7.3 expires_in and interval should be required to be integers

[Joseph Heenan]

expires_in and interval in the authentication response are (I believe) intended to integers, but it's not actually stated anywhere I could find.

We should probably be explicit that it's a positive integer, or alternatively we could use a more RFC6749 type definition:

A.14. "expires_in" Syntax

The "expires_in" element is defined in Sections 4.2.2 and 5.1:

expires-in = 1*DIGIT

[Brian Campbell]

It's interesting to note that the device flow made it through numerous reviews (WGCL, AD, & IESG) from sometimes pedantic reviewers as well as several implementations with the same missing specificity on effectively the same parameters: https://tools.ietf.org/html/draft-ietf-oauth-device-flow-13#section-3.2

Nonetheless, specificity in specifications is typically a good thing so a bit more text to indicate that they are to be positive integers should probably be added.

[Brian Campbell]

The general consensus on the Jan 8th 2019 call http://lists.openid.net/pipermail/openid-specs-mobile-profile/Week-of-Mon-20190107/001408.html was to add text being explicit that these two are positive integers.

[Brian Campbell]

Pull request #56 has proposed changes that make it explicit that expires_in and interval of the Authentication Request Acknowledgement are positive integers represented as JSON numbers

[Brian Campbell]

237fcd3