I was really happy that finally these kinda tool was released to catch retained cycle which have been pain in my ass for a long time. I installed through Cocoapods, followed the instruction for basic setup and had played around with it. And guess what, it couldn't stay for a minute :( .It's 100% reproducible and steps are following:

1. open app with FBMemoryProfiler
2. toggle profile window
3. click expand button
4. click retain cycles

FBRetainCycleUnits.m

FBObjectiveCGraphElement *FBWrapObjectGraphElementWithContext(id object,
                                                              FBObjectGraphConfiguration *configuration,
                                                              NSArray<NSString *> *namePath) {
  if (FBObjectIsBlock((__bridge void *)object)) {
    return [[FBObjectiveCBlock alloc] initWithObject:object
                                      configuration:configuration
                                            namePath:namePath];
  } else {
    if ([object_getClass(object) isSubclassOfClass:[NSTimer class]] &&
        configuration.shouldInspectTimers) {
      return [[FBObjectiveCNSCFTimer alloc] initWithObject:object
                                             configuration:configuration
                                                  namePath:namePath];
    } else {
      return [[FBObjectiveCObject alloc] initWithObject:object
                                          configuration:configuration
                                               namePath:namePath];
    }
  }
}

//crash here
FBObjectiveCGraphElement *FBWrapObjectGraphElement(id object,
                                                   FBObjectGraphConfiguration *configuration) {
  return FBWrapObjectGraphElementWithContext(object, configuration, nil);
}

Update: I followed the call stacks and found out that it happened when mutating a collection while enumeration. The call stack right before the crash is following:

    NSInteger tries = 10;
    for (NSInteger i = 0; i < tries; ++i) {
      // If collection is mutated we want to rollback and try again - let's keep refs in temporary set
      NSMutableSet *temporaryRetainedObjects = [NSMutableSet new];
      @try {
        for (id subobject in self.object) {
          if (retainsKeys) {
           //crash here
            [temporaryRetainedObjects addObject:FBWrapObjectGraphElement(subobject, self.configuration)];
          }
          if (isKeyValued && retainsValues) {
            [temporaryRetainedObjects addObject:FBWrapObjectGraphElement([self.object objectForKey:subobject],
                                                                         self.configuration)];
          }
        }
      }
      @catch (NSException *exception) {
        // mutation happened, we want to try enumerating again
        continue;
      }

Update2: Turn on zombie objects and got following: [_UILabelLayer respondsToSelector:]: message sent to deallocated instance 0x110982130 0x0000000110982130

I guess when tableview was filled with objects and clicking retain cycle (highlighting) caused the issue due to sending message to a object which is never allocated before? It seems working fine with few items

I've followed your posted instructions: all 3 frameworks built via carthage, FBAllocationTrackerManager initialized in main(), and FBMemoryProfiler initialized in application:didFinishLaunchingWithOptions. I've turned off all of my appearance proxies and verified that my Large Text accessibility settings are off. I've tried on the simulator (6 and 6+) and on actual hardware (6S+).

In all cases, the profiler UI comes up looking like this, with no entries, a truncated Mark Generations button, and missing buttons for Retain Cycles and Expand. The memory readout changes as I interact with the app, so some part of it is working correctly.

Any ideas on what could be wrong?

FBAllocationTrackerSummary instances with className being nil crash the Retain Cycle detection.

You could just filter nil entries in [FBMemoryProfilerDataSource _refilterSectionAtIndex:] but I guess we should find out, why a className can be nil in the first place.

This is a the Quickfix I implemented:

FBMemoryProfilerDataSource
- (NSArray *)_refilterSectionAtIndex:(NSInteger)index
{
  NSArray *filtered = [_data[index] filteredArrayUsingPredicate:
                       [NSPredicate predicateWithBlock:^BOOL(FBAllocationTrackerSummary *entry, NSDictionary *bindings) {
    NSString *className = entry.className.lowercaseString;
    if (_classFilter && [className rangeOfString:_classFilter].location == NSNotFound) {
      return NO;
    }

    if (entry.aliveObjects > 0 && entry.className) {
      return YES;
    }

    return NO;
  }]];
}

The JSON objects from the request of https://api.github.com/orgs/facebook/repos?per_page=300 may conatin null value, like the repo https://github.com/facebook/caf8teen, there is no repo description, when you create GithubRepository object, the shortDescription's value is [NSNull null]. When you want to show the repos list, it will crash when executing cell.detailTextLabel.text = _data[indexPath.row].shortDescription;.

