feat(debugger): debug Ruby programs and tests with rdbg (#2173)

Ruby files, `rails server`, Rake tasks, RSpec and Minitest configurations
can be debugged with rdbg, using the project's Ruby. In a Bundler project
it runs through the bundle; if the bundle lacks the `debug` gem, debugging
stops with an error asking to add `gem "debug"` to the Gemfile.

src/features/run/ConfigForm.tsx

@@ -64,6 +64,7 @@ const ADAPTERS: ReadonlyArray<{ id: string; label: string }> = [
   { id: "codelldb", label: "CodeLLDB (Rust, C, C++)" },
   { id: "lldb-dap", label: "lldb-dap (C, C++, Swift)" },
   { id: "php-debug", label: "php-debug (PHP)" },
+  { id: "rdbg", label: "rdbg (Ruby)" },
 ];
 
 /** Options "Modify options" adds to the form: value fields (shown once added) and flags (chips). */

src/features/run/producers.ruby.test.ts

@@ -22,6 +22,7 @@ describe("Ruby file run", () => {
   it("puts Sources roots on the load path", () => {
     const p = produceContext(input("/work/app/test/integration/a_test.rb"), env);
     expect(p?.config?.args).toEqual(["-Ilib", "test/integration/a_test.rb"]);
+    expect(p?.config?.debugAdapter).toBe("rdbg");
   });
 
   it("adds none for files outside the project", () => {

src/features/run/producers.ts

@@ -887,10 +887,14 @@ export function produceFile(input: ContextInput, env: ToolEnv): Produced | null
     }
     case "ruby":
       // Sources roots go on the load path (`-Ilib`), as `rake test` does; paths are project-relative.
-      return simple(lang, s, env, lang, () => [
-        ...(s.inProject ? rubyLoadPath(currentRoots(), s.cwd, input.root) : []),
-        s.arg,
-      ]);
+      return simple(
+        lang,
+        s,
+        env,
+        lang,
+        () => [...(s.inProject ? rubyLoadPath(currentRoots(), s.cwd, input.root) : []), s.arg],
+        "rdbg",
+      );
     case "php":
       if (env.php) return { name: s.file, scope: "file", config: fileConfig(s, "php", env.php, [s.arg], "php-debug") };
       return simple(lang, s, env, lang, () => [s.arg], "php-debug");