Re: Allow empty property names

On 25 March 2016 at 21:19, Scott Arciszewski <scott@paragonie.com> wrote: > On Fri, Mar 25, 2016 at 1:45 PM, Nikita Popov <nikita.ppv@gmail.com> > wrote: > > > Hi internals, > > > > Currently we do not allow (*) creating empty property names on objects, > > i.e. > > > > $obj->{''} = 42; > > > > is illegal. While empty property names are unlikely to be useful per se, > > they are problematic for deserialization of foreign formats like JSON. To > > avoid this issue {"": null} will currently decode to a property named > > "_empty_" rather than "". Notably, this means that JSON decode and > > encode > > do not round-trip (as we do not convert _empty_ back to an empty name > while > > encoding). > > > > There is no technical reason (that I can see) for keeping this arbitrary > > restriction. I believe that the original reason for the restriction was > our > > use of NUL-prefixed property names for name mangling, combined with the > > fact that an empty string at the C level happens to "start" with a NUL > > byte. > > > > A patch to drop the restriction and allow empty property names: > > https://github.com/php/php-src/pull/1836 It does not touch > > the JSON > > handling, as there are BC concerns involved there, I leave that to the > > ext/json maintainer. > > > > Any objections to changing this? > > > > Regards, > > Nikita > > > > (*) There are roundabout ways to create them anyway. > > > > ​Currently, this succeeds: > > $x = json_decode('{"_empty_": "no", "": > "foo"}', true); > > While this does not: > > $x = json_decode('{"_empty_": "no", "": > "foo"}'); > > ​https://3v4l.org/FJHVV > ​https://3v4l.org/15Sfm​ > > I'm personally 50/50 on it. ​I think allowing an empty property is kind of > weird, but not the weirdest behavior PHP allows. Overall, it might > (ironically enough!) make working with JSON _more_ consistent, and probably > have other benefits that I can't even imagine at the moment. > Note that also that these ones won't work at the moment: var_dump((object) ['' => 'foo']); var_dump((object) ["\0*\0" => 'foo']); var_dump((object) ["\0Foo\0" => 'foo']); Seems to work consistently on HHVM though: https://3v4l.org/7MO7E Marco Pivetta http://twitter.com/Ocramius http://ocramius.github.com/