Fix ISO8601 bug

[lucasmichot]

Fix ISO8601 BC

---

FIx #861

[dereuromark]

@lucasmichot I think your changes revert the BC break, so they "could" make sense after all.

[lucasmichot]

Yeah but is this really a BC - or more an expected behaviour as per your comment in #861 ? It's not that obvious
Ping @briannesbitt

[briannesbitt]

Ya I mentioned awhile ago that its a breaking change but also a bug fix to implement correct behaviour. I guess the issue is people are relying on the incorrect behaviour so thats why its a break.

I had changed it to use the atom format awhile ago but I guess it never got released. I guess save it for 2.0 at this point to mimic PHP behaviour.

[ameliaikeda]

It's probably worth noting that technically both formats are valid under ISO8601, but PHP's default handling of dates (createFromFormat being the biggest problem) doesn't allow parsing ISO8601 properly, as it's too rigid. Not everyone uses new/parse though, and interop for proper handling of iso8601 is terrible in general.

[ameliaikeda]

potential encoding error in your client here, maybe?

[lucasmichot]

@briannesbitt I think that even if PHP does not exactly the ISO, it should be worth to merge this in 1.x
Somehow it's globally accepted in the PHP community

[ameliaikeda]

@lucasmichot PHP isn't actually wrong, however: ISO8601 is a very large standard. Both Y-m-d\TH:i:sO and Y-m-d\TH:i:sP are correct under ISO8601, as is Y-m-d, Y-m-d H:i:s and Y-m. PHP just doesn't have very flexible handling by default.

[lucasmichot]

Thanks for making it clearer @ameliaikeda
Neverheless we should maybe provide the default \DateTime::ISO8601 format value

[jaylinski]

I wrote a little blog post on this issue: https://dev.karriere.at/a/iso-8601-dates-in-php-and-browsers

[Glavic]

You want to have a date before 1970? Sorry, you should not use timestamps.

Why not? You can use negative timestamp, like this: https://eval.in/958817

[jaylinski]

@Glavic You are right, this works in PHP and in browsers. I will update the article.

[kylekatarnls]

Won't fix as we do not wish to align on a PHP documented bug. If you need the legacy ISO8601 format, just use ->format(Carbon::ISO8601)