<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Jun 28, 2008, at 9:11 AM, Nikita Zhuk wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; ">On 26.6.2008, at 21.24, Ted Kremenek wrote:<br><br><blockquote type="cite">What would help me with such feedback is to always provide concrete code examples. These give me a clear idea of what to implement in the static analyzer, and it provides test cases we can put into the test suite.<br></blockquote><br>I was writing you a long reply describing these idioms in more detail with some concrete examples, but then I took a look how analyzer actually works with an open source project called Adium and I got little confused.<br><br>Adium contains several classes which use the self-ownership idiom, most of them are subclasses of NSWindowController. Each such controller object configures, displays and manages input and output of a single window. Each controller object is created usually in a class method of its own class. Each controller object releases itself later at some point (usually when the window or sheet it manages is closed by the user).<br><br>So I was expecting memory leak warning for each case where such controller object gets created. However, analyzer somehow does seem to handle those cases correctly.<br><br>For example, check:<br><a href="http://trac.adiumx.com/browser/trunk/Source/AIDockIconSelectionSheet.m#L38">http://trac.adiumx.com/browser/trunk/Source/AIDockIconSelectionSheet.m#L38</a><br><br>An object of class 'AIDockIconSelectionSheet' is created and stored into 'controller' variable. It's then passed to the [NSApp beginSheet:...] method. It's not released (or autoreleased) explicitly. After user closes the sheet, sheetDidEnd:... callback is called by AppKit (line 58), and the controller object created on line 40 releases itself. Analyzer doesn't report any memory leaks here (which is correct, but I actually expected to get false positive here).<br><br>However, when I duplicated the whole + (void)showDockIconSelectorOnWindow:... method and made it an instance method, without any other changes, analyzer did report a memory leak: "Object allocated on line 40 and stored into 'controller' is no longer referenced after this point and has a retain count of +1 (object leaked)".<br><br>I tried to reproduce this behavior in a simplified test case (so one wouldn't have to build the whole Adium to test this), but there seem to be some factors which I'm unaware of which cause memory leak errors to be suppressed in Adium but not in my test cases. So what am I missing here?<br></span></blockquote></div><br><div>Hi Nikita,</div><div><br></div><div>Thanks for the excellent example. I'm not going to get a chance to look at it until next week, but the first thing I am going to do is verify why the analyzer is not emitting a warning when showDockIconSelectorOnWindow:... is a class method versus when it is an instance method. The analyzer appearing to "get it right" in some cases could just be it not tracking an allocation correctly (or even a bug in Clang), or something else that I'm not remembering off the top of my head. Once I investigate this a little further I'll follow up again on this message.</div><div><br></div><div>Thanks again.</div><div><br></div><div>Ted</div></body></html>