From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 21 May 2013 22:20:47 GMT
Subject: Re: Reading commit objects
Message-ID: <7v4ndwm0u8.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CABx5MBQ57-=MPamvV-peZUdD_KDLX+5cy9vD7CL7p_Vz9BkvTg@mail.gmail.com>

Chico Sokol <chico.sokol@gmail.com> writes:

> Hello,
>
> I'm building a library to manipulate git repositories (interacting
> directly with the filesystem).
>
> Currently, we're trying to parse commit objects. After decompressing
> the contents of a commit object file we got the following output:

Who wrote this commit object you are trying to read?  Us, or your
library (this question is to see if you are chasing the right
problem)?

> commit 191
> author Francisco Sokol <chico.sokol@gmail.com> 1369140112 -0300
> committer Francisco Sokol <chico.sokol@gmail.com> 1369140112 -0300
>
> first commit
>
> We hoped to get the same output of a "git cat-file -p <sha1>", but
> that didn't happened. From a commit object, how can I find tree object
> hash of this commit?

If you care about the byte-for-byte compatibility, never use
"cat-file -p".  That is meant for human consumption.

"git cat-file commit <sha1>" gives you the raw representation after
inflating and stripping out the first "<type> SP <length> LF" line.