[RFC] Tracking file copies

[Martin Pool]

On 19 Jun 2006, Jelmer Vernooij <jelmer at samba.org> wrote:

> > Doing it as metadata is not really a problem. The question is what kind
> > of performance do you want from this. eg. Are you willing to wait for a
> > complete search through history to find the point where the file_id was
> > marked as a copy from the other id? Do we only allow creating a copy
> > record at the time of creation, or can you do it at any time.
> Perhaps it's best to look at the use cases for this information. I can
> see this being used for:
> 
> 1) annotate
> 2) log
> 3) copying data back into foreign branches
> 4) not having to look back into history to figure out file ids in
> Subversion. This actually requires more than simply tracking copies; it
> also requires that more than one InventoryEntry with the same fileid can
> exist, making it all significantly more complicated. Probably not a good
> idea.

5) possibly doing copy-aware or file-split merges at some point in the
future (which is a bit like people who have their heads frozen in the
hope that sometime in the future it will be possible to resurrect them
*and* someone will want to... and there is a similar issue here that
people will only be motivated to do this kind of copying when they know
the merge will work.)

I think the first four are useful even, so by all means work on a spec
that will support them.  It seems like if you explicitly know about the
copy at all, you will know at commit time?

-- 
Martin