Upgrade dependency RamlToOpenApiConverter to version 0.40.0 (#1505)

* Upgrade dependency RamlToOpenApiConverter to version 0.40.0

* fix code comment

* .

* Potential fix for pull request finding 'Constant condition'

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

* Potential fix for pull request finding 'Constant condition'

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

* fix

---------

Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

examples/WireMock.Net.OpenApiParser.ConsoleApp/WireMock.Net.OpenApiParser.ConsoleApp.csproj

@@ -6,7 +6,7 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="Microsoft.OpenApi.YamlReader" Version="3.7.0" />
+        <!--<PackageReference Include="Microsoft.OpenApi.YamlReader" Version="3.7.0" />-->
         
         <ProjectReference Include="..\..\src\WireMock.Net.Abstractions\WireMock.Net.Abstractions.csproj" />
         <ProjectReference Include="..\..\src\WireMock.Net.OpenApiParser\WireMock.Net.OpenApiParser.csproj" />

src/WireMock.Net.OpenApiParser/Extensions/DictionaryExtensions.cs

@@ -1,10 +1,13 @@
 // Copyright © WireMock.Net
 
-#if NETSTANDARD2_0
+
+using System.Diagnostics.CodeAnalysis;
+
 namespace System.Collections.Generic;
 
 internal static class DictionaryExtensions
 {
+#if NETSTANDARD2_0
     public static bool TryAdd<TKey, TValue>(this Dictionary<TKey, TValue>? dictionary, TKey key, TValue value)
     {
         if (dictionary is null || dictionary.ContainsKey(key))
@@ -16,5 +19,29 @@ internal static class DictionaryExtensions
 
         return true;
     }
-}
 #endif
+
+    public static bool TryGetFirstValue<TKey, TValue>(this IDictionary<TKey, TValue>? dictionary, out TValue? value)
+    {
+        if (dictionary != null && dictionary.Count > 0)
+        {
+            value = dictionary.First().Value;
+            return true;
+        }
+
+        value = default;
+        return false;
+    }
+
+    public static bool TryGetFirstOrDefault<TKey, TValue>(this IDictionary<TKey, TValue>? dictionary, out KeyValuePair<TKey, TValue> value)
+    {
+        if (dictionary != null && dictionary.Count > 0)
+        {
+            value = dictionary.First();
+            return true;
+        }
+
+        value = default;
+        return false;
+    }
+}

src/WireMock.Net.OpenApiParser/Extensions/OpenApiSchemaExtensions.cs

@@ -1,7 +1,5 @@
 // Copyright © WireMock.Net
 
-using System.Collections.Generic;
-using System.Linq;
 using System.Reflection;
 using System.Text.Json;
 using System.Text.Json.Nodes;
@@ -56,37 +54,25 @@ internal static class OpenApiSchemaExtensions
 
     public static SchemaFormat GetSchemaFormat(this IOpenApiSchema? schema)
     {
-        switch (schema?.Format)
+        return (schema?.Format) switch
         {
-            case "float":
-                return SchemaFormat.Float;
+            "float" => SchemaFormat.Float,
+            "double" => SchemaFormat.Double,
+            "int32" => SchemaFormat.Int32,
+            "int64" => SchemaFormat.Int64,
+            "date" => SchemaFormat.Date,
+            "date-time" => SchemaFormat.DateTime,
+            "password" => SchemaFormat.Password,
+            "byte" => SchemaFormat.Byte,
+            "binary" => SchemaFormat.Binary,
+            _ => SchemaFormat.Undefined,
+        };
+    }
 
