203875 2019-11-05 18:24:47 -0800 JSC should not be using WTF::String::createCFString(). 2019-11-06 11:25:46 -0800 1 1 1 Unclassified WebKit JavaScriptCore WebKit Nightly Build Unspecified Unspecified NEW https://bugs.webkit.org/show_bug.cgi?id=203873 P2 Normal --- 1 mark.lam webkit-unassigned fpizlo keith_miller msaboff rmorisset saam tzagallo ysuzuki oldest_to_newest 1587638 0 mark.lam 2019-11-05 18:24:47 -0800 After https://bugs.webkit.org/show_bug.cgi?id=203873, there's only one instance of this bad idiom: formatLocaleDate() in DatePrototype.cpp. 1587712 1 ysuzuki 2019-11-06 00:59:37 -0800 There is other WTF functions that are internally using createCFString (like, mac/FileSystemMac.mm). So they should be changed too since these functions can be called from JSC. 1587837 2 keith_miller 2019-11-06 10:46:54 -0800 Why is this a bad idiom? Just because we don't want to allocate CF strings? 1587846 3 mark.lam 2019-11-06 11:25:46 -0800 (In reply to Keith Miller from comment #2) > Why is this a bad idiom? Just because we don't want to allocate CF strings? Because String::createCFString() uses StringImpl::createCFString(), which relies on the concept of isMainThread(), which is only meaningful if WebCore is the client of JSC. For all other clients, this can result in badness.