WIP: object concurrency debugging utilities

Sources/Internal/NSManagedObject+Logging.swift

@@ -0,0 +1,240 @@
+//
+//  NSManagedObject+Logging.swift
+//  CoreStore
+//
+//  Copyright © 2017 John Rommel Estropia
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+//
+
+import Foundation
+import CoreData
+
+
+// MARK: - NSManagedObject
+
+internal extension NSManagedObject {
+    
+    @nonobjc
+    internal static func cs_swizzleMethodsForLogging() {
+        
+        struct Static {
+            
+            static let isSwizzled = Static.swizzle()
+            
+            private static func swizzle() -> Bool {
+                
+                NSManagedObject.cs_swizzle(
+                    original: #selector(NSManagedObject.willAccessValue(forKey:)),
+                    proxy: #selector(NSManagedObject.cs_willAccessValue(forKey:))
+                )
+                NSManagedObject.cs_swizzle(
+                    original: #selector(NSManagedObject.willChangeValue(forKey:)),
+                    proxy: #selector(NSManagedObject.cs_willChangeValue(forKey:))
+                )
+                NSManagedObject.cs_swizzle(
+                    original: #selector(NSManagedObject.willChangeValue(forKey:withSetMutation:using:)),
+                    proxy: #selector(NSManagedObject.cs_willChangeValue(forKey:withSetMutation:using:))
+                )
+                return true
+            }
+        }
+        assert(Static.isSwizzled)
+    }
+    
+    @nonobjc
+    private static func cs_swizzle(original originalSelector: Selector, proxy swizzledSelector: Selector) {
+        
+        let originalMethod = class_getInstanceMethod(NSManagedObject.self, originalSelector)
+        let swizzledMethod = class_getInstanceMethod(NSManagedObject.self, swizzledSelector)
+        let didAddMethod = class_addMethod(
+            NSManagedObject.self,
+            originalSelector,
+            method_getImplementation(swizzledMethod),
+            method_getTypeEncoding(swizzledMethod)
+        )
+        if didAddMethod {
+            
+            class_replaceMethod(
+                NSManagedObject.self,
+                swizzledSelector,
+                method_getImplementation(originalMethod),
+                method_getTypeEncoding(originalMethod)
+            )
+        }
+        else {
+            
+            method_exchangeImplementations(originalMethod, swizzledMethod)
+        }
+    }
+    
+    private dynamic func cs_willAccessValue(forKey key: String?) {
+        
+        self.cs_willAccessValue(forKey: key)
+        
+        guard CoreStore.logger.enableObjectConcurrencyDebugging else {
+            
+            return
+        }
+        
+        guard let context = self.managedObjectContext else {
+            
+            CoreStore.log(
+                .warning,
+                message: "Attempted to access the \"\(key ?? "")\" key of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(NSManagedObjectContext.self))."
+            )
+            return
+        }
+        if context.isTransactionContext {
+            
+            guard let transaction = context.parentTransaction else {
+                
+                CoreStore.log(
+                    .warning,
+                    message: "Attempted to access the \"\(key ?? "")\" key of an object of type \(cs_typeName(self)) after has been deleted from its transaction."
+                )
+                return
+            }
+            CoreStore.assert(
+                transaction.isRunningInAllowedQueue(),
+                "Attempted to access the \"\(key ?? "")\" key of an object of type \(cs_typeName(self)) outside its transaction's designated queue."
+            )
+            return
+        }
+        if context.isDataStackContext {
+            
+            guard context.parentStack != nil else {
+                
+                CoreStore.log(
+                    .warning,
+                    message: "Attempted to access the \"\(key ?? "")\" key of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(DataStack.self)).")
+                return
+            }
+            CoreStore.assert(
+                Thread.isMainThread,
+                "Attempted to access the \"\(key ?? "")\" key of an object of type \(cs_typeName(self)) outside the main thread."
+            )
+            return
+        }
+    }
+    
+    private dynamic func cs_willChangeValue(forKey key: String?) {
+        
+        self.cs_willChangeValue(forKey: key)
+        
+        guard CoreStore.logger.enableObjectConcurrencyDebugging else {
+            
+            return
+        }
+        
+        guard let context = self.managedObjectContext else {
+            
+            CoreStore.log(
+                .warning,
+                message: "Attempted to change the \"\(key ?? "")\" of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(NSManagedObjectContext.self))."
+            )
+            return
+        }
+        if context.isTransactionContext {
+            
+            guard let transaction = context.parentTransaction else {
+                
+                CoreStore.log(
+                    .warning,
+                    message: "Attempted to change the \"\(key ?? "")\" of an object of type \(cs_typeName(self)) after has been deleted from its transaction."
+                )
+                return
+            }
+            CoreStore.assert(
+                transaction.isRunningInAllowedQueue(),
+                "Attempted to change the \"\(key ?? "")\" of an object of type \(cs_typeName(self)) outside its transaction's designated queue."
+            )
+            return
+        }
+        if context.isDataStackContext {
+            
+            guard context.parentStack != nil else {
+                
+                CoreStore.log(
+                    .warning,
+                    message: "Attempted to change the \"\(key ?? "")\" of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(DataStack.self)).")
+                return
+            }
+            CoreStore.assert(
+                Thread.isMainThread,
+                "Attempted to change the \"\(key ?? "")\" of an object of type \(cs_typeName(self)) outside the main thread."
+            )
+            return
+        }
+    }
+    
+    private dynamic func cs_willChangeValue(forKey inKey: String, withSetMutation inMutationKind: NSKeyValueSetMutationKind, using inObjects: Set<AnyHashable>) {
+        
+        self.cs_willChangeValue(
+            forKey: inKey,
+            withSetMutation: inMutationKind,
+            using: inObjects
+        )
+        
+        guard CoreStore.logger.enableObjectConcurrencyDebugging else {
+            
+            return
+        }
+        
+        guard let context = self.managedObjectContext else {
+            
+            CoreStore.log(
+                .warning,
+                message: "Attempted to mutate the \"\(inKey)\" of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(NSManagedObjectContext.self))."
+            )
+            return
+        }
+        if context.isTransactionContext {
+            
+            guard let transaction = context.parentTransaction else {
+                
+                CoreStore.log(
+                    .warning,
+                    message: "Attempted to mutate the \"\(inKey)\" of an object of type \(cs_typeName(self)) after has been deleted from its transaction."
+                )
+                return
+            }
+            CoreStore.assert(
+                transaction.isRunningInAllowedQueue(),
+                "Attempted to mutate the \"\(inKey)\" of an object of type \(cs_typeName(self)) outside its transaction's designated queue."
+            )
+            return
+        }
+        if context.isDataStackContext {
+            
+            guard context.parentStack != nil else {
+                
+                CoreStore.log(
+                    .warning,
+                    message: "Attempted to mutate the \"\(inKey)\" of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(DataStack.self)).")
+                return
+            }
+            CoreStore.assert(
+                Thread.isMainThread,
+                "Attempted to mutate the \"\(inKey)\" of an object of type \(cs_typeName(self)) outside the main thread."
+            )
+            return
+        }
+    }
+}