-            case "double":
-                return SchemaFormat.Double;
-
-            case "int32":
-                return SchemaFormat.Int32;
-
-            case "int64":
-                return SchemaFormat.Int64;
-
-            case "date":
-                return SchemaFormat.Date;
-
-            case "date-time":
-                return SchemaFormat.DateTime;
-
-            case "password":
-                return SchemaFormat.Password;
-
-            case "byte":
-                return SchemaFormat.Byte;
-
-            case "binary":
-                return SchemaFormat.Binary;
-
-            default:
-                return SchemaFormat.Undefined;
-        }
+    internal static JsonNode? FindFirstExample(this IOpenApiSchema? schema)
+    {
+#pragma warning disable CS0618 // Type or member is obsolete
+        return schema?.Examples?.FirstOrDefault() ?? schema?.Example;
+#pragma warning restore CS0618 // Type or member is obsolete
     }
 }

src/WireMock.Net.OpenApiParser/Extensions/WireMockServerExtensions.cs

@@ -1,10 +1,8 @@
 // Copyright © WireMock.Net
 
-using System.IO;
-using System.Linq;
 using JetBrains.Annotations;
+using Microsoft.OpenApi.Reader;
 using Stef.Validation;
-using WireMock.Net.OpenApiParser.Models;
 using WireMock.Net.OpenApiParser.Settings;
 using WireMock.Server;
 
@@ -16,7 +14,8 @@ namespace WireMock.Net.OpenApiParser.Extensions;
 public static class WireMockServerExtensions
 {
     /// <summary>
-    /// Register the mappings via an OpenAPI (swagger) V2/V3/V3.1 file.
+    /// Register the mappings via an OpenAPI (swagger) V2/V3/V3.1/V3.2 file.
+    /// In case of an error, no mappings are registered and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="server">The WireMockServer instance</param>
     /// <param name="path">Path containing OpenAPI file to parse and use the mappings.</param>
@@ -28,7 +27,8 @@ public static class WireMockServerExtensions
     }
 
     /// <summary>
-    /// Register the mappings via an OpenAPI (swagger) V2/V3/V3.1 file.
+    /// Register the mappings via an OpenAPI (swagger) V2/V3/V3.1/V3.2 file.
+    /// In case of an error, no mappings are registered and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="server">The WireMockServer instance</param>
     /// <param name="path">Path containing OpenAPI file to parse and use the mappings.</param>
@@ -46,7 +46,8 @@ public static class WireMockServerExtensions
     }
 
     /// <summary>
-    /// Register the mappings via an OpenAPI (swagger) V2/V3/V3.1 stream.
+    /// Register the mappings via an OpenAPI (swagger) V2/V3/V3.1/V3.2 stream.
+    /// In case of an error, no mappings are registered and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="server">The WireMockServer instance</param>
     /// <param name="stream">Stream containing OpenAPI description to parse and use the mappings.</param>
@@ -58,7 +59,8 @@ public static class WireMockServerExtensions
     }
 
     /// <summary>
-    /// Register the mappings via an OpenAPI (swagger) V2/V3/V3.1 stream.
+    /// Register the mappings via an OpenAPI (swagger) V2/V3/V3.1/V3.2 stream.
+    /// In case of an error, no mappings are registered and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="server">The WireMockServer instance</param>
     /// <param name="stream">Stream containing OpenAPI description to parse and use the mappings.</param>
@@ -77,7 +79,8 @@ public static class WireMockServerExtensions
     }
 
     /// <summary>
-    /// Register the mappings via an OpenAPI (swagger) V2/V3/V3.1 document.
+    /// Register the mappings via an OpenAPI (swagger) V2/V3/V3.1/V3.2 document.
+    /// In case of an error, no mappings are registered and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="server">The WireMockServer instance</param>
     /// <param name="document">The OpenAPI document to use as mappings.</param>

