exercises/egit/git/change-a-series-of-commits.txt~

== Change a series of commits
In this exercise you learn how you can rewrite the local history
before you share it with others. After you have committed locally you
can still change all commits in your local feature branch.

=== Preparation
Follow the exercise link:merge-rebase-and-resolving-conflicts.html[
Merge, Rebase and Resolving Conflicts]. After the rebase you end up
with a branch which is two commits ahead of the remote branch
'origin/master', it's the local 'master' branch in the screenshot
below. Now you realize that you want to change the first commit and
keep the second one on top of the changed commit.

image:history-view-8.png[History View]

=== Change the first commit

* Create a new branch that points to the commit you want to change, in
  the screenshot below it's the 'Add multiply operation' commit. Use
  'Create Branch' to create a new branch, e.g. named 'newMaster'.
+
image:history-view-9.png[History View]
+
image:history-view-10.png[History View]

* Edit the files in the workspace, e.g. add a class comment for the
  'Multiply' class.
* Now create a new commit with the combined changes of your first
  commit and your current changes:
** Select your project in the Package Explorer and select
   'Team > Commit' or click 'Commit' in the Git Toolbar.
** Press the 'Amend' button as shown below:
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image:commit-changes-with-amend-2.png[Commit Changes with Amend]

** Click the Commit button

* Now your history should look like this:
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image:history-view-11.png[History View]
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Note that the first version of your changed commit is still there, but
your branch points now to the new one. Git always creates new commits
when you rewrite history, it does not change old ones (from time to
time it removes commits which are not reachable by a reference, e.g.
a branch or a tag).

=== Cherry-pick the rest

* Select 'Cherry Pick' on the other commit. This will add the
difference of this commit compared to its parent on top of your new
commit.
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image:cherry-pick.png[Cherry Pick]

* You may have to resolve conflicts
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image:cherry-pick-conflict.png[Cherry Pick Conflict]
+
In that case, edit the conflicting files, add the changes and commit
like in the exercise link:merge-rebase-and-resolving-conflicts.html[
Merge, Rebase and Resolving Conflicts].

* The result should look like this:
+
image:history-view-12.png[History View]

If you want to change more than one commit in a series git offers the
powerful tool 'git rebase --interactive'. This is not yet available in
EGit, but can be used from the Git commandline.

link:index.html[Git Exercises]