[PATCH STABLE-V2] help: add an help topic about the Changesets obsolescence concept

[Pierre-Yves David]

On Fri, Aug 03, 2012 at 03:39:25PM +0200, Laurens Holst wrote:
> Op 01-08-12 19:50, pierre-yves.david at logilab.fr schreef:
> >+Obsolescence markers make it possible to mark changesets that have been
> >+deleted or superset in a new version of the changeset.
> >+
> >+Unlike the previous way of handling such changes, by stripping the old
> >+changesets from the repository, obsolescence markers can be propagated
> >+between repositories. This allows for a safe and simple way of exchanging
> >+mutable history and altering it after the fact. Changeset phases are
> >+respected, such that only draft and secret changesets can be altered (see
> >+:hg:`hg phases` for details).
> >+
> >+Obsolescence is tracked using "obsolete markers", a piece of metadata
> >+tracking which changesets have been made obsolete, potential successors for
> >+a given changeset, the moment the changeset was marked as obsolete, and the
> >+user who performed the rewriting operation. The markers are stored
> >+separately from standard changeset data can be exchanged without any of the
> >+precursor changesets, preventing unnecessary exchange of obsolescence data.
> 
> By the way Pierre-Yves, on an unrelated note,
> 
> Are obsolete markers also exchanged for secret changesets?

Yes because you have no absolute way to know if an obsolescence marker is
relevant of not remotly.

> I think this should not be needed unless the secret changesets are
> also exchanged.

They could have been turned secret manually (by mq or by the user)

> Also if it does, mutating a secret changeset would (mildly) affect their
> secrecy because the changeset ID leaks to the public...

Again, secret changeset are "not exchanged" not absolutly secret and safe for
hide nuclear launch code into changeset hash. If you really want that you will
have a rely on some overlay. (sorry)


-- 
Pierre-Yves David

http://www.logilab.fr/

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