Re: merge result

Lynn Lin [off-list ref] writes:

quoted

quoted

   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/