forked from OSchip/llvm-project
40 lines
1.2 KiB
ReStructuredText
40 lines
1.2 KiB
ReStructuredText
.. title:: clang-tidy - objc-nsinvocation-argument-lifetime
|
|
|
|
objc-nsinvocation-argument-lifetime
|
|
===================================
|
|
|
|
Finds calls to ``NSInvocation`` methods under ARC that don't have proper
|
|
argument object lifetimes. When passing Objective-C objects as parameters
|
|
to the ``NSInvocation`` methods ``getArgument:atIndex:`` and
|
|
``getReturnValue:``, the values are copied by value into the argument pointer,
|
|
which leads to to incorrect releasing behavior if the object pointers are
|
|
not declared ``__unsafe_unretained``.
|
|
|
|
For code:
|
|
|
|
.. code-block:: objc
|
|
|
|
id arg;
|
|
[invocation getArgument:&arg atIndex:2];
|
|
|
|
__strong id returnValue;
|
|
[invocation getReturnValue:&returnValue];
|
|
|
|
The fix will be:
|
|
|
|
.. code-block:: objc
|
|
|
|
__unsafe_unretained id arg;
|
|
[invocation getArgument:&arg atIndex:2];
|
|
|
|
__unsafe_unretained id returnValue;
|
|
[invocation getReturnValue:&returnValue];
|
|
|
|
The check will warn on being passed instance variable references that have
|
|
lifetimes other than ``__unsafe_unretained``, but does not propose a fix:
|
|
|
|
.. code-block:: objc
|
|
|
|
// "id _returnValue" is declaration of instance variable of class.
|
|
[invocation getReturnValue:&self->_returnValue];
|