Fix issues with extension API that come up when moving Svelte into an extension (#9611)

We're doing it. Svelte support is moving into an extension. This PR
fixes some issues that came up along the way.

Notes

* extensions need to be able to retrieve the path the `node` binary
installed by Zed
* previously we were silently swallowing any errors that occurred while
loading a grammar
* npm commands ran by extensions weren't run in the right directory
* Tree-sitter's WASM stdlib didn't support a C function (`strncmp`)
needed by the Svelte parser's external scanner
* the way that LSP installation status was reported was unnecessarily
complex

Release Notes:

- Removed built-in support for the Svelte and Gleam languages, because
full support for those languages is now available via extensions. These
extensions will be suggested for download when you open a `.svelte` or
`.gleam` file.

---------

Co-authored-by: Marshall <marshall@zed.dev>

crates/extension_api/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "zed_extension_api"
-version = "0.0.1"
+version = "0.0.4"
 description = "APIs for creating Zed extensions in Rust"
 repository = "https://github.com/zed-industries/zed"
 documentation = "https://docs.rs/zed_extension_api"
@@ -15,7 +15,7 @@ workspace = true
 path = "src/extension_api.rs"
 
 [dependencies]
-wit-bindgen = "0.18"
+wit-bindgen = "0.22"
 
 [package.metadata.component]
 target = { path = "wit" }

crates/extension_api/src/extension_api.rs

@@ -1,6 +1,4 @@
-pub struct Guest;
 pub use wit::*;
-
 pub type Result<T, E = String> = core::result::Result<T, E>;
 
 pub trait Extension: Send + Sync {
@@ -10,14 +8,14 @@ pub trait Extension: Send + Sync {
 
     fn language_server_command(
         &mut self,
-        config: wit::LanguageServerConfig,
-        worktree: &wit::Worktree,
+        config: LanguageServerConfig,
+        worktree: &Worktree,
     ) -> Result<Command>;
 
     fn language_server_initialization_options(
         &mut self,
-        _config: wit::LanguageServerConfig,
-        _worktree: &wit::Worktree,
+        _config: LanguageServerConfig,
+        _worktree: &Worktree,
     ) -> Result<Option<String>> {
         Ok(None)
     }
@@ -54,11 +52,13 @@ pub static ZED_API_VERSION: [u8; 6] = *include_bytes!(concat!(env!("OUT_DIR"), "
 
 mod wit {
     wit_bindgen::generate!({
-        exports: { world: super::Component },
-        skip: ["init-extension"]
+        skip: ["init-extension"],
+        path: "./wit/0.0.4",
     });
 }
 
+wit::export!(Component);
+
 struct Component;
 
 impl wit::Guest for Component {

crates/extension_api/wit/0.0.1/extension.wit

@@ -48,6 +48,9 @@ world extension {
     /// Gets the current operating system and architecture
     import current-platform: func() -> tuple<os, architecture>;
 
+    /// Get the path to the node binary used by Zed.
+    import node-binary-path: func() -> result<string, string>;
+
     /// Gets the latest version of the given NPM package.
     import npm-package-latest-version: func(package-name: string) -> result<string, string>;
 

crates/extension_api/wit/0.0.4/extension.wit

@@ -0,0 +1,93 @@
+package zed:extension;
+
+world extension {
+    export init-extension: func();
+
+    record github-release {
+        version: string,
+        assets: list<github-release-asset>,
+    }
+
+    record github-release-asset {
+        name: string,
+        download-url: string,
+    }
+
+    record github-release-options {
+        require-assets: bool,
+        pre-release: bool,
+    }
+
+    enum os {
+        mac,
+        linux,
+        windows,
+    }
+
+    enum architecture {
+        aarch64,
+        x86,
+        x8664,
+    }
+
+    enum downloaded-file-type {
+        gzip,
+        gzip-tar,
+        zip,
+        uncompressed,
+    }
+
+    variant language-server-installation-status {
+        none,
+        downloading,
+        checking-for-update,
+        failed(string),
+    }
+
+    /// Gets the current operating system and architecture
+    import current-platform: func() -> tuple<os, architecture>;
+
+    /// Get the path to the node binary used by Zed.
+    import node-binary-path: func() -> result<string, string>;
+
+    /// Gets the latest version of the given NPM package.
+    import npm-package-latest-version: func(package-name: string) -> result<string, string>;
+
+    /// Returns the installed version of the given NPM package, if it exists.
+    import npm-package-installed-version: func(package-name: string) -> result<option<string>, string>;
+
+    /// Installs the specified NPM package.
+    import npm-install-package: func(package-name: string, version: string) -> result<_, string>;
+
+    /// Gets the latest release for the given GitHub repository.
+    import latest-github-release: func(repo: string, options: github-release-options) -> result<github-release, string>;
+
+    /// Downloads a file from the given url, and saves it to the given filename within the extension's
+    /// working directory. Extracts the file according to the given file type.
+    import download-file: func(url: string, output-filename: string, file-type: downloaded-file-type) -> result<_, string>;
+
+    /// Updates the installation status for the given language server.
+    import set-language-server-installation-status: func(language-server-name: string, status: language-server-installation-status);
+
+    type env-vars = list<tuple<string, string>>;
+
+    record command {
+        command: string,
+        args: list<string>,
+        env: env-vars,
+    }
+
+    resource worktree {
+        read-text-file: func(path: string) -> result<string, string>;
+        which: func(binary-name: string) -> option<string>;
+        shell-env: func() -> env-vars;
+    }
+
+    record language-server-config {
+        name: string,
+        language-name: string,
+    }
+
+    export language-server-command: func(config: language-server-config, worktree: borrow<worktree>) -> result<command, string>;
+    export language-server-initialization-options: func(config: language-server-config, worktree: borrow<worktree>) -> result<option<string>, string>;
+}