Re: can we prevent reflog deletion when branch is deleted?

On 11/14/2013 01:44 PM, Jeff King wrote:

On Thu, Nov 14, 2013 at 05:48:50AM +0530, Sitaram Chamarty wrote:

quoted

Is there *any* way we can preserve a reflog for a deleted branch,
perhaps under logs/refs/deleted/<timestamp>/full/ref/name ?

I had patches to do something like this here:

  http://thread.gmane.org/gmane.comp.version-control.git/201715/focus=201752

but there were definitely some buggy corners, as much of the code
assumed you needed to have a ref to have a reflog. I don't even run with
it locally anymore.

At GitHub, we log each change to an "audit log" in addition to the
regular reflog (we also stuff extra data from the environment into the
reflog message). So even after a branch is deleted, its audit log
entries remain, though you have to pull out the data by hand (git
doesn't know about it at all, except as an append-only sink for
writing). And git doesn't use the audit log for connectivity, either, so
eventually the objects could be pruned.

quoted

Just some basic protection -- don't delete the reflog, and instead,
rename it to something that preserves the name but in a different
namespace.

That part is easy. Accessing it seamlessly and handling reflog
expiration are a little harder. Not because they're intractable, but
just because there are some low-level assumptions in the git code. The
patch series I mentioned above mostly works. It probably just needs
somebody to go through and find the corner cases.

The use cases I am talking about are those where someone deleted
something and it was noticed well within Git's the earliest of Git's
expire timeouts.

So, no need to worry about expiry times and connecting it with object
pruning.  Really, just the eqvt of a "cp" or "mv" of one file is all
that most people need.

Gitolite's log is the same.  So no one who uses Gitolite needs this
feature.  But people shouldn't have to install Gitolite or anything else
just to get this either!