increase_indent_pattern = ":\\s*[|>]?\\s*$"
 prettier_parser_name = "yaml"
+tab_size = 2