Bug in iOS14 batch fetches

Incremental Store/EncryptedStore.m

@@ -3530,7 +3530,19 @@ -(id)expressionDescriptionTypeValue:(NSExpressionDescription *)expressionDescrip
 
  */
 - (NSDictionary *)whereClauseWithFetchRequest:(NSFetchRequest *)request {
-    NSDictionary *result = [self recursiveWhereClauseWithFetchRequest:request predicate:[request predicate]];
+    NSPredicate *predicate = [request predicate];
+
+    // Perform substitution in predicate if substitutionVariables are available
+    SEL substitutionVariablesSelector = NSSelectorFromString(@"substitutionVariables");
+    if ([request respondsToSelector:substitutionVariablesSelector]) {
+        // See https://stackoverflow.com/questions/7017281/performselector-may-cause-a-leak-because-its-selector-is-unknown for explanation of this pattern
+        IMP  imp = [request methodForSelector:substitutionVariablesSelector];
+        NSDictionary *(*func)(id, SEL) = (void *)imp;
+        NSDictionary *substitutionVariables = func(request, substitutionVariablesSelector);
+        predicate = [predicate predicateWithSubstitutionVariables:substitutionVariables];
+    }
+
+    NSDictionary *result = [self recursiveWhereClauseWithFetchRequest:request predicate:predicate];
     NSString *query = result[@"query"];
 
     if ([self entityNeedsEntityTypeColumn:request.entity]) {
@@ -3707,7 +3719,16 @@ - (void)bindWhereClause:(NSDictionary *)clause toStatement:(sqlite3_statement *)
     NSArray *bindings = [clause objectForKey:@"bindings"];
 
     [bindings enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
+        // downconvert objects and objectIDs to concrete values
+        if ([obj isKindOfClass:[NSManagedObject class]]) {
+            obj = [obj objectID];
+        }
 
+        if ([obj isKindOfClass:[NSManagedObjectID class]]) {
+            // objects with temporary ids haven't been inserted yet, so look for an id we know will never match
+            obj = [obj isTemporaryID] ? @"-1" : [self referenceObjectForObjectID:obj];
+        }
+
         // string
         if ([obj isKindOfClass:[NSString class]]) {
             const char* str = [obj UTF8String];
@@ -3732,19 +3753,6 @@ - (void)bindWhereClause:(NSDictionary *)clause toStatement:(sqlite3_statement *)
             }
         }
 
-        // managed object id
-        else if ([obj isKindOfClass:[NSManagedObjectID class]]) {
-            id referenceObject = [self referenceObjectForObjectID:obj];
-            sqlite3_bind_int64(statement, ((int)idx + 1), [referenceObject unsignedLongLongValue]);
-        }
-
-        // managed object
-        else if ([obj isKindOfClass:[NSManagedObject class]]) {
-            NSManagedObjectID *objectID = [obj objectID];
-            id referenceObject = [self referenceObjectForObjectID:objectID];
-            sqlite3_bind_int64(statement, ((int)idx + 1), [referenceObject unsignedLongLongValue]);
-        }
-
         // date
         else if ([obj isKindOfClass:[NSDate class]]) {
             sqlite3_bind_double(statement, ((int)idx + 1), [obj timeIntervalSince1970]);
@@ -4145,15 +4153,8 @@ - (void)parseExpression:(NSExpression *)expression
                 *operand = @"?";
             *bindings = [NSString stringWithFormat:[operator objectForKey:@"format"], value];
         } else if ([value isKindOfClass:[NSManagedObject class]] || [value isKindOfClass:[NSManagedObjectID class]]) {
-            NSManagedObjectID * objectId = [value isKindOfClass:[NSManagedObject class]] ? [value objectID]:value;
             *operand = @"?";
-            // We're not going to be able to look up an object with a temporary id, it hasn't been inserted yet
-            if ([objectId isTemporaryID]) {
-                // Just look for an id we know will never match
-                *bindings = @"-1";
-            } else {
-                *bindings = value;
-            }
+            *bindings = value;
         }
         else if (!value || value == [NSNull null]) {
             *bindings = nil;

exampleProjects/IncrementalStore/Tests/IncrementalStoreTests.m

@@ -851,6 +851,42 @@ -(void)test_predicateEqualityComparisonUsingDates
     }];
 }
 
+-(void)test_predicateForSelfInComparisonWithUnpersistedObjects {
+    NSArray *users = @[
+        [NSEntityDescription insertNewObjectForEntityForName:@"User" inManagedObjectContext:context],
+        [NSEntityDescription insertNewObjectForEntityForName:@"User" inManagedObjectContext:context]
+    ];
+
+    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"User"];
+    [request setPredicate:[NSPredicate predicateWithFormat:@"SELF IN %@", users]];
+
+    NSError *error;
+    NSArray<NSManagedObject *> *results = [context executeFetchRequest:request error:&error];
+    XCTAssertNotNil(results);
+    XCTAssertEqual([results count], 2);
+}
+
+-(void)test_batchFetchWithNestedContextsAndUnpersistedObjects {
+    NSManagedObjectContext *parentContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
+    [parentContext setPersistentStoreCoordinator: coordinator];
+
+    NSManagedObjectContext *childContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
+    [childContext setParentContext:parentContext];
+    NSManagedObject *user = [NSEntityDescription insertNewObjectForEntityForName:@"User" inManagedObjectContext:childContext];
+
+    NSError *error;
+    BOOL saved = [childContext save:&error];
+    XCTAssertTrue(saved, @"Failed to save child context: %@", error);
+
+    NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"User"];
+    [request setFetchBatchSize:20];
+
+    NSArray<NSManagedObject *> *results = [childContext executeFetchRequest:request error:&error];
+    XCTAssertNotNil(results, @"Failed to fetch saved user from parent context: %@", error);
+    XCTAssertEqual([results count], 1);
+    XCTAssertEqualObjects([results[0] objectID], [user objectID]);
+}
+
 -(void)test_sumExpression {
 
     [self createUsers:10];