malloc error on recursive/chained calls to stubbed method

[albsala]

I'm trying to stub an async method in a partial mock:

id mock = OCMPartialMock([[MyClass alloc] init]);

void (^theBlock)(NSInvocation *) = ^(NSInvocation *invocation) {
    MyObjectWithAction *owa = nil;
    [invocation getArgument:&owa atIndex:3];
    if (owa && owa.action) {
        owa.action();
    }
};
OCMStub([mock myMethodWithParam:[OCMArg any]]).andDo(theBlock);

But inside "action()", I'm calling to "myMethodWithParam:" one more time (but this time with a "MyObjectWithAction" without action).

...and I'm getting:

malloc: *** error for object 0xdd59a20: pointer being freed was not allocated

[albsala]

I have tried this with the same result:

id mock = OCMPartialMock([[MyClass alloc] init]);

void (^theBlock)(NSInvocation *) = ^(NSInvocation *invocation) {
    MyObjectWithAction *owa = nil;
    [invocation getArgument:&owa atIndex:3];
    if (owa && owa.action) {
        dispatch_async(dispatch_get_main_queue(), ^(void) {
            owa.action();
        });
    }
};
OCMStub([mock myMethodWithParam:[OCMArg any]]).andDo(theBlock);

[erikdoe]

Could you set a breakpoint on the malloc error and post the result here? In case you haven't done this before: http://stackoverflow.com/questions/14045208/how-to-set-a-breakpoint-in-malloc-error-break-to-debug

[albsala]

I did it, but all I see is assembly, maybe I'm doing something wrong.

libsystem_malloc.dylib`malloc_error_break:
0x4b3a7f9:  pushl  %ebp
0x4b3a7fa:  movl   %esp, %ebp
0x4b3a7fc:  subl   $0x8, %esp
0x4b3a7ff:  nop    
0x4b3a800:  nopl   (%eax)
0x4b3a804:  addl   $0x8, %esp
0x4b3a807:  popl   %ebp
0x4b3a808:  ret    

I'm starting to think that I am doing something wrong with the mock too. I am mocking a method of "MyClass" and I am testing another one of the same class, using the mock for the call, i mean:

[mock methodIWantToTest];

[carllindberg]

NSInvocation and ARC don't play together very well. It's causing a double-release.

You declared MyObjectWithAction as a local strong variable. However, the value gets assigned by NSInvocation, which takes a "void *" argument, so ARC has no way to know an object came into scope and does not add a retain. However, it will add a release when it goes out of scope. Boom, that's a crash.

Declare the variable as __unsafe_unretained so ARC doesn't touch it. If you want, declare one variable as __unsafe_unretained, use getArgument:atIndex: on that, and then immediately assign to a local (normally declared) variable, which will then have a local strong reference, if you want to guard against deallocation during the block.

[albsala]

I get it. So it could not be an OCMock problem.
I had to change the way I was testing this class, avoiding the chained calls refactoring it and adding a dependency, so I can not test it now. I guess that was the problem.
Thank you for your time.