Re: [PATCH 3/3] receive-pack: allow a maximum input size to be specified

From: Christian Couder <christian.couder@gmail.com>
Date: Aug 18, 2016, 14:06 UTC
Message-ID: <CAP8UFD0Wtekn-qR+RvRmj+rHFZS2DvFhqYdnygU0LwSabYLyoA@mail.gmail.com>
In-Reply-To: <20160816162141.b3jtmun3kynjnwxs@sigill.intra.peff.net>

On Tue, Aug 16, 2016 at 6:21 PM, Jeff King <peff@peff.net> wrote:

Show 19 quoted lines

>> >
>> > Is there any reason to use different filenames and sizes for the two
>> > runs? They should behave identically, so it would make more sense to me
>> > to subject them to identical inputs.
>>
>> About the sizes, I thought that some people might want to try sizes
>> closer to the limit and also that it is good anyway in general to add
>> a bit of "randomness", or at least variability, in the tests.
>
> In general, I'd prefer a systematic approach to introducing variables
> into tests. If it's important that we test different sizes, then we
> should do so, and not only test some combinations (and if it is not
> important to test different sizes, then we should not waste CPU time and
> the mental energy of people reading the tests).
>
> IOW, when I see this, I wonder why the index-pack code path is not
> tested against a 2k file. But there really isn't a good reason. So
> either it does matter, and our tests do not have good coverage, or it
> does not, and it is just making me wonder if the tests are buggy.

I don't see things in the same way, but I will make the second file a 1k file too as I don't really care much about that.

> Worse, both files are created with the same seed via test-genrandom. So
> I suspect the 2k file is a superset of the 1k file, and we may send it
> is a thin delta (so it really is only testing a 1k input anyway!).

Yeah, I will use a different seed for the second file.

Show 8 quoted lines

>> I thought that it would be a bit less wasteful to use the same "dest"
>> and also it would make the test more realistic as people often push in
>> non empty repos.
>
> I doubt it is expensive enough to matter in practice. Though note that
> if you push the same commit to two new repositories, then you can
> amortize the test-genrandom/add/commit step (i.e., push the exact same
> packfile in both cases).

Yeah, it probably doesn't matter anyway regarding efficiency, but I still prefer to not create a new repo as I would find it more confusing for the reader to use different repos.

Thanks, Christian.