idempotency: clarify "effect"

[mnot]

Gili:

 Can the authors officially weigh in on the meaning of "idempotent" 

with response to response codes? Do idempotent methods have to return the same response code in the face of multiple invocations? Or are they allowed to return different response codes so long as the state is not modified by subsequent requests? See http://stackoverflow.com/q/741192/14731 for the discussion that fueled this question.

 PS: It would be nice if the spec officially clarified this point as 

I've seen it brought up again and again in different discussions.

Reported by julian.reschke@gmx.de, migrated from https://trac.ietf.org/trac/httpbis/ticket/501

[mnot]

julian.reschke@gmx.de commented:

From 2427:

Clarify that idempotency is about effects on the server, and mention that response messages may vary for repeated requests (see #501)

[mnot]

• julian.reschke@gmx.de changed milestone from unassigned to 25
• julian.reschke@gmx.de changed resolution to incorporated
• julian.reschke@gmx.de changed status from new to closed

[mnot]

fielding@gbiv.com commented:

From 2481:

(editorial) slight wording change to 2427 for idempotent methods; see #501