Subject: Re: [PATCH v4 4/6] pack-objects: generate cruft packs at most one object over threshold

From: Junio C Hamano <[email-masked]>
Date: Thu, 13 Mar 2025 05:16:39 -0700

Elijah Newren <[email-masked]> writes:

>> With below-size and max-size set to say 180 and 200 respectively, an
>> attempt to combine the crufts may end up filling a cruft pack to 170
>> but the smallest of the remaining cruft may weigh 40, which means
>> including it would cause the max-size to be exceeded.  In such a
>> scenario, there may not be a solution to satisfy given constraints,
>> i.e. go above the below-size without stay below the max-size.
>>
>> So I am not sure if the approach would really solve much.
>>
>> Other than that a separate names, especially losing "max" from the
>> threshold that really does not mean "max", would solve the confusion
>> that comes from naming, that is.
>
> --max-pack-size is a constraint.  --combine-cruft-below-size is not.
> Think particularly of the case where the user doesn't even have any
> cruft packs yet and has only accumulated a little bit of cruft.  That
> option is merely a guide post to say that if it's smaller than that
> size, then feel free to keep trying to add to it (so long as it
> doesn't violate constraints such as --max-pack-size).

That is correct and it is why I said the suggestion solves the name
confusion.  But think about the sample situation, before and after
such a repack with two thresholds.  You had below- and max-size set
to 180 and 200 respectively, and a cruft pack of size 170, and you
failed to grow that cruft pack beyond 180 because the next available
cruft weighed 40.  Then you'll repeat the exercise again, find 170
that is smaller than the below- threshold, try to cram more and
would fail.  Isn't that what Taylor's series wanted to prevent from
happening, and isn't the two-threshod approach supposed to be a way
to improve on it?