# [PATCH v2] reset: add an example of how to split a commit into two 5 messages from 2017-02-03 to 2017-02-04. Participants: Jacob Keller, Junio C Hamano, Duy Nguyen, Philip Oakley. Thread: https://gitlist.dev/t/45039 ## Jacob Keller, 2017-02-03 20:28 Subject: [PATCH v2] reset: add an example of how to split a commit into two Message-ID: <20170203202833.17666-1-jacob.e.keller@intel.com> URL: https://gitlist.dev/e/20170203202833.17666-1-jacob.e.keller%40intel.com ``` From: Jacob Keller It is often useful to break a commit into multiple parts that are more logical separations. This can be tricky to learn how to do without the brute-force method if re-writing code or commit messages from scratch. Add a section to the git-reset documentation which shows an example process for how to use git add -p and git commit -c HEAD@{1} to interactively break a commit apart and re-use the original commit message as a starting point when making the new commit message. Signed-off-by: Jacob Keller --- Documentation/git-reset.txt | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/Documentation/git-reset.txt b/Documentation/git-reset.txt index 25432d9257f9..add6220fce77 100644 --- a/Documentation/git-reset.txt +++ b/Documentation/git-reset.txt @@ -292,6 +292,44 @@ $ git reset --keep start <3> <3> But you can use "reset --keep" to remove the unwanted commit after you switched to "branch2". +Split a commit into two:: ++ +Suppose that you have created a commit, but later decide that you want to break +apart the changes into two logical chunks and commit each separately. You want +to include part of the original commit into the first commit, while including +the remainder in a second commit. You can use git reset to rewind the history +without changing the index, and then use git add -p to interactively select +which hunks to put into the first commit. ++ +------------ +$ git reset HEAD^ <1> +$ git add -p <2> +$ git diff --cached <3> +$ git commit -c HEAD@{1} <4> +... +$ git add ... <5> +$ git diff --cached <6> +$ git commit ... <7> +------------ ++ +<1> First, reset the history back one commit so that we remove the original + commit, but leave the working tree with all the changes. +<2> Now, interactively select hunks to add to a new commit using git add -p. + This will ask for each hunk separately and you can use simple commands like + "yes, include", "no don't include" or even "edit". +<3> Once satisfied with the hunks, you should verify that it is what you + expected by using git diff --cached to show all changes in the index. +<4> Next, commit the changes stored in the index. "-c" specifies to load the + editor with a commit message from a previous commit so that you can re-use the + original commit message. HEAD@{1} is special notation to reference what + HEAD used to be prior to the reset command. See linkgit:git-reflog[1] for + more details. +<5> Now you've created the first commit, and can repeat steps 2-4 as often as + you like to break the work into any number of commits. Here we show a second + step which simply adds the remaining changes. +<6> Then check again that the changes are what you expected to add. +<7> And finally commit the remaining changes. + DISCUSSION ---------- -- 2.11.0.864.ge7592a54611d ``` ## Junio C Hamano, 2017-02-03 20:46 Subject: Re: [PATCH v2] reset: add an example of how to split a commit into two Message-ID: URL: https://gitlist.dev/e/xmqqzii3dmub.fsf%40gitster.mtv.corp.google.com In-Reply-To: <20170203202833.17666-1-jacob.e.keller@intel.com> ``` Jacob Keller writes: > +Split a commit into two:: Let's say "...into two (or more)" to match what appears in "SPLITTING COMMITS" section of "rebase -i" documentation. Yours is written as a sequence of more concrete steps than the existing one over there, so it may also make sense to add reference to bring readers of "git rebase --help" to this section. > ++ > +Suppose that you have created a commit, but later decide that you want to break > +apart the changes into two logical chunks and commit each separately. You want "two (or more)" again. In <5> you already hint that the user can repeat 2-4 number of times. > +to include part of the original commit into the first commit, while including > +the remainder in a second commit. You can use git reset to rewind the history > +without changing the index, and then use git add -p to interactively select > +which hunks to put into the first commit. > ++ > +------------ > +$ git reset HEAD^ <1> > +$ git add -p <2> > +$ git diff --cached <3> > +$ git commit -c HEAD@{1} <4> > +... > +$ git add ... <5> > +$ git diff --cached <6> > +$ git commit ... <7> > +------------ > ++ > +<1> First, reset the history back one commit so that we remove the original > + commit, but leave the working tree with all the changes. > +<2> Now, interactively select hunks to add to a new commit using git add -p. > + This will ask for each hunk separately and you can use simple commands like > + "yes, include", "no don't include" or even "edit". > +<3> Once satisfied with the hunks, you should verify that it is what you > + expected by using git diff --cached to show all changes in the index. > +<4> Next, commit the changes stored in the index. "-c" specifies to load the > + editor with a commit message from a previous commit so that you can re-use the > + original commit message. HEAD@{1} is special notation to reference what > + HEAD used to be prior to the reset command. See linkgit:git-reflog[1] for > + more details. > +<5> Now you've created the first commit, and can repeat steps 2-4 as often as > + you like to break the work into any number of commits. Here we show a second > + step which simply adds the remaining changes. > +<6> Then check again that the changes are what you expected to add. > +<7> And finally commit the remaining changes. > + ``` ## Duy Nguyen, 2017-02-04 11:06 Subject: Re: [PATCH v2] reset: add an example of how to split a commit into two Message-ID: URL: https://gitlist.dev/e/CACsJy8B2gyw7RQBh6Qfm5HxOyKWted-0ZeDfd2_U3MvWCO1HEA%40mail.gmail.com In-Reply-To: <20170203202833.17666-1-jacob.e.keller@intel.com> ``` On Sat, Feb 4, 2017 at 3:28 AM, Jacob Keller wrote: > +------------ > +$ git reset HEAD^ <1> It may be a good idea to add -N here, so that 'add -p' can pick up the new files if they are added in HEAD. > +$ git add -p <2> -- Duy ``` ## Philip Oakley, 2017-02-04 12:16 Subject: Re: [PATCH v2] reset: add an example of how to split a commit into two Message-ID: URL: https://gitlist.dev/e/E363F108ABEF45CB99C2C721A90B5EA2%40PhilipOakley In-Reply-To: ``` From: "Duy Nguyen" > On Sat, Feb 4, 2017 at 3:28 AM, Jacob Keller > wrote: >> +------------ >> +$ git reset HEAD^ <1> > > It may be a good idea to add -N here, so that 'add -p' can pick up the > new files if they are added in HEAD. When looking at the man page for `reset` [1] it implies that `-N` requires `--mixed` also to be given. Is that correct? Or could the man page be clearer? > >> +$ git add -p <2> > -- > Duy > Philip [1] https://git-scm.com/docs/git-reset ``` ## Duy Nguyen, 2017-02-04 12:36 Subject: Re: [PATCH v2] reset: add an example of how to split a commit into two Message-ID: URL: https://gitlist.dev/e/CACsJy8Bk%3DpnyYNr2OxhQCYgxQQtOU%3DGqXUfgseL1HatB6SQPnQ%40mail.gmail.com In-Reply-To: ``` On Sat, Feb 4, 2017 at 7:16 PM, Philip Oakley wrote: > From: "Duy Nguyen" >> >> On Sat, Feb 4, 2017 at 3:28 AM, Jacob Keller >> wrote: >>> >>> +------------ >>> +$ git reset HEAD^ <1> >> >> >> It may be a good idea to add -N here, so that 'add -p' can pick up the >> new files if they are added in HEAD. > > > When looking at the man page for `reset` [1] it implies that `-N` requires > `--mixed` also to be given. Is that correct? Yes. But since --mixed is the default mode, "reset -N" equals "reset --mixed -N" > Or could the man page be clearer? If someone makes questions, I guess the answer is yes it should be made clearer. -- Duy ```