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

Martin Thomson <notifications@github.com> Tue, 31 July 2018 23:52 UTC

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Subject: Re: [quicwg/base-drafts] are flow control frames really idempotent? (#1612)
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Yes, we generally couple a *MAY result in an error* text with a MUST for the peer (because a MAY is always a MUST in the sense that it mandates tolerance).  In this case, we're saying MUST NOT go backwards, coupled with a MUST NOT generate an error if the peer doesn't comply.  That was explicitly to enable the sort of thing that @marten-seemann and @dtikhonov do, even if that is maybe slightly objectionable to the purists.

I think that the fix is as follows:

> A receiver cannot renege on an advertisement; that is, once a receiver advertises an offset, advertising a smaller offset has no effect. A sender MUST ignore any flow control offset that does not increase maximum (stream) data.

Would that work for people?

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