Fix issue with wrong protocol version when using the srun --no-allocate

option.

NEWS

@@ -69,6 +69,8 @@ documents those changes that are of interest to users and administrators.
  -- Add [Alloc|Req]Nodes to sacct to be more like cpus.
  -- Fix sacct documentation about [Alloc|Req]TRES
  -- Put node count in TRES string for steps.
+ -- Fix issue with wrong protocol version when using the srun --no-allocate
+    option.
 
 * Changes in Slurm 15.08.0
 ==========================

src/api/step_launch.c

@@ -805,7 +805,9 @@ void slurm_step_launch_fwd_signal(slurm_step_ctx_t *ctx, int signo)
 	slurm_msg_t_init(&req);
 	req.msg_type = REQUEST_SIGNAL_TASKS;
 	req.data     = &msg;
-	req.protocol_version = ctx->step_resp->use_protocol_ver;
+
+	if (ctx->step_resp->use_protocol_ver)
+		req.protocol_version = ctx->step_resp->use_protocol_ver;
 
 	debug3("sending signal %d to job %u on host %s",
 	       signo, ctx->job_id, name);
@@ -1599,7 +1601,9 @@ static int _fail_step_tasks(slurm_step_ctx_t *ctx, char *node, int ret_code)
 	slurm_msg_t_init(&req);
 	req.msg_type = REQUEST_STEP_COMPLETE;
 	req.data = &msg;
-	req.protocol_version = ctx->step_resp->use_protocol_ver;
+
+	if (ctx->step_resp->use_protocol_ver)
+		req.protocol_version = ctx->step_resp->use_protocol_ver;
 
 	if (slurm_send_recv_controller_rc_msg(&req, &rc) < 0)
 	       return SLURM_ERROR;
@@ -1643,7 +1647,9 @@ static int _launch_tasks(slurm_step_ctx_t *ctx,
 	slurm_msg_t_init(&msg);
 	msg.msg_type = REQUEST_LAUNCH_TASKS;
 	msg.data = launch_msg;
-	msg.protocol_version = ctx->step_resp->use_protocol_ver;
+
+	if (ctx->step_resp->use_protocol_ver)
+		msg.protocol_version = ctx->step_resp->use_protocol_ver;
 
 #ifdef HAVE_FRONT_END
 	slurm_cred_get_args(ctx->step_resp->cred, &cred_args);