Index: client/climisc.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/client/climisc.c,v
retrieving revision 1.111
diff -u -r1.111 climisc.c
--- client/climisc.c	12 Feb 2003 22:22:33 -0000	1.111
+++ client/climisc.c	14 Feb 2003 01:07:59 -0000
@@ -274,7 +274,12 @@
     my_snprintf(buf, bufsiz, _("The %s gives shared vision"),
 		get_nation_name_plural(pclause->from->nation));
     break;
+  case CLAUSE_LEASE:
+    my_snprintf(buf, bufsiz, _("The %s lease their technology"),
+		get_nation_name_plural(pclause->from->nation));
+    break;
   default:
+    assert(FALSE);
     if (bufsiz > 0) *buf = '\0';
     break;
   }
Index: client/packhand.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/client/packhand.c,v
retrieving revision 1.288
diff -u -r1.288 packhand.c
--- client/packhand.c	12 Feb 2003 22:22:33 -0000	1.288
+++ client/packhand.c	14 Feb 2003 01:08:00 -0000
@@ -1235,6 +1235,7 @@
   pplayer->government=pinfo->government;
   pplayer->embassy=pinfo->embassy;
   pplayer->gives_shared_vision = pinfo->gives_shared_vision;
+  pplayer->gives_lease = pinfo->gives_lease;
   pplayer->city_style=pinfo->city_style;
 
   for (i = 0; i < MAX_NUM_PLAYERS + MAX_NUM_BARBARIANS; i++) {
Index: client/gui-gtk/diplodlg.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/client/gui-gtk/diplodlg.c,v
retrieving revision 1.38
diff -u -r1.38 diplodlg.c
--- client/gui-gtk/diplodlg.c	15 Nov 2002 21:24:28 -0000	1.38
+++ client/gui-gtk/diplodlg.c	14 Feb 2003 01:08:00 -0000
@@ -65,6 +65,8 @@
   GtkWidget *dip_pact_menu;
   GtkWidget *dip_vision_button0;
   GtkWidget *dip_vision_button1;
+  GtkWidget *dip_lease_button0;
+  GtkWidget *dip_lease_button1;
 
   GtkWidget *dip_label;
   GtkWidget *dip_clauselabel;
@@ -114,6 +116,7 @@
 static void diplomacy_dialog_peace_callback(GtkWidget *w, gpointer data);
 static void diplomacy_dialog_alliance_callback(GtkWidget *w, gpointer data);
 static void diplomacy_dialog_vision_callback(GtkWidget *w, gpointer data);
+static void diplomacy_dialog_lease_callback(GtkWidget *w, gpointer data);
 static void close_diplomacy_dialog(struct Diplomacy_dialog *pdialog);
 static void update_diplomacy_dialog(struct Diplomacy_dialog *pdialog);
 static gint diplomacy_dialog_mbutton_callback(GtkWidget *w, GdkEvent *event);
@@ -453,6 +456,26 @@
   if (gives_shared_vision(plr1, plr0))
     gtk_widget_set_sensitive(pdialog->dip_vision_button1, FALSE);
 
+  pdialog->dip_lease_button0 = gtk_button_new_with_label(_("Lease technology"));
+  gtk_box_pack_start(GTK_BOX(pdialog->dip_vbox0), pdialog->dip_lease_button0,
+		     FALSE, FALSE, 2);
+  gtk_signal_connect(GTK_OBJECT(pdialog->dip_lease_button0), "clicked",
+		     GTK_SIGNAL_FUNC(diplomacy_dialog_lease_callback),
+		     (gpointer)pdialog);
+  if (gives_lease(plr0, plr1) || !player_has_embassy(plr1, plr0)) {
+    gtk_widget_set_sensitive(pdialog->dip_lease_button0, FALSE);
+  }
+
+  pdialog->dip_lease_button1 = gtk_button_new_with_label(_("Lease technology"));
+  gtk_box_pack_start(GTK_BOX(pdialog->dip_vbox1), pdialog->dip_lease_button1,
+		     FALSE, FALSE, 2);
+  gtk_signal_connect(GTK_OBJECT(pdialog->dip_lease_button1), "clicked",
+		     GTK_SIGNAL_FUNC(diplomacy_dialog_lease_callback),
+		     (gpointer)pdialog);
+  if (gives_lease(plr1, plr0) || !player_has_embassy(plr0, plr1)) {
+    gtk_widget_set_sensitive(pdialog->dip_lease_button1, FALSE);
+  }
+
   /* Start of pact button insertion */
 