src/WireMock.Net.OpenApiParser/ILRepack.targets

@@ -1,29 +0,0 @@
-<?xml version="1.0" encoding="utf-8" ?>
-
-<!-- See also https://github.com/ravibpatel/ILRepack.Lib.MSBuild.Task/issues/26 -->
-<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-    <Target Name="ILRepacker" AfterTargets="Build" Condition="'$(Configuration)' == 'Release'">
-        <ItemGroup>
-            <InputAssemblies Include="$(OutputPath)WireMock.Net.OpenApiParser.dll" />
-            <InputAssemblies Include="@(ReferencePathWithRefAssemblies)" Condition="'%(filename)' == 'Microsoft.OpenApi.YamlReader'" />
-            <InputAssemblies Include="@(ReferencePathWithRefAssemblies)" Condition="'%(filename)' == 'Microsoft.OpenApi'" />
-            <LibraryPath Include="%(ReferencePathWithRefAssemblies.RelativeDir)" />
-        </ItemGroup>
-    
-        <ItemGroup>
-            <DoNotInternalizeAssemblies Include="WireMock.Net.OpenApiParser" />
-        </ItemGroup>
-    
-        <ILRepack
-            Parallel="true"
-            Internalize="true"
-            RenameInternalized="true"
-            InternalizeExclude="@(DoNotInternalizeAssemblies)"
-            InputAssemblies="@(InputAssemblies)"
-            LibraryPath="@(LibraryPath)"
-            TargetKind="Dll"
-            KeyFile="../../src/WireMock.Net/WireMock.Net.snk"
-            OutputFile="$(OutputPath)$(AssemblyName).dll"
-        />
-    </Target>
-</Project>

src/WireMock.Net.OpenApiParser/IWireMockOpenApiParser.cs

@@ -1,9 +1,7 @@
 // Copyright © WireMock.Net
 
-using System.Collections.Generic;
-using System.IO;
+using Microsoft.OpenApi.Reader;
 using WireMock.Admin.Mappings;
-using WireMock.Net.OpenApiParser.Models;
 using WireMock.Net.OpenApiParser.Settings;
 
 namespace WireMock.Net.OpenApiParser;
@@ -15,6 +13,7 @@ public interface IWireMockOpenApiParser
 {
     /// <summary>
     /// Generate <see cref="IReadOnlyList{MappingModel}"/> from a file-path.
+    /// In case of an error, an empty list is returned and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="path">The path to read the OpenApi/Swagger/V2/V3/V31 or Raml file.</param>
     /// <param name="diagnostic">OpenApiDiagnostic output</param>
@@ -23,6 +22,7 @@ public interface IWireMockOpenApiParser
 
     /// <summary>
     /// Generate <see cref="IReadOnlyList{MappingModel}"/> from a file-path.
+    /// In case of an error, an empty list is returned and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="path">The path to read the OpenApi/Swagger/V2/V3/V31 or Raml file.</param>
     /// <param name="settings">Additional settings</param>
@@ -40,6 +40,7 @@ public interface IWireMockOpenApiParser
 
     /// <summary>
     /// Generate <see cref="IReadOnlyList{MappingModel}"/> from a <seealso cref="Stream"/>.
+    /// In case of an error, an empty list is returned and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="stream">The source stream</param>
     /// <param name="diagnostic">OpenApiDiagnostic output</param>
@@ -48,6 +49,7 @@ public interface IWireMockOpenApiParser
 
     /// <summary>
     /// Generate <see cref="IReadOnlyList{MappingModel}"/> from a <seealso cref="Stream"/>.
+    /// In case of an error, an empty list is returned and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="stream">The source stream</param>
     /// <param name="settings">Additional settings</param>
@@ -57,6 +59,7 @@ public interface IWireMockOpenApiParser
 
     /// <summary>
     /// Generate <see cref="IReadOnlyList{MappingModel}"/> from a <seealso cref="string"/>.
+    /// In case of an error, an empty list is returned and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="text">The source text</param>
     /// <param name="diagnostic">OpenApiDiagnostic output</param>
@@ -65,6 +68,7 @@ public interface IWireMockOpenApiParser
 
     /// <summary>
     /// Generate <see cref="IReadOnlyList{MappingModel}"/> from a <seealso cref="string"/>.
+    /// In case of an error, an empty list is returned and <see cref="OpenApiDiagnostic"/> contains the error details.
     /// </summary>
     /// <param name="text">The source text</param>
     /// <param name="settings">Additional settings</param>

src/WireMock.Net.OpenApiParser/Mappers/OpenApiPathsMapper.cs

@@ -53,7 +53,7 @@ internal class OpenApiPathsMapper(WireMockOpenApiParserSettings settings)
                 Headers = MapRequestHeaders(requestHeaders),
                 Body = GetRequestBodyModel(operation.RequestBody)
             },
-            Response = GetResponseModel(operation.Responses?.FirstOrDefault())
+            Response = operation.Responses?.TryGetFirstOrDefault(out var firstResponse) == true ? GetResponseModel(firstResponse) : new ResponseModel { StatusCode = 200 }
         };
     }
 
