How are conflict situations resolved when resources or identifiers match?

Various mechanisms are used in iOS to resolve conflicts when resources or identifiers match:

• Unique identifiers — for example, UUIDs for objects to avoid duplication.
• Conflict resolution priorities and policies — for instance, in Core Data, rules can be set during data synchronization to determine which data source has priority.
• Locks and semaphores — to prevent simultaneous access to a resource.
• Error handling and retries — if a resource is busy, the application can retry the operation later.

Example: when saving data in Core Data, if a version conflict occurs, you can use mergePolicy, for example:

context.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy

This means that in case of property conflicts, the current changes will take precedence.

Thus, conflict resolution is achieved through unique identifiers, merge rules configuration, and access management to resources.