[BrowserKit] Cookie expiration at current timestamp

[iquito]

Q	A
Branch?	3.4
Bug fix?	yes
New feature?	no
Deprecations?	no
License	MIT

In Symfony\Component\BrowserKit\Cookie a cookie is expired if the expires timestamp is in the past. I would like to change it to also be expired if the expires timestamp equals the current exact timestamp. This would still be in line with RFC 6265, as it states The Expires attribute indicates the maximum lifetime of the cookie, represented as the date and time at which the cookie expires.

Reason for this change: Cookies usually both have expires and Max-Age set, and Symfony sets Max-Age to zero if a cookie is expired (in Symfony\Component\HttpFoundation\Cookie). When converting cookies between string and object representations, Max-Age is the preferred source of truth for the expiration, but Max-Age set to zero is converted to an expires timestamp at this exact second, currently making the cookie not expired in Symfony\Component\BrowserKit\Cookie, even though it should be.

I noticed this discrepancy in my tests when checking if a cookie no longer existed after deleting it, yet it was still there, because Cookie thought it would only expire after the expires timestamp had passed. I am also thinking of raising an issue for Symfony\Component\HttpFoundation\Cookie, as importing and exporting an expired cookie (via strings) changes the expired value. I thought this change was a simpler one for now, and should have no negative/unexpected impact.

[fabpot]

Can you rebase on 3.4?

[iquito]

Did the rebase on 3.4

[fabpot]

Thank you @iquito.