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    <p>First, even though you are using ARC zeroing weak references in your project (<code>@property (weak)</code>), other projects and frameworks may not be (and are probably not) using zeroing weak references.</p> <p>In other words, assume that all delegates in frameworks are <code>__unsafe_unretained</code> unless:</p> <ol> <li>The delegate property is declared <code>weak</code> in a header</li> <li>The documentation/header explicitly states otherwise</li> </ol> <hr> <p>That said, let's talk about your example. Your object ownership chart looks something like this:</p> <p><img src="https://i.stack.imgur.com/o1GoQ.png" alt="Object ownership chart"></p> <p>(Note: I'm not entirely sure which class in your project uses SubFoo. Based on common practice, I'm assuming that you have a class with a strong reference to SubFoo, and that class is also set up to be a SubFooDelegate)</p> <p>Ultimately, your instance of SubFoo is losing its last strong reference and is deallocating. In a perfect ARC-enabled world, the WebView's pointer to SubFoo would nil out at this time. However, it's not a perfect world yet, and WebView's frameLoadDelegate is <code>__unsafe_unretained</code>. Due to run loop interaction, the WebView is outliving SubFoo. The web request completes, and a dead pointer is dereferenced.</p> <p>To fix this, you need to call <code>[aWebView setFrameLoadDelegate:nil];</code> in SubFoo's dealloc method. You also need to call it when you reassign aWebView, as you are losing track of the old aWebView:</p> <p>SubFoo.m</p> <pre><code>@implementation SubFoo - (void)dealloc { [aWebView setFrameLoadDelegate:nil]; // Also nil out any other unsafe-unretained references } - (void)performRequest { if (self.fileIdentifier) { [aWebView setFrameLoadDelegate:nil]; // Protects us if performRequest is called twice. Is a no-op if aWebView is nil aWebView = [[WebView alloc] init]; [aWebView setFrameLoadDelegate:self]; [[aWebView mainFrame] loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"theURL"]]; } } - (void)webView:(WebView *)sender didFinishLoadForFrame:(WebFrame *)frame { // ... } </code></pre>
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    1. POWeird memory issues, with ARC enabled
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    1. CONote: I'm fairly sure that you have two issues here. One is the crash/delegate issues. The other issue is that your SubFoo is dying too early. After fixing the crash, you probably want to follow CRD/mohsenr's advice to address the early dying.
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    2. COYour answers have helped me understand that the problem os that dealloc is indeed being ran in SubFoo. I am calling SubFoo using __strong. This is the way I am doing it: Class1 is calling Class2, using __strong and Class2 is calling SubFoo, using __strong too. Both SubFoo and Class2 are being deallocated, but Class1 is never deallocated. This is a server app acting as a webserver, so I am trying to get some data from a client, returning an answer saying I got that answer and then doing some jobs on the background. Class1 is the http class.
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    3. COCan we see more code from Class1 which interacts with Class2? That could help us better diagnose why Class2 is going away early. Regardless, you need to clear the setFrameLoadDelegate: weak reference in SubFoo (as shown above) to prevent crashes.
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