fix(amplify-codegen): swift-codegen add has-many associatedWithFields for CPK use case

Author: lawmicha

packages/appsync-modelgen-plugin/src/__tests__/visitors/__snapshots__/appsync-swift-visitor.test.ts.snap

@@ -73,7 +73,7 @@ extension Post {
     model.fields(
       .field(post.id, is: .required, ofType: .string),
       .field(post.title, is: .required, ofType: .string),
-      .hasMany(post.comments, is: .optional, ofType: Comment.self, associatedWith: Comment.keys.postCommentsId),
+      .hasMany(post.comments, is: .optional, ofType: Comment.self, associatedWithFields: [Comment.keys.postCommentsId, Comment.keys.postCommentsTitle]),
       .field(post.createdAt, is: .optional, isReadOnly: true, ofType: .dateTime),
       .field(post.updatedAt, is: .optional, isReadOnly: true, ofType: .dateTime)
     )

packages/appsync-modelgen-plugin/src/visitors/appsync-swift-visitor.ts

@@ -615,9 +615,13 @@ export class AppSyncSwiftVisitor<
     // connected field
     if (connectionInfo) {
       if (connectionInfo.kind === CodeGenConnectionType.HAS_MANY) {
-        return `.hasMany(${name}, is: ${isRequired}, ofType: ${typeName}, associatedWith: ${this.getModelName(
-          connectionInfo.connectedModel,
-        )}.keys.${this.getFieldName(connectionInfo.associatedWith)})`;
+        let connectedModelName = this.getModelName(connectionInfo.connectedModel);
+        const associatedWithAttrStr = this.isCustomPKEnabled()
+          ? `associatedWithFields: [${connectionInfo.associatedWithFields
+              .map(target => `${connectedModelName}.keys.${this.getFieldName(target)}`)
+              .join(', ')}]`
+          : `associatedWith: ${connectedModelName}.keys.${this.getFieldName(connectionInfo.associatedWith)}`;
+        return `.hasMany(${name}, is: ${isRequired}, ofType: ${typeName}, ${associatedWithAttrStr})`;
       }
       if (connectionInfo.kind === CodeGenConnectionType.HAS_ONE) {
         const targetNameAttrStr = this.isCustomPKEnabled()