Fix go scalar collection cast

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Fixed Go generation bug when dealing with scalar collection body. [#4380](https://github.com/microsoft/kiota/issues/4380)
 - Fixed a bug where multiple Visual Studio Code instances would make the extension install/update fail. [#3686](https://github.com/microsoft/kiota/issues/3686)
 - Fixed a bug where models properties named "additionalData" or "backingstore" would be ignored. [#4224](https://github.com/microsoft/kiota/issues/4224)
 - PREVIEW: Renamed the config commands to workspace. [#4310](https://github.com/microsoft/kiota/issues/4310)

src/Kiota.Builder/Writers/Go/CodeMethodWriter.cs

@@ -723,16 +723,23 @@ private void WriteFieldDeserializer(CodeProperty property, LanguageWriter writer
     private static string GetTypeAssertion(string originalReference, string typeImportName, string? assignVarName = default, string? statusVarName = default) =>
         $"{assignVarName}{(!string.IsNullOrEmpty(statusVarName) && !string.IsNullOrEmpty(assignVarName) ? ", " : string.Empty)}{statusVarName}{(string.IsNullOrEmpty(statusVarName) && string.IsNullOrEmpty(assignVarName) ? string.Empty : " := ")}{originalReference}.({typeImportName})";
 
-    private static void WriteCollectionCast(string propertyTypeImportName, string sourceVarName, string targetVarName, LanguageWriter writer, string pointerSymbol = "*", bool dereference = true)
+    private static void WriteCollectionCast(string propertyTypeImportName, string sourceVarName, string targetVarName, LanguageWriter writer, string pointerSymbol = "*", bool dereference = true, bool scalar = false)
     {
         writer.WriteLines($"{targetVarName} := make([]{propertyTypeImportName}, len({sourceVarName}))",
             $"for i, v := range {sourceVarName} {{");
         writer.IncreaseIndent();
-        writer.StartBlock("if v != nil {");
-        var derefPrefix = dereference ? "*(" : string.Empty;
-        var derefSuffix = dereference ? ")" : string.Empty;
-        writer.WriteLine($"{targetVarName}[i] = {GetTypeAssertion(derefPrefix + "v", pointerSymbol + propertyTypeImportName)}{derefSuffix}");
-        writer.CloseBlock();
+        if (!scalar)
+        {
+            writer.StartBlock("if v != nil {");
+            var derefPrefix = dereference ? "*(" : string.Empty;
+            var derefSuffix = dereference ? ")" : string.Empty;
+            writer.WriteLine($"{targetVarName}[i] = {GetTypeAssertion(derefPrefix + "v", pointerSymbol + propertyTypeImportName)}{derefSuffix}");
+            writer.CloseBlock();
+        }
+        else
+        {
+            writer.WriteLine($"{targetVarName}[i] = v");
+        }
         writer.CloseBlock();
     }
 
@@ -909,7 +916,14 @@ private void WriteRequestGeneratorBody(CodeMethod codeElement, RequestParams req
                 writer.WriteBlock("if err != nil {", "}", "return nil, err");
             }
             else
+            {
+                if (requestParams.requestBody.Type.IsCollection)
+                {
+                    WriteCollectionCast("interface{}", bodyParamReference, "cast", writer, string.Empty, false, true);
+                    bodyParamReference = "cast";
+                }
                 writer.WriteLine($"{RequestInfoVarName}.SetContentFromScalar{collectionSuffix}({contextParameterName}, m.{requestAdapterPropertyName}, \"{sanitizedRequestBodyContentType}\", {bodyParamReference})");
+            }
         }
 
         writer.WriteLine($"return {RequestInfoVarName}, nil");

tests/Kiota.Builder.Tests/Writers/Go/CodeMethodWriterTests.cs

@@ -1168,6 +1168,7 @@ public async Task WritesRequestGeneratorBodyForScalar()
         Assert.Contains("if c.Q != nil", result);
         Assert.Contains("requestInfo.AddQueryParameters(", result);
         Assert.Contains("requestInfo.AddRequestOptions(", result);
+        Assert.DoesNotContain("cast[i] = v", result);
         Assert.Contains("requestInfo.SetContentFromScalar(ctx, m.BaseRequestBuilder.RequestAdapter", result);
         Assert.Contains("return requestInfo, nil", result);
         AssertExtensions.CurlyBracesAreClosed(result);
@@ -1205,6 +1206,8 @@ public async Task WritesRequestGeneratorBodyForScalarCollection()
         Assert.Contains("if c.Q != nil", result);
         Assert.Contains("requestInfo.AddQueryParameters(", result);
         Assert.Contains("requestInfo.AddRequestOptions(", result);
+        Assert.Contains("cast := make([]interface{}, ", result);
+        Assert.Contains("cast[i] = v", result);
         Assert.Contains("requestInfo.SetContentFromScalarCollection(ctx, m.BaseRequestBuilder.RequestAdapter", result);
         Assert.Contains("return requestInfo, nil", result);
         AssertExtensions.CurlyBracesAreClosed(result);
@@ -1305,6 +1308,7 @@ public async Task WritesRequestGeneratorBodyForParsableCollection()
         Assert.Contains("if c.Q != nil", result);
         Assert.Contains("requestInfo.AddQueryParameters(", result);
         Assert.Contains("requestInfo.AddRequestOptions(", result);
+        Assert.Contains("cast[i] =", result);
         Assert.Contains("requestInfo.SetContentFromParsableCollection(ctx, m.BaseRequestBuilder.RequestAdapter", result);
         Assert.Contains("return requestInfo, nil", result);
         AssertExtensions.CurlyBracesAreClosed(result);