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Re: Why do we check the base checksum so often?

From: Julian Foad <julianfoad_at_btopenworld.com>
Date: Mon, 6 Feb 2012 17:18:08 +0000 (GMT)

> Hyrum K Wright wrote:

>> What's driving this discussion is this:  Up until this point in the
>> Ev2 shims we've been supplying a NULL base checksum for apply
>> textdelta, which the receivers have dutifully ignored.  However, when
>> the Ev2 shims attempt to be honest about the fact that they are using
>> the empty stream for the text base, the receivers start complaining,
>> because that's not what they expected---even though the end result is
>> the same.  In essence, all these checks are returning false positives,
>> which is extremely unpleasant.
>> I don't know that there is an easy way around this, since by the time
>> we're translated from Ev2->delta-editor, we don't have the original
>> text base, or its checksum, available to us.  We have the full text,
>> which is the reason the new text base is the empty stream: it's the
>> only one we need.
>> Does that make any sense?

Yes that makes sense.  (Sorry I got sidetracked when I thought you were saying the producer should be able to choose any arbitrary base.)
- Julian
Received on 2012-02-06 18:18:45 CET

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