# rewrite history 9 messages from 2011-06-16 to 2011-06-16. Participants: Ilya Basin, Jeff King, Junio C Hamano, Marc Branchaud. Thread: https://gitlist.dev/t/27638 ## Ilya Basin, 2011-06-16 19:17 Subject: rewrite history Message-ID: <362053118.20110616231758@gmail.com> URL: https://gitlist.dev/e/362053118.20110616231758%40gmail.com ``` Hi list. There were 2 branches. One's HEAD was modified to match a specific commit at another branch. Now, how to merge them according to this scheme? A---B---X---E---F => C---D---X---E---F C---D---X' X and X' have no difference. I tried to write a script to cherry-pick E and F, but some of commits are merges and cherry-pick fails. ``` ## Jeff King, 2011-06-16 19:26 Subject: Re: rewrite history Message-ID: <20110616192644.GB13466@sigill.intra.peff.net> URL: https://gitlist.dev/e/20110616192644.GB13466%40sigill.intra.peff.net In-Reply-To: <362053118.20110616231758@gmail.com> ``` On Thu, Jun 16, 2011 at 11:17:58PM +0400, Ilya Basin wrote: > Hi list. There were 2 branches. One's HEAD was modified to match a > specific commit at another branch. Now, how to merge them according to > this scheme? > > A---B---X---E---F > => C---D---X---E---F > C---D---X' > > X and X' have no difference. I tried to write a script to cherry-pick > E and F, but some of commits are merges and cherry-pick fails. I think you just want to rebase using the "-p" option to preserve merges. Something like: $ git checkout -b rebased-branch F $ git rebase -p --onto D B that will pick X, E, and F, and replay them on top of D, resulting in the graph you showed above. You could also do: $ git rebase -p --onto X' X if you wanted to keep X' instead of X. The new history will be stored on "rebased-branch". You can make sure it looks good to you, and then: $ git branch -f my_original_branch rebased-branch to move the state over to your original branch. You could also just do the rebase directly on the original A-B-X-E-F branch. -Peff ``` ## Junio C Hamano, 2011-06-16 19:43 Subject: Re: rewrite history Message-ID: <7vhb7ph8aj.fsf@alter.siamese.dyndns.org> URL: https://gitlist.dev/e/7vhb7ph8aj.fsf%40alter.siamese.dyndns.org In-Reply-To: <20110616192644.GB13466@sigill.intra.peff.net> ``` Jeff King writes: > On Thu, Jun 16, 2011 at 11:17:58PM +0400, Ilya Basin wrote: > >> Hi list. There were 2 branches. One's HEAD was modified to match a >> specific commit at another branch. Now, how to merge them according to >> this scheme? >> >> A---B---X---E---F >> => C---D---X---E---F >> C---D---X' >> >> X and X' have no difference. I tried to write a script to cherry-pick >> E and F, but some of commits are merges and cherry-pick fails. > > I think you just want to rebase using the "-p" option to preserve > merges. Something like: > > $ git checkout -b rebased-branch F > $ git rebase -p --onto D B > > that will pick X, E, and F, and replay them on top of D, resulting in > the graph you showed above. Eh, careful. Nobody said the change between B and X is any similar to the change between D and X'. Replaying the changes E and F introduce on top of X' to arrive at C--D--X'-E--F is the best you could do, i.e. > $ git rebase -p --onto X' X > > if you wanted to keep X' instead of X. is more like "even if you wanted to keep X instead of X'". If you prefer commit message of X over X', you can rebase -i it after you are done the first round to get rid of A and B, though. But wouldn't filter-branch a better tool for this? Graft to pretend that the parent of X is D instead of B, and filter the branch with F at its tip, that is. ``` ## Jeff King, 2011-06-16 19:49 Subject: Re: rewrite history Message-ID: <20110616194911.GA14355@sigill.intra.peff.net> URL: https://gitlist.dev/e/20110616194911.GA14355%40sigill.intra.peff.net In-Reply-To: <7vhb7ph8aj.fsf@alter.siamese.dyndns.org> ``` On Thu, Jun 16, 2011 at 12:43:00PM -0700, Junio C Hamano wrote: > >> Hi list. There were 2 branches. One's HEAD was modified to match a > >> specific commit at another branch. Now, how to merge them according to > >> this scheme? > >> > >> A---B---X---E---F > >> => C---D---X---E---F > >> C---D---X' > >> > >> X and X' have no difference. I tried to write a script to cherry-pick > >> E and F, but some of commits are merges and cherry-pick fails. > > > > I think you just want to rebase using the "-p" option to preserve > > merges. Something like: > > > > $ git checkout -b rebased-branch F > > $ git rebase -p --onto D B > > > > that will pick X, E, and F, and replay them on top of D, resulting in > > the graph you showed above. > > Eh, careful. Nobody said the change between B and X is any similar to the > change between D and X'. Replaying the changes E and F introduce on top of > X' to arrive at C--D--X'-E--F is the best you could do, i.e. I thought that was exactly what Ilya said with "X and X' have no difference". I assumed that meant "they are semantically similar commits on different bases" (i.e., a cherry-pick) and not "they have the exact same tree state" (i.e., "git diff X X'" is empty). > But wouldn't filter-branch a better tool for this? Graft to pretend that > the parent of X is D instead of B, and filter the branch with F at its > tip, that is. If my assumption on the meanings is reversed (i.e., X and X' really are the same tree state, not introducing equivalent commits), then yeah, that would be better. -Peff ``` ## Ilya Basin, 2011-06-16 20:06 Subject: Re[2]: rewrite history Message-ID: <17721660.20110617000644@gmail.com> URL: https://gitlist.dev/e/17721660.20110617000644%40gmail.com In-Reply-To: <20110616194911.GA14355@sigill.intra.peff.net> ``` JK> On Thu, Jun 16, 2011 at 12:43:00PM -0700, Junio C Hamano wrote: >> >> Hi list. There were 2 branches. One's HEAD was modified to match a >> >> specific commit at another branch. Now, how to merge them according to >> >> this scheme? >> >> >> >> A---B---X---E---F >> >> => C---D---X---E---F >> >> C---D---X' >> >> >> >> X and X' have no difference. I tried to write a script to cherry-pick >> >> E and F, but some of commits are merges and cherry-pick fails. >> > >> > I think you just want to rebase using the "-p" option to preserve >> > merges. Something like: >> > >> > $ git checkout -b rebased-branch F >> > $ git rebase -p --onto D B >> > >> > that will pick X, E, and F, and replay them on top of D, resulting in >> > the graph you showed above. >> >> Eh, careful. Nobody said the change between B and X is any similar to the >> change between D and X'. Replaying the changes E and F introduce on top of >> X' to arrive at C--D--X'-E--F is the best you could do, i.e. JK> I thought that was exactly what Ilya said with "X and X' have no JK> difference". I assumed that meant "they are semantically similar commits JK> on different bases" (i.e., a cherry-pick) and not "they have the exact JK> same tree state" (i.e., "git diff X X'" is empty). >> But wouldn't filter-branch a better tool for this? Graft to pretend that >> the parent of X is D instead of B, and filter the branch with F at its >> tip, that is. JK> If my assumption on the meanings is reversed (i.e., X and X' really are JK> the same tree state, not introducing equivalent commits), then yeah, JK> that would be better. JK> -Peff sorry, git diff X X' is empty -- ``` ## Jeff King, 2011-06-16 20:13 Subject: Re: rewrite history Message-ID: <20110616201300.GA14674@sigill.intra.peff.net> URL: https://gitlist.dev/e/20110616201300.GA14674%40sigill.intra.peff.net In-Reply-To: <17721660.20110617000644@gmail.com> ``` On Fri, Jun 17, 2011 at 12:06:44AM +0400, Ilya Basin wrote: > JK> I thought that was exactly what Ilya said with "X and X' have no > JK> difference". I assumed that meant "they are semantically similar commits > JK> on different bases" (i.e., a cherry-pick) and not "they have the exact > JK> same tree state" (i.e., "git diff X X'" is empty). > [...] > sorry, > git diff X X' is empty Oh, then ignore everything I said. :) I think you want to graft and filter-branch as Junio mentioned. -Peff ``` ## Marc Branchaud, 2011-06-16 21:33 Subject: Re: rewrite history Message-ID: <4DFA76B6.5030407@xiplink.com> URL: https://gitlist.dev/e/4DFA76B6.5030407%40xiplink.com In-Reply-To: <362053118.20110616231758@gmail.com> ``` On 11-06-16 03:17 PM, Ilya Basin wrote: > Hi list. There were 2 branches. One's HEAD was modified to match a > specific commit at another branch. Now, how to merge them according to > this scheme? > > A---B---X---E---F > => C---D---X---E---F > C---D---X' > > X and X' have no difference. I tried to write a script to cherry-pick > E and F, but some of commits are merges and cherry-pick fails. > > ... > > git diff X X' is empty It sounds like you really want to apply X--E--F on top of D, but I don't know how you can do that since you need to do *something* to D in order to get a tree that matches X, and that something is (presumably) *different* from the change that X applied to B. So if diff B X != diff D X' then I think Junio's right that the best you can do is change the meta-data in X' (commit message, Author, etc) to match X then apply E and F on top of that. But filter-branch seems like overkill to me here -- I'd just use "rebase -p" but not quite as Peff described: git checkout X' git commit --amend .... # Replaces X' with X" git rebase -p --onto HEAD X F Giving you C---D---X"---E---F where diff D X' == diff D X" and meta_data(X") == meta_data(X) But if you're happy with C---D---X'---E---F then you can skip the "git commit --amend" step. M. ``` ## Ilya Basin, 2011-06-16 21:55 Subject: Re[2]: rewrite history Message-ID: <7310048292.20110617015509@gmail.com> URL: https://gitlist.dev/e/7310048292.20110617015509%40gmail.com In-Reply-To: <20110616201300.GA14674@sigill.intra.peff.net> ``` >> sorry, >> git diff X X' is empty JK> Oh, then ignore everything I said. :) JK> I think you want to graft and filter-branch as Junio mentioned. JK> -Peff I'm puzzled. How to undo an unfortunate attempt of filter-branch? git log origin/master returns irrelevant info, although I didn't push it to origin and I also tried git branch -D master, -rD master and git fetch -f -- ``` ## Ilya Basin, 2011-06-16 22:18 Subject: Re[3]: rewrite history Message-ID: <724671388.20110617021841@gmail.com> URL: https://gitlist.dev/e/724671388.20110617021841%40gmail.com In-Reply-To: <7310048292.20110617015509@gmail.com> ``` >>> sorry, >>> git diff X X' is empty JK>> Oh, then ignore everything I said. :) JK>> I think you want to graft and filter-branch as Junio mentioned. JK>> -Peff IB> I'm puzzled. How to undo an unfortunate attempt of filter-branch? IB> git log origin/master returns irrelevant info, although I didn't push IB> it to origin and I also tried git branch -D master, -rD master and git IB> fetch -f Nevermind, forgot to rm .git/info/grafts -- ```