git rebase with multiple sub-branches

Question

I am having trouble getting git to do what I want in moderately complicated branching scenarios. It seems like some of my work is being lost whenever I use the rebase command. I am new to git, coming from a Perforce background. Am I using the wrong commands or missing some flags? Is my intuition about the internal state of my local repository correct?

Note: branchB is dependent on branchA, and branchC is dependent on branchB.

git checkout master
git pull master
git checkout -b branchA
```
 ==O master \\==A branchA 
```
edit branchA
git add ...
git commit
git review

git checkout -b branchB

 ==O==O master \\==A branchA \\==B branchB

edit branchB
code review requires changes to branchA
git add ...
git commit
git checkout branchA
edit branchA
git add ...
git commit --amend <== should I use --amend here?
git review
git checkout branchB
edit branchB some more
git add ...
git commit
git review

git checkout -b branchC

 ==O==O==O==O master \\==A branchA \\==B branchB \\==C branchC

edit branchC
branchA passes code review
git add ...
git commit
git checkout master
git pull master
git checkout branchA
git rebase master branchA
resolve merge conflicts
git checkout master

git merge branchA

 ==O==O==O==O==A master \\==B branchB <== is this correct? \\==C branchC

git checkout branchB
git rebase master branchB

resolve merge conflicts

 ==O==O==O==O==A master \\ \\==B branchB \\==C branchC <== is this correct?

git checkout branchC
git rebase branchB branchC
resolve merge conflicts <== often redo the same merge conflicts as branchB
```
 ==O==O==O==O==A master \\==B branchB \\==C branchC 
```
design change requires refactoring branchA
git checkout master
git pull

git checkout -b refactorA

 ==O==O==O==O==A master |==A' refactorA |==B branchB \\==C branchC

edit refactorA
git add ...
git commit
git review
git checkout branchB
git rebase refactorA branchB <== is this a mistake?

resolve merge conflicts (three sets of conflicts)

 ==O==O==O==O==A master \\==A' refactorA \\ \\==B branchB <== is this correct? \\==C branchC

git review <== complains about multiple commits
git log <== shows that branchB now has a few instances of branchA's commit

Answer 1

You need to understand that commits are dependents from the previous one and branches are just pointers to one commit of the commit graph.

Here is the commit graph evolution, numbers are commits, upper are newer, references and branches are aside commits, HEAD is your current position.

You can see your evolution of the commit graph by launching git log --graph --oneline --all --decorate at each step.

git checkout master
```
 1 origin/master, HEAD -> master | 0 
```
git pull master
```
 1 origin/master, HEAD -> master | 0 
```

git checkout -b branchA

 1 origin/master, master, HEAD -> branchA | 0

edit branchA
git add ...
git commit

git review

 2 HEAD -> branchA | 1 origin/master, master | 0

git checkout -b branchB

 2 branchA, HEAD -> branchB | 1 origin/master, master | 0

edit branchB
code review requires changes to branchA
git add ...

git commit

 3 HEAD -> branchB | 2 branchA | 1 origin/master, master | 0

git checkout branchA

 3 branchB | 2 HEAD -> branchA | 1 origin/master, master | 0

edit branchA
git add ...
git commit --amend => By using --amend you create a new commit with the same parent

git review

 3 branchB | | 2' HEAD -> branchA | | 2 | |/ 1 origin/master, master | 0

git checkout branchB

 3 HEAD -> branchB | | 2' branchA | | 2 | |/ 1 origin/master, master | 0

edit branchB some more
git add ...
git commit

git review

 4 HEAD -> branchB | 3 | | 2' branchA | | 2 | |/ 1 origin/master, master | 0

git checkout -b branchC

 4 branchB, HEAD -> branchC | 3 | | 2' branchA | | 2 | |/ 1 origin/master, master | 0

edit branchC
branchA passes code review
git add ...

git commit

 5 HEAD -> branchC | 4 branchB | 3 | | 2' branchA | | 2 | |/ 1 origin/master, master | 0

git checkout master

 5 branchC | 4 branchB | 3 | | 2' branchA | | 2 | |/ 1 origin/master, HEAD -> master | 0

git pull master

 5 branchC | 4 branchB | 3 | | 2' branchA | | 2 | | | | | 6 origin/master, HEAD -> master | | | |/ / | / |/ 2 | 0

git checkout branchA

 5 branchC | 4 branchB | 3 | | 2' HEAD -> branchA | | 2 | | | | | 6 origin/master, master | | | |/ / | / |/ 1 | 0

git rebase master branchA

resolve merge conflicts

 5 branchC | 4 branchB | 3 | | 2'' HEAD -> branchA | | 2 | | | | 6 origin/master, master | | | / | / |/ 1 | 0

git checkout master

 