[issue1233] Report unsolvability for bounded search algos if the bound was not used.

src/search/search_algorithm.cc

@@ -51,7 +51,8 @@ SearchAlgorithm::SearchAlgorithm(
       bound(bound),
       cost_type(cost_type),
       is_unit_cost(task_properties::is_unit_cost(task_proxy)),
-      max_time(max_time) {
+      max_time(max_time),
+      bound_was_used(false) {
     if (bound < 0) {
         cerr << "error: negative cost bound " << bound << endl;
         utils::exit_with(ExitCode::SEARCH_INPUT_ERROR);
@@ -70,13 +71,13 @@ SearchStatus SearchAlgorithm::get_status() const {
 SearchStatus SearchAlgorithm::get_finished_search_status() const {
     if (found_solution()) {
         return SOLVED;
-    } else if (is_unbounded() && is_complete_within_bound()) {
-        log << "Search terminated -- no plan exists!" << endl;
-        return UNSOLVABLE;
-    } else if (is_complete_within_bound()) {
+    } else if (bound_was_used && is_complete_within_bound()) {
         log << "Search terminated -- no plan with cost " << bound - 1
             << " or less exists!" << endl;
         return UNSOLVABLE_WITHIN_BOUND;
+    } else if (is_complete_within_bound()) {
+        log << "Search terminated -- no plan exists!" << endl;
+        return UNSOLVABLE;
     } else {
         log << "Search terminated without finding a plan!" << endl;
         return FAILED;

src/search/search_algorithm.h

@@ -57,6 +57,7 @@ class SearchAlgorithm : public components::TaskSpecificComponent {
     OperatorCost cost_type;
     bool is_unit_cost;
     double max_time;
+    bool bound_was_used;
 
     virtual void initialize() {
     }
@@ -91,9 +92,6 @@ class SearchAlgorithm : public components::TaskSpecificComponent {
     int get_bound() {
         return bound;
     }
-    bool is_unbounded() const {
-        return bound == std::numeric_limits<int>::max();
-    }
     PlanManager &get_plan_manager() {
         return plan_manager;
     }

src/search/search_algorithms/eager_search.cc

@@ -223,8 +223,10 @@ void EagerSearch::generate_successors(const SearchNode &node) {
 
     for (OperatorID op_id : applicable_operators) {
         OperatorProxy op = task_proxy.get_operators()[op_id];
-        if ((node.get_real_g() + op.get_cost()) >= bound)
+        if ((node.get_real_g() + op.get_cost()) >= bound) {
+            bound_was_used = true;
             continue;
+        }
 
         State succ_state = state_registry.get_successor_state(state, op);
         statistics.inc_generated();

src/search/search_algorithms/enforced_hill_climbing_search.cc

@@ -196,8 +196,10 @@ SearchStatus EnforcedHillClimbingSearch::ehc() {
         int d = parent_node.get_g() - current_phase_start_g +
                 get_adjusted_cost(last_op);
 
-        if (parent_node.get_real_g() + last_op.get_cost() >= bound)
+        if (parent_node.get_real_g() + last_op.get_cost() >= bound) {
+            bound_was_used = true;
             continue;
+        }
 
         State state = state_registry.get_successor_state(parent_state, last_op);
         statistics.inc_generated();

src/search/search_algorithms/lazy_search.cc

@@ -111,12 +111,14 @@ void LazySearch::generate_successors() {
         int new_g = current_g + get_adjusted_cost(op);
         int new_real_g = current_real_g + op.get_cost();
         bool is_preferred = preferred_operators.contains(op_id);
-        if (new_real_g < bound) {
-            EvaluationContext new_eval_context(
-                current_eval_context, new_g, is_preferred, nullptr);
-            open_list->insert(
-                new_eval_context, make_pair(current_state.get_id(), op_id));
+        if (new_real_g >= bound) {
+            bound_was_used = true;
+            continue;
         }
+        EvaluationContext new_eval_context(
+            current_eval_context, new_g, is_preferred, nullptr);
+        open_list->insert(
+            new_eval_context, make_pair(current_state.get_id(), op_id));
     }
 }