newcomer question not found in the FAQ

[Steve Borho]

On Mon, Dec 21, 2009 at 10:20 PM, tristan stag <trstag75 at yahoo.fr> wrote:
> Hi all,
>
> I started using Mercurial (coming from Subversion) and
> I've got a question that I haven't found in the FAQs
> / Wikis.  I probably overlooked the answers because
> I'm new and a bit confuzzabled by something simple.
>
> I'd like to know the "philosophy" underlying the
> following problem: what am I supposed to do with
> a changeset that either broke something or that
> is simply not working at all, but that I still
> want to keep as an example of "what not to do"?
>
> Here's an example, changeset 3: is bad but I'd still like to keep it.
>
> The problem is that altough I manage to go
> back and start from changeset 2: the changeset 3:
> is still in there.
>
> It's not an issue: ideally I'd like to keep it around,
> but apparently as soon as I do a merge it gets merged.
>
> I know changeset 3: is broken, I'll never ever want to
> merge it again nor to fix it.  It's an approach that is
> not working.
>
> Ideally I'd like to keep it around as an example of what
> not to do but removing it altogether would be fine.
>
> What am I supposed to do with that changeset 3: ?
>
> AFAICT when I did merge the "sh*t hit the fan" and
> that changeset 3: got merged.
>
> (btw Mercurial 1.4.1 on OS X 10.6 and 1.0.1 on a
> stock Debian Lenny 5.0.3)
>
> I guess it comes down to:
>
> - what am I supposed to do with a changeset that broke
>  something but I'd still like to keep around?
>
> and:
>
> - what am I supposed to do with an approach that simply
>  didn't work and that I don't necessarily want to keep
>  around? (I mean: in some case I really couldn't care
>  less about that changeset, I can either keep it or
>  delete it once and for all, I don't care as long as
>  it shall never interfere again with the rest of the
>  code).
>
>
> [nonet at saturn 27.5G ~/example/proj/] $ hg gl
> @  changeset:   5:d69ac2cb7713
> |  tag:         tip
> |  user:        nonet at saturn.xyp
> |  summary:     even better
> |
> o  changeset:   4:485cada3297c
> |  parent:      2:056a28fae544
> |  user:        nonet at saturn.xyp
> |  summary:     Heuristic algo giving very good results
> |
> | o  changeset:   3:21697fa637b5
> | |  parent:      1:9d83166bce20
> | |  user:        nonet at saturn.xyp
> | |  summary:     No closed formula, heuristic algo giving terribly bad
> | |               results: example of what not to do
> | |
> o |  changeset:   2:056a28fae544
> |/   user:        nonet at saturn.xyp
> |    summary:     Algo passing all test on data set, moderately fast
> |
> o  changeset:   1:9d83166bce20
> |  user:        nonet at saturn.xyp
> |  summary:     Added data set to test algos
> |
> o  changeset:   0:2f01508c3f15
>   user:        nonet at saturn.xyp
>   summary:     Initial import

hg up 5
hg merge --config ui.merge=internal:local
hg commit

This does a merge, while always selecting the local (changeset 5)
version of all files.

--
Steve Borho