Fix null reference and XML escaping in XmlDocumentationGenerator

src/Refitter.Core/XmlDocumentationGenerator.cs

@@ -46,11 +46,11 @@ public void AppendInterfaceDocumentationByTag(OpenApiDocument document, string t
             return;
         }
 
-        var controllerTag = document.Tags.FirstOrDefault(t => t.Name.SanitizeControllerTag() == tag);
+        var controllerTag = document.Tags?.FirstOrDefault(t => t.Name.SanitizeControllerTag() == tag);
         var controllerDescription = controllerTag?.Description;
         if (!string.IsNullOrEmpty(controllerDescription))
         {
-            this.AppendXmlCommentBlock(SummaryTag, EscapeSymbols(controllerDescription), code, indent: Separator);
+            this.AppendXmlCommentBlock(SummaryTag, EscapeSymbols(controllerDescription!), code, indent: Separator);
         }
     }
 
@@ -88,7 +88,7 @@ public void AppendSingleInterfaceDocumentation(OpenApiDocument document, StringB
         var title = document.Info?.Title;
         if (!string.IsNullOrEmpty(title))
         {
-            this.AppendXmlCommentBlock(SummaryTag, EscapeSymbols(title), code, indent: Separator);
+            this.AppendXmlCommentBlock(SummaryTag, EscapeSymbols(title!), code, indent: Separator);
         }
     }
 
@@ -334,6 +334,7 @@ private string BuildResponseDescription(string text, IEnumerable<CSharpResponseM
     private string EscapeSymbols(string input)
     {
         return input
+            .Replace("&", "&amp;")
             .Replace("<", "&lt;")
             .Replace(">", "&gt;");
     }

src/Refitter.SourceGenerator.Tests/AdditionalFiles/Generated/SwaggerPetstoreMultipleInterfaces.g.cs

@@ -191,6 +191,7 @@ public partial interface IUpdatePetWithFormEndpoint
     public partial interface IDeletePetEndpoint
     {
         /// <summary>Deletes a pet</summary>
+        /// <param name="api_key">api_key parameter</param>
         /// <param name="petId">Pet id to delete</param>
         /// <param name="cancellationToken">The cancellation token to cancel the request.</param>
         /// <returns>A <see cref="Task"/> that completes when the request is finished.</returns>
@@ -218,6 +219,7 @@ public partial interface IUploadFileEndpoint
         /// <summary>uploads an image</summary>
         /// <param name="petId">ID of pet to update</param>
         /// <param name="additionalMetadata">Additional Metadata</param>
+        /// <param name="body">body parameter</param>
         /// <param name="cancellationToken">The cancellation token to cancel the request.</param>
         /// <returns>
         /// A <see cref="Task"/> representing the <see cref="IApiResponse"/> instance containing the result:
@@ -256,6 +258,7 @@ public partial interface IPlaceOrderEndpoint
     {
         /// <summary>Place an order for a pet</summary>
         /// <remarks>Place a new order in the store</remarks>
+        /// <param name="body">body parameter</param>
         /// <param name="cancellationToken">The cancellation token to cancel the request.</param>
         /// <returns>successful operation</returns>
         /// <exception cref="ApiException">
@@ -357,6 +360,7 @@ public partial interface ICreateUsersWithListInputEndpoint
     {
         /// <summary>Creates list of users with given input array</summary>
         /// <remarks>Creates list of users with given input array</remarks>
+        /// <param name="body">body parameter</param>
         /// <param name="cancellationToken">The cancellation token to cancel the request.</param>
         /// <returns>Successful operation</returns>
         /// <exception cref="ApiException">Thrown when the request returns a non-success status code.</exception>

src/Refitter.Tests/Examples/NumericFormatWithPatternTests.cs

@@ -1,4 +1,4 @@
-using FluentAssertions;
+using FluentAssertions;
 using Refitter.Core;
 using Refitter.Tests.Build;
 using Refitter.Tests.TestUtilities;

src/Refitter.Tests/XmlDocumentationGeneratorTests.cs

@@ -41,14 +41,46 @@ public void Can_Generate_Interface_Doc_With_Linebreaks()
     public void Can_Generate_Interface_Doc_From_Controller_Tag()
     {
         var docs = new StringBuilder();
-        var controllerTag =  new OpenApiTag { Name = "TestController", Description = "TestControllerDescription" };
-        var document =  new OpenApiDocument { Tags = [controllerTag] };
+        var controllerTag = new OpenApiTag { Name = "TestController", Description = "TestControllerDescription" };
+        var document = new OpenApiDocument { Tags = [controllerTag] };
 
         this._generator.AppendInterfaceDocumentationByTag(document, "TestController", docs);
 
         docs.ToString().Trim().Should().Be("/// <summary>TestControllerDescription</summary>");
     }
 
+    [Test]
+    public void Can_Handle_Null_Document_Tags()
+    {
+        var docs = new StringBuilder();
+        var document = new OpenApiDocument { Tags = null };
+
+        this._generator.AppendInterfaceDocumentationByTag(document, "TestController", docs);
+
+        docs.ToString().Trim().Should().BeEmpty();
+    }
+
+    [Test]
+    public void Can_Escape_Xml_Special_Characters_In_Interface_Doc()
+    {
+        var docs = new StringBuilder();
+        var controllerTag = new OpenApiTag { Name = "TestController", Description = "Test <tag> & content" };
+        var document = new OpenApiDocument { Tags = [controllerTag] };
+
+        this._generator.AppendInterfaceDocumentationByTag(document, "TestController", docs);
+
+        docs.ToString().Trim().Should().Be("/// <summary>Test &lt;tag&gt; &amp; content</summary>");
+    }
+
+    [Test]
+    public void Can_Escape_Xml_Special_Characters_In_Method_Summary()
+    {
+        var docs = new StringBuilder();
+        var method = CreateOperationModel(new OpenApiOperation { Summary = "Test <tag> & content", });
+        this._generator.AppendMethodDocumentation(method, false, false, false, false, docs);
+        docs.ToString().Trim().Should().StartWith("/// <summary>Test &lt;tag&gt; &amp; content</summary>");
+    }
+
     [Test]
     public void Can_Generate_Method_Summary()
     {