Ensure all ruby-lsp dependencies are installed before launch (#2730)

ruby-lsp.gemspec

@@ -18,6 +18,7 @@ Gem::Specification.new do |s|
   s.executables = ["ruby-lsp", "ruby-lsp-check"]
   s.require_paths = ["lib"]
 
+  # Dependencies must be kept in sync with the checks in the extension side on workspace.ts
   s.add_dependency("language_server-protocol", "~> 3.17.0")
   s.add_dependency("prism", ">= 1.2", "< 2.0")
   s.add_dependency("rbs", ">= 3", "< 4")

vscode/src/workspace.ts

@@ -225,13 +225,24 @@ export class Workspace implements WorkspaceInterface {
       "rubyLsp.lastGemUpdate",
     );
 
-    const { stdout } = await asyncExec("gem list ruby-lsp", {
+    // Theses are the Ruby LSP's own dependencies, listed in `ruby-lsp.gemspec`
+    const dependencies = [
+      "ruby-lsp",
+      "language_server-protocol",
+      "prism",
+      "rbs",
+      "sorbet-runtime",
+    ];
+
+    const { stdout } = await asyncExec(`gem list ${dependencies.join(" ")}`, {
       cwd: this.workspaceFolder.uri.fsPath,
       env: this.ruby.env,
     });
 
-    // If the gem is not yet installed, install it
-    if (!/^ruby-lsp[\s]/.exec(stdout)) {
+    // If any of the Ruby LSP's dependencies are missing, we need to install them. For example, if the user runs `gem
+    // uninstall prism`, then we must ensure it's installed or else rubygems will fail when trying to launch the
+    // executable
+    if (!dependencies.every((dep) => new RegExp(`${dep}\\s`).exec(stdout))) {
       await asyncExec("gem install ruby-lsp", {
         cwd: this.workspaceFolder.uri.fsPath,
         env: this.ruby.env,
@@ -254,7 +265,7 @@ export class Workspace implements WorkspaceInterface {
         );
       } catch (error) {
         this.outputChannel.info(
-          `Tried deleting ${vscode.Uri.joinPath(this.workspaceFolder.uri, ".ruby - lsp")}, but it doesn't exist`,
+          `Tried deleting ${vscode.Uri.joinPath(this.workspaceFolder.uri, ".ruby-lsp")}, but it doesn't exist`,
         );
       }
     }