Re: Identify Commit ID from an Extracted Source Snapshot

[Michael Schubert <mschub@elegosoft.com>]

On 02/17/2012 12:19 AM, Sam Vilain wrote:
> On 2/16/12 3:00 PM, Michael Schubert wrote:
>> On 02/16/2012 11:06 PM, James Walmsley wrote:
>>> I couldn't find this on google, and I have no idea if its even 
>>> possible. I have several zip files from previous versions of my 
>>> source code. (I imported svn into git). I would like to add TAGS
>>> to git which represent the versions based on the files in my zip 
>>> archives.
>>> 
>>> Does anyone know how to do this?
>> 
>> If it's just about providing the ancient code together with the 
>> (imported) more recent history from SVN, you could create an extra 
>> orphan branch for each zip packet, add the files, commit and 
>> eventually tag.
>> 
>> If your question is more like "how do I tell git to find out where 
>> this old code fits in my history and eventually place it there", 
>> the answer is: you cannot do it. No VCS will do this and
>> especially not Git.
> 
> Once you've got a tree in git which corresponds to the contents of
> the zip file, you can use git diff --stat TREEID COMMITID
> 
> You can get the commitid by obtaining the most recent timestamp for a
> file within the archive, then just using git rev-list --all
> --since=... --until=... to get a window of commit IDs, and hunt
> around until you find the one with the smallest diff.
> 
> It's hardly a straightforward thing, usually because the contents of
> the zip file never quite match the exact contents of source
> control—think autoconf and other files generated for distribution but
> not stored in the history.  So you need to use a fuzzy search.

I totally disregared the "slicing and rebuilding history approach", just
because I didn't think that's what James is asking about. Could be fun.