LGTM2 On Wed, Oct 3, 2018 at 2:42 PM Adam Klein <ad...@chromium.org> wrote:
> LGTM > > On Wed, Oct 3, 2018 at 8:09 AM 'Mathias Bynens' via v8-users < > v8-users@googlegroups.com> wrote: > >> Contact emails >> >> math...@chromium.org >> >> Spec >> >> https://github.com/tc39/proposal-well-formed-stringify >> >> Summary >> >> A Stage 3 proposal changes JSON.stringify to prevent it from returning >> ill-formed Unicode strings. >> >> Motivation >> >> RFC 8259 section 8.1 <https://tools.ietf.org/html/rfc8259#section-8.1> >> requires JSON text exchanged outside the scope of a closed ecosystem to be >> encoded using UTF-8, but JSON.stringify >> <https://tc39.github.io/ecma262/#sec-json.stringify> can return strings >> including code points that have no representation in UTF-8 (specifically, >> surrogate code points U+D800 through U+DFFF). And contrary to the >> description of JSON.stringify >> <https://tc39.github.io/ecma262/#sec-json.stringify>, such strings are >> not “in UTF-16” because “isolated UTF-16 code units in the range >> D800₁₆..DFFF₁₆ are ill-formed” per The Unicode Standard, Version 10.0.0, >> Section 3.4 <https://unicode.org/versions/Unicode10.0.0/ch03.pdf#G7404> >> at definition D91 and excluded from being “in UTF-16” per definition D89. >> >> However, returning such invalid Unicode strings is unnecessary, because >> JSON strings can include Unicode escape sequences. >> >> Interoperability and compatibility risk >> >> This change is backwards-compatible, under an assumption of consumer >> compliance with the JSON specification. User-visible effects are limited to >> the replacement of some rare single UTF-16 code units in JSON.stringify >> output with equivalent six-character escape sequences that can be >> represented both in UTF-16 and in UTF-8. Any consumer accepting the current >> ill-formed output is unaffected by this change (this is true in particular >> of ECMAScript JSON.parse). Any consumer rejecting the current ill-formed >> output will have a new opportunity to accept its well-formed >> representation, although such consumers may still reject input that >> specifies strings including Unicode code points that are not scalar values >> (e.g. because they only accept I-JSON >> <https://tools.ietf.org/html/rfc7493> input), but those that accept it >> must have mechanisms for dealing with unpaired surrogates (as mentioned in >> the specification of JSON). >> >> This feature has a ready-to-land Firefox/SpiderMonkey implementation >> <https://bugzilla.mozilla.org/show_bug.cgi?id=1469021>. There are >> tracking bugs for Edge/Chakra >> <https://github.com/Microsoft/ChakraCore/issues/5735> and >> Safari/JavaScriptCore <https://bugs.webkit.org/show_bug.cgi?id=190110>. >> >> Is this feature fully tested? >> >> Yes. In addition to V8’s own tests ( >> v8/test/mjsunit/harmony/well-formed-json-stringify*.js and >> v8/test/cctest/test-strings*), Test262 includes tests >> <https://github.com/tc39/test262/search?q=%22features%3A+%5Bwell-formed-json-stringify%5D%22> >> for this feature <https://github.com/tc39/test262/pull/1787>. >> >> Note: Mathias rolled the latest test262 tests in to V8 ( https://chromium-review.googlesource.com/c/v8/v8/+/1259865) and V8 passes the test262 tests for this feature. > Tracking bug >> >> https://bugs.chromium.org/p/v8/issues/detail?id=7782 >> >> Link to entry on the Chrome Platform Status dashboard >> >> https://www.chromestatus.com/feature/5752304045129728 >> >> Requesting approval to ship? >> >> Yes. Note that since this is a V8/JS feature, this post is just an FYI to >> blink-dev — no signoff from Blink API owners is required. >> >> -- >> -- >> v8-users mailing list >> v8-users@googlegroups.com >> http://groups.google.com/group/v8-users >> --- >> You received this message because you are subscribed to the Google Groups >> "v8-users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to v8-users+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > -- > -- > v8-users mailing list > v8-users@googlegroups.com > http://groups.google.com/group/v8-users > --- > You received this message because you are subscribed to the Google Groups > "v8-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to v8-users+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
