migrate all async tokio to server & swap to single-thread runtime (#149)

Author: joshuadavidthomas

Cargo.toml

@@ -13,15 +13,12 @@ djls-templates = { path = "crates/djls-templates" }
 anyhow = "1.0"
 async-trait = "0.1"
 pyo3 = "0.24"
-pyo3-async-runtimes = "0.24"
 pyo3-build-config = "0.24"
 salsa = { git = "https://github.com/salsa-rs/salsa.git", rev = "7edce6e248f35c8114b4b021cdb474a3fb2813b3" }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 tempfile = "3.19"
 thiserror = "2.0"
-tokio = { version = "1.42", features = ["full"] }
-tower-lsp-server = { version = "0.21", features = ["proposed"] }
 
 [workspace.lints.clippy]
 pedantic = { level = "warn", priority = -1 }

crates/djls-project/Cargo.toml

@@ -10,7 +10,6 @@ default = []
 [dependencies]
 pyo3 = { workspace = true }
 salsa = { workspace = true }
-tower-lsp-server = { workspace = true, features = ["proposed"] }
 
 which = "7.0.1"
 

crates/djls-server/Cargo.toml

@@ -17,10 +17,10 @@ pyo3 = { workspace = true }
 salsa = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }
-tokio = { workspace = true }
-tower-lsp-server = { workspace = true }
 
-percent-encoding = "2.3"
+percent-encoding = "2.3.1"
+tokio = { version = "1.45.0", features = ["full"] }
+tower-lsp-server = { version = "0.21.1", features = ["proposed"] }
 
 [build-dependencies]
 djls-dev = { workspace = true }

crates/djls-server/src/documents.rs

@@ -25,13 +25,6 @@ pub struct Store {
 }
 
 impl Store {
-    pub fn new() -> Self {
-        Self {
-            documents: HashMap::new(),
-            versions: HashMap::new(),
-        }
-    }
-
     pub fn handle_did_open(&mut self, db: &dyn Database, params: &DidOpenTextDocumentParams) {
         let uri = params.text_document.uri.to_string();
         let version = params.text_document.version;

crates/djls-server/src/lib.rs

@@ -5,4 +5,25 @@ mod server;
 mod session;
 mod workspace;
 
-pub use crate::server::DjangoLanguageServer;
+use anyhow::Result;
+use tower_lsp_server::LspService;
+use tower_lsp_server::Server;
+
+use crate::server::DjangoLanguageServer;
+
+pub fn run() -> Result<()> {
+    let runtime = tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()?;
+
+    runtime.block_on(async {
+        let stdin = tokio::io::stdin();
+        let stdout = tokio::io::stdout();
+
+        let (service, socket) = LspService::build(DjangoLanguageServer::new).finish();
+
+        Server::new(stdin, stdout, socket).serve(service).await;
+
+        Ok(())
+    })
+}

crates/djls-server/src/queue.rs

@@ -19,7 +19,9 @@ use tokio::sync::oneshot;
 ///   required for self-referential `async` blocks.
 /// - `Box`: Allocates the `Future` on the heap.
 /// - `dyn Future`: Type erasure - hides the specific concrete `Future` type.
-/// - `+ Send`: Ensures the `Future` can be safely sent across threads.
+/// - `+ Send`: Ensures the `Future` can be safely sent across threads and required
+///   by the tower-lsp-server LSP server trait bounds, even in our single-threaded
+///   runtime.
 type TaskFuture = Pin<Box<dyn Future<Output = Result<()>> + Send>>;
 
 /// Type alias for a type-erased, heap-allocated, Send-able closure that,
@@ -34,7 +36,8 @@ type TaskFuture = Pin<Box<dyn Future<Output = Result<()>> + Send>>;
 ///   arguments.
 /// - `-> TaskFuture`: Specifies that calling the closure produces the type-erased future.
 /// - `+ Send + 'static`: Ensures the closure itself can be safely sent across
-///   threads and has a static lifetime (doesn't borrow short-lived data).
+///   threads and has a static lifetime (doesn't borrow short-lived data). Required
+///   for compatibility with our async runtime and LSP traits.
 type TaskClosure = Box<dyn FnOnce() -> TaskFuture + Send + 'static>;
 
