[wasm][debugger] Fix exceptions on eval

src/mono/wasm/debugger/BrowserDebugProxy/DevToolsHelper.cs

@@ -125,42 +125,42 @@ public struct Result
         public JObject Value { get; private set; }
         public JObject Error { get; private set; }
 
-        public bool IsOk => Value != null;
-        public bool IsErr => Error != null;
+        public bool IsOk => Error == null;
 
-        private Result(JObject result, JObject error)
+        private Result(JObject resultOrError, bool isError)
         {
-            if (result != null && error != null)
-                throw new ArgumentException($"Both {nameof(result)} and {nameof(error)} arguments cannot be non-null.");
-
-            bool resultHasError = string.Equals((result?["result"] as JObject)?["subtype"]?.Value<string>(), "error");
-            if (result != null && resultHasError)
+            bool resultHasError = isError || string.Equals((resultOrError?["result"] as JObject)?["subtype"]?.Value<string>(), "error");
+            if (resultHasError)
             {
-                this.Value = null;
-                this.Error = result;
+                Value = null;
+                Error = resultOrError;
             }
             else
             {
-                this.Value = result;
-                this.Error = error;
+                Value = resultOrError;
+                Error = null;
             }
         }
-
         public static Result FromJson(JObject obj)
         {
-            //Log ("protocol", $"from result: {obj}");
-            return new Result(obj["result"] as JObject, obj["error"] as JObject);
+            var error = obj["error"] as JObject;
+            if (error != null)
+                return new Result(error, true);
+            var result = obj["result"] as JObject;
+            return new Result(result, false);
         }
 
-        public static Result Ok(JObject ok) => new Result(ok, null);
+        public static Result Ok(JObject ok) => new Result(ok, false);
 
         public static Result OkFromObject(object ok) => Ok(JObject.FromObject(ok));
 
-        public static Result Err(JObject err) => new Result(null, err);
+        public static Result Err(JObject err) => new Result(err, true);
+
+        public static Result Err(string msg) => new Result(JObject.FromObject(new { message = msg }), true);
 
-        public static Result Err(string msg) => new Result(null, JObject.FromObject(new { message = msg }));
+        public static Result UserVisibleErr(JObject result) => new Result { Value = result };
 
-        public static Result Exception(Exception e) => new Result(null, JObject.FromObject(new { message = e.Message }));
+        public static Result Exception(Exception e) => new Result(JObject.FromObject(new { message = e.Message }), true);
 
         public JObject ToJObject(MessageId target)
         {
@@ -186,7 +186,7 @@ public JObject ToJObject(MessageId target)
 
         public override string ToString()
         {
-            return $"[Result: IsOk: {IsOk}, IsErr: {IsErr}, Value: {Value?.ToString()}, Error: {Error?.ToString()} ]";
+            return $"[Result: IsOk: {IsOk}, IsErr: {!IsOk}, Value: {Value?.ToString()}, Error: {Error?.ToString()} ]";
         }
     }
 

src/mono/wasm/debugger/BrowserDebugProxy/DevToolsProxy.cs

@@ -234,7 +234,7 @@ internal void SendResponse(MessageId id, Result result, CancellationToken token)
         private void SendResponseInternal(MessageId id, Result result, CancellationToken token)
         {
             JObject o = result.ToJObject(id);
-            if (result.IsErr)
+            if (!result.IsOk)
                 logger.LogError($"sending error response for id: {id} -> {result}");
 
             Send(this.ide, o, token);

src/mono/wasm/debugger/BrowserDebugProxy/EvaluateExpression.cs

@@ -390,17 +390,21 @@ internal static async Task<JObject> CompileAndRunTheExpression(string expression
             if (expressionTree == null)
                 throw new Exception($"BUG: Unable to evaluate {expression}, could not get expression from the syntax tree");
 
