Improve handling of fatal errors and errors in dfhack.lua

* Several fatal errors that occurred during core initialization didn't
  stop initialization or set 'errorstate' properly, which caused
  update hooks and other code to crash later. This has been fixed and
  should address crashes like the one mentioned in #470.
* Errors when loading dfhack.lua now cause Lua::Open() to fail, which
  triggers a fatal error in Core::Init()
* Failure to initialize the console no longer results in a call to
  fatal() (since it didn't actually stop initialization previously)

library/Core.cpp

@@ -1336,15 +1336,19 @@ Core::Core()
     script_path_mutex = new mutex();
 };
 
-void Core::fatal (std::string output, bool deactivate)
+void Core::fatal (std::string output)
 {
+    errorstate = true;
     stringstream out;
     out << output ;
-    if(deactivate)
+    if (output[output.size() - 1] != '\n')
+        out << '\n';
     out << "DFHack will now deactivate.\n";
     if(con.isInited())
     {
         con.printerr("%s", out.str().c_str());
+        con.reset_color();
+        con.print("\n");
     }
     fprintf(stderr, "%s\n", out.str().c_str());
 #ifndef LINUX_BUILD
@@ -1395,7 +1399,7 @@ bool Core::Init()
         delete vif;
         vif = NULL;
         errorstate = true;
-        fatal(out.str(), true);
+        fatal(out.str());
         return false;
     }
     p = new DFHack::Process(vif);
@@ -1403,7 +1407,7 @@ bool Core::Init()
 
     if(!vinfo || !p->isIdentified())
     {
-        fatal ("Not a known DF version.\n", true);
+        fatal("Not a known DF version.\n");
         errorstate = true;
         delete p;
         p = NULL;
@@ -1429,7 +1433,7 @@ bool Core::Init()
     else if(con.init(false))
         cerr << "Console is running.\n";
     else
-        fatal ("Console has failed to initialize!\n", false);
+        cerr << "Console has failed to initialize!\n";
 /*
     // dump offsets to a file
     std::ofstream dump("offsets.log");
@@ -1476,7 +1480,11 @@ bool Core::Init()
     }
 
     // initialize common lua context
-    Lua::Core::Init(con);
+    if (!Lua::Core::Init(con))
+    {
+        fatal("Lua failed to initialize");
+        return false;
+    }
 
     // create mutex for syncing with interactive tasks
     misc_data_mutex=new mutex();

library/LuaTools.cpp

@@ -1701,7 +1701,11 @@ lua_State *DFHack::Lua::Open(color_ostream &out, lua_State *state)
         Lua::Core::InitCoreContext();
 
     // load dfhack.lua
-    Require(out, state, "dfhack");
+    if (!Require(out, state, "dfhack"))
+    {
+        out.printerr("Could not load dfhack.lua\n");
+        return NULL;
+    }
 
     lua_settop(state, 0);
     if (!lua_checkstack(state, 64))
@@ -1868,15 +1872,17 @@ void DFHack::Lua::Core::onUpdate(color_ostream &out)
         run_timers(out, State, tick_timers, frame[1], world->frame_counter);
 }
 
-void DFHack::Lua::Core::Init(color_ostream &out)
+bool DFHack::Lua::Core::Init(color_ostream &out)
 {
-    if (State)
+    if (State) {
-        return;
+        out.printerr("state already exists\n");
+        return false;
+    }
 
     State = luaL_newstate();
 
     // Calls InitCoreContext after checking IsCoreContext
-    Lua::Open(out, State);
+    return (Lua::Open(out, State) != NULL);
 }
 
 static void Lua::Core::InitCoreContext()

library/include/Core.h

@@ -217,7 +217,7 @@ namespace DFHack
         void operator=(Core const&);    // Don't implement
 
         // report error to user while failing
-        void fatal (std::string output, bool will_deactivate);
+        void fatal (std::string output);
 
         // 1 = fatal failure
         bool errorstate;

library/include/LuaTools.h

@@ -380,7 +380,7 @@ namespace DFHack {namespace Lua {
         DFHACK_EXPORT extern lua_State *State;
 
         // Not exported; for use by the Core class
-        void Init(color_ostream &out);
+        bool Init(color_ostream &out);
         void Reset(color_ostream &out, const char *where);
 
         // Events signalled by the core

plugins/dwarfmonitor.cpp

@@ -1977,6 +1977,8 @@ DFhackCExport command_result plugin_init(color_ostream &out, std::vector <Plugin
         ));
 
     dm_lua::state = Lua::Open(out);
+    if (dm_lua::state == NULL)
+        return CR_FAILURE;
 
     return CR_OK;
 }