 /// A simple asynchronous task queue for sequential execution.
@@ -43,8 +46,9 @@ type TaskClosure = Box<dyn FnOnce() -> TaskFuture + Send + 'static>;
 /// to a dedicated worker task which executes them one at a time in the order
 /// they were received. This ensures sequential processing of background tasks.
 ///
-/// The queue is cloneable (`Arc`-based internally), allowing multiple producers
-/// to submit tasks concurrently.
+/// The queue runs within our single-threaded runtime but maintains compatibility
+/// with the Send+Sync requirements of the LSP. This provides the benefits of
+/// simpler execution while maintaining the required trait bounds.
 ///
 /// Shutdown is handled gracefully when the last `Queue` instance is dropped.
 #[derive(Clone)]

crates/djls-server/src/session.rs

@@ -19,6 +19,10 @@ pub struct Session {
     /// where we're using the `StorageHandle` to create a thread-safe handle that can be
     /// shared between threads. When we need to use it, we clone the handle to get a new reference.
     ///
+    /// This handle allows us to create database instances as needed.
+    /// Even though we're using a single-threaded runtime, we still need
+    /// this to be thread-safe because of LSP trait requirements.
+    ///
     /// Usage:
     /// ```rust,ignore
     /// // Use the StorageHandle in Session
@@ -41,20 +45,6 @@ pub struct Session {
 }
 
 impl Session {
-    pub fn new(client_capabilities: ClientCapabilities) -> Self {
-        Self {
-            client_capabilities: Some(client_capabilities),
-            project: None,
-            documents: Store::new(),
-            settings: Settings::default(),
-            db_handle: StorageHandle::new(None),
-        }
-    }
-
-    pub fn client_capabilities(&self) -> Option<&ClientCapabilities> {
-        self.client_capabilities.as_ref()
-    }
-
     pub fn client_capabilities_mut(&mut self) -> &mut Option<ClientCapabilities> {
         &mut self.client_capabilities
     }
@@ -83,14 +73,6 @@ impl Session {
         &mut self.settings
     }
 
-    /// Get the raw database handle from the session
-    ///
-    /// Note: In most cases, you'll want to use `db()` instead to get a usable
-    /// database instance directly.
-    pub fn db_handle(&self) -> &StorageHandle<ServerDatabase> {
-        &self.db_handle
-    }
-
     /// Get a database instance directly from the session
     ///
     /// This creates a usable database from the handle, which can be used

crates/djls-templates/Cargo.toml

@@ -5,7 +5,6 @@ edition = "2021"
 
 [dependencies]
 anyhow = { workspace = true }
-tower-lsp-server = { workspace = true }
 serde = { workspace = true }
 thiserror = { workspace = true }
 toml = "0.8"

crates/djls-templates/src/error.rs

@@ -1,6 +1,5 @@
 use serde::Serialize;
 use thiserror::Error;
-use tower_lsp_server::lsp_types;
 
 use crate::ast::AstError;
 use crate::ast::Span;
@@ -52,17 +51,6 @@ impl TemplateError {
         }
     }
 
-    #[must_use]
-    pub fn severity(&self) -> lsp_types::DiagnosticSeverity {
-        match self {
-            TemplateError::Lexer(_) | TemplateError::Parser(_) => {
-                lsp_types::DiagnosticSeverity::ERROR
-            }
-            TemplateError::Validation(_) => lsp_types::DiagnosticSeverity::WARNING,
-            _ => lsp_types::DiagnosticSeverity::INFORMATION,
-        }
-    }
-
     #[must_use]
     pub fn code(&self) -> &'static str {
         match self {
@@ -75,26 +63,6 @@ impl TemplateError {
     }
 }
 
-pub fn to_lsp_diagnostic(error: &TemplateError, _source: &str) -> lsp_types::Diagnostic {
-    let range = error.span().map_or_else(lsp_types::Range::default, |span| {
-        let start = lsp_types::Position::new(0, span.start());
-        let end = lsp_types::Position::new(0, span.start() + span.length());
-        lsp_types::Range::new(start, end)
-    });
-
-    lsp_types::Diagnostic {
-        range,
-        severity: Some(error.severity()),
-        code: Some(lsp_types::NumberOrString::String(error.code().to_string())),
-        code_description: None,
-        source: Some("djls-template".to_string()),
-        message: error.to_string(),
-        related_information: None,
-        tags: None,
-        data: None,
-    }
-}
-
 pub struct QuickFix {
     pub title: String,
     pub edit: String,

crates/djls-templates/src/lib.rs

@@ -6,7 +6,6 @@ mod tagspecs;
 mod tokens;
 
 use ast::Ast;
-pub use error::to_lsp_diagnostic;
 pub use error::QuickFix;
 pub use error::TemplateError;
 use lexer::Lexer;