fix: Prevent debugger crashing on circuits with no opcodes

tooling/debugger/src/dap.rs

@@ -125,9 +125,9 @@ impl<'a, R: Read, W: Write, B: BlackBoxFunctionSolver> DapSession<'a, R, W, B> {
     }
 
     pub fn run_loop(&mut self) -> Result<(), ServerError> {
-        self.running = true;
+        self.running = self.context.get_current_opcode_location().is_some();
 
-        if matches!(self.context.get_current_source_location(), None) {
+        if self.running && matches!(self.context.get_current_source_location(), None) {
             // TODO: remove this? This is to ensure that the tool has a proper
             // source location to show when first starting the debugger, but
             // maybe the default behavior should be to start executing until the

tooling/debugger/src/repl.rs

@@ -38,14 +38,13 @@
             initial_witness.clone(),
             foreign_call_executor,
         );
-        Self {
-            context,
-            blackbox_solver,
-            circuit,
-            debug_artifact,
-            initial_witness,
-            last_result: DebugCommandResult::Ok,
-        }
+        let last_result = if context.get_current_opcode_location().is_none() {
+            // handle circuit with no opcodes
+            DebugCommandResult::Done
+        } else {
+            DebugCommandResult::Ok
+        };
+        Self { context, blackbox_solver, circuit, debug_artifact, initial_witness, last_result }
     }
 
     pub fn show_current_vm_status(&self) {
@@ -471,7 +470,7 @@
             },
         )
         .add(
             "regset",
             command! {
                 "update a Brillig register with the given value",
                 (index: usize, value: String) => |index, value| {