This is causing asserts in these tests: dom/tests/mochitest/dom-level1-core/test_nodeappendchildchildexists.html dom/tests/mochitest/dom-level1-core/test_nodeinsertbeforenewchildexists.html dom/tests/mochitest/dom-level1-core/test_nodereplacechildnewchildexists.html with a stack like so: 11:22:36 INFO - [Parent 277] ###!!! ASSERTION: Ancestors of nodes with frames to be constructed lazily should have frames: '!noPrimaryFrame', file ../../../layout/base/nsCSSFrameConstructor.cpp, line 6248 11:22:36 INFO - nsCSSFrameConstructor::ContentAppended(nsIContent*, nsIContent*, bool) [layout/base/nsCSSFrameConstructor.cpp:6519] 11:22:36 INFO - PresShell::ContentAppended(nsIDocument*, nsIContent*, nsIContent*, int) [layout/base/nsPresShell.cpp:4064] 11:22:36 INFO - nsNodeUtils::ContentAppended(nsIContent*, nsIContent*, int) [obj-firefox/dist/include/nsTObserverArray.h:309] 11:22:36 INFO - nsINode::doInsertChildAt(nsIContent*, unsigned int, bool, nsAttrAndChildArray&) [content/base/src/nsINode.cpp:1394] 11:22:36 INFO - nsINode::ReplaceOrInsertBefore(bool, nsINode*, nsINode*, mozilla::ErrorResult&) [content/base/src/nsINode.cpp:1992] 11:22:36 INFO - mozilla::dom::NodeBinding::appendChild [obj-firefox/dist/include/mozilla/ErrorResult.h:96]

(In reply to Boris Zbarsky (:bz) from comment #0) > This is causing asserts in these tests: Just to be clear: "this" is bug 890193's patch, right?

No, "this" is this bug. TBug 890193 just (re)exposed this bug by making the unhooking not be a no-op again.

This appears to have had the same cause as bug 943804, so I backed out the assertion annotations: https://hg.mozilla.org/integration/mozilla-inbound/rev/eef2361b1f9b The test case no longer asserts either.

https://hg.mozilla.org/mozilla-central/rev/eef2361b1f9b https://hg.mozilla.org/releases/mozilla-aurora/rev/5567a9a910e3

Given in-testsuite coverage this fix will not be manually verified by QA. If you believe this warrants extra QA attention please nominate for testing by removing this whiteboard tag and adding the verifyme keyword. Please also provide any details you have that may inform our testing.