[wasm][debugger]Evaluate a sum between an object and a string (#90175)

* Support sum an object and a string

* Update src/mono/wasm/debugger/BrowserDebugProxy/EvaluateExpression.cs
Co-authored-by: NAnkit Jain <radical@gmail.com>

* Apply suggestions from code review
Co-authored-by: NAnkit Jain <radical@gmail.com>

* Addressing @radical comments

* Adding more tests as suggested by @radical.

---------
Co-authored-by: NAnkit Jain <radical@gmail.com>

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

@@ -24,6 +24,11 @@
 
 namespace Microsoft.WebAssembly.Diagnostics
 {
+    internal sealed record VariableDefinition(
+        string IdName,
+        JObject Obj,
+        string Definition);
+
     internal static partial class ExpressionEvaluator
     {
         internal static Script<object> script = CSharpScript.Create(
@@ -47,7 +52,8 @@ private sealed partial class ExpressionSyntaxReplacer : CSharpSyntaxWalker
             private int visitCount;
             public bool hasMethodCalls;
             public bool hasElementAccesses;
-            internal List<string> variableDefinitions = new List<string>();
+            public bool hasStringExpressionStatement;
+            internal List<VariableDefinition> variableDefinitions = new ();
 
             public void VisitInternal(SyntaxNode node)
             {
@@ -92,6 +98,13 @@ public override void Visit(SyntaxNode node)
                     hasElementAccesses = true;
                 }
 
+                if (node is BinaryExpressionSyntax)
+                {
+                    var binaryExpression = node as BinaryExpressionSyntax;
+                    if (binaryExpression.Left.Kind() == SyntaxKind.StringLiteralExpression || binaryExpression.Right.Kind() == SyntaxKind.StringLiteralExpression)
+                        hasStringExpressionStatement = true;
+                }
+
                 if (node is AssignmentExpressionSyntax)
                     throw new Exception("Assignment is not implemented yet");
                 base.Visit(node);
@@ -214,7 +227,7 @@ void AddLocalVariableWithValue(string idName, JObject value)
                     if (localsSet.Contains(idName))
                         return;
                     localsSet.Add(idName);
-                    variableDefinitions.Add(ConvertJSToCSharpLocalVariableAssignment(idName, value));
+                    variableDefinitions.Add(new (idName, value, ConvertJSToCSharpLocalVariableAssignment(idName, value)));
                 }
             }
         }
@@ -445,12 +458,49 @@ private static async Task<IList<JObject>> ResolveElementAccess(ExpressionSyntaxR
 
                 syntaxTree = replacer.ReplaceVars(syntaxTree, null, null, null, elementAccessValues);
             }
-
             expressionTree = syntaxTree.GetCompilationUnitRoot(token);
             if (expressionTree == null)
                 throw new Exception($"BUG: Unable to evaluate {expression}, could not get expression from the syntax tree");
+            var variableDef = await GetVariableDefinitions(resolver, replacer.variableDefinitions, invokeToStringInObject: replacer.hasStringExpressionStatement, token);
+            return await EvaluateSimpleExpression(resolver, syntaxTree.ToString(), expression, variableDef, logger, token);
+        }
+
+        internal static async Task<List<string>> GetVariableDefinitions(MemberReferenceResolver resolver, List<VariableDefinition> variableDefinitions, bool invokeToStringInObject, CancellationToken token)
+        {
+            var variableDefStrings = new List<string>();
+            foreach (var definition in variableDefinitions)
+            {
+                if (!invokeToStringInObject || definition.Obj?["type"]?.Value<string>() != "object")
+                {
+                    variableDefStrings.Add(definition.Definition);
+                    continue;
+                }
+
+                if (definition.Obj["subtype"]?.Value<string>()?.Equals("null") == true)
+                {
+                    variableDefStrings.Add($"string {definition.IdName} = \"\";");
+                    continue;
+                }
 
-            return await EvaluateSimpleExpression(resolver, syntaxTree.ToString(), expression, replacer.variableDefinitions, logger, token);
+                if (DotnetObjectId.TryParse(definition.Obj?["objectId"]?.Value<string>(), out DotnetObjectId objectId))
+                {
+                    if (objectId.IsValueType)
+                    {
+                        variableDefStrings.Add($"string {definition.IdName} = \"{definition.Obj["description"].Value<string>()}\";");
+                    }
+                    else
+                    {
+                        var typeIds = await resolver.GetContext().SdbAgent.GetTypeIdsForObject(objectId.Value, withParents: true, token);
+                        var toString = await resolver.GetContext().SdbAgent.InvokeToStringAsync(typeIds, isValueType: false, isEnum: false, objectId.Value, BindingFlags.DeclaredOnly, invokeToStringInObject: true, token);
+                        variableDefStrings.Add($"string {definition.IdName} = \"{toString}\";");
+                    }
+                }
+                else
+                {
+                    variableDefStrings.Add(definition.Definition);
+                }
+            }
+            return variableDefStrings;
         }
 
         internal static async Task<JObject> EvaluateSimpleExpression(

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

@@ -297,7 +297,7 @@ private async Task<JObject> ReadAsObjectValue(MonoBinaryReader retDebuggerCmdRea
         }
         else
         {
-            var toString = await _sdbAgent.InvokeToStringAsync(typeIds, isValueType: false, isEnum: false, objectId, BindingFlags.DeclaredOnly, token);
+            var toString = await _sdbAgent.InvokeToStringAsync(typeIds, isValueType: false, isEnum: false, objectId, BindingFlags.DeclaredOnly, invokeToStringInObject: false, token);
             if (toString != null)
                 description = toString;
         }

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

@@ -31,6 +31,7 @@ internal sealed class MemberReferenceResolver
         private readonly ILogger logger;
         private bool localsFetched;
         private int linqTypeId;
+        public ExecutionContext GetContext() => context;
 
         public MemberReferenceResolver(MonoProxy proxy, ExecutionContext ctx, SessionId sessionId, int scopeId, ILogger logger)
         {
@@ -365,7 +366,7 @@ async Task<JObject> ResolveAsInstanceMember(ArraySegment<string> parts, JObject
             }
         }
 
-        public async Task<JObject> Resolve(ElementAccessExpressionSyntax elementAccess, Dictionary<string, JObject> memberAccessValues, JObject indexObject, List<string> variableDefinitions, CancellationToken token)
+        public async Task<JObject> Resolve(ElementAccessExpressionSyntax elementAccess, Dictionary<string, JObject> memberAccessValues, JObject indexObject, List<VariableDefinition> variableDefinitions, CancellationToken token)
         {
             try
             {
@@ -422,9 +423,10 @@ public async Task<JObject> Resolve(ElementAccessExpressionSyntax elementAccess,
                         if (type == "string")
                         {
                             var eaExpressionFormatted = elementAccessStrExpression.Replace('.', '_'); // instance_str
-                            variableDefinitions.Add(ExpressionEvaluator.ConvertJSToCSharpLocalVariableAssignment(eaExpressionFormatted, rootObject));
+                            variableDefinitions.Add(new (eaExpressionFormatted, rootObject, ExpressionEvaluator.ConvertJSToCSharpLocalVariableAssignment(eaExpressionFormatted, rootObject)));
                             var eaFormatted = elementAccessStr.Replace('.', '_'); // instance_str[1]
-                            return await ExpressionEvaluator.EvaluateSimpleExpression(this, eaFormatted, elementAccessStr, variableDefinitions, logger, token);
+                            var variableDef = await ExpressionEvaluator.GetVariableDefinitions(this, variableDefinitions, invokeToStringInObject: false, token);
+                            return await ExpressionEvaluator.EvaluateSimpleExpression(this, eaFormatted, elementAccessStr, variableDef, logger, token);
                         }
                         if (indexObject is null && elementIdxInfo.IndexingExpression is null)
                             throw new InternalErrorException($"Unable to write index parameter to invoke the method in the runtime.");
@@ -511,7 +513,8 @@ async Task<ElementIndexInfo> GetElementIndexInfo()
                     else
                     {
                         string expression = arg.ToString();
-                        indexObject = await ExpressionEvaluator.EvaluateSimpleExpression(this, expression, expression, variableDefinitions, logger, token);
+                        var variableDef = await ExpressionEvaluator.GetVariableDefinitions(this, variableDefinitions, invokeToStringInObject: false, token);
+                        indexObject = await ExpressionEvaluator.EvaluateSimpleExpression(this, expression, expression, variableDef, logger, token);
                         string idxType = indexObject["type"].Value<string>();
                         if (idxType != "number")
                             throw new InvalidOperationException($"Cannot index with an object of type '{idxType}'");

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

@@ -1933,14 +1933,14 @@ public Task<JObject> InvokeMethod(DotnetObjectId dotnetObjectId, CancellationTok
                 : throw new ArgumentException($"Cannot invoke method with id {methodId} on {dotnetObjectId}", nameof(dotnetObjectId));
         }
 
-        public async Task<string> InvokeToStringAsync(IEnumerable<int> typeIds, bool isValueType, bool isEnum, int objectId, BindingFlags extraFlags, CancellationToken token)
+        public async Task<string> InvokeToStringAsync(IEnumerable<int> typeIds, bool isValueType, bool isEnum, int objectId, BindingFlags extraFlags, bool invokeToStringInObject, CancellationToken token)
         {
             try
             {
                 foreach (var typeId in typeIds)
                 {
                     var typeInfo = await GetTypeInfo(typeId, token);
-                    if (typeInfo == null || typeInfo.Name == "object")
+                    if (typeInfo == null || (typeInfo.Name == "object" && !invokeToStringInObject))
                         continue;
                     Microsoft.WebAssembly.Diagnostics.MethodInfo methodInfo = typeInfo.Info.Methods.FirstOrDefault(m => m.Name == "ToString");
                     if (isEnum != true && methodInfo == null)

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

@@ -130,7 +130,7 @@ public async Task<JObject> ToJObject(MonoSDBHelper sdbAgent, bool forDebuggerDis
             string description = className;
             if (ShouldAutoInvokeToString(className) || IsEnum)
             {
-                var toString = await sdbAgent.InvokeToStringAsync(new int[]{ TypeId }, isValueType: true, IsEnum, Id.Value, IsEnum ? BindingFlags.Default : BindingFlags.DeclaredOnly, token);
+                var toString = await sdbAgent.InvokeToStringAsync(new int[]{ TypeId }, isValueType: true, IsEnum, Id.Value, IsEnum ? BindingFlags.Default : BindingFlags.DeclaredOnly, invokeToStringInObject: false, token);
                 if (toString == null)
                     sdbAgent.logger.LogDebug($"Error while evaluating ToString method on typeId = {TypeId}");
                 else
@@ -147,7 +147,7 @@ public async Task<JObject> ToJObject(MonoSDBHelper sdbAgent, bool forDebuggerDis
                 }
                 else
                 {
-                    var toString = await sdbAgent.InvokeToStringAsync(new int[]{ TypeId }, isValueType: true, IsEnum, Id.Value, IsEnum ? BindingFlags.Default : BindingFlags.DeclaredOnly, token);
+                    var toString = await sdbAgent.InvokeToStringAsync(new int[]{ TypeId }, isValueType: true, IsEnum, Id.Value, IsEnum ? BindingFlags.Default : BindingFlags.DeclaredOnly, invokeToStringInObject: false, token);
                     if (toString != null)
                         description = toString;
                 }

src/mono/wasm/debugger/DebuggerTestSuite/EvaluateOnCallFrame2Tests.cs

@@ -711,5 +711,25 @@ public async Task EvaluateLocalObjectFromAssemblyNotRelatedButLoaded()
                    ("EvaluateStaticGetterInValueType.A", TNumber(5))
                 );
            });
+
+        [Fact]
+        public async Task EvaluateSumBetweenObjectAndString() => await CheckInspectLocalsAtBreakpointSite(
+             $"DebuggerTests.SumObjectAndString", "run", 7, "DebuggerTests.SumObjectAndString.run",
+            $"window.setTimeout(function() {{ invoke_static_method ('[debugger-test] DebuggerTests.SumObjectAndString:run'); 1 }})",
+            wait_for_event_fn: async (pause_location) =>
+            {
+                var id = pause_location["callFrames"][0]["callFrameId"].Value<string>();
+                await EvaluateOnCallFrameAndCheck(id,
+                   ("myList+\"asd\"", TString("System.Collections.Generic.List`1[System.Int32]asd")),
+                   ("dt+\"asd\"", TString("1/1/0001 12:00:00 AMasd")),
+                   ("myClass+\"asd\"", TString("OverridenToStringasd")),
+                   ("listNull+\"asd\"", TString("asd"))
+                );
+                await CheckEvaluateFail(id,
+                    ("myClass+dt", "Cannot evaluate '(myClass+dt\n)': (3,9): error CS0019: Operator '+' cannot be applied to operands of type 'object' and 'object'"),
+                    ("myClass+1", "Cannot evaluate '(myClass+1\n)': (2,9): error CS0019: Operator '+' cannot be applied to operands of type 'object' and 'int'"),
+                    ("dt+1", "Cannot evaluate '(dt+1\n)': (2,9): error CS0019: Operator '+' cannot be applied to operands of type 'object' and 'int'")
+                );
+           });
     }
 }

src/mono/wasm/debugger/tests/debugger-test/debugger-evaluate-test.cs

@@ -2156,3 +2156,28 @@ public struct EvaluateStaticGetterInValueType
 {
     public static int A => 5;
 }
+
+namespace DebuggerTests
+{
+    public class SumObjectAndString
+    {
+        public class MyClass
+        {
+            public override string ToString()
+            {
+                return "OverridenToString";
+            }
+        }
+        public static void run()
+        {
+            DateTime dt = new DateTime();
+            List<int> myList = new();
+            List<int> listNull = null;
+            object o = new();
+            MyClass myClass = new();
+            myList.Add(1);
+            Console.WriteLine(myList);
+            Console.WriteLine(dt);
+        }
+    }
+}
\ No newline at end of file