Re: Retrieving a file at a before a specified commit

From: Jeff King <peff@peff.net>
Date: May 30, 2013, 02:34 UTC
Message-ID: <20130530023446.GA19860@sigill.intra.peff.net>
In-Reply-To: <20130530104932.d7ba4bfb426044ab9653057e@mega-nerd.com>

On Thu, May 30, 2013 at 10:49:32AM +1000, Erik de Castro Lopo wrote:

Show 16 quoted lines

> Look at this commit:
> 
>     git log --name-status f51ac745a6d4087cc4d77a3cee01db0412955c79
> 
> and notice that one of the files modified is "pib/chkpib2.7", so lets
> look at the parent version of that file:
> 
>     git show f51ac745a6d4087cc4d77a3cee01db0412955c79^:pib/chkpib2.7
> 
> which produces no output and exits with 0 status.
> 
> However looking at the diff for commit f51ac745a suggests that while
> the file pib/chkpib2.7 may have existed before that commit, it must
> have been empty (ie zero length).
> 
> Does this explanation make sense?

Yes, that is what I would expect git to do in such a situation. You can inspect it further, too:

  $ git rev-parse f51ac745^:pib/chkpib2.7
  e69de29bb2d1d6434b8b29ae775ad8c2e48c5391

That's the sha1 of the blob containing the content. You can investigate information about that object like this:

  $ git cat-file -t e69de29b
  blob
  $ git cat-file -s e69de29b
  0
  $ git cat-file blob e69de29b

Of course since its size is 0, the last one is not that interesting. :)

You could also just look at the tree, which gives similar information:

  $ git ls-tree -lr f51ac745^ | grep pib/chkpib2.7
  100644 blob e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 0 pib/chkpib2.7

Hope that helps.

-Peff