-            try {
+            try
+            {
                 var newScript = script.ContinueWith(
                     string.Join("\n", findVarNMethodCall.variableDefinitions) + "\nreturn " + syntaxTree.ToString());
 
                 var state = await newScript.RunAsync(cancellationToken: token);
-
                 return JObject.FromObject(ConvertCSharpToJSType(state.ReturnValue, state.ReturnValue.GetType()));
             }
-            catch (Exception)
+            catch (CompilationErrorException cee)
+            {
+                throw new ReturnAsErrorException($"Cannot evaluate '{expression}': {cee.Message}", "CompilationError");
+            }
+            catch (Exception ex)
             {
-                throw new ReturnAsErrorException($"Cannot evaluate '{expression}'.", "CompilationError");
+                throw new Exception($"Internal Error: Unable to run {expression}, error: {ex.Message}.", ex);
             }
         }
 
@@ -429,22 +433,38 @@ private static object ConvertCSharpToJSType(object v, Type type)
 
     internal class ReturnAsErrorException : Exception
     {
-        public Result Error { get; }
+        private Result _error;
+        public Result Error
+        {
+            get
+            {
+                _error.Value["exceptionDetails"]["stackTrace"] = StackTrace;
+                return _error;
+            }
+            set { }
+        }
         public ReturnAsErrorException(JObject error)
             => Error = Result.Err(error);
 
         public ReturnAsErrorException(string message, string className)
         {
-            Error = Result.Err(JObject.FromObject(new
+            var result = new
             {
-                result = new
+                type = "object",
+                subtype = "error",
+                description = message,
+                className
+            };
+            _error = Result.UserVisibleErr(JObject.FromObject(
+                new
                 {
-                    type = "object",
-                    subtype = "error",
-                    description = message,
-                    className
-                }
-            }));
+                    result = result,
+                    exceptionDetails = new
+                    {
+                        exception = result,
+                        stackTrace = StackTrace
+                    }
+                }));
         }
     }
 }

src/mono/wasm/debugger/BrowserDebugProxy/MemberReferenceResolver.cs

@@ -219,7 +219,7 @@ async Task<JObject> ResolveAsLocalOrThisMember(string name)
                 if (scopeCache.Locals.Count == 0 && !localsFetched)
                 {
                     Result scope_res = await proxy.GetScopeProperties(sessionId, scopeId, token);
-                    if (scope_res.IsErr)
+                    if (!scope_res.IsOk)
                         throw new Exception($"BUG: Unable to get properties for scope: {scopeId}. {scope_res}");
                     localsFetched = true;
                 }

src/mono/wasm/debugger/BrowserDebugProxy/MonoProxy.cs

@@ -674,7 +674,7 @@ private async Task<bool> CallOnFunction(MessageId id, JObject args, Cancellation
                     return false;
             }
             Result res = await SendMonoCommand(id, MonoCommands.CallFunctionOn(RuntimeId, args), token);
-            if (res.IsErr)
+            if (!res.IsOk)
             {
                 SendResponse(id, res, token);
                 return true;
@@ -1004,7 +1004,7 @@ async Task<bool> SkipMethod(bool isSkippable, bool shouldBeSkipped, StepKind ste
         private async Task<bool> OnReceiveDebuggerAgentEvent(SessionId sessionId, JObject args, CancellationToken token)
         {
             Result res = await SendMonoCommand(sessionId, MonoCommands.GetDebuggerAgentBufferReceived(RuntimeId), token);
-            if (res.IsErr)
+            if (!res.IsOk)
                 return false;
 
             ExecutionContext context = GetContext(sessionId);

src/mono/wasm/debugger/BrowserDebugProxy/MonoSDBHelper.cs

@@ -435,10 +435,10 @@ public MonoBinaryReader(byte [] data) : base(new MemoryStream(data)) {}
         public static MonoBinaryReader From(Result result)
         {
             byte[] newBytes = Array.Empty<byte>();
-            if (!result.IsErr) {
+            if (result.IsOk) {
                 newBytes = Convert.FromBase64String(result.Value?["result"]?["value"]?["value"]?.Value<string>());
             }
-            return new MonoBinaryReader(new MemoryStream(newBytes), result.IsErr);
+            return new MonoBinaryReader(new MemoryStream(newBytes), !result.IsOk);
         }
 
