Add go backing store support.

src/Kiota.Builder/KiotaBuilder.cs

@@ -1349,7 +1349,7 @@ private void CreatePropertiesForModelClass(OpenApiUrlTreeNode currentNode, OpenA
     private const string AdditionalDataPropName = "AdditionalData";
     private const string BackingStorePropertyName = "BackingStore";
     private const string BackingStoreInterface = "IBackingStore";
-    private const string BackedModelInterface = "IBackedModel";
+    internal const string BackedModelInterface = "IBackedModel";
     private const string ParseNodeInterface = "IParseNode";
     internal const string AdditionalHolderInterface = "IAdditionalDataHolder";
     internal static void AddSerializationMembers(CodeClass model, bool includeAdditionalProperties, bool usesBackingStore) {

src/Kiota.Builder/Refiners/GoRefiner.cs

@@ -3,6 +3,7 @@
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+using System.Xml.Linq;
 using Kiota.Builder.CodeDOM;
 using Kiota.Builder.Configuration;
 using Kiota.Builder.Extensions;
@@ -139,6 +140,7 @@ public override Task Refine(CodeNamespace generatedCode, CancellationToken cance
             RemoveHandlerFromRequestBuilder(generatedCode);
             AddContextParameterToGeneratorMethods(generatedCode);
             CorrectTypes(generatedCode);
+            CorrectCoreTypesForBackingStore(generatedCode, $"{conventions.StoreHash}.GetDefaultBackingStoreInstance().CreateBackingStore()");
         }, cancellationToken);
     }
 
@@ -414,9 +416,11 @@ x.Type is CodeType pType &&
             "github.com/microsoft/kiota-abstractions-go/serialization", "MergeDeserializersForIntersectionWrapper"),
         new (static x => x is CodeProperty prop && prop.IsOfKind(CodePropertyKind.Headers),
             "github.com/microsoft/kiota-abstractions-go", "RequestHeaders"),
+        new (static x => x is CodeProperty prop && prop.IsOfKind(CodePropertyKind.BackingStore), "github.com/microsoft/kiota-abstractions-go/store","BackingStore"),
     };//TODO add backing store types once we have them defined
-    private static void CorrectImplements(ProprietableBlockDeclaration block) {
+    private void CorrectImplements(ProprietableBlockDeclaration block) {
         block.ReplaceImplementByName(KiotaBuilder.AdditionalHolderInterface, "AdditionalDataHolder");
+        block.ReplaceImplementByName(KiotaBuilder.BackedModelInterface, "BackedModel");
     }
     private static void CorrectMethodType(CodeMethod currentMethod) {
         var parentClass = currentMethod.Parent as CodeClass;

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

@@ -387,9 +387,19 @@ private void WriteGetterBody(CodeMethod codeElement, LanguageWriter writer, Code
                     writer.WriteLines($"value = {codeElement.AccessedProperty.DefaultValue};",
                         $"m.Set{codeElement.AccessedProperty?.Name?.ToFirstCharacterUpperCase()}(value);");
                     writer.CloseBlock();
-                    writer.WriteLine("return value;");
-                } else
-                    writer.WriteLine($"return m.Get{backingStore.Name.ToFirstCharacterUpperCase()}().Get(\"{codeElement.AccessedProperty?.Name?.ToFirstCharacterLowerCase()}\");");
+                    writer.WriteLine("return value");
+                }
+                else
+                {
+                    var returnType = conventions.GetTypeString(codeElement.ReturnType, codeElement.Parent);
+
+                    writer.WriteLine($"val , err := m.Get{backingStore.Name.ToFirstCharacterUpperCase()}().Get(\"{codeElement.AccessedProperty?.Name?.ToFirstCharacterLowerCase()}\")");
+
+                    writer.WriteBlock("if val != nil {", "}", $"return val.({returnType})");
+                    writer.WriteBlock("if err != nil {", "}", "panic(err)");
+
+                    writer.WriteLine("return nil");
+                }
         }
         private void WriteApiConstructorBody(CodeClass parentClass, CodeMethod method, LanguageWriter writer) {
             var requestAdapterProperty = parentClass.GetPropertyOfKind(CodePropertyKind.RequestAdapter);
@@ -483,7 +493,10 @@ private static void WriteSetterBody(CodeMethod codeElement, LanguageWriter write
             if(backingStore == null)
                 writer.WriteLine($"m.{codeElement.AccessedProperty?.Name?.ToFirstCharacterLowerCase()} = value");
             else
-                writer.WriteLine($"m.Get{backingStore.Name.ToFirstCharacterUpperCase()}().Set(\"{codeElement.AccessedProperty?.Name?.ToFirstCharacterLowerCase()}\", value)");
+            {
+                writer.WriteLine($"err := m.Get{backingStore.Name.ToFirstCharacterUpperCase()}().Set(\"{codeElement.AccessedProperty?.Name?.ToFirstCharacterLowerCase()}\", value)");
+                writer.WriteBlock("if err != nil {", "}", "panic(err)");
+            }
         }
         private void WriteIndexerBody(CodeMethod codeElement, CodeClass parentClass, LanguageWriter writer, string returnType) {
             var pathParametersProperty = parentClass.GetPropertyOfKind(CodePropertyKind.PathParameters);

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

@@ -17,6 +17,7 @@ public class GoConventionService : CommonLanguageConventionService
     #pragma warning disable CA1822 // Method should be static
     public string AbstractionsHash => "i2ae4187f7daee263371cb1c977df639813ab50ffa529013b7437480d1ec0158f";
     public string SerializationHash => "i878a80d2330e89d26896388a3f487eef27b0a0e6c010c493bf80be1452208f91";
+    public string StoreHash => "ie8677ce2c7e1b4c22e9c3827ecd078d41185424dd9eeb92b7d971ed2d49a392e";
     public string StringsHash => "ie967d16dae74a49b5e0e051225c5dac0d76e5e38f13dd1628028cbce108c25b6";
 
     public string ContextVarTypeName => "context.Context";
@@ -94,6 +95,7 @@ public string TranslateType(CodeTypeBase type, bool includeImportSymbol)
             "string" or "float32" or "float64" or "int32" or "int64" => type.Name,
             "String" or "Int64" or "Int32" or "Float32" or "Float64" => type.Name.ToFirstCharacterLowerCase(), //casing hack
             "context.Context" => "context.Context",
+            "BackedModel" => $"{StoreHash}.BackedModel",
             _ => type.Name.ToFirstCharacterUpperCase() ?? "Object",
         };
     }

src/Kiota.Builder/Writers/LanguageWriter.cs

@@ -83,6 +83,13 @@ internal void CloseBlock(string symbol = "}", bool decreaseIndent = true)
             WriteLine(symbol);
         }
 
+        internal void WriteBlock(string startSymbol = "{", string closeSymbol = "}", params string[] lines)
+        {
+            StartBlock(startSymbol);
+            WriteLines(lines);
+            CloseBlock(closeSymbol);
+        }
+
         internal void Write(string text, bool includeIndent = true)
         {
             writer.Write(includeIndent ? GetIndent() + text : text);