166911 2017-01-10 17:19:10 -0800 REGRESSION: LayoutTest fast/dom/Window/window-properties-performance-resource-timing.html is a flaky failure 2017-01-18 17:02:27 -0800 1 1 1 Unclassified WebKit New Bugs Other Unspecified Unspecified NEW P2 Normal --- 1 ryanhaddad webkit-unassigned ap fpizlo ggaren oldest_to_newest 1265597 0 ryanhaddad 2017-01-10 17:19:10 -0800 LayoutTest fast/dom/Window/window-properties-performance-resource-timing.html is a flaky failure https://build.webkit.org/results/Apple%20Sierra%20Debug%20WK2%20(Tests)/r210559%20(1599)/results.html https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=fast%2Fdom%2FWindow%2Fwindow-properties-performance-resource-timing.html --- /Volumes/Data/slave/sierra-debug-tests-wk2/build/layout-test-results/fast/dom/Window/window-properties-performance-resource-timing-expected.txt +++ /Volumes/Data/slave/sierra-debug-tests-wk2/build/layout-test-results/fast/dom/Window/window-properties-performance-resource-timing-actual.txt @@ -42,6 +42,12 @@ window.performance.timing.unloadEventEnd [number] window.performance.timing.unloadEventStart [number] window.performance.timing [printed above as window.performance.timing] -window.performance.navigation [printed above as window.performance.navigation] +window.performance.navigation [object PerformanceNavigation] +window.performance.navigation.TYPE_BACK_FORWARD [number] +window.performance.navigation.TYPE_NAVIGATE [number] +window.performance.navigation.TYPE_RELOAD [number] +window.performance.navigation.TYPE_RESERVED [number] +window.performance.navigation.redirectCount [number] +window.performance.navigation.type [number] window.performance [string] 1265624 1 ryanhaddad 2017-01-10 17:36:43 -0800 Also seeing a flaky failure with the same diff with test: fast/dom/Window/window-properties-performance.html https://build.webkit.org/results/Apple%20Sierra%20Debug%20WK1%20(Tests)/r210566%20(2403)/results.html 1266693 2 ryanhaddad 2017-01-13 17:21:09 -0800 Alexey mentioned to me that this issue could be related to the GC, and looking at the flakiness dashboard, that theory does seem to line up. The test was flaky around the time the new GC was enabled, but has definitely become much flakier in the past two weeks. 1266789 3 ap 2017-01-13 23:46:46 -0800 The symptom means that window.performance.navigation.__visitedByLogValue__ disappears while the test is running, which would mean that JS wrapper for the object gets collected. The flakiness dashboard only has results since December 12th, and the test was failing in the same way back then. So, I don't think that we can find out if the test was failing in the same way before concurrent GC (which was enabled on the 11th). It's possible that concurrent GC is simply more effective at quickly collecting the wrapper, and the bug is in the bindings. I do not know if one needs to do anything custom to protect the GC wrapper these days. Do we still need to add visitAdditionalChildren() functions everywhere? 1267951 4 ryanhaddad 2017-01-18 17:02:27 -0800 Marked the two tests as flaky in https://trac.webkit.org/changeset/210901