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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Attribute for "arc-retain-cycles" check in addition to "add" and "set" method selector prefix convention"
href="http://llvm.org/bugs/show_bug.cgi?id=17669">17669</a>
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<th>Summary</th>
<td>Attribute for "arc-retain-cycles" check in addition to "add" and "set" method selector prefix convention
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>Macintosh
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<th>OS</th>
<td>MacOS X
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>-New Bugs
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>fortinmike@gmail.com
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
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</tr></table>
<p>
<div>
<pre>This enhancement request pertains to Objective-C warnings generated by clang.
I am implementing a few methods in a library that take block arguments and
store them for later, repeated execution. However, those methods do not benefit
from the "arc-retain-cycles" warning because their signature doesn't begin with
"add" nor "set"; it’s pretty easy to create a retain cycle by accident,
particularly for novice Objective-C devs. I would like to annotate the methods
I know can lead to cycles for inclusion in this check to save others (and
myself) from introducing leaks in the future.
I’m proposing adding an Objective-C-specific attribute (if that’s the
appropriate construct) to indicate that a method’s usages should be checked for
potential retain cycles without requiring the method to begin with “add” or
“set". Something like:
- (void)doSomethingWithObject:(id)anObject andBlock:(void (^)())aBlock
__attribute__((check_retain_cycles));
In addition, it would probably be nice to offer the complementary ability to
exclude some “add” and “set”-prefixed methods from the retain cycle check if we
know it’s not relevant in a specific case, like the NSOperationQueue
“addOperationWithBlock” exclusion that’s currently hard-coded in the
isSetterLikeSelector() function (SemaChecking.cpp:6620) but in a dynamic way
using an attribute:
- (void)addOperationWithBlock:(void (^)(void))block
__attribute__((dont_check_retain_cycles));</pre>
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