@@ -70,8 +70,7 @@ internal class OpenApiPathsMapper(WireMockOpenApiParserSettings settings)
 
         var requestExample = requestContent?.Example;
         var requestExamples = requestContent?.Examples;
-        var requestSchemaExample = requestContent?.Schema?.Example;
-        var requestSchemaExamples = requestContent?.Schema?.Examples;
+        var requestSchemaExample = requestContent?.Schema.FindFirstExample();
 
         JsonNode? request;
         if (requestExample != null)
@@ -86,10 +85,6 @@ internal class OpenApiPathsMapper(WireMockOpenApiParserSettings settings)
         {
             request = requestExamples.FirstOrDefault().Value.Value;
         }
-        else if (requestSchemaExamples != null)
-        {
-            request = requestSchemaExamples.FirstOrDefault();
-        }
         else
         {
             var requestSchema = content?.FirstOrDefault().Value.Schema;
@@ -99,16 +94,15 @@ internal class OpenApiPathsMapper(WireMockOpenApiParserSettings settings)
         return MapRequestBody(request) ?? new BodyModel();
     }
 
-    private ResponseModel GetResponseModel(KeyValuePair<string, IOpenApiResponse>? openApiResponse)
+    private ResponseModel GetResponseModel(KeyValuePair<string, IOpenApiResponse> openApiResponse)
     {
-        var content = openApiResponse?.Value.Content;
+        var content = openApiResponse.Value.Content;
 
         TryGetContent(content, out var responseContent, out var contentType);
 
         var responseExample = responseContent?.Example;
         var responseExamples = responseContent?.Examples;
-        var responseSchemaExample = responseContent?.Schema?.Example;
-        var responseSchemaExamples = responseContent?.Schema?.Examples;
+        var responseSchemaExample = responseContent?.Schema.FindFirstExample();
 
         JsonNode? response;
         if (responseExample != null)
@@ -119,24 +113,19 @@ internal class OpenApiPathsMapper(WireMockOpenApiParserSettings settings)
         {
             response = responseSchemaExample;
         }
-        else if (responseExamples != null)
+        else if (responseExamples.TryGetFirstValue(out var firstResponseFromExamples))
         {
-            response = responseExamples.FirstOrDefault().Value.Value;
-        }
-        else if (responseSchemaExamples != null)
-        {
-            response = responseSchemaExamples.FirstOrDefault();
+            response = firstResponseFromExamples?.Value;
         }
         else
         {
-            var responseSchema = content?.FirstOrDefault().Value?.Schema;
-            response = MapSchemaToObject(responseSchema);
+            response = content.TryGetFirstValue(out var firstContent) ? MapSchemaToObject(firstContent?.Schema) : null;
         }
 
         return new ResponseModel
         {
-            StatusCode = int.TryParse(openApiResponse?.Key, out var httpStatusCode) ? httpStatusCode : 200,
-            Headers = MapHeaders(contentType, openApiResponse?.Value.Headers),
+            StatusCode = int.TryParse(openApiResponse.Key, out var httpStatusCode) ? httpStatusCode : 200,
+            Headers = MapHeaders(contentType, openApiResponse.Value.Headers),
             BodyAsJson = response != null ? JsonConvert.DeserializeObject(SystemTextJsonSerializer.Serialize(response)) : null
         };
     }

src/WireMock.Net.OpenApiParser/Models/OpenApiDiagnostic.cs

@@ -1,28 +0,0 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
-// Licensed under the MIT license.
-
-using System.Collections.Generic;
-using RamlToOpenApiConverter;
-
-namespace WireMock.Net.OpenApiParser.Models;
-
-/// <summary>
-/// Object containing all diagnostic information related to Open API parsing.
-/// </summary>
-public class OpenApiDiagnostic
-{
-    /// <summary>
-    /// List of all errors.
-    /// </summary>
-    public List<OpenApiError> Errors { get; set; } = [];
-
-    /// <summary>
-    /// List of all warnings
-    /// </summary>
-    public List<OpenApiError> Warnings { get; set; } = [];
-
-    /// <summary>
-    /// Open API specification version of the document parsed.
-    /// </summary>
-    public OpenApiSpecificationVersion SpecificationVersion { get; set; }
-}

