Re: A generalization of git notes from blobs to trees - git metadata?

[Jon Seymour <jon.seymour@gmail.com>]

On Sun, Feb 7, 2010 at 8:15 PM, Jakub Narebski <jnareb@gmail.com> wrote:
> Jon Seymour <jon.seymour@gmail.com> writes:
>
> [cut]
>
>> As I see it, the existing use of notes is a special instance of a more
>> general metadata capability in which the metadata is constrained to be
>> a single blob. If notes continued to be constrained in this way, there
>> is no reason to change anything with respect to its current userspace
>> behaviour. That said, most of the plumbing which enabled notes could
>> be generalized to enable the arbitrary tree case [ which admittedly, I
>> have yet to sell successfully !]
>>
>> In one sense, there is a sense in the merge issue doesn't exist. When
>> the maintainer publishes a tag no-one expects to have to deal with
>> downstream conflicting definitions of the tag. Likewise, if the
>> maintainer were to publish the /man and /html metadata trees (per my
>> previous example) for a release tag, anyone who received
>> /refs/metadata/doc would expect to receive the metadata trees as
>> published by the maintainer. Anyone who didn't wouldn't have to pull
>> /refs/metadata/doc.
>>
>> I can see there are use cases where multiple parties might want to
>> contribute metadata and I do not currently have a good solution to
>> that problem, but that is not to say there isn't one - surely it is
>> just a question of applying a little intellect creatively?
>
> Are you trying to repeat fail of Apple's / MacOS / HFS+ filesystem
> data/resource forks, and Microsoft's Alternate Data Streams in git? :-)
>

No I am not. I don't see why a metadata proposal is any more exposed
to subversive payloads than say, use of git merge -s ours [ a
subversive payload could be made reachable from a commit that
otherwise merges in favour of the legitimate source - who would know?
]

Really, I can't see why the rationale that makes a single blob used
for extending a commit message justified can't be used to justify
associating a metadata tree of arbitrary complexity to an arbitrary
sha1 object. What makes maintaining a mapping to a single blob
acceptable but maintaining a mapping to a tree unacceptable? Is there
really any fundamental difference?

jon.