Re: Manually decoding a git object

From: Philip Oakley <philipoakley@iee.org>
Date: Feb 20, 2012, 07:58 UTC
Message-ID: <B268B28A80B446BBADED9B3B6BA4B205@PhilipOakley>
In-Reply-To: <CAMocUqRNNXpGOJ2ZG8bWpkieKkVfoo0=Lkevjw+E3Tssw68Hwg@mail.gmail.com>

From: "??" <xudifsd@gmail.com> Sent: Monday, February 20, 2012 4:45 AM

Show 12 quoted lines

> 2012/2/20 Philip Oakley <philipoakley@iee.org>:
>> If I have a renamed file which is a git object, such a "Git_Object", was
>> 8c-something-or-other, what is the easiest way of examining / decoding /
>> recreating the original file (either as its sha1, or a cat-file).
>>
> I don't think I fully understood what you mean, I assume you just move
> an object file from $GIT_DIR/objects/ to somewhere and rename it,
> let's call it "obj", so if you want to exam its content you can just
> simply call "git cat-file -p obj". And you can also use "git cat-file
> -t obj" to exam its object type. If it's a blob you can use "git
> cat-file -p obj > original" to recreate it, else it's meaningless to
> recreate it.

When I tried it from my home directory (not in a git directory): $ git cat-file -p Git-Object fatal: Not a git repository (or any of the parent directories): .git

Because its sha1 isn't yet known I can't put it into the correct .git/objects/xx/ subdirectory of an fresh 'git init', and I have located an unzip programme that will take the plain git object and decode it - they all expect archives.

I've described the background use-case at http://stackoverflow.com/questions/9341278/how-to-track-the-git-directory-in-git-in-its-own-store - the edit links to a typical corporate scenario.

Even just locating a zlib implementation that simply confirms the file stream is compressesd and deflates it would be a start. Philip