   pdialog->dip_pact_menu=gtk_menu_new();
@@ -799,6 +822,26 @@
 			     &pa);
 }
 
+/****************************************************************
+  ...
+*****************************************************************/
+static void diplomacy_dialog_lease_callback(GtkWidget *w, gpointer data)
+{
+  struct Diplomacy_dialog *pdialog = (struct Diplomacy_dialog *)data;
+  struct packet_diplomacy_info pa;
+  struct player *pgiver;
+
+  pgiver = (w == pdialog->dip_lease_button0) ? 
+    pdialog->treaty.plr0 : pdialog->treaty.plr1;
+
+  pa.plrno0 = pdialog->treaty.plr0->player_no;
+  pa.plrno1 = pdialog->treaty.plr1->player_no;
+  pa.clause_type = CLAUSE_LEASE;
+  pa.plrno_from = pgiver->player_no;
+  pa.value = 0;
+  send_packet_diplomacy_info(&aconnection, PACKET_DIPLOMACY_CREATE_CLAUSE,
+			     &pa);
+}
 
 /****************************************************************
 ...
Index: client/gui-gtk/helpdlg.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/client/gui-gtk/helpdlg.c,v
retrieving revision 1.62
diff -u -r1.62 helpdlg.c
--- client/gui-gtk/helpdlg.c	30 Jan 2003 19:26:08 -0000	1.62
+++ client/gui-gtk/helpdlg.c	14 Feb 2003 01:08:00 -0000
@@ -232,6 +232,7 @@
   case TECH_UNKNOWN:	      bg = COLOR_STD_RED;	      break;
   case TECH_KNOWN:	      bg = COLOR_STD_GROUND;	      break;
   case TECH_REACHABLE:        bg = COLOR_STD_YELLOW;	      break;
+  case TECH_LEASED:           bg = COLOR_STD_OCEAN;	      break;
   default:		      bg = COLOR_STD_WHITE;	      break;
   }
   d->tech = tech;
Index: common/capstr.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/capstr.c,v
retrieving revision 1.124
diff -u -r1.124 capstr.c
--- common/capstr.c	12 Feb 2003 18:38:59 -0000	1.124
+++ common/capstr.c	14 Feb 2003 01:08:00 -0000
@@ -76,7 +76,7 @@
 
 #define CAPABILITY "+1.14.0 conn_info +occupied team tech_impr_gfx " \
                    "city_struct_minor_cleanup obsolete_last class_legend " \
-                   "+impr_req +waste +fastfocus +continent"
+                   "+impr_req +waste +fastfocus +continent +lease"
   
 /* "+1.14.0" is protocol for 1.14.0 release.
  *
@@ -108,7 +108,9 @@
  *
  * "fastfocus" removes the server from client unit focus.
  *
- * +continent": the server gives the client continent information
+ * "continent" means the server gives the client continent information
+ *
+ * "lease" adds a new feature, the technology lend lease pact type
  */
 
