ORKHealthKitQuantityTypeAnswerFormat crashes

[mab5vot9us9a]

Setting

• Swift: Apple Swift version 5.3.2 (swiftlang-1200.0.45 clang-1200.0.32.28)
• ResearchKit: main branch (0651bf0)
• iOS: 14.4 (18D52) & Simulator 14.4 (18D46)
• Device: iPhone 12 Pro & Simulator (iPhone 12 Pro)

When trying to use ORKHealthKitQuantityTypeAnswerFormat in a survey, the app crashes with

2021-03-11 14:12:47.787140+0100 app[10884:14047917] <ORKTaskViewController: 0x7fa7c280ba00> <ORKQuestionStepViewController: 0x7fa7c2847800>
2021-03-11 14:12:47.813883+0100 app[10884:14047917] -[ORKHealthKitQuantityTypeAnswerFormat hideUnitWhenAnswerIsEmpty]: unrecognized selector sent to instance 0x600000fcab20
2021-03-11 14:12:47.825667+0100 app[10884:14047917] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ORKHealthKitQuantityTypeAnswerFormat hideUnitWhenAnswerIsEmpty]: unrecognized selector sent to instance 0x600000fcab20'
*** First throw call stack:
(
	0   CoreFoundation                      0x00007fff20421af6 __exceptionPreprocess + 242
	1   libobjc.A.dylib                     0x00007fff20177e78 objc_exception_throw + 48
	2   CoreFoundation                      0x00007fff204306f7 +[NSObject(NSObject) instanceMethodSignatureForSelector:] + 0
	3   CoreFoundation                      0x00007fff20426036 ___forwarding___ + 1489
	4   CoreFoundation                      0x00007fff20428068 _CF_forwarding_prep_0 + 120
	5   ResearchKit                         0x000000010428e05e -[ORKSurveyAnswerCellForNumber numberCell_initialize] + 446
	6   ResearchKit                         0x000000010428f8ae -[ORKSurveyAnswerCellForNumber prepareView] + 94
	7   ResearchKit                         0x00000001041896ac -[ORKSurveyAnswerCell setStep:] + 92
	8   ResearchKit                         0x00000001041895b4 -[ORKSurveyAnswerCell initWithStyle:reuseIdentifier:step:answer:delegate:] + 292
	9   ResearchKit                         0x0000000104372ab3 -[ORKQuestionStepViewController answerCellForTableView:] + 1283
	10  ResearchKit                         0x000000010436d4ff -[ORKQuestionStepViewController stepDidChange] + 4767
	11  ResearchKit                         0x000000010436eb57 -[ORKQuestionStepViewController viewDidLoad] + 71
	12  UIKitCore                           0x00007fff23f5e36e -[UIViewController _sendViewDidLoadWithAppearanceProxyObjectTaggingEnabled] + 88
	13  UIKitCore                           0x00007fff23f62cd7 -[UIViewController loadViewIfRequired] + 1084
	14  UIKitCore                           0x00007fff23e97f1a -[UINavigationController _updateScrollViewFromViewController:toViewController:] + 162
	15  UIKitCore                           0x00007fff23e98204 -[UINavigationController _startTransition:fromViewController:toViewController:] + 154
	16  UIKitCore                           0x00007fff23e9927d -[UINavigationController _startDeferredTransitionIfNeeded:] + 851
	17  UIKitCore                           0x00007fff23e80259 -[UINavigationController _setViewControllers_7_0:transition:animated:operation:] + 3773
	18  UIKitCore                           0x00007fff23e7f097 -[UINavigationController _setViewControllers:transition:animated:operation:] + 566
	19  UIKitCore                           0x00007fff23e7e29d __54-[UINavigationController setViewControllers:animated:]_block_invoke + 1452
	20  UIKitCore                           0x00007fff23f71274 +[UIViewController _performWithoutDeferringTransitionsAllowingAnimation:actions:] + 153
	21  UIKitCore                           0x00007fff23e7dc35 -[UINavigationController setViewControllers:animated:] + 600
	22  ResearchKit                         0x00000001041259fe -[ORKTaskViewController showStepViewController:goForward:animated:] + 3038
	23  ResearchKit                         0x0000000104123411 -[ORKTaskViewController viewWillAppear:] + 433
	24  UIKitCore                           0x00007fff23f68c66 -[UIViewController _setViewAppearState:isAnimating:] + 654
	25  UIKitCore                           0x00007fff23f6948f -[UIViewController __viewWillAppear:] + 106
	26  UIKitCore                           0x00007fff23e3e1c3 __56-[UIPresentationController runTransitionForCurrentState]_block_invoke.466 + 1201
	27  UIKitCore                           0x00007fff24b9107a -[_UIAfterCACommitBlock run] + 54
	28  UIKitCore                           0x00007fff246a5954 _runAfterCACommitDeferredBlocks + 333
	29  UIKitCore                           0x00007fff246959fc _cleanUpAfterCAFlushAndRunDeferredBlocks + 221
	30  UIKitCore                           0x00007fff246c72ac _afterCACommitHandler + 85
	31  CoreFoundation                      0x00007fff2038f1f8 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
	32  CoreFoundation                      0x00007fff20389a77 __CFRunLoopDoObservers + 547
	33  CoreFoundation                      0x00007fff2038a01a __CFRunLoopRun + 1113
	34  CoreFoundation                      0x00007fff203896d6 CFRunLoopRunSpecific + 567
	35  GraphicsServices                    0x00007fff2c257db3 GSEventRunModal + 139
	36  UIKitCore                           0x00007fff24696cf7 -[UIApplication _run] + 912
	37  UIKitCore                           0x00007fff2469bba8 UIApplicationMain + 101
	38  app                                 0x000000010184e98b main + 75
	39  libdyld.dylib                       0x00007fff2025a3e9 start + 1
	40  ???                                 0x0000000000000007 0x0 + 7
)
libc++abi.dylib: terminating with uncaught exception of type NSException
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ORKHealthKitQuantityTypeAnswerFormat hideUnitWhenAnswerIsEmpty]: unrecognized selector sent to instance 0x600000fcab20'
terminating with uncaught exception of type NSException
CoreSimulator 732.18.6 - Device: iPhone 12 Pro (A9B7C477-7F9A-4507-AD26-8388ABB76A90) - Runtime: iOS 14.4 (18D46) - DeviceType: iPhone 12 Pro

