From bcabfa595ebdf78111acebeb5863c68ad0c85b16 Mon Sep 17 00:00:00 2001
From: Siddharth Kucheria <kucheria@usc.edu>
Date: Tue, 21 May 2019 11:31:50 -0700
Subject: [PATCH] user friendly error messages for invalid transitions

---
 rcl_action/include/rcl_action/goal_handle.h |  4 ++++
 rcl_action/include/rcl_action/types.h       |  1 +
 rcl_action/src/rcl_action/goal_handle.c     | 13 ++++++++++---
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/rcl_action/include/rcl_action/goal_handle.h b/rcl_action/include/rcl_action/goal_handle.h
index c1410a4c60..c1c2e8e56a 100644
--- a/rcl_action/include/rcl_action/goal_handle.h
+++ b/rcl_action/include/rcl_action/goal_handle.h
@@ -29,6 +29,10 @@ extern "C"
 /// Internal rcl action goal implementation struct.
 struct rcl_action_goal_handle_impl_t;
 
+/// User friendly error messages for invalid trasntions
+extern const char * goal_state_descriptions[];
+extern const char * goal_event_descriptions[];
+
 /// Goal handle for an action.
 typedef struct rcl_action_goal_handle_t
 {
diff --git a/rcl_action/include/rcl_action/types.h b/rcl_action/include/rcl_action/types.h
index 783165b4c5..3d69972202 100644
--- a/rcl_action/include/rcl_action/types.h
+++ b/rcl_action/include/rcl_action/types.h
@@ -93,6 +93,7 @@ typedef int8_t rcl_action_goal_state_t;
 #define GOAL_STATE_ABORTED action_msgs__msg__GoalStatus__STATUS_ABORTED
 #define GOAL_STATE_NUM_STATES 7
 
+
 /// Goal state transition events
 typedef enum rcl_action_goal_event_t
 {
diff --git a/rcl_action/src/rcl_action/goal_handle.c b/rcl_action/src/rcl_action/goal_handle.c
index e456042bfe..06c9ec7811 100644
--- a/rcl_action/src/rcl_action/goal_handle.c
+++ b/rcl_action/src/rcl_action/goal_handle.c
@@ -22,6 +22,13 @@ extern "C"
 #include "rcl/rcl.h"
 #include "rcl/error_handling.h"
 
+const char * goal_state_descriptions[] =
+{"UNKNOWN", "ACCEPTED", "EXECUTING", "CANCELING", "SUCCEEDED", "CANCELED", "ABORTED"};
+
+const char * goal_event_descriptions[] =
+{"EXECUTE", "CANCEL_GOAL", "SUCCEED", "ABORT", "CANCELED", "NUM_EVENTS"};
+
+
 typedef struct rcl_action_goal_handle_impl_t
 {
   rcl_action_goal_info_t info;
@@ -89,9 +96,9 @@ rcl_action_update_goal_state(
     goal_handle->impl->state, goal_event);
   if (GOAL_STATE_UNKNOWN == new_state) {
     RCL_SET_ERROR_MSG_WITH_FORMAT_STRING(
-      "goal_handle attempted invalid transition from state %d with event %d",
-      goal_handle->impl->state,
-      goal_event);
+      "goal_handle attempted invalid transition from state %s with event %s",
+      goal_state_descriptions[goal_handle->impl->state],
+      goal_event_descriptions[goal_event]);
     return RCL_RET_ACTION_GOAL_EVENT_INVALID;
   }
   goal_handle->impl->state = new_state;