'RLMException' when deleting an object using swipeActions (List, Realm)

Question

AlessioPoggi OP

Created Nov ’22

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I build a simple ToDo app using Realm. I wrote a RealmManager to handle CRUD actions and I have some views that use it.

That's the git repo: https://github.com/AlessioPoggi99/ToDo

RealmManager has a @Published var that's an array with all the tasks and I'm using the RealmManager as a @EnvironmentObject so I have access to tasks array in my views.

This is the main view code:

//
//  TasksView.swift
//  ToDo
//
//  Created by Alessio Poggi on 28/11/22.
//

import SwiftUI

struct TasksView: View {
    @EnvironmentObject var realmManager: RealmManager
    
    var body: some View {
        VStack {
            Text("My tasks")
                .font(.title2).bold()
                .padding(.horizontal)
                .padding(.top)
                .frame(maxWidth: .infinity, alignment: .leading)
            
            if realmManager.tasks.count > 0 {
                List {
                    ForEach(realmManager.tasks, id: \.id) { task in
                        if !task.isInvalidated && !task.isFrozen {
                            TaskRow(task: task.title, completed: task.completed)
                                .onTapGesture {
                                    realmManager.updateTask(id: task.id, completed: !task.completed)
                                }
                                .swipeActions {
                                    Button(role: .destructive) {
                                        realmManager.deleteTask(id: task.id)
                                    } label: {
                                        Label("Delete", systemImage: "trash")
                                    }
                                }
                        }
                    }
                    .listRowSeparator(.hidden)
                }
                .scrollContentBackground(.hidden)
            }
            
            Spacer()
        }
    }
}

Problem

The problem is that every time I use the swipeActions to delete the task, the app crashes with this error 'RLMException', reason: 'Object has been deleted or invalidated.'

The fact is that I found some solutions, instead of using swipeActions. The fist solution is to use a simple button below each 'TaskRow' and using the same delete method.

The second solution I found is using .onDelete on the forEach cycle, and using again the same delete method:

    List {
        ForEach(realmManager.tasks, id: \.id) { task in
            if !task.isInvalidated && !task.isFrozen {
                TaskRow(task: task.title, completed: task.completed)
                    .onTapGesture {
                        realmManager.updateTask(id: task.id, completed: !task.completed)
                    }
            }
        }
        .onDelete { indexSet in
            indexSet.forEach { index in
                let taskTodelete = realmManager.tasks[index]
                realmManager.deleteTask(id: taskTodelete.id)
            }
        }
        .listRowSeparator(.hidden)
    }

Question

The delete method works well, and I implemented 2 ways to use it, so the question is: Why does the app crash when using the delete method inside .swipeActions ?

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