[Freeciv-Dev] Re: (PR#15408) ai_select_tech can return A_UNSET in choice

["Mike Kaufman" <kaufman@xxxxxxxxxxxxxxxxxxxxxx>]

<URL: http://bugs.freeciv.org/Ticket/Display.html?id=15408 >

a better patch which deals with an error condition.

-mike

Index: ai/aitech.c
===================================================================
--- ai/aitech.c (revision 11503)
+++ ai/aitech.c (working copy)
@@ -69,6 +69,22 @@
   goal_values[A_UNSET] = -1;
   goal_values[A_NONE] = -1;
 
+  /* if we are researching future techs, then simply continue with that. 
+   * we don't need to do anything below. */
+  if (is_future_tech(get_player_research(pplayer)->researching)) {
+    if (choice) {
+      choice->choice = get_player_research(pplayer)->researching;
+      choice->want = 1;
+      choice->current_want = 1;
+    }
+    if (goal) {
+      goal->choice = get_player_research(pplayer)->tech_goal;
+      goal->want = 1;
+      goal->current_want = 1;
+    }
+    return;
+  }  
+
   /* Fill in values for the techs: want of the tech 
    * + average want of those we will discover en route */
   tech_type_iterate(i) {
@@ -157,6 +173,13 @@
            goal_values[newgoal],
            num_cities_nonzero);
   }
+
+  /* we can't have this, which will happen in the circumstance 
+   * where all ai.tech_wants are negative */
+  if (choice && choice->choice == A_UNSET) {
+    choice->choice = get_player_research(pplayer)->researching;
+  }
+
   return;
 }