Re: [Monotone-devel] some basic notes on object versioning

[Derek Scherger]

Nathaniel Smith wrote:
> On Mon, Jun 06, 2005 at 11:15:39AM +0200, Georg-W. Koltermann wrote:
> 
>>I'm not sure how much the lifetime means here.  There is certainly a
>>point in time (birth) when an object is first added, but dropping would
>>just remove the object from some revision.  The object would still exist
>>in other revisions and other branches as well.  It might actually be
>>merged again later, so it might exist in the mainline branch Mon thru
>>Wed, be deleted Thu and Fri, and be merged into mainline again (from
>>some other branch) on Sat.
> 
> 
> Monotone ATM considers file resurrection to be impossible (as do all
> the other modern VCSes I can think of off-hand, though this
> particular corner isn't something I'm super-familiar with
> everywhere...).  What this means is that they enforce the invariant
> that once a file is dead in a revision R, it is dead in all
> descendents of that revision.  If you want to merge it back in from
> another branch, well, firstly you have to do some work, because the
> merge will just delete it, and secondly, the best you can do is to get
> a drop/add pair that breaks its history across the merge.

I guess I was thinking along the lines of a drop/add pair, with the
understanding that add gives birth to a completely new object. Although
this object has the same name, it does not have the same identity or
history and wouldn't be merged with the old object under that name.

I hadn't thought about merging beyond the drop, but yeah it does seem
like merging with a drop results in a drop. Really, I wasn't thinking
about merging at all when I wrote these things down, I was thinking more
about "what are the things that are being versioned and how could they
be represented." Merging versioned things seems like the next level up,
once we know exactly what they are.

Cheers,
Derek