Sources/Logging/CoreStoreLogger.swift

@@ -47,6 +47,11 @@ public enum LogLevel {
  */
 public protocol CoreStoreLogger {
     
+    /**
+     When `true`, all `NSManagedObject` attribute and relationship access will raise an assertion when executed on the wrong transaction/datastack queue. Defaults to `false` if not implemented.
+     */
+    var enableObjectConcurrencyDebugging: Bool { get set }
+    
     /**
      Handles log messages sent by the `CoreStore` framework.
      
@@ -94,6 +99,12 @@ public protocol CoreStoreLogger {
 
 extension CoreStoreLogger {
     
+    public var enableObjectConcurrencyDebugging: Bool {
+        
+        get { return false }
+        set {}
+    }
+    
     public func abort(_ message: String, fileName: StaticString, lineNumber: Int, functionName: StaticString) {
         
         Swift.fatalError(message, file: fileName, line: UInt(lineNumber))

Sources/Logging/DefaultLogger.swift

@@ -33,6 +33,11 @@ import Foundation
  */
 public final class DefaultLogger: CoreStoreLogger {
     
+    /**
+     When `true`, all `NSManagedObject` attribute and relationship access will raise an assertion when executed on the wrong transaction/datastack queue. Defaults to `false`.
+     */
+    public var enableObjectConcurrencyDebugging: Bool = false
+    
     /**
      Creates a `DefaultLogger`.
      */

Sources/Setup/DataStack.swift

@@ -59,6 +59,8 @@ public final class DataStack: Equatable {
      */
     public required init(model: NSManagedObjectModel, migrationChain: MigrationChain = nil) {
         
+        _ = DataStack.isGloballyInitialized
+        
         CoreStore.assert(
             migrationChain.valid,
             "Invalid migration chain passed to the \(cs_typeName(DataStack.self)). Check that the model versions' order is correct and that no repetitions or ambiguities exist."
@@ -499,6 +501,12 @@ public final class DataStack: Equatable {
     
     // MARK: Private
     
+    private static let isGloballyInitialized: Bool = {
+        
+        NSManagedObject.cs_swizzleMethodsForLogging()
+        return true
+    }()
+    
     private var configurationStoreMapping = [String: NSPersistentStore]()
     private var entityConfigurationsMapping = [String: Set<String>]()