In the example, we only use three values, repo's name, description, html_url, the name and url must be valid, only the description my has nothing.

Environment: Xcode 8.1 beta2, Simulator iPhone 7 Plus

I have added memory profile to the Objective-C project and initialised project but the Profile button is not appearing on the screen.

 [[FBAllocationTrackerManager sharedManager] startTrackingAllocations];
    [[FBAllocationTrackerManager sharedManager] enableGenerations];


    FBMemoryProfiler *memoryProfiler = [FBMemoryProfiler new];
    [memoryProfiler enable];

{( ( "-> NWConcrete_nw_resolver ", "-> update_block -> NSMallocBlock " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> viability_changed_handler -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> connected_child -> NWConcrete_nw_endpoint_handler ", "-> parent_handler -> NWConcrete_nw_endpoint_handler ", "-> mode_handler -> NWConcrete_nw_endpoint_resolver " ), ( "-> NWConcrete_nw_endpoint_handler ", "-> mode_handler -> NWConcrete_nw_endpoint_resolver ", "-> resolver -> NWConcrete_nw_resolver ", "-> update_block -> NSMallocBlock " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> parent_endpoint_handler -> NWConcrete_nw_endpoint_handler ", "-> tls_prepare_block -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> parent_endpoint_handler -> NWConcrete_nw_endpoint_handler ", "-> tls_message_block -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> connected_endpoint_handler -> NWConcrete_nw_endpoint_handler ", "-> parent_handler -> NWConcrete_nw_endpoint_handler ", "-> tls_message_block -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> parent_endpoint_handler -> NWConcrete_nw_endpoint_handler ", "-> mode_handler -> NWConcrete_nw_endpoint_resolver ", "-> connected_child -> NWConcrete_nw_endpoint_handler ", "-> tls_prepare_block -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> connected_endpoint_handler -> NWConcrete_nw_endpoint_handler ", "-> parent_handler -> NWConcrete_nw_endpoint_handler ", "-> tls_prepare_block -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> path_changed_handler -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> client_handler -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> read_close_handler -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> connected_endpoint_handler -> NWConcrete_nw_endpoint_handler ", "-> tls_prepare_block -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> write_close_handler -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> better_path_available_handler -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> parent_endpoint_handler -> NWConcrete_nw_endpoint_handler ", "-> mode_handler -> NWConcrete_nw_endpoint_resolver ", "-> connected_child -> NWConcrete_nw_endpoint_handler ", "-> tls_message_block -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ), ( "-> tc_nwconn -> NWConcrete_nw_connection ", "-> connected_endpoint_handler -> NWConcrete_nw_endpoint_handler ", "-> tls_message_block -> NSMallocBlock ", "-> NWConcrete_tcp_connection " ) )}

Thanks a lot for taking the time to create this tool! ARC makes it easier to code, because it's still easy to create retain cycles or not create memory pressure because of missing autoreleasepool usage.

About the crash: It can happen, that there are FBAllocationTrackerSummary instances with nil className. This will result in a crash in the FBMemoryProfilerDataSource's classNamesForSection: method.

Sometimes I can constantly reproduce it, sometimes it disappears. I've seen it both on device and simulator.

I've tried to look into this and the FBAllocationTrackerSummary do get created with an empty class name:

Also a screenshot about the kv instance state in the FBAllocationTrackerManager.mm's _getSingleGenerationSummary, when the FBAllocationTrackerSummary is created.

I hope that this is helpful :)

Though your define @property (nonatomic, copy, readonly, nonnull) NSString *className; It maybe nil. In FBMemoryProfilerDataSource the 241 line.[array addObject:object.className] may add nil.

Hi, we use FBMemoryProfiler in my project, but I found some misjudged retained cycle. In the code, using FBObjectiveCGraphElement to save the information of retain cycled object. But the property of FBObjectiveCGraphElement object is weak. When I checked a retained cycle, and notify the observers, at the same time, the retained cycle have been broken, the object was deallocated. Finally the observers receive a retained cycle chain like this: ( "-> _traitCollection -> (null) ", "-> _image -> (null) ", "-> _borderImageHL -> (null) " ) I think it is not retained cycle. I don't know if I have some wrong in the analysis. Could you check it?

