Re: [quicwg/base-drafts] are flow control frames really idempotent? (#1612)

Martin Thomson <> Tue, 31 July 2018 03:57 UTC

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From: Martin Thomson <>
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Subject: Re: [quicwg/base-drafts] are flow control frames really idempotent? (#1612)
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So this was opened and closed already in #447, though there wasn't a whole lot of discussion and the issue was closed with no action.

The action that @marten-seemann suggests is slightly bad - retransmitting packets is rarely the best choice from a correctness perspective - but the conclusion from the other issue was that there was little point in allowing endpoints to police continuous increases to limits.

Note that this advice would also need to apply to stream limits.

(To answer the question in the issue: Yes, these packets are still idempotent - the definition of idempotency has to allow for the state of the world to change in a way that changes the result the action when attempted again.  For example. `GET /foo` is idempotent, but if there is a `DELETE /foo` that happens, the result of another `GET /foo` will be different.)

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