src/WireMock.Net.OpenApiParser/Models/OpenApiError.cs

@@ -1,46 +0,0 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
-// Licensed under the MIT license.
-
-namespace WireMock.Net.OpenApiParser.Models;
-
-/// <summary>
-/// Error related to the Open API Document.
-/// </summary>
-public class OpenApiError
-{
-    /// <summary>
-    /// Initializes the <see cref="OpenApiError"/> class.
-    /// </summary>
-    public OpenApiError(string? pointer, string message)
-    {
-        Pointer = pointer;
-        Message = message;
-    }
-
-    /// <summary>
-    /// Initializes a copy of an <see cref="OpenApiError"/> object
-    /// </summary>
-    public OpenApiError(OpenApiError error)
-    {
-        Pointer = error.Pointer;
-        Message = error.Message;
-    }
-
-    /// <summary>
-    /// Message explaining the error.
-    /// </summary>
-    public string Message { get; set; }
-
-    /// <summary>
-    /// Pointer to the location of the error.
-    /// </summary>
-    public string? Pointer { get; set; }
-
-    /// <summary>
-    /// Gets the string representation of <see cref="OpenApiError"/>.
-    /// </summary>
-    public override string ToString()
-    {
-        return Message + (!string.IsNullOrEmpty(Pointer) ? " [" + Pointer + "]" : "");
-    }
-}

src/WireMock.Net.OpenApiParser/Models/OpenApiMapper.cs

@@ -1,25 +0,0 @@
-// Copyright © WireMock.Net
-
-using System.Linq;
-using RamlToOpenApiConverter;
-using MicrosoftOpenApiDiagnostic = Microsoft.OpenApi.Reader.OpenApiDiagnostic;
-
-namespace WireMock.Net.OpenApiParser.Models;
-
-internal static class OpenApiMapper
-{
-    internal static OpenApiDiagnostic? Map(MicrosoftOpenApiDiagnostic? openApiDiagnostic)
-    {
-        if (openApiDiagnostic == null)
-        {
-            return null;
-        }
-
-        return new OpenApiDiagnostic
-        {
-            Errors = openApiDiagnostic.Errors.Select(e => new OpenApiError(e.Pointer, e.Message)).ToList(),
-            Warnings = openApiDiagnostic.Warnings.Select(e => new OpenApiError(e.Pointer, e.Message)).ToList(),
-            SpecificationVersion = (OpenApiSpecificationVersion)openApiDiagnostic.SpecificationVersion
-        };
-    }
-}

src/WireMock.Net.OpenApiParser/Utils/ExampleValueGenerator.cs

@@ -39,7 +39,7 @@ internal class ExampleValueGenerator
 
     public JsonNode GetExampleValue(IOpenApiSchema? schema)
     {
-        var schemaExample = schema?.Example;
+        var schemaExample = schema?.FindFirstExample();
         var schemaEnum = schema?.Enum?.FirstOrDefault();
 
         _exampleValues.Schema = schema;

src/WireMock.Net.OpenApiParser/WireMock.Net.OpenApiParser.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
         <Description>An OpenApi (swagger) parser to generate MappingModel or mapping.json file.</Description>
@@ -40,23 +40,11 @@
 
     <ItemGroup>
         <PackageReference Include="Newtonsoft.Json" Version="13.0.4" />
-        <PackageReference Include="RamlToOpenApiConverter.SourceOnly" Version="0.21.0" />
-        <PackageReference Include="YamlDotNet" Version="18.1.0" />
+        <PackageReference Include="RamlToOpenApiConverter" Version="0.40.0" />
         <PackageReference Include="RandomDataGenerator.Net" Version="1.0.19.1" />
         <PackageReference Include="Stef.Validation" Version="0.3.0" />
     </ItemGroup>
 
