fix: alliance-crash when leader faction died

src/common/gamecode/creport.c

@@ -944,10 +944,11 @@ show_alliances_cr(FILE * F, const faction * f)
 {
   if (f->alliance) {
     alliance * al = f->alliance;
-    assert(al->leader);
+    faction * lead = alliance_get_leader(al);
+    assert(lead);
     fprintf(F, "ALLIANCE %d\n", al->id);
     fprintf(F, "\"%s\";name\n", al->name);
-    fprintf(F, "%d;leader\n", al->leader->no);
+    fprintf(F, "%d;leader\n", lead->no);
   }
 }
 

src/common/gamecode/laws.c

@@ -1618,7 +1618,8 @@ name_cmd(unit * u, struct order * ord)
   case P_ALLIANCE:
     if (foreign==false && u->faction->alliance) {
       alliance * al = u->faction->alliance;
-      if (al->leader==u->faction) {
+      faction * lead = alliance_get_leader(al);
+      if (lead==u->faction) {
         s = &al->name;
       }
     }

src/common/gamecode/report.c

@@ -2074,7 +2074,7 @@ report_plaintext(const char * filename, report_context * ctx, const char * chars
     }
   }
   if (f->alliance) {
-    m = msg_message("nr_alliance", "leader name id", f->alliance->leader, f->alliance->name, f->alliance->id);
+    m = msg_message("nr_alliance", "leader name id", alliance_get_leader(f->alliance), f->alliance->name, f->alliance->id);
     nr_render(m, f->locale, buf, sizeof(buf), f);
     msg_release(m);
     centre(F, buf, true);

src/common/kernel/alliance.c

@@ -89,9 +89,15 @@ typedef struct alliance_transaction {
 static struct alliance_transaction * transactions[ALLIANCE_MAX];
 
 
-static faction * alliance_leader(const alliance * al)
+faction *
+alliance_get_leader(alliance * al)
 {
-  return al->leader;
+  if (!al->_leader) {
+    if (al->members) {
+      al->_leader = al->members->data;
+    }
+  }
+  return al->_leader;
 }
 
 // static alliance_transaction **
@@ -166,7 +172,7 @@ perform_kick(void)
     alliance_transaction * ta = *tap;
     alliance * al = ta->u->faction->alliance;
 
-    if (al && alliance_leader(al)==ta->u->faction) {
+    if (al && alliance_get_leader(al)==ta->u->faction) {
       faction * f;
       init_tokens(ta->ord);
       skip_token();
@@ -237,14 +243,14 @@ perform_transfer(void)
     alliance_transaction * ta = *tap;
     alliance * al = ta->u->faction->alliance;
 
-    if (al && alliance_leader(al)==ta->u->faction) {
+    if (al && alliance_get_leader(al)==ta->u->faction) {
       faction * f;
       init_tokens(ta->ord);
       skip_token();
       skip_token();
       f = getfaction();
       if (f && f->alliance==al) {
-        al->leader = f;
+        al->_leader = f;
       }
     }
     *tap = ta->next;
@@ -390,11 +396,11 @@ setalliance(struct faction * f, alliance * al)
       flistp = &flist->next;
     }
 
-    if (f->alliance->leader==f) {
+    if (f->alliance->_leader==f) {
       if (f->alliance->members) {
-        f->alliance->leader = f->alliance->members->data;
+        f->alliance->_leader = f->alliance->members->data;
       } else {
-        f->alliance->leader = NULL;
+        f->alliance->_leader = NULL;
       }
     }
   }
@@ -410,8 +416,8 @@ setalliance(struct faction * f, alliance * al)
     }
     *flistp = flist;
     flist->next = NULL;
-    if (al->leader==NULL) {
-      al->leader = f;
+    if (al->_leader==NULL) {
+      al->_leader = f;
     }
     flist = NULL;
   }

src/common/kernel/alliance.h

@@ -36,7 +36,7 @@ enum {
 
 typedef struct alliance {
   struct alliance * next;
-  struct faction * leader;
+  struct faction * _leader;
   struct faction_list * members;
   unsigned int flags;
   int id;
@@ -49,7 +49,7 @@ extern alliance * makealliance(int id, const char * name);
 extern const char * alliancename(const struct alliance * al);
 extern void setalliance(struct faction * f, alliance * al);
 void free_alliance(struct alliance * al);
-
+extern struct faction * alliance_get_leader(struct alliance * al);
 extern void alliance_cmd(void);
 
 void alliance_setname(alliance * self, const char * name);

src/common/kernel/save.c

@@ -563,7 +563,7 @@ read_alliances(struct storage * store)
     store->r_str_buf(store, aname, sizeof(aname));
     al = makealliance(id, aname);
     if (store->version>=ALLIANCELEADER_VERSION) {
-      read_reference(&al->leader, store, read_faction_reference, resolve_faction);
+      read_reference(&al->_leader, store, read_faction_reference, resolve_faction);
       id = store->r_id(store);
     } else{
       store->r_str_buf(store, pbuf, sizeof(pbuf));
@@ -577,11 +577,11 @@ write_alliances(struct storage * store)
 {
   alliance * al = alliances;
   while (al) {
-    if (al->leader) {
+    if (al->_leader) {
       store->w_id(store, al->id);
       store->w_str(store, al->name);
       if (store->version>=ALLIANCELEADER_VERSION) {
-        write_faction_reference(al->leader, store);
+        write_faction_reference(al->_leader, store);
       }
       store->w_brk(store);
     }