 void init_our_capability(void)
Index: common/city.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/city.c,v
retrieving revision 1.183
diff -u -r1.183 city.c
--- common/city.c	12 Feb 2003 22:22:33 -0000	1.183
+++ common/city.c	14 Feb 2003 01:08:00 -0000
@@ -2242,10 +2242,10 @@
 {
   struct player *p = city_owner(pcity);
   int power = 3;
-  if (get_invention(p, game.rtech.cathedral_minus /*A_COMMUNISM */ ) ==
-      TECH_KNOWN) power--;
-  if (get_invention(p, game.rtech.cathedral_plus /*A_THEOLOGY */ ) ==
-      TECH_KNOWN) power++;
+  if (get_invention(p, game.rtech.cathedral_minus) == TECH_KNOWN 
+      || get_invention(p, game.rtech.cathedral_minus) == TECH_LEASED) 
+    power--;
+  if (get_invention(p, game.rtech.cathedral_plus) == TECH_KNOWN) power++;
   if (improvement_variant(B_MICHELANGELO) == 1
       && city_affected_by_wonder(pcity, B_MICHELANGELO))
     power *= 2;
Index: common/diptreaty.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/diptreaty.h,v
retrieving revision 1.9
diff -u -r1.9 diptreaty.h
--- common/diptreaty.h	15 Nov 2002 21:24:30 -0000	1.9
+++ common/diptreaty.h	14 Feb 2003 01:08:00 -0000
@@ -18,7 +18,7 @@
 enum clause_type { CLAUSE_ADVANCE, CLAUSE_GOLD, CLAUSE_MAP,
 		   CLAUSE_SEAMAP, CLAUSE_CITY, 
 		   CLAUSE_CEASEFIRE, CLAUSE_PEACE, CLAUSE_ALLIANCE,
-		   CLAUSE_VISION};
+		   CLAUSE_VISION, CLAUSE_LEASE };
 
 #define is_pact_clause(x) \
   ((x == CLAUSE_CEASEFIRE) || (x == CLAUSE_PEACE) || (x == CLAUSE_ALLIANCE))
Index: common/government.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/government.c,v
retrieving revision 1.38
diff -u -r1.38 government.c
--- common/government.c	29 Jan 2003 05:10:50 -0000	1.38
+++ common/government.c	14 Feb 2003 01:08:00 -0000
@@ -250,6 +250,7 @@
     return FALSE;
   } else {
     return (get_invention(pplayer, req) == TECH_KNOWN
+            || get_invention(pplayer, req) == TECH_LEASED
 	    || player_owns_active_govchange_wonder(pplayer));
   }
 }
Index: common/improvement.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/improvement.c,v
retrieving revision 1.31
diff -u -r1.31 improvement.c
--- common/improvement.c	12 Feb 2003 22:22:33 -0000	1.31
+++ common/improvement.c	14 Feb 2003 01:08:00 -0000
@@ -527,7 +527,8 @@
     return FALSE;
 
   /* Make sure we have the tech /now/.*/
-  if (get_invention(p, improvement_types[id].tech_req) == TECH_KNOWN)
+  if (get_invention(p, improvement_types[id].tech_req) == TECH_KNOWN
+      || get_invention(p, improvement_types[id].tech_req) == TECH_LEASED)
     return TRUE;
   return FALSE;
 }
Index: common/packets.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/packets.c,v
retrieving revision 1.237
diff -u -r1.237 packets.c
--- common/packets.c	10 Feb 2003 21:43:42 -0000	1.237
+++ common/packets.c	14 Feb 2003 01:08:00 -0000
@@ -900,6 +900,7 @@
   dio_put_uint8(&dout, pinfo->barbarian_type);
 
   dio_put_uint32(&dout, pinfo->gives_shared_vision);
+  DIO_BV_PUT(&dout, pinfo->gives_lease);
 
   SEND_PACKET_END;
 }
@@ -959,6 +960,7 @@
   /* Unfortunately the second argument to iget_uint32 is int, not uint: */
   dio_get_uint32(&din, &i);
   pinfo->gives_shared_vision = i;
+  DIO_BV_GET(&din, pinfo->gives_lease);
 
   RECEIVE_PACKET_END(pinfo);
 }
Index: common/packets.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/packets.h,v
retrieving revision 1.138
diff -u -r1.138 packets.h
--- common/packets.h	10 Feb 2003 21:43:42 -0000	1.138
+++ common/packets.h	14 Feb 2003 01:08:01 -0000
@@ -482,6 +482,7 @@
   bool ai;
   int barbarian_type;
   unsigned int gives_shared_vision;
+  bv_lease gives_lease;
 };
 
 /**************************************************************************
Index: common/player.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/player.c,v
retrieving revision 1.111
diff -u -r1.111 player.c
--- common/player.c	12 Feb 2003 22:22:33 -0000	1.111
+++ common/player.c	14 Feb 2003 01:08:01 -0000
@@ -104,6 +104,8 @@
   plr->gives_shared_vision = 0;
   plr->really_gives_vision = 0;
 