         public override string ReadString()

src/mono/wasm/debugger/DebuggerTestSuite/CallFunctionOnTests.cs

@@ -534,7 +534,6 @@ public async Task CFOWithSilentReturnsErrors(string eval_fn, string bp_loc, int
             // doesn't get reported, and the execution is NOT paused even with setPauseOnException=true
             result = await cli.SendCommand("Runtime.callFunctionOn", cfo_args, token);
             Assert.False(result.IsOk, "result.IsOk");
-            Assert.True(result.IsErr, "result.IsErr");
 
             var hasErrorMessage = result.Error["exceptionDetails"]?["exception"]?["description"]?.Value<string>()?.Contains(error_msg);
             Assert.True((hasErrorMessage ?? false), "Exception message not found");
@@ -785,7 +784,7 @@ public async Task RunOnInvalidCfoId(string eval_fn, string bp_loc, int line, int
                });
 
                var res = await cli.SendCommand("Runtime.callFunctionOn", cfo_args, token);
-               Assert.True(res.IsErr);
+               Assert.False(res.IsOk);
            });
 
         [Theory]
@@ -811,7 +810,7 @@ public async Task RunOnInvalidThirdSegmentOfObjectId(string eval_fn, string bp_l
             });
 
             var res = await cli.SendCommand("Runtime.callFunctionOn", cfo_args, token);
-            Assert.True(res.IsErr);
+            Assert.False(res.IsOk);
         }
 
         [Theory]

src/mono/wasm/debugger/DebuggerTestSuite/DebuggerTestBase.cs

@@ -1008,7 +1008,7 @@ internal async Task<Result> RemoveBreakpoint(string id, bool expect_ok = true)
             });
 
             var res = await cli.SendCommand("Debugger.removeBreakpoint", remove_bp, token);
-            Assert.True(expect_ok ? res.IsOk : res.IsErr);
+            Assert.True(expect_ok ? res.IsOk : !res.IsOk);
 
             return res;
         }
@@ -1020,7 +1020,7 @@ internal async Task<Result> SetBreakpoint(string url_key, int line, int column,
                 JObject.FromObject(new { lineNumber = line, columnNumber = column, urlRegex = url_key, condition });
 
             var bp1_res = await cli.SendCommand("Debugger.setBreakpointByUrl", bp1_req, token);
-            Assert.True(expect_ok ? bp1_res.IsOk : bp1_res.IsErr);
+            Assert.True(expect_ok ? bp1_res.IsOk : !bp1_res.IsOk);
 
             return bp1_res;
         }

src/mono/wasm/debugger/DebuggerTestSuite/Inspector.cs

@@ -259,7 +259,7 @@ public async Task OpenSessionAsync(Func<InspectorClient, CancellationToken, List
                     }
 
                     Result res = completedTask.Result;
-                    if (res.IsErr)
+                    if (!res.IsOk)
                         throw new ArgumentException($"Command {cmd_name} failed with: {res.Error}. Remaining commands: {RemainingCommandsToString(cmd_name, init_cmds)}");
 
                     init_cmds.RemoveAt(cmdIdx);

src/mono/wasm/debugger/DebuggerTestSuite/MiscTests.cs

@@ -34,7 +34,7 @@ public async Task ExceptionThrownInJS()
             });
 
             var eval_res = await cli.SendCommand("Runtime.evaluate", eval_req, token);
-            Assert.True(eval_res.IsErr);
+            Assert.False(eval_res.IsOk);
             Assert.Equal("Uncaught", eval_res.Error["exceptionDetails"]?["text"]?.Value<string>());
         }
 
@@ -245,7 +245,7 @@ await EvaluateAndCheck(
                    });
 
                    var frame_props = await cli.SendCommand("Runtime.getProperties", get_prop_req, token);
-                   Assert.True(frame_props.IsErr);
+                   Assert.False(frame_props.IsOk);
                }
             );
         }