-    <ItemGroup Condition="'$(Configuration)' == 'Debug'">
-        <PackageReference Include="Microsoft.OpenApi.YamlReader" Version="3.7.0" />
-    </ItemGroup>
-
-    <ItemGroup Condition="'$(Configuration)' == 'Release'">
-        <PackageReference Include="ILRepack.Lib.MSBuild.Task" Version="2.0.43" PrivateAssets="All" />
-        <PackageReference Include="Microsoft.OpenApi" Version="3.7.0" PrivateAssets="All" />
-        <PackageReference Include="Microsoft.OpenApi.YamlReader" Version="3.7.0" PrivateAssets="All" />
-        <PackageReference Include="SharpYaml" Version="2.1.5" />
-    </ItemGroup>
-
     <ItemGroup>
         <ProjectReference Include="..\..\src\WireMock.Net.Abstractions\WireMock.Net.Abstractions.csproj" />
     </ItemGroup>

src/WireMock.Net.OpenApiParser/WireMockOpenApiParser.cs

@@ -1,8 +1,6 @@
 // Copyright © WireMock.Net
 
-using System;
-using System.Collections.Generic;
-using System.IO;
+using System.Diagnostics.CodeAnalysis;
 using System.Text;
 using JetBrains.Annotations;
 using Microsoft.OpenApi;
@@ -11,14 +9,12 @@ using Microsoft.OpenApi.YamlReader;
 using RamlToOpenApiConverter;
 using WireMock.Admin.Mappings;
 using WireMock.Net.OpenApiParser.Mappers;
-using WireMock.Net.OpenApiParser.Models;
 using WireMock.Net.OpenApiParser.Settings;
-using OpenApiDiagnostic = WireMock.Net.OpenApiParser.Models.OpenApiDiagnostic;
 
 namespace WireMock.Net.OpenApiParser;
 
 /// <summary>
-/// Parse a OpenApi/Swagger/V2/V3/V3.1 to WireMock.Net MappingModels.
+/// Parse a OpenApi/Swagger/V2/V3/V3.1/V3.2 to WireMock.Net MappingModels.
 /// </summary>
 public class WireMockOpenApiParser : IWireMockOpenApiParser
 {
@@ -32,8 +28,15 @@ public class WireMockOpenApiParser : IWireMockOpenApiParser
         _readerSettings = new OpenApiReaderSettings();
         _readerSettings.AddMicrosoftExtensionParsers();
         _readerSettings.AddJsonReader();
-        _readerSettings.TryAddReader(OpenApiConstants.Yaml, new OpenApiYamlReader());
-        _readerSettings.TryAddReader(OpenApiConstants.Yml, new OpenApiYamlReader());
+
+        var openApiYamlReaderSettings = new OpenApiYamlReaderSettings
+        {
+            MaxAliasExpansionNodeCount = 1_000_000
+        };
+        var openApiYamlReader = new OpenApiYamlReader(openApiYamlReaderSettings);
+
+        _readerSettings.TryAddReader(OpenApiConstants.Yaml, openApiYamlReader);
+        _readerSettings.TryAddReader(OpenApiConstants.Yml, openApiYamlReader);
     }
 
     /// <inheritdoc />
@@ -55,7 +58,12 @@ public class WireMockOpenApiParser : IWireMockOpenApiParser
         }
         else
         {
-            document = Read(File.OpenRead(path), out diagnostic);
+            if (!TryRead(File.OpenRead(path), out var documentFromYaml, out diagnostic))
+            {
+                return [];
+            }
+
+            document = documentFromYaml;
         }
 
         return FromDocument(document, settings);
@@ -74,14 +82,24 @@ public class WireMockOpenApiParser : IWireMockOpenApiParser
     [PublicAPI]
     public IReadOnlyList<MappingModel> FromStream(Stream stream, out OpenApiDiagnostic diagnostic)
     {
-        return FromDocument(Read(stream, out diagnostic));
+        if (TryRead(stream, out var openApiDocument, out diagnostic))
+        {
+            return FromDocument(openApiDocument);
+        }
+
+        return [];
     }
 
