Re: Fwd: Seems to be pushing more than necessary

> Graham Hay <grahamrhay@gmail.com> writes:
>
>> We have a fairly large repo (~2.4GB), mainly due to binary resources
>> (for an ios app). I know this can generally be a problem, but I have a
>> specific question.
>>
>> If I cut a branch, and edit a few (non-binary) files, and push, what
>> should be uploaded? I assumed it was just the diff (I know whole
>> compressed files are used, I mean the differences between my branch
>> and where I cut it from). Is that correct?
>
> If you start from this state:
>
>  (the 'origin')                    (you)
>     ---Z---A         clone ->    ---Z---A
>
> and edit a few files, say, a/b, a/c and d/e/f, and committed to make
> the history look like this:
>
>  (the 'origin')                    (you)
>     ---Z---A                     ---Z---A---B
>
> i.e. "git diff --name-only A B" would show these three files, then
> the next push from you to the origin, i.e.
>
>  (the 'origin')                    (you)
>     ---Z---A---B    <- push      ---Z---A---B
>
> would involve transferring from you to the origin of the following:
>
>  * The commit object that holds the message, authorship, etc. for B
>  * The top-level tree object of commit B (as that is different from
>    that of A)
>  * The tree object for 'a', 'd', 'd/e' and the blob object for
>    'a/b', 'a/c', and 'd/e/f'.
>
> However, that assumes that nothing is happening on the 'origin'
> side.
>
> If the 'origin', for example, rewound its head to Z before you
> attempt to push your B, then you may end up sending objects that do
> not exist in Z that are reachable from B.  Just like the above
> bullet points enumerated what is different between A and B, you
> can enumerate what is different between Z and A and add that to the
> above set.  That would be what will be sent.
>
> If the 'origin' updated its tip to a commit you do not even know
> about, normally you will be prevented from pushing B because we
> would not want you to lose somebody else's work.  If you forced such
> push, then you may end up sending a lot more.