I just want to find it once.But it has to find retain cycle every time.Can you support it?

• (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { // Retain cycle detection kicks in NSString *className = [tableView cellForRowAtIndexPath:indexPath].textLabel.text; NSInteger generationIndex = indexPath.section;

  [self _findRetainCyclesForClassesNamed:@[className] inGeneration:generationIndex presentDetails:YES]; }

Description

This pull request allows projects with a deployment target of iOS 7.0 to integrate FBMemoryProfiler.

Note

The podspecs of FBMemoryProfilers dependencies have to be changed as well: https://github.com/facebook/FBAllocationTracker/pull/5 https://github.com/facebook/FBRetainCycleDetector/pull/5

I wrote a ViewController to test memory leak detection, but I found that the log did not detect it. Why?

The ViewController is written like this:

@interface TableView : NSObject
@property(nonatomic) Byte *space;
@property(nonatomic, copy) void (^block)();
-(void)sayHello;
@end

#define kTenMB  1048576 * 10
@implementation TableView
- (instancetype)init {
    self = [super init];
    if (self) {
        //分配 10MB 内存
        self.space = malloc(kTenMB);
        memset(self.space, 0, kTenMB);
    }
    return self;
}
-(void)sayHello {
    NSLog(@"Hello!");
}
- (void)dealloc {
    NSLog(@"=== %s",__func__);
    free(self.space);
}
@end


@interface AViewController ()
@property(nonatomic, copy) void (^block)();
@property(nonatomic, strong) TableView *tableView;

@end

@implementation AViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.title = @"A";
    self.view.backgroundColor = UIColor.greenColor;
    
// ---- Block ,self leak ----
   self.block = ^{
//        [self test];
       NSLog(@"== title:%@",self.title);
   };
   self.block();

   // ---- tableView leak ----
   TableView *tableView = [TableView new];
   tableView.block = ^{
       [tableView sayHello];
   };
    
}
-(void)test{
    NSLog(@"==== %s %@",__func__,self);

}
- (void)dealloc {
    NSLog(@"==== %s %@",__func__,self);
}

@end

The configuration of FBMemoryProfiler is like this: main.m

#import <UIKit/UIKit.h>
#import <FBAllocationTracker/FBAllocationTrackerManager.h>
#import <FBRetainCycleDetector/FBRetainCycleDetector.h>
#import "AppDelegate.h"

int main(int argc, char *argv[]) {
   [FBAssociationManager hook];
   [[FBAllocationTrackerManager sharedManager] startTrackingAllocations];
   [[FBAllocationTrackerManager sharedManager] enableGenerations];

    NSString *appDelegateClassName;
    @autoreleasepool {
        // Setup code that might create autoreleased objects goes here.
        appDelegateClassName = NSStringFromClass([AppDelegate class]);
    }
    return UIApplicationMain(argc, argv, nil, appDelegateClassName);
}

AppDelegate.m

#import <FBMemoryProfiler/FBMemoryProfiler.h>
#import <FBRetainCycleDetector/FBRetainCycleDetector.h>
#import "AppDelegate.h"

@interface RetainCycleLoggerPlugin : NSObject <FBMemoryProfilerPluggable>
@end
@implementation RetainCycleLoggerPlugin

- (void)memoryProfilerDidFindRetainCycles:(NSSet *)retainCycles {
   NSLog(@"=== cycle retains：%@\n", retainCycles);
}
@end


@interface AppDelegate () {
    FBMemoryProfiler *_memoryProfiler;
}
@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

   _memoryProfiler = [[FBMemoryProfiler alloc] initWithPlugins:@[[RetainCycleLoggerPlugin new]] retainCycleDetectorConfiguration:nil];
   [_memoryProfiler enable];

    return YES;
}

@end

Tried building the project in both Xcode 9.2 and 9.3 and ran into the semantic issue "Array has incomplete element type 'struct rcd _rebranding'" on lines 164 and 184 inFBAssociationManager.