+  BV_CLR_ALL(plr->gives_lease);
+
   /* Initialise list of improvements with Player-wide equiv_range */
   improvement_status_init(plr->improvements, ARRAY_SIZE(plr->improvements));
 
@@ -426,7 +428,8 @@
   int t;
   if (!improvement_exists(id)) return FALSE;
   t = get_improvement_type(id)->tech_req;
-  return (get_invention(pplayer, t) == TECH_KNOWN);
+  return (get_invention(pplayer, t) == TECH_KNOWN
+          || get_invention(pplayer, t) == TECH_LEASED);
 }
 
 /**************************************************************************
@@ -588,4 +591,12 @@
 bool gives_shared_vision(struct player *me, struct player *them)
 {
   return TEST_BIT(me->gives_shared_vision, them->player_no);
+}
+
+/**************************************************************************
+  Return TRUE iff the player me gives lend lease to player them.
+**************************************************************************/
+bool gives_lease(struct player *me, struct player *them)
+{
+  return BV_ISSET(me->gives_lease, them->player_no);
 }
Index: common/player.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/player.h,v
retrieving revision 1.93
diff -u -r1.93 player.h
--- common/player.h	10 Feb 2003 21:43:42 -0000	1.93
+++ common/player.h	14 Feb 2003 01:08:01 -0000
@@ -166,6 +166,7 @@
   see doc/HACKING
 ***************************************************************************/
 
+BV_DEFINE(bv_lease, MAX_NUM_PLAYERS);
 struct player {
   int player_no;
   char name[MAX_LEN_NAME];
@@ -199,6 +200,7 @@
   struct player_tile *private_map;
   unsigned int gives_shared_vision; /* bitvector those that give you shared vision */
   unsigned int really_gives_vision; /* takes into account that p3 may see what p1 has via p2 */
+  bv_lease gives_lease;             /* bitvector for lend/lease deals */
   Impr_Status improvements[B_LAST]; /* improvements with equiv_range==Player */
   Impr_Status *island_improv; /* improvements with equiv_range==Island, dimensioned to
 			 	 [map.num_continents][game.num_impr_types] */
@@ -266,6 +268,7 @@
 bool is_barbarian(const struct player *pplayer);
 
 bool gives_shared_vision(struct player *me, struct player *them);
+bool gives_lease(struct player *me, struct player *them);
 
 #define players_iterate(PI_player)                                            \
 {                                                                             \
Index: common/tech.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/tech.c,v
retrieving revision 1.57
diff -u -r1.57 tech.c
--- common/tech.c	12 Feb 2003 22:22:34 -0000	1.57
+++ common/tech.c	14 Feb 2003 01:08:01 -0000
@@ -48,7 +48,16 @@
 enum tech_state get_invention(struct player *pplayer, Tech_Type_id tech)
 {
   assert(tech >= 0 || tech < game.num_tech_types);
-
+  if (pplayer->research.inventions[tech].state != TECH_KNOWN) {
+   players_iterate(aplayer) {
+     if (pplayer != aplayer
+         && aplayer->is_alive
+         && gives_lease(aplayer, pplayer)
+         && aplayer->research.inventions[tech].state == TECH_KNOWN) {
+       return TECH_LEASED;
+     }
+   } players_iterate_end;
+  }
   return pplayer->research.inventions[tech].state;
 }
 
@@ -393,6 +402,11 @@
   /* Research becomes more expensive. */
   if (game.year > 0) {
     cost *= 2;
+  }
+
+  /* Leased technology becomes cheaper. */
+  if (get_invention(pplayer, tech) == TECH_LEASED) {
+    cost /= 2;
   }
 
   switch (game.rgame.tech_leakage) {
Index: common/tech.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/tech.h,v
retrieving revision 1.38
diff -u -r1.38 tech.h
--- common/tech.h	13 Jan 2003 23:27:12 -0000	1.38
+++ common/tech.h	14 Feb 2003 01:08:01 -0000
@@ -69,7 +69,8 @@
 enum tech_state {
   TECH_UNKNOWN = 0,
   TECH_KNOWN = 1,
-  TECH_REACHABLE = 2
+  TECH_REACHABLE = 2,
+  TECH_LEASED = 3
 };
 
