Re: Regarding "git log" on "git series" metadata

On Sat, Nov 05, 2016 at 09:50:07PM -0700, Jacob Keller wrote:

On Sat, Nov 5, 2016 at 1:25 PM, Josh Triplett [off-list ref] wrote:

quoted

On Sat, Nov 05, 2016 at 09:21:58PM +0100, Christian Couder wrote:

quoted

On Sat, Nov 5, 2016 at 4:18 PM, Josh Triplett [off-list ref] wrote:

quoted

On Sat, Nov 05, 2016 at 01:45:27PM +0100, Christian Couder wrote:

quoted

And with what Peff says above it looks like we will need ways
configure and tweak commit reachability with gitlink/gitref anyway. So
the point of gitref compared to gitlink would be that they just have a
different reachability by default. But couldn't that be replaced by a
default rule saying that when a gitlink is reached "this way or that
way" then the commit reachability should be enforced, and otherwise it
should not be?

Any version of git unaware of that rule, though, would consider objects
only reachable by gitlink as unreachable and delete them, causing data
loss.  Likewise for a server not aware of that rule.  And a server
unaware of that rule would not supply those objects to a client pulling
such a branch.

Yeah, so you would really need an up-to-date server and client to
store the git-series data.
But anyway if we create a gitref object, you would also need
up-to-date servers and clients to make it work.

Agreed, but gitrefs have the advantage of failing safe, rather than
failing with dataloss.

- Josh Triplett

Isn't the "failing safe" only true if the client disconnects when a
server doesn't advertise "i understand gitrefs"? So couldn't we, as
part of the rules for reachability advertise a capability that does a
similar thing and fails safe as well?

We could, but if we (or one of the many third-party git implementations)
miss a case, gitlinks+reachability may appear to work in many cases with
dataloss afterward, while gitrefs will fail early and not appear
functional.