Fix invalid reference bug

src/Microsoft.OpenApi/Properties/SRResource.resx

@@ -139,7 +139,7 @@
     <value>Invalid Reference identifier '{0}'.</value>
   </data>
   <data name="InvalidReferenceType" xml:space="preserve">
-    <value>Invalid Reference Type.</value>
+    <value>Invalid Reference Type '{0}'.</value>
   </data>
   <data name="LocalReferenceRequiresType" xml:space="preserve">
     <value>Local reference must have type specified.</value>

src/Microsoft.OpenApi/Services/OpenApiReferenceResolver.cs

@@ -259,6 +259,13 @@ private void ResolveTags(IList<OpenApiTag> tags)
             {
                 try
                 {
+                    var referencedObject = typeof(T).Name;
+                    var referenceType = reference?.Type.ToString();
+                    if (referenceType is not null && !referencedObject.Contains(referenceType))
+                    {
+                        throw new OpenApiException(string.Format(Properties.SRResource.InvalidReferenceType, referenceType));
+                    }
+
                     return _currentDocument.ResolveReference(reference, false) as T;
                 }
                 catch (OpenApiException ex)

test/Microsoft.OpenApi.Readers.Tests/V3Tests/OpenApiDocumentTests.cs

@@ -9,8 +9,10 @@
 using System.Threading;
 using FluentAssertions;
 using Microsoft.OpenApi.Any;
+using Microsoft.OpenApi.Exceptions;
 using Microsoft.OpenApi.Interfaces;
 using Microsoft.OpenApi.Models;
+using Microsoft.OpenApi.Readers.Interface;
 using Microsoft.OpenApi.Validations;
 using Microsoft.OpenApi.Validations.Rules;
 using Microsoft.OpenApi.Writers;
@@ -1355,5 +1357,15 @@ public void ValidateExampleShouldNotHaveDataTypeMismatch()
             var warnings = diagnostic.Warnings;
             Assert.False(warnings.Any());
         }
+
+        [Fact]
+        public void ParseDocumetWithWrongReferenceTypeShouldReturnADiagnosticError()
+        {
+            using var stream = Resources.GetStream(Path.Combine(SampleFolderPath, "docWithWrongRef.json"));
+            _ = new OpenApiStreamReader().Read(stream, out var diagnostic);
+
+            diagnostic.Errors.Should().BeEquivalentTo(new List<OpenApiError> {
+                new( new OpenApiException("Invalid Reference Type 'Schema'.")) });
+        }
     }
 }

test/Microsoft.OpenApi.Readers.Tests/V3Tests/Samples/OpenApiDocument/docWithWrongRef.json

@@ -0,0 +1,27 @@
+{
+    "openapi":"3.0.0",
+    "info":{
+        "title":"some api",
+        "description":"some description",
+        "version": "1"
+    },
+    "servers":[{"url":"https://localhost"}],
+    "paths":{
+        "/count":{
+            "get":{
+                "responses":{
+                    "200":{
+                        "$ref":"#/components/schemas/count"
+                    },
+                },
+            }
+        }
+    },
+    "components":{
+        "schemas":{
+            "count":{
+                "type": "number"
+            }
+        }
+    }
+}