💡Fix iCloud Sync Issues with initializeCloudKitSchema

TL;DR: Use `initializeCloudKitSchema` to resolve iCloud sync issues in Core Data or SwiftData. Call it after enabling sync or updating the data model, then comment it out for future stability.

Background

In iOS development, when implementing iCloud data synchronization using Core Data or SwiftData, developers often encounter incomplete data sync issues. While some operations sync correctly, newly created data may fail to appear in the cloud. This issue is frequently related to the initialization of the CloudKit schema.

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Why Use initializeCloudKitSchema?

If you notice discrepancies between your local data model and the CloudKit schema in the CloudKit Dashboard, it’s likely because the initializeCloudKitSchema method has not been properly utilized. While CloudKit may automatically generate a schema when the first data is created in simple models, automatic creation often fails in the following scenarios:

• The data model contains complex relationships
• The initial data creation does not involve all relationship objects
• The model structure has been modified

When to Use initializeCloudKitSchema

You should use initializeCloudKitSchema in the following situations:

1. When enabling iCloud sync for the first time
2. After making modifications to your local data model

Implementation in Core Data