objective c - Block implicitly retains 'self'; explicitly mention 'self' to indicate this is intended behavior

Question

Given the following:

- (void) someMethod
{
    dispatch_async(dispatch_get_main_queue(), ^{
        myTimer = [NSTimer scheduledTimerWithTimeInterval: 60
                                                           target: self
                                                         selector: @selector(doSomething)
                                                         userInfo: nil
                                                          repeats: NO];
    });
}

Where myTimer is declared in a private interface:

@interface MyClass()
{
    NSTimer * myTimer;
}
@end

How would one fix the following warning:

Block implicitly retains 'self'; explicitly mention 'self' to indicate this is intended behavior

From what I have found so far, most suggestions involve putting something such as:

- (void) someMethod
{
    __typeof__(self) __weak wself = self;
    dispatch_async(dispatch_get_main_queue(), ^{
        wself.myTimer = [NSTimer scheduledTimerWithTimeInterval: 60
                                                           target: self
                                                         selector: @selector(doSomething)
                                                         userInfo: nil
                                                          repeats: NO];
    });
}

Except, that myTimer is an ivar, meaning wself does not have access to any properties.

I guess my questions are:

1. Do/should I care?
2. Should I declare myTimer as a property?

I use ivars quite a bit through my code. I just added the -Weverything flag to my project to see if I can find any underlying issues and this is by far the most common warning. I have no problem going though and fixing it by making my ivars properties, but I want to make sure I get a better understanding before I do that.

Answer 1

Details

Xcode: 9.2, 10.2, 11.0 (11A420a)

Warnings in Objective-C Pods

I have swift project. Warning Block implicitly retains 'self'; explicitly mention 'self' to indicate this is intended behavior appears when I use Objective-C pods:

• Bolts
• FBSDKCoreKit
• FBSDKLoginKit

Solution 1 (manual)

CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = NO

Solution 2 (automatic)

Add to the end of your Podfile:

post_install do |installer|
      installer.pods_project.targets.each do |target|
           target.build_configurations.each do |config|
                config.build_settings['CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF'] = 'NO'
           end
      end
 end

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