     /// <inheritdoc />
     [PublicAPI]
     public IReadOnlyList<MappingModel> FromStream(Stream stream, WireMockOpenApiParserSettings settings, out OpenApiDiagnostic diagnostic)
     {
-        return FromDocument(Read(stream, out diagnostic), settings);
+        if (TryRead(stream, out var openApiDocument, out diagnostic))
+        {
+            return FromDocument(openApiDocument, settings);
+        }
+
+        return [];
     }
 
     /// <inheritdoc  />
@@ -98,7 +116,7 @@ public class WireMockOpenApiParser : IWireMockOpenApiParser
         return FromStream(new MemoryStream(Encoding.UTF8.GetBytes(text)), settings, out diagnostic);
     }
 
-    private OpenApiDocument Read(Stream stream, out OpenApiDiagnostic diagnostic)
+    private bool TryRead(Stream stream, [NotNullWhen(true)] out OpenApiDocument? openApiDocument, out OpenApiDiagnostic diagnostic)
     {
         if (stream is not MemoryStream memoryStream)
         {
@@ -107,8 +125,9 @@ public class WireMockOpenApiParser : IWireMockOpenApiParser
 
         var result = OpenApiDocument.Load(memoryStream, settings: _readerSettings);
 
-        diagnostic = OpenApiMapper.Map(result.Diagnostic) ?? new OpenApiDiagnostic();
-        return result.Document ?? throw new InvalidOperationException("The document is null.");
+        diagnostic = result.Diagnostic ?? new OpenApiDiagnostic();
+        openApiDocument = result.Document;
+        return openApiDocument != null && !diagnostic.Errors.Any();
     }
 
     private static MemoryStream ReadStreamIntoMemoryStream(Stream stream)

test/WireMock.Net.Tests/OpenApiParser/WireMockOpenApiParserTests.cs

@@ -36,12 +36,38 @@ public class WireMockOpenApiParserTests
         var openApiDocument = File.ReadAllText(Path.Combine("OpenApiParser", "payroc-openapi-spec.yaml"));
 
         // Act
-        var mappings = _sut.FromText(openApiDocument, settings, out _);
+        var mappings = _sut.FromText(openApiDocument, settings, out var diagnostic);
+
+        // Assert
+        mappings.Should().NotBeEmpty();
+        diagnostic.Should().NotBeNull();
+        diagnostic.Errors.Should().BeEmpty();
 
         // Verify
         await Verify(mappings);
     }
 
+    [Fact]
+    public void FromText_UsingInvalidYaml_ShouldReturnEmptyMappingsWithDiagnostic()
+    {
+        // Arrange
+        var settings = new WireMockOpenApiParserSettings
+        {
+            ExampleValues = _exampleValuesMock.Object
+        };
+
+        var openApiDocument = File.ReadAllText(Path.Combine("OpenApiParser", "invalid.yaml"));
+
+        // Act
+        var mappings = _sut.FromText(openApiDocument, settings, out var diagnostic);
+
+        // Assert
+        mappings.Should().BeEmpty();
+        diagnostic.Should().NotBeNull();
+        diagnostic.Errors.Should().HaveCount(1);
+        diagnostic.Errors[0].Message.Should().Be("Responses must contain at least one response");
+    }
+
     [Fact]
     public async Task FromText_UsingJson_WithPlainTextExample_ShouldReturnMappings()
     {
@@ -54,7 +80,12 @@ public class WireMockOpenApiParserTests
         var openApiDocument = File.ReadAllText(Path.Combine("OpenApiParser", "oas-content-example.json"));
 
         // Act
-        var mappings = _sut.FromText(openApiDocument, settings, out _);
+        var mappings = _sut.FromText(openApiDocument, settings, out var diagnostic);
+
+        // Assert
+        mappings.Should().NotBeEmpty();
+        diagnostic.Should().NotBeNull();
+        diagnostic.Errors.Should().BeEmpty();
 
         // Verify
         await Verify(mappings);

test/WireMock.Net.Tests/OpenApiParser/invalid.yaml

@@ -0,0 +1,12 @@
+openapi: 3.2.0
+info:
+  version: '1'
+  title: Invalid API
+  description: Invalid
+
+paths:
+  /funding-recipients:
+    summary: Create and manage funding recipients.
+    post:
+      tags:
+        - Funding recipients