Re: merge result
- From
Matthieu Moy <matthieu.moy@grenoble-inp.fr>
- Date
- Sep 10, 2011, 11:35 UTC
- Message-ID
- <vpqr53oeijq.fsf@bauges.imag.fr>
- In-Reply-To
- <CAPgpnMTMPQQPkS-gKLvUJNKLfMWuAT-oA3NCiSRFxu7PknYsnA@mail.gmail.com>
Lynn Lin <lynn.xin.lin@gmail.com> writes:
Show 24 quoted lines
>>> 1->2->3-4>5 Master >>> | >>> 4->6->7 A >> >> A more accurate drawing would be >> >> 1->2->3-4>5 Master >> | >> 4'->6->7 A >> >> and after merging, you'd get >> >> 1->2->3-4>5-->8 A, master >> | / >> 4'->6->7 >> >> with 8 having both 4 and 4' as ancestors. There's nothing wrong with it. >> Git cannot remove either 4 or 4' without rewritting history, and "git >> merge" does not rewrite history. > so confused here.If 4' is just next 4 commit,how can the diff work? for example > > 1->2->4->4'->6->... > > diff 4 and 4' is a little confused,correct?
History is not linear. When you type "git log", you may think that 4 and 4' follow each other, but try "gitk" or "git log --oneline --graph" to see a better view of history.
It's possible to have several times the same change applied to multiple branches (e.g. when doing cherry-picking), but having twice the same change in a row is not really possible.
Suppose your commit 4 removes the line "foobar". Then, commits 1, 2 and 3 have the line "foobar" (think of commits as snapshots in history, not as diff. 3 is a snapshot, and when you run "git show 3", it shows you the diff from 2 to 3). Commits 4 and 4' don't have it anymore, and then obviously 5, 6, 7 don't have it either. At the time of merge, Git will notice that neither of the merges to commit have the line "foobar" and the result 8 won't have it either.
-- Matthieu Moy http://www-verimag.imag.fr/~moy/