Open Radar

 
09-Jan-2012 05:38 PM Tom Harrington:
'ValidationFail.zip' was successfully uploaded

09-Jan-2012 05:38 PM Tom Harrington:
Summary:

Core Data ignores validation constraints that set a minimum value for a string attribute's length.

Steps to Reproduce:

1. Create a new iOS project that includes Core Data.
2. In the data model editor, create an entity with a string attribute.
3. For the attribute in step 2, add validation constraints for the string's length. Add both minimum and maximum length constraints.
4. In code, create an instance of this entity and an NSString which is too short to pass the minimum length constraint.
5. Call -validateValue:forKey:error: on the instance using the string attribute and the too-short NSString. Validation passes.
6. Set the NSString as the value for the string attribute and call -validateForInsert: on the instance. Again, validation passes.

Expected Results:

Since the attribute has a constraint specifying minimum string length, a string that is too short to pass this test would cause a validation error.

Actual Results:

Validation succeeds. In the test project attached, the Item entity has a string attribute called "name" that has validation constraints giving a minimum length of 3 and a maximum length of 10. I wondered if Xcode's GUI was showing incorrect state so I looked in the data model file and found:

<attribute name="name" optional="YES" attributeType="String" minValueString="3" maxValueString="10" syncable="YES"/>

So that looks OK. If I inspect the constraints in the Xcode debugger however, I get this:

(gdb) [[[[item entity] attributesByName] objectForKey:@"name"] validationPredicates]
<__NSArrayM 0x897bcd0>(
length <= 10
)

The minimum constraint is not present. A second attribute ("style") has only a minimum length constraint, which is also present in the data model but not at run time.

The code used to check on this is as follows, and is included in the attached project.

	NSManagedObject *item = [NSEntityDescription insertNewObjectForEntityForName:@"Item" inManagedObjectContext:[self managedObjectContext]];
	NSString *tooShortString = @"a";
	NSError *validationError;
	
	NSLog(@"Validation predicates for name: %@", [[[[item entity] attributesByName] objectForKey:@"name"] validationPredicates]);
	NSLog(@"Validation predicates for style: %@", [[[[item entity] attributesByName] objectForKey:@"style"] validationPredicates]);
	
	validationError = nil;
	[item validateValue:&tooShortString forKey:@"name" error:&validationError];
	
	validationError = nil;
	[item validateValue:&tooShortString forKey:@"style" error:&validationError];
	
	validationError = nil;
	[item validateForInsert:&validationError];

Regression:

Unknown.

Notes:

Mac OS X 10.7.2, Xcode 4.2.1, iOS 5.0.1, results are the same in the simulator and on an iPhone 4s.

[Openradar: Demo code is at http://dl.dropbox.com/u/14191/openradar/10666148/ValidationFail.zip]

14-Feb-2012 12:07 PM Tom Harrington:
FWIW the same problem shows up for decimal fields with min/max values. It's possible to configure both in the model editor but only the max constraint will exist at run time.