Re: [Gnu-arch-users] [BUG] FEATURE PLAN: two stage commit

[Tom Lord]

    > From: Jason McCarty <address@hidden>

    > Tom Lord wrote:
    > >     > Anyway, hopefully the above will contribute in some way.

    > > Of course.  It helps to get "many eyeballs" on the design before it's
    > > finalized.  In this case, it got me to remember and write down why I
    > > decided that a commit was needed to kill a composite transaction
    > > rather than just a `tla lock-revision --break'.

    > Something I should have mentioned before then: If I understand
    > correctly, if B, C, ... are half-committed and dependant on A, one way
    > of breaking the lock on B is to commit A', which makes the commit of A
    > fail, thus causing B, C, ... to be uncommitted. What if the person who
    > wants to break the lock on B doesn't have permission to commit
    > A'?

Tough luck, for the most part.  Giving out/managing permissions to
commit to a particular archive has to take that into account.

Of course, there is still the usual range of by-hand work-arounds
that, formally speaking, break consistency but as a practical matter
are often, well, practical.


    > Further, whose responsibility is it to actually remove the half-
    > committed B, C, ... when it's discovered that committing A must fail
    > (especially if the process committing A dies in the middle of things)?

Anyone with write permission can do it the same way anyone can break a
lock.

-t