An example step to reproduce this crash would be:

let heartRate = ORKQuestionStep(identifier: "heart-rate")
heartRate.title = "Heart Rate"
heartRate.text = "What is your current heart rate?"
let heartRateType = HKQuantityType.quantityType(forIdentifier: .heartRate)!
let heartRateUnit = HKUnit.count().unitDivided(by: HKUnit.minute())
heartRate.answerFormat = ORKHealthKitQuantityTypeAnswerFormat(quantityType: heartRateType,
                                                              unit: heartRateUnit,
                                                              style: .integer)
heartRate.isOptional = false

This DOES NOT happen when the Question is part of an ORKFormStep. So the following does NOT crash the app.

let heartRateType = HKQuantityType.quantityType(forIdentifier: .heartRate)!
let heartRateUnit = HKUnit.count().unitDivided(by: HKUnit.minute())
let heartRateAnswer = ORKHealthKitQuantityTypeAnswerFormat(quantityType: heartRateType,
                                                           unit: heartRateUnit,
                                                           style: .integer)
let heartRateItem = ORKFormItem(identifier: "heart-rate",
                            text: "Heart Rate",
                            answerFormat: heartRateAnswer)

heartRateItem.isOptional = false

let hrSeparator = ORKFormItem(sectionTitle: "What is your current heart rate?")

let heartRateGroup = ORKFormStep(identifier: "heart-rate-group")
heartRateGroup.title = "Heart Rate"
heartRateGroup.formItems = [hrSeparator, heartRateItem]
heartRateGroup.isOptional = false