Re: Retrieving a file at a before a specified commit

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

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