Support additional properties

packages/typespec-ts/src/modular/emitModels.ts

@@ -409,13 +409,6 @@ function addExtendedDictInfo(
     }
     modelInterface.extends.push(`Record<string, any>`);
   } else {
-    reportDiagnostic(context.program, {
-      code: "compatible-additional-properties",
-      format: {
-        modelName: modelInterface?.name ?? ""
-      },
-      target: NoTarget
-    });
     modelInterface.properties?.push({
       name: "additionalProperties",
       docs: ["Additional properties"],

packages/typespec-ts/src/modular/serialization/buildSerializerFunction.ts

@@ -2,6 +2,7 @@ import { FunctionDeclarationStructure, StructureKind } from "ts-morph";
 import {
   SdkArrayType,
   SdkDictionaryType,
+  SdkModelPropertyType,
   SdkModelType,
   SdkType,
   SdkUnionType,
@@ -10,7 +11,7 @@ import {
 import { toCamelCase, toPascalCase } from "../../utils/casingUtils.js";
 
 import { SdkContext } from "../../utils/interfaces.js";
-import { getRequestModelMapping } from "../helpers/operationHelpers.js";
+import { getAllAncestors, getAllProperties, getRequestModelMapping } from "../helpers/operationHelpers.js";
 import { normalizeModelName } from "../emitModels.js";
 import { NameType } from "@azure-tools/rlc-common";
 import { isAzureCoreErrorType } from "../../utils/modelUtils.js";
@@ -331,11 +332,7 @@ function buildModelTypeSerializer(
     statements: ["return item;"]
   };
 
-  // This is only handling the compatibility mode, will need to update when we handle additionalProperties property.
-  const additionalPropertiesSpread = hasAdditionalProperties(type)
-    ? "...item"
-    : "";
-
+  const additionalPropertiesSpread = getAdditionalPropertiesStatement(context, type);
   const { directAssignment, propertiesStr } = getRequestModelMapping(
     context,
     type,
@@ -365,6 +362,19 @@ function buildModelTypeSerializer(
   return serializerFunction;
 }
 
+function getAdditionalPropertiesStatement(context: SdkContext, type: SdkModelType): string | undefined {
+  return hasAdditionalProperties(type)
+    ? (!context.rlcOptions?.compatibilityMode && hasAdditionalPropertiesProperty(type) ? "...item.additionalProperties" : "...item")
+    : undefined;
+}
+
+function hasAdditionalPropertiesProperty(type: SdkModelType) {
+  const allParents = getAllAncestors(type);
+  const properties: SdkModelPropertyType[] =
+    getAllProperties(type, allParents) ?? [];
+  return properties.some((p) => p.name === "additionalProperties");
+}
+
 function buildDictTypeSerializer(
   context: SdkContext,
   type: SdkDictionaryType,

packages/typespec-ts/test/modularUnit/scenarios/models/serialization/additionalProperties.md

@@ -18,6 +18,7 @@ interface D {
 ```
 
 This is the tsp configuration.
+
 ```yaml
 compatibilityMode: true
 ```
@@ -36,4 +37,189 @@ export interface SimpleModel extends Record<string, string> {
 export function simpleModelSerializer(item: SimpleModel): any {
   return { ...item, propA: item["propA"], propB: item["propB"] };
 }
-```
+```
+
+# Should generate serializer for additional properties with `additionalProperties` property for non-legacy code
+
+## TypeSpec
+
+This is tsp definition.
+
+```tsp
+model SimpleModel {
+    ...Record<int32>;
+    propA: string;
+    propB: string;
+}
+
+@route("/serialize")
+interface D {
+  op bar(@body body: SimpleModel): void;
+}
+```
+
+This is the tsp configuration.
+
+```yaml
+compatibilityMode: false
+```
+
+## Provide generated models and its serializer
+
+Generated Models.
+
+```ts models
+/** model interface SimpleModel */
+export interface SimpleModel {
+  propA: string;
+  propB: string;
+  /** Additional properties */
+  additionalProperties?: Record<string, number>;
+}
+
+export function simpleModelSerializer(item: SimpleModel): any {
+  return {
+    ...item.additionalProperties,
+    propA: item["propA"],
+    propB: item["propB"]
+  };
+}
+```
+
+# Should treat a property named with `additionalProperties` as normal property
+
+## TypeSpec
+
+This is tsp definition.
+
+```tsp
+model SimpleModel {
+    additionalProperties: string;
+    propA: string;
+    propB: string;
+}
+
+@route("/serialize")
+interface D {
+  op bar(@body body: SimpleModel): void;
+}
+```
+
+This is the tsp configuration.
+
+```yaml
+compatibilityMode: true
+```
+
+## Provide generated models and its serializer
+
+Generated Models.
+
+```ts models
+/** model interface SimpleModel */
+export interface SimpleModel {
+  additionalProperties: string;
+  propA: string;
+  propB: string;
+}
+
+export function simpleModelSerializer(item: SimpleModel): any {
+  return {
+    additionalProperties: item["additionalProperties"],
+    propA: item["propA"],
+    propB: item["propB"]
+  };
+}
+```
+
+# Should generate serializer for additional properties with `additionalProperties` property for non-legacy code
+
+## TypeSpec
+
+This is tsp definition.
+
+```tsp
+model SimpleModel {
+    ...Record<int32>;
+    propA: string;
+    propB: string;
+}
+
+@route("/serialize")
+interface D {
+  op bar(@body body: SimpleModel): void;
+}
+```
+
+This is the tsp configuration.
+
+```yaml
+compatibilityMode: false
+```
+
+## Provide generated models and its serializer
+
+Generated Models.
+
+```ts models
+/** model interface SimpleModel */
+export interface SimpleModel {
+  propA: string;
+  propB: string;
+  /** Additional properties */
+  additionalProperties?: Record<string, number>;
+}
+
+export function simpleModelSerializer(item: SimpleModel): any {
+  return {
+    ...item.additionalProperties,
+    propA: item["propA"],
+    propB: item["propB"]
+  };
+}
+```
+
+# Should not generate `additionalProperties` property for non-legacy code if additional property is the same type
+
+## TypeSpec
+
+This is tsp definition.
+
+```tsp
+model SimpleModel {
+    ...Record<string>;
+    propA: string;
+    propB: string;
+}
+
+@route("/serialize")
+interface D {
+  op bar(@body body: SimpleModel): void;
+}
+```
+
+This is the tsp configuration.
+
+```yaml
+compatibilityMode: false
+```
+
+## Provide generated models and its serializer
+
+Generated Models.
+
+```ts models
+/** model interface SimpleModel */
+export interface SimpleModel extends Record<string, string> {
+  propA: string;
+  propB: string;
+}
+
+export function simpleModelSerializer(item: SimpleModel): any {
+  return {
+    ...item,
+    propA: item["propA"],
+    propB: item["propB"]
+  };
+}
+```