> 14754 [NNNNN] WARNING: NS_ENSURE_SUCCESS(EnsureScriptEnvironment(), nullptr) failed with result 0x80040111: file docshell/base/nsDocShell.cpp, line 4607 0x80040111 is NS_ERROR_NOT_AVAILABLE. This warning [1] is rather widespread across tests, it is most frequent during mochitest-browser-chrome-2, a few more verbose tests: > 97 warnings from test browser/components/sessionstore/test/browser_354894_perwindowpb.js > 76 warnings from test browser/components/sessionstore/test/browser_522545.js > 48 warnings from test browser/components/downloads/test/browser/browser_iframe_gone_mid_download.js It looks like this can happen if |mIsBeingDestroyed| is true [2] or if |do_GetInterface(mTreeOwner)| fails [3]. Given the frequency of this warning it seems like we should just remove it (or possibly move it to |EnsureScriptEnvironment| where we can get a better idea of what is actually failing). [1] https://hg.mozilla.org/mozilla-central/annotate/02f640a72dcd/docshell/base/nsDocShell.cpp#l4607 [2] https://hg.mozilla.org/mozilla-central/annotate/0b2f5e8b7be5/docshell/base/nsDocShell.cpp#l12780 [3] https://hg.mozilla.org/mozilla-central/annotate/0b2f5e8b7be5/docshell/base/nsDocShell.cpp#l12795

Note: This is the most verbose warning during linux64 debug testing.

Comment on attachment 8626364 [details] [diff] [review] Stop warning if EnsureScriptEnvironment returns NS_ERROR_NOT_AVAILABLE I don't think it is useful to warn ever. So just return NS_SUCCEEDED(EnsureScriptEnvironment()) ? mScriptGlobal : nullptr; Or even EnsureScriptEnvironment(); return mScriptGlobal; But I think I'd prefer the first one.

(In reply to Olli Pettay [:smaug] from comment #2) > Comment on attachment 8626364 [details] [diff] [review] > Stop warning if EnsureScriptEnvironment returns NS_ERROR_NOT_AVAILABLE > > I don't think it is useful to warn ever. > So just > > return NS_SUCCEEDED(EnsureScriptEnvironment()) ? mScriptGlobal : nullptr; > > Or even > EnsureScriptEnvironment(); > return mScriptGlobal; > > But I think I'd prefer the first one. Thanks for the quick review! I'll update to use the tristate.