 struct advance {
Index: common/unittype.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/unittype.c,v
retrieving revision 1.26
diff -u -r1.26 unittype.c
--- common/unittype.c	1 Feb 2003 02:10:45 -0000	1.26
+++ common/unittype.c	14 Feb 2003 01:08:01 -0000
@@ -429,8 +429,10 @@
   if (unit_type_flag(id, F_FANATIC)
       && !government_has_flag(get_gov_pplayer(p), G_FANATIC_TROOPS))
     return FALSE;
-  if (get_invention(p,unit_types[id].tech_requirement)!=TECH_KNOWN)
+  if (get_invention(p,unit_types[id].tech_requirement) != TECH_KNOWN
+      && get_invention(p,unit_types[id].tech_requirement) != TECH_LEASED) {
     return FALSE;
+  }
 
   /* If the unit has a building requirement, we check to see if the player
    * can build that building.  Note that individual cities may not have
Index: server/diplhand.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/diplhand.c,v
retrieving revision 1.65
diff -u -r1.65 diplhand.c
--- server/diplhand.c	15 Nov 2002 21:24:30 -0000	1.65
+++ server/diplhand.c	14 Feb 2003 01:08:02 -0000
@@ -54,6 +54,8 @@
 static struct treaty_list treaties;
 static bool did_init_treaties;
 
+static void give_lease(struct player *me, struct player *them);
+
 /**************************************************************************
 Checks if the player numbers in the packet are sane.
 **************************************************************************/
@@ -146,6 +148,13 @@
 
       if (pclause->from == pplayer) {
 	switch(pclause->type) {
+        case CLAUSE_LEASE:
+          if (!player_has_embassy(other, pplayer)) {
+            freelog(LOG_ERROR, "%s tried to lease tech to %s, who has no "
+                    "embassy", pplayer->name, other->name);
+            return;
+          }
+          break;
 	case CLAUSE_ADVANCE:
 	  if (get_invention(pplayer, pclause->value) != TECH_KNOWN) {
 	    freelog(LOG_ERROR,
@@ -381,7 +390,16 @@
 			 pgiver->name);
 	check_city_workers(plr0);
 	check_city_workers(plr1);
-	break;          
+	break;
+      case CLAUSE_LEASE:
+        give_lease(pgiver, pdest);
+        notify_player_ex(pgiver, -1, -1, E_TREATY_SHARED_VISION,
+                         _("Game: You lease your technology to %s."),
+                         pdest->name);
+        notify_player_ex(pdest, -1, -1, E_TREATY_SHARED_VISION,
+                         _("Game: %s leases his technology to you!"),
+                         pgiver->name);
+        break;
       case CLAUSE_VISION:
 	give_shared_vision(pgiver, pdest);
 	notify_player_ex(pgiver, -1, -1, E_TREATY_SHARED_VISION,
@@ -402,6 +420,18 @@
   }
 }
 
+/**************************************************************************
+  Set lend/lease treaty
+**************************************************************************/
+static void give_lease(struct player *me, struct player *them)
+{
+  assert(me != them);
+  if (gives_lease(me, them)) {
+    freelog(LOG_ERROR, "%s attempting to give duplicate tech lease to %s.",
+            me->name, them->name);
+  }
+  BV_SET(me->gives_lease, them->player_no);
+}
 
 /**************************************************************************
 ...
Index: server/plrhand.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/plrhand.c,v
retrieving revision 1.260
diff -u -r1.260 plrhand.c
--- server/plrhand.c	12 Feb 2003 22:22:34 -0000	1.260
+++ server/plrhand.c	14 Feb 2003 01:08:02 -0000
@@ -1178,6 +1178,7 @@
 
     packet->embassy = plr->embassy;
     packet->gives_shared_vision = plr->gives_shared_vision;
+    packet->gives_lease = plr->gives_lease;
     for(i=0; i<MAX_NUM_PLAYERS+MAX_NUM_BARBARIANS; i++) {
       packet->diplstates[i].type       = plr->diplstates[i].type;
       packet->diplstates[i].turns_left = plr->diplstates[i].turns_left;