STRs: - Build with ac_add_options --enable-debug - set dom.webcomponents.shadowdom.enabled to true - load attached document - click on button - reload the page (ctrl+R) I usually get to a Tab Crashed or the page loads infinitely and Firefox crashes. The stacktrace is: Assertion failure: !node->AsElement()->HasServoData(), at /builds/worker/workspace/build/src/dom/base/nsDocument.cpp:4105 #01: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x37774b2] #02: DumpBidiLine[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x37efb66] #03: DumpBidiLine[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x37e893f] #04: DumpBidiLine[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x37f0a27] #05: DumpBidiLine[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x3836dff] #06: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x37843f6] #07: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x3785f6c] #08: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x3785901] #09: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x377dcfe] #10: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x3785ee0] #11: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x3785901] #12: DumpBidiLine[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x37ec4d8] #13: av1_temporal_filter_apply_sse2[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x49ed623] #14: av1_temporal_filter_apply_sse2[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x49eb230] #15: av1_temporal_filter_apply_sse2[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x49eefe0] #16: DumpCompleteHeap[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0xe410cf] #17: DumpCompleteHeap[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0xe40935] #18: DumpCompleteHeap[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0xe3f1eb] #19: DumpCompleteHeap[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0xe3ff08] #20: DumpCompleteHeap[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0xe406ad] #21: nsXPTCStubBase::Stub249()[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x1d9f7e] #22: mozilla_dump_image[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x15d0022] #23: mozilla_dump_image[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x15c51f5] #24: mozilla_dump_image[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x15f6bcc] #25: thread-local wrapper routine for mozilla::SchedulerGroup::sTlsValidatingAccess[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0xec34b] #26: thread-local wrapper routine for mozilla::SchedulerGroup::sTlsValidatingAccess[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x1029d1] #27: thread-local wrapper routine for mozilla::SchedulerGroup::sTlsValidatingAccess[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x111993] #28: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x33c3fd1] #29: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x343028e] #30: __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__[/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation +0xa3721] #31: __CFRunLoopDoSource0[/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation +0x15d0ac] #32: __CFRunLoopDoSources0[/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation +0x86260] #33: __CFRunLoopRun[/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation +0x856dd] #34: CFRunLoopRunSpecific[/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation +0x84f43] #35: RunCurrentEventLoopInMode[/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox +0x2fe26] #36: ReceiveNextEventCommon[/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox +0x2fb96] #37: _BlockUntilNextEventMatchingListInModeWithFilter[/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox +0x2f914] #38: _DPSNextEvent[/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit +0x41f5f] #39: -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:][/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit +0x7d7b4c] #40: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x342f486] #41: -[NSApplication run][/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit +0x36d6d] #42: thread-local wrapper routine for mozilla::dom::FlushRejections::sDispatched[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x3430ad3] #43: catch_exception_raise[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x4e3adc9] #44: nsXPTCStubBase::Stub249()[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x705372] #45: nsXPTCStubBase::Stub249()[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x6b6207] #46: catch_exception_raise[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/XUL +0x4e3a923] #47: start[/Users/jdescottes/Development/hg/fx-team/objdir-frontend.noindex/dist/NightlyDebug.app/Contents/MacOS/plugin-container.app/Contents/MacOS/plugin-container +0xee9] ###!!! [Parent][MessageChannel] Error: (msgtype=0x150081,name=PBrowser::Msg_Destroy) Channel error: cannot send/recv ###!!! [Parent][MessageChannel] Error: (msgtype=0x150081,name=PBrowser::Msg_Destroy) Channel error: cannot send/recv

Thanks. FWIW, stack traces without symbols aren't really useful.

Well, so the element with servo data is the <div>, and it's obvious why. Will write something.

I've got two different fixes, not sure which one is the best... We'll see.

Comment on attachment 8952174 [details] Bug 1439016: Clear servo data on slot changes too. https://reviewboard.mozilla.org/r/221410/#review227266

Comment on attachment 8952175 [details] Bug 1439016: Assert that there's no stale servo data in shadow roots either. https://reviewboard.mozilla.org/r/221412/#review227268

Comment on attachment 8952176 [details] Bug 1439016: Crashtest. https://reviewboard.mozilla.org/r/221414/#review227270 ::: commit-message-877e7:3 (Diff revision 1) > +The crashtest will crash whenever the shell is destroyed, which is annoying, > +but... Add this as a comment to the crashtest so that it's apparent to whoever looks at it later? ::: layout/base/crashtests/1439016.html:2 (Diff revision 1) > +<!DOCTYPE html> > +<host> There's no actual HTML element called <host>, right? Assuming that's the case, could you make this <div id="host"> instead to make it clearer?

Comment on attachment 8952177 [details] Bug 1439016: Remove dead code from Shadow DOM v0. https://reviewboard.mozilla.org/r/221416/#review227272

Thanks for the reviews Bobby!

Comment on attachment 8952176 [details] Bug 1439016: Crashtest. https://reviewboard.mozilla.org/r/221414/#review227270 > Add this as a comment to the crashtest so that it's apparent to whoever looks at it later? Sure thing :) > There's no actual HTML element called <host>, right? Assuming that's the case, could you make this <div id="host"> instead to make it clearer? Yup, done.

Pushed by ecoal95@gmail.com: https://hg.mozilla.org/integration/autoland/rev/577a507f9ee1 Clear servo data on slot changes too. r=bholley https://hg.mozilla.org/integration/autoland/rev/6ec2d0d818ce Assert that there's no stale servo data in shadow roots either. r=bholley https://hg.mozilla.org/integration/autoland/rev/b8cd6601b753 Crashtest. r=bholley https://hg.mozilla.org/integration/autoland/rev/84dbe2d215f7 Remove dead code from Shadow DOM v0. r=bholley

Pushed by ecoal95@gmail.com: https://hg.mozilla.org/integration/autoland/rev/d32d276d2917 followup: Reuse AssertNoStaleServoDataIn in CreateShell too. r=me

https://hg.mozilla.org/mozilla-central/rev/577a507f9ee1 https://hg.mozilla.org/mozilla-central/rev/6ec2d0d818ce https://hg.mozilla.org/mozilla-central/rev/b8cd6601b753 https://hg.mozilla.org/mozilla-central/rev/84dbe2d215f7 https://hg.mozilla.org/mozilla-central/rev/d32d276d2917