When the Add-ons Compatibility checking dialog or the Profile Manager UI is displayed during startup, we call nsCocoaWindow::SetModal while setting up the window. This happens outside the event loop, so our main autorelease pool is not in place, and therefore when cocoa internally uses autorelease, it will leak objects to the root pool (which we are trying to get rid of). From a run with the Reading symbols for shared libraries . done WARNING: NS_ENSURE_TRUE(compMgr) failed: file nsComponentManagerUtils.cpp, line 90 <....snip....> WARNING: dependent window created without a parent: file /Users/jonathan/mozdev/mozilla-central/toolkit/components/startup/src/nsAppStartup.cpp, line 456 ++DOCSHELL 0x1166d5e70 == 1 ++DOMWINDOW == 1 (0x11a0050d8) [serial = 1] [outer = 0x0] ++DOMWINDOW == 2 (0x117011c98) [serial = 2] [outer = 0x11a005080] 2010-04-14 19:46:25.524 firefox-bin[46501:a0f] *** __NSAutoreleaseNoPool(): Object 0x11ef1f670 of class NSRunningApplication autoreleased with no pool in place - just leaking The attached patch adds a local autorelease pool in SetModal to fix this.

Oops, that should have read "From a run with the -P option, to display the profile manager. The same leak occurs when upgrading from an older version, causing the Add-ons dialog to appear."

Comment on attachment 439049 [details] [diff] [review] add local autorelease pool in nsCocoaWindow::SetModal, for startup dialogs Looks good but please fix this comment: + // therefore, it needs to provide an autorelease pool to avoid cocoa + // object leakage messages. We're not trying to avoid leak *messages*, we're trying to avoid *leaks*. Thanks!

Pushed http://hg.mozilla.org/mozilla-central/rev/8df1936a0f3d (with edited comment).