[lldb-dap] Add breakpoints after debugger initialization in DExTer

cross-project-tests/debuginfo-tests/dexter/dex/debugger/DAP.py

@@ -763,20 +763,27 @@ def launch(self, cmdline):
 
         launch_request = self._get_launch_params(cmdline)
 
-        # For some reason, we *must* submit in the order launch->configurationDone, and then we will receive responses
-        # in the order configurationDone->launch.
-        self._flush_breakpoints()
+        # Per DAP protocol, the correct sequence is:
+        # 1. Send launch request
+        # 2. Wait for launch response and "initialized" event
+        # 3. Set breakpoints
+        # 4. Send configurationDone to start the process
         launch_req_id = self.send_message(self.make_request("launch", launch_request))
-        config_done_req_id = self.send_message(self.make_request("configurationDone"))
-        config_done_response = self._await_response(config_done_req_id)
-        assert config_done_response["success"], "Should simply receive an affirmative?"
         launch_response = self._await_response(launch_req_id)
         if not launch_response["success"]:
             raise DebuggerException(
                 f"failure launching debugger: \"{launch_response['body']['error']['format']}\""
             )
-        # We can't interact meaningfully with the process until we have the thread ID and confirmation that the process
-        # has finished launching.
+
+        # Set breakpoints after receiving launch response but before configurationDone.
+        self._flush_breakpoints()
+
+        # Send configurationDone to allow the process to start running.
+        config_done_req_id = self.send_message(self.make_request("configurationDone"))
+        config_done_response = self._await_response(config_done_req_id)
+        assert config_done_response["success"]
+
+        # Wait for the process to launch and obtain a thread ID.
         while self._debugger_state.thread is None or not self._debugger_state.launched:
             time.sleep(0.001)