[wasm][debugger] Fix DebuggerTypeProxy for structs and for classes with multiple constructors (#77039)

* Adding any new constructor breaks UsingDebuggerTypeProxy test.

* Fix: now objects won't get identified as valueTypes by a mistake.

* Test logic fix: rely on comparison with fixed entities only.

* Fix: choosing proxy's matching constructor works.

* Support DebuggerProxy in valueTypes.

* Fix test to not rely on `testPropertiesNone`.

* Fix tests.

* Fix tests.

* Edit and disable rootHidden test.

Author: ilonatommy

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

@@ -150,10 +150,10 @@ private static async Task<JArray> GetRootHiddenChildren(
                 {
                     // a collection - expose elements to be of array scheme
                     var memberNamedItems = members
-                        .Where(m => m["name"]?.Value<string>() == "Items" || m["name"]?.Value<string>() == "_items")
+                        .Where(m => m["name"]?.Value<string>() == "Items")
                         .FirstOrDefault();
                     if (memberNamedItems is not null &&
-                        (DotnetObjectId.TryParse(memberNamedItems["value"]?["objectId"]?.Value<string>(), out DotnetObjectId itemsObjectId)) &&
+                        DotnetObjectId.TryParse(memberNamedItems["value"]?["objectId"]?.Value<string>(), out DotnetObjectId itemsObjectId) &&
                         itemsObjectId.Scheme == "array")
                     {
                         rootObjectId = itemsObjectId;
@@ -550,7 +550,8 @@ public static async Task<GetMembersResult> GetObjectMemberValues(
             // 2
             if (!getCommandType.HasFlag(GetObjectCommandOptions.ForDebuggerDisplayAttribute))
             {
-                GetMembersResult debuggerProxy = await sdbHelper.GetValuesFromDebuggerProxyAttribute(objectId, typeIdsIncludingParents[0], token);
+                GetMembersResult debuggerProxy = await sdbHelper.GetValuesFromDebuggerProxyAttributeForObject(
+                    objectId, typeIdsIncludingParents[0], token);
                 if (debuggerProxy != null)
                     return debuggerProxy;
             }

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

@@ -2121,8 +2121,7 @@ public async Task<int> GetTypeByName(string typeToSearch, CancellationToken toke
             return retDebuggerCmdReader.ReadInt32();
         }
 
-        // FIXME: support valuetypes
-        public async Task<GetMembersResult> GetValuesFromDebuggerProxyAttribute(int objectId, int typeId, CancellationToken token)
+        public async Task<GetMembersResult> GetValuesFromDebuggerProxyAttributeForObject(int objectId, int typeId, CancellationToken token)
         {
             try
             {
@@ -2132,25 +2131,11 @@ public async Task<GetMembersResult> GetValuesFromDebuggerProxyAttribute(int obje
 
                 using var ctorArgsWriter = new MonoBinaryWriter();
                 ctorArgsWriter.Write((byte)ValueTypeId.Null);
-
-                // FIXME: move method invocation to valueTypeclass?
-                if (ValueCreator.TryGetValueTypeById(objectId, out var valueType))
-                {
-                    //FIXME: Issue #68390
-                    //ctorArgsWriter.Write((byte)0); //not used but needed
-                    //ctorArgsWriter.Write(0); //not used but needed
-                    //ctorArgsWriter.Write((int)1); // num args
-                    //ctorArgsWriter.Write(valueType.Buffer);
-                    return null;
-                }
-                else
-                {
-                    ctorArgsWriter.Write((byte)0); //not used
-                    ctorArgsWriter.Write(0); //not used
-                    ctorArgsWriter.Write((int)1); // num args
-                    ctorArgsWriter.Write((byte)ElementType.Object);
-                    ctorArgsWriter.Write(objectId);
-                }
+                ctorArgsWriter.Write((byte)0); //not used
+                ctorArgsWriter.Write(0); //not used
+                ctorArgsWriter.Write((int)1); // num args
+                ctorArgsWriter.Write((byte)ElementType.Object);
+                ctorArgsWriter.Write(objectId);
 
                 var retMethod = await InvokeMethod(ctorArgsWriter.GetParameterBuffer(), methodId, token);
                 if (!DotnetObjectId.TryParse(retMethod?["value"]?["objectId"]?.Value<string>(), out DotnetObjectId dotnetObjectId))
@@ -2170,6 +2155,39 @@ public async Task<GetMembersResult> GetValuesFromDebuggerProxyAttribute(int obje
             return null;
         }
 
+        public async Task<GetMembersResult> GetValuesFromDebuggerProxyAttributeForValueTypes(int valueTypeId, int typeId, CancellationToken token)
+        {
+            try
+            {
+                var typeName = await GetTypeName(typeId, token);
+                int methodId = await FindDebuggerProxyConstructorIdFor(typeId, token);
+                if (methodId == -1)
+                   return null;
+
+                using var ctorArgsWriter = new MonoBinaryWriter();
+                ctorArgsWriter.Write((byte)ValueTypeId.Null);
+
+                if (!ValueCreator.TryGetValueTypeById(valueTypeId, out var valueType))
+                    return null;
+                ctorArgsWriter.Write((byte)0); //not used but needed
+                ctorArgsWriter.Write(0); //not used but needed
+                ctorArgsWriter.Write((int)1); // num args
+                ctorArgsWriter.Write(valueType.Buffer);
+                var retMethod = await InvokeMethod(ctorArgsWriter.GetParameterBuffer(), methodId, token);
+                if (!DotnetObjectId.TryParse(retMethod?["value"]?["objectId"]?.Value<string>(), out DotnetObjectId dotnetObjectId))
+                    throw new Exception($"Invoking .ctor ({methodId}) for DebuggerTypeProxy on type {typeId} returned {retMethod}");
+                GetMembersResult members = await GetTypeMemberValues(dotnetObjectId,
+                                                                            GetObjectCommandOptions.WithProperties | GetObjectCommandOptions.ForDebuggerProxyAttribute,
+                                                                            token);
+                return members;
+            }
+            catch (Exception e)
+            {
+                logger.LogDebug($"Could not evaluate DebuggerTypeProxyAttribute of type {await GetTypeName(typeId, token)} - {e}");
+                return null;
+            }
+        }
+
         private async Task<int> FindDebuggerProxyConstructorIdFor(int typeId, CancellationToken token)
         {
             try
@@ -2178,59 +2196,79 @@ private async Task<int> FindDebuggerProxyConstructorIdFor(int typeId, Cancellati
                 if (getCAttrsRetReader == null)
                     return -1;
 
-                var methodId = -1;
                 var parmCount = getCAttrsRetReader.ReadInt32();
-                for (int j = 0; j < parmCount; j++)
+                if (parmCount != 1)
+                    throw new InternalErrorException($"Expected to find custom attribute with only one argument, but it has {parmCount} parameters.");
+
+                byte monoParamTypeId = getCAttrsRetReader.ReadByte();
+                // FIXME: DebuggerTypeProxyAttribute(string) - not supported
+                if ((ValueTypeId)monoParamTypeId != ValueTypeId.Type)
                 {
-                    var monoTypeId = getCAttrsRetReader.ReadByte();
-                    // FIXME: DebuggerTypeProxyAttribute(string) - not supported
-                    if ((ValueTypeId)monoTypeId != ValueTypeId.Type)
-                        continue;
+                    logger.LogDebug($"DebuggerTypeProxy attribute is only supported with a System.Type parameter type. Got {(ValueTypeId)monoParamTypeId}");
+                    return -1;
+                }
+
+                var typeProxyTypeId = getCAttrsRetReader.ReadInt32();
+
+                using var commandParamsWriter = new MonoBinaryWriter();
+                commandParamsWriter.Write(typeProxyTypeId);
+                var originalClassName = await GetTypeNameOriginal(typeProxyTypeId, token);
 
-                    var cAttrTypeId = getCAttrsRetReader.ReadInt32();
-                    using var commandParamsWriter = new MonoBinaryWriter();
-                    commandParamsWriter.Write(cAttrTypeId);
-                    var className = await GetTypeNameOriginal(cAttrTypeId, token);
-                    if (className.IndexOf('[') > 0)
+                if (originalClassName.IndexOf('[') > 0)
+                {
+                    string className = originalClassName;
+                    className = className.Remove(className.IndexOf('['));
+                    var assemblyId = await GetAssemblyIdFromType(typeProxyTypeId, token);
+                    var assemblyName = await GetFullAssemblyName(assemblyId, token);
+
+                    StringBuilder typeToSearch = new(className);
+                    typeToSearch.Append('[');
+                    List<int> genericTypeArgs = await GetTypeParamsOrArgsForGenericType(typeId, token);
+                    for (int k = 0; k < genericTypeArgs.Count; k++)
                     {
-                        className = className.Remove(className.IndexOf('['));
-                        var assemblyId = await GetAssemblyIdFromType(cAttrTypeId, token);
-                        var assemblyName = await GetFullAssemblyName(assemblyId, token);
-                        var typeToSearch = className;
-                        typeToSearch += "[["; //System.Collections.Generic.List`1[[System.Int32,mscorlib,Version=4.0.0.0,Culture=neutral,PublicKeyToken=b77a5c561934e089]],mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
-                        List<int> genericTypeArgs = await GetTypeParamsOrArgsForGenericType(typeId, token);
-                        for (int k = 0; k < genericTypeArgs.Count; k++)
-                        {
-                            var assemblyIdArg = await GetAssemblyIdFromType(genericTypeArgs[k], token);
-                            var assemblyNameArg = await GetFullAssemblyName(assemblyIdArg, token);
-                            var classNameArg = await GetTypeNameOriginal(genericTypeArgs[k], token);
-                            typeToSearch += classNameArg + ", " + assemblyNameArg;
-                            if (k + 1 < genericTypeArgs.Count)
-                                typeToSearch += "], [";
-                            else
-                                typeToSearch += "]";
-                        }
-                        typeToSearch += "]";
-                        typeToSearch += ", " + assemblyName;
-                        var genericTypeId = await GetTypeByName(typeToSearch, token);
-                        if (genericTypeId < 0)
-                            break;
-                        cAttrTypeId = genericTypeId;
+                        // typeToSearch += '[';
+                        var assemblyIdArg = await GetAssemblyIdFromType(genericTypeArgs[k], token);
+                        var assemblyNameArg = await GetFullAssemblyName(assemblyIdArg, token);
+                        var classNameArg = await GetTypeNameOriginal(genericTypeArgs[k], token);
+                        typeToSearch.Append($"{(k == 0 ? "" : ",")}[{classNameArg}, {assemblyNameArg}]");
                     }
-                    int[] methodIds = await GetMethodIdsByName(cAttrTypeId, ".ctor", BindingFlags.Default, token);
-                    if (methodIds != null)
-                        methodId = methodIds[0];
-                    break;
+                typeToSearch.Append($"], {assemblyName}");
+                var genericTypeId = await GetTypeByName(typeToSearch.ToString(), token);
+                    if (genericTypeId < 0)
+                    {
+                        logger.LogDebug($"Could not find instantiated generic type id for {typeToSearch}.");
+                        return -1;
+                    }
+                    typeProxyTypeId = genericTypeId;
                 }
+                int[] constructorIds = await GetMethodIdsByName(typeProxyTypeId, ".ctor", BindingFlags.DeclaredOnly, token);
+                if (constructorIds is null)
+                    throw new InternalErrorException($"Could not find any constructor for DebuggerProxy type: {originalClassName}");
+
+                if (constructorIds.Length == 1)
+                    return constructorIds[0];
 
-                return methodId;
+                string expectedConstructorParamType = await GetTypeName(typeId, token);
+                foreach (var methodId in constructorIds)
+                {
+                    var methodInfoFromRuntime = await GetMethodInfo(methodId, token);
+                    // avoid calling to runtime if possible
+                    var ps = methodInfoFromRuntime.Info.GetParametersInfo();
+                    if (ps.Length != 1)
+                        continue;
+                    string parameters = await GetParameters(methodId, token);
+                    if (string.IsNullOrEmpty(parameters))
+                        throw new InternalErrorException($"Could not get method's parameter types. MethodId = {methodId}.");
+                    if (parameters == $"({expectedConstructorParamType})")
+                        return methodId;
+                }
+                throw new InternalErrorException($"Could not find a matching constructor for DebuggerProxy type: {originalClassName}");
             }
             catch (Exception e)
             {
                 logger.LogDebug($"Could not evaluate DebuggerTypeProxyAttribute of type {await GetTypeName(typeId, token)} - {e}");
+                return -1;
             }
-
-            return -1;
         }
 
         public ValueTypeClass GetValueTypeClass(int valueTypeId)

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

@@ -213,9 +213,7 @@ public async Task<GetMembersResult> GetMemberValues(
             if (!getObjectOptions.HasFlag(GetObjectCommandOptions.ForDebuggerDisplayAttribute))
             {
                 // FIXME: cache?
-                result = await sdbHelper.GetValuesFromDebuggerProxyAttribute(Id.Value, TypeId, token);
-                if (result != null)
-                    Console.WriteLine($"Investigate GetValuesFromDebuggerProxyAttribute\n{result}. There was a change of logic from loop to one iteration");
+                result = await sdbHelper.GetValuesFromDebuggerProxyAttributeForValueTypes(Id.Value, TypeId, token);
             }
 
             if (result == null && getObjectOptions.HasFlag(GetObjectCommandOptions.AccessorPropertiesOnly))

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

@@ -41,7 +41,7 @@ public async Task UsingDebuggerDisplay()
         [ConditionalFact(nameof(RunningOnChrome))]
         public async Task UsingDebuggerTypeProxy()
         {
-            var bp = await SetBreakpointInMethod("debugger-test.dll", "DebuggerTests.DebuggerCustomViewTest", "run", 15);
+            var bp = await SetBreakpointInMethod("debugger-test.dll", "DebuggerTests.DebuggerCustomViewTest", "run", 16);
             var pause_location = await EvaluateAndCheck(
                 "window.setTimeout(function() { invoke_static_method ('[debugger-test] DebuggerTests.DebuggerCustomViewTest:run'); }, 1);",
                 "dotnet://debugger-test.dll/debugger-custom-view-test.cs",
@@ -61,6 +61,10 @@ public async Task UsingDebuggerTypeProxy()
             props = await GetObjectOnFrame(frame, "b");
             await CheckString(props, "Val2", "one");
 
+            await CheckValueType(locals, "bs", "DebuggerTests.WithProxyStruct", description:"DebuggerTests.WithProxyStruct");
+            props = await GetObjectOnFrame(frame, "bs");
+            await CheckString(props, "Val2", "one struct");
+
             await CheckObject(locals, "openWith", "System.Collections.Generic.Dictionary<string, string>", description: "Count = 3");
             props = await GetObjectOnFrame(frame, "openWith");
             Assert.Equal(1, props.Count());
@@ -106,7 +110,7 @@ async Task<bool> CheckProperties(JObject pause_location)
                 Assert.True(task.Result);
             }
         }
-        
+
         [ConditionalFact(nameof(RunningOnChrome))]
         public async Task InspectObjectOfTypeWithToStringOverriden()
         {

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

@@ -772,9 +772,17 @@ internal async Task CheckProps(JToken actual, object exp_o, string label, int nu
                     var exp_i = exp_v_arr[i];
                     var act_i = actual_arr[i];
 
-                    AssertEqual(i.ToString(), act_i["name"]?.Value<string>(), $"{label}-[{i}].name");
+                    string exp_name = exp_i["name"]?.Value<string>();
+                    if (string.IsNullOrEmpty(exp_name))
+                        exp_name = i.ToString();
+
+                    AssertEqual(exp_name, act_i["name"]?.Value<string>(), $"{label}-[{i}].name");
                     if (exp_i != null)
-                        await CheckValue(act_i["value"], exp_i, $"{label}-{i}th value");
+                    {
+                        await CheckValue(act_i["value"],
+                            ((JObject)exp_i).GetValue("value")?.HasValues == true ? exp_i["value"] : exp_i,
+                            $"{label}-{i}th value");
+                    }
                 }
                 return;
             }