From 0c30a6f3030d755b406aaf4c8059c4e6d11570e2 Mon Sep 17 00:00:00 2001
From: Anton <aasoft@pm.me>
Date: Fri, 29 Aug 2025 22:55:20 -0700
Subject: [PATCH] Use a single rust LSP server instance for entire cargo
 workspace (#2292)

---
 packages/opencode/src/lsp/server.ts | 30 ++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/packages/opencode/src/lsp/server.ts b/packages/opencode/src/lsp/server.ts
index 2636df96..da743628 100644
--- a/packages/opencode/src/lsp/server.ts
+++ b/packages/opencode/src/lsp/server.ts
@@ -515,7 +515,35 @@ export namespace LSPServer {
 
   export const RustAnalyzer: Info = {
     id: "rust",
-    root: NearestRoot(["Cargo.toml", "Cargo.lock"]),
+    root: async (file, app) => {
+      const crateRoot = await NearestRoot(["Cargo.toml", "Cargo.lock"])(file, app)
+      if (crateRoot === undefined) {
+        return undefined
+      }
+      let currentDir = crateRoot
+
+      while (currentDir !== path.dirname(currentDir)) {
+        // Stop at filesystem root
+        const cargoTomlPath = path.join(currentDir, "Cargo.toml")
+        try {
+          const cargoTomlContent = await Bun.file(cargoTomlPath).text()
+          if (cargoTomlContent.includes("[workspace]")) {
+            return currentDir
+          }
+        } catch (err) {
+          // File doesn't exist or can't be read, continue searching up
+        }
+
+        const parentDir = path.dirname(currentDir)
+        if (parentDir === currentDir) break // Reached filesystem root
+        currentDir = parentDir
+
+        // Stop if we've gone above the app root
+        if (!currentDir.startsWith(app.path.root)) break
+      }
+
+      return crateRoot
+    },
     extensions: [".rs"],
     async spawn(_, root) {
       const bin = Bun.which("rust-analyzer")