Initial world.Error() implementation (#1598)

Co-authored-by: ike709 <[email protected]>
Co-authored-by: wixoa <[email protected]>

OpenDreamRuntime/DreamManager.cs

@@ -303,9 +303,22 @@ public DreamValue LocateRef(string refString) {
             return DreamValue.Null;
         }
 
-        public void HandleException(Exception e) {
+        public void HandleException(Exception e, string msg = "", string file = "", int line = 0) {
+            if (string.IsNullOrEmpty(msg)) { // Just print the C# exception if we don't override the message
+                msg = e.Message;
+            }
+
             LastDMException = e;
             OnException?.Invoke(this, e);
+
+            // Invoke world.Error()
+            var obj =_objectTree.CreateObject<DreamObjectException>(_objectTree.Exception);
+            obj.Name = e.Message;
+            obj.Description = msg;
+            obj.Line = line;
+            obj.File = file;
+
+            WorldInstance.SpawnProc("Error", usr: null, new DreamValue(obj));
         }
     }
 

OpenDreamRuntime/DreamThread.cs

@@ -343,8 +343,7 @@ public void AppendStackTrace(StringBuilder builder) {
             {
                 builder.Append("(init)...");
             }
-            else
-            {
+            else {
                 _current.AppendStackFrame(builder);
             }
             builder.AppendLine();
@@ -368,7 +367,7 @@ public void HandleException(Exception exception) {
             _current?.Cancel();
 
             var dreamMan = IoCManager.Resolve<DreamManager>();
-            dreamMan.HandleException(exception);
+
 
             StringBuilder builder = new();
             builder.AppendLine($"Exception occurred: {exception.Message}");
@@ -381,7 +380,20 @@ public void HandleException(Exception exception) {
             builder.AppendLine(exception.ToString());
             builder.AppendLine();
 
-            dreamMan.WriteWorldLog(builder.ToString(), LogLevel.Error);
+            var msg = builder.ToString();
+
+            // TODO: Defining world.Error() causes byond to no longer print exceptions to the log unless ..() is called
+            dreamMan.WriteWorldLog(msg, LogLevel.Error);
+
+            // Instantiate an /exception and invoke world.Error()
+            string file = string.Empty;
+            int line = 0;
+            if(_current is DMProcState dmProc) { // TODO: Cope with the other ProcStates
+                var source = dmProc.GetCurrentSource();
+                file = source.Item1;
+                line = source.Item2;
+            }
+            dreamMan.HandleException(exception, msg, file, line);
 
             IoCManager.Resolve<IDreamDebugManager>().HandleException(this, exception);
         }

OpenDreamRuntime/Objects/DreamObjectTree.cs

@@ -162,6 +162,8 @@ public DreamObject CreateObject(TreeEntry type) {
             throw new Exception("Cannot create objects of type /client");
         if (type.ObjectDefinition.IsSubtypeOf(Turf))
             throw new Exception("New turfs must be created by the map manager");
+        if (type.ObjectDefinition.IsSubtypeOf(Exception))
+            return new DreamObjectException(type.ObjectDefinition);
 
         return new DreamObject(type.ObjectDefinition);
     }

OpenDreamRuntime/Objects/Types/DreamObjectException.cs

@@ -0,0 +1,29 @@
+namespace OpenDreamRuntime.Objects.Types;
+
+public sealed class DreamObjectException(DreamObjectDefinition objectDefinition) : DreamObject(objectDefinition) {
+    public string Name = string.Empty;
+    public string Description = string.Empty;
+    public string File = string.Empty;
+    public int Line = 0;
+
+    //TODO: Match the format of BYOND exceptions since SS13 does splittext and other things to extract data from exceptions
+
+    protected override bool TryGetVar(string varName, out DreamValue value) {
+        switch (varName) {
+            case "name":
+                value = new DreamValue(Name);
+                return true;
+            case "desc":
+                value = new DreamValue(Description);
+                return true;
+            case "file":
+                value = new DreamValue(File);
+                return true;
+            case "line":
+                value = new DreamValue(Line);
+                return true;
+            default:
+                return base.TryGetVar(varName, out value);
+        }
+    }
+}

OpenDreamRuntime/Procs/DMProc.cs

@@ -437,6 +437,10 @@ public override void AppendStackFrame(StringBuilder builder) {
             builder.Append(Proc.GetSourceAtOffset(_pc - 1).Line);
         }
 
+        public (string, int) GetCurrentSource() {
+            return Proc.GetSourceAtOffset(_pc - 1);
+        }
+
         public void Jump(int position) {
             _pc = position;
         }