Re: Rephrasing: question about merging branches

[Jamie Wellnitz]

On Tue, Nov 04, 2003 at 01:27:09PM -0500, Derek Robert Price wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> If branch A and branch B in your example don't branch form the same
> point on the trunk, a merge from point 2 to point 4 into the trunk might
> still not do what you want.  If branch B branched first, then 2->4 may
> back out changes made to the trunk between the base of B and the base of
> A.  If A branched first, then 2->4 will attempt to remerge changes made
> to the trunk between the base of A and the base of B, causing the same
> sort of spurious conflicts you were attempting to avoid.
> 
> The only clean way to do this in the general case is to tag branch B
> before and after your merge from A at point 3 and merge B back into the
> trunk as two merges:
> 
> ~    cvs up -j 1 -j pre-3
> ~    cvs up -j post-3 -j 4

If you do this, are you missing the changes between points 2 and 3 on
branchA that should (I think) end up merged to the trunk?

> 
> Please note that I am using numeric tags in the above example, per the
> ascii art below, despite the fact that tags that start with a number are
> invalid.
> 
> Derek

Thanks,
Jamie

> 
> Get CVS support at <http://ximbiot.com>!
> 
> 
> David Wood wrote:
> 
> |I would say your ascii graphic is admirable!
> |
> |What you are saying matches what I'm seeing in tests, and I think I get it
> |now.
> |
> |I believe my problem has been a silly confusion with the way update -j -j
> |works.
> |
> |I understand a merge between 1 and 4 (and for that matter, a reverse-merge
> |between 4 and 1) well enough.
> |
> |Essentially, I mistakenly envisioned a merge between 3' and 4 - rather
> |than 2 and 4. Hence my fear about loss or mistreatment of changes before
> |the child-to-child merge.
> |
> |I think what all this means is that branchB is now essentially merging
> |against branchA (having received common chagnes by, and resolved conflicts
> |with) branchA... and the merge delta with the trunk must now use branchA
> |(at point 2) as a reference point in order to correctly reflect changes
> |against the trunk.
> |
> |It is potentially confusing, but you have made it seem very simple. Thank
> |you!
> |
> |-David
> |
> |Jamie Wellnitz <address@hidden> wrote on 11/04/2003 11:50:35
> |AM:
> |
> |>Sorry for the ascii graphic in advance . . .
> |>
> |>If you have (* indicates merge point):
> |>
> |>branchA and branchB originated from trunk at point 1.
> |>branchA merged to trunk at point 2 on branchA and 2' on trunk.
> |>branchA then merged to branchB at point 3 on branchA and 3' on branchB.
> |>Now, we want to merge branchB (point 4) to the trunk (4').
> |>
> |>              branchA  2    3
> |>            /---------\-----\-------->
> |>         1 /           \     \           4'
> |>trunk ------------------*---- \ ---------*---->
> |>           \            2'     \        /
> |>            \-------------------*------/-->
> |>              branchB           3'     4
> |>
> |>I think you want the common ancestor of the current branchB tip and
> |>trunk tip.  That would be point2 on branchA.  (This is assuming you
> |>did a full merges, not just a few changes, from A->trunk and A->B.)
> |>So assuming you put tags down to keep track of the merge points, you
> |>might try (on the trunk):
> |>
> |>cvs update -j point2 -j point4
> |>
> |>It looks like my point2 is your "first child merge point" and "second
> |>child" is the tip of branchB (where you put a tag before the merge).
> |>
> |>Which changes before the "first child merge point" are you wondering
> |>about?
> |>
> |>Thanks,
> |>Jamie Wellnitz
> |>address@hidden
> |>
> |>On Tue, Nov 04, 2003 at 11:06:44AM -0500, David Wood wrote:
> |>
> |>>Let me try to put it another way.
> |>>
> |>>I have a parent branch, and it has two child branches. If I want one
> |
> |child
> |
> |>>to merge to the parent, and then to the other child, how does that
> |
> |other
> |
> |>>child later merge to the parent as well?
> |>>
> |>>Is it (on the parent): update -j first_child_merge_point -j second
> |
> |child
> |
> |>>If so, what happens to changes from before the
> |
> |first_child_merge_point?
> |
> |>>-David
> |>>
> 
> - --
> ~                *8^)
> 
> Email: address@hidden
> 
> Get CVS support at <http://ximbiot.com>!
> - --
> I know of no safe depository of the ultimate powers of the society but
> the people themselves, and if we think them not enlightened enough to
> exercise that control with a wholesome discretion, the remedy is not to
> take it from them, but to inform their discretion.
> 
>            - Thomas Jefferson, 1820.
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.0.7 (GNU/Linux)
> Comment: Using GnuPG with Netscape - http://enigmail.mozdev.org
> 
> iD8DBQE/p+98LD1OTBfyMaQRAkYYAJsFs2zGGAUbt4iA5k/o3GxATtu9ZgCfcngq
> sDzUwcIwQzAV5U0g6Tjo05w=
> =0iYB
> -----END PGP SIGNATURE-----
> 
> 
> 
> 
> _______________________________________________
> Info-cvs mailing list
> address@hidden
> http://mail.gnu.org/mailman/listinfo/info-cvs