Fixes trac:487

Give a more intelligible error message when someone passes -nolocal and the only available node is the local node.

This commit was SVN r12325.

The following Trac tickets were found above:
  Ticket 487 --> https://svn.open-mpi.org/trac/ompi/ticket/487

orte/mca/rmaps/base/help-orte-rmaps-base.txt

@@ -42,3 +42,14 @@ that match the requested mapping:
 
 OR the requested resources in that mapping have already been consumed. Verify that you have mapped the allocated resources properly using the 
 --host specification.
+[orte-rmaps-base:nolocal-no-available-resources]
+There are no available nodes allocated to this job. This could be because
+no nodes were found or all the available nodes were already used.
+
+Note that since the -nolocal option was given no processes can be 
+launched on the local node.
+[orte-rmaps-base:no-available-resources]
+There are no nodes allocated to this job.
+[orte-rmaps-base:all-available-resources-used]
+All nodes which are allocated for this job are already filled.
+

orte/mca/rmaps/base/rmaps_base_support_fns.c

@@ -101,6 +101,7 @@ int orte_rmaps_base_get_target_nodes(opal_list_t *allocated_nodes, orte_jobid_t
     opal_list_item_t *item, *next;
     orte_ras_node_t *node;
     int rc;
+    size_t nodelist_size;
     orte_std_cntr_t num_slots=0;
 
     /** set default answer */
@@ -112,6 +113,8 @@ int orte_rmaps_base_get_target_nodes(opal_list_t *allocated_nodes, orte_jobid_t
         return rc;
     }
 
+    nodelist_size = opal_list_get_size(allocated_nodes);
+
     /* If the "no local" option was set, then remove the local node
         from the list */
     if (nolocal) {
@@ -148,6 +151,20 @@ int orte_rmaps_base_get_target_nodes(opal_list_t *allocated_nodes, orte_jobid_t
 
     /* Sanity check to make sure we have resources available */
     if (0 == opal_list_get_size(allocated_nodes)) {
+        /* so there are 3 reasons we could be erroring here:
+         * 1. There were no nodes allocated to this job 
+         * 2. The local node was the only one available and nolocal was passed 
+         * 3. All the nodes were full */
+        if(0 == nodelist_size) {
+            opal_show_help("help-orte-rmaps-base.txt", 
+                           "orte-rmaps-base:no-available-resources", true);
+        } else if(nolocal) {
+            opal_show_help("help-orte-rmaps-base.txt", 
+                           "orte-rmaps-base:nolocal-no-available-resources", true);
+        } else {
+            opal_show_help("help-orte-rmaps-base.txt", 
+                           "orte-rmaps-base:all-available-resources-used", true);
+        }
         ORTE_ERROR_LOG(ORTE_ERR_TEMP_OUT_OF_RESOURCE);
         return ORTE_ERR_TEMP_OUT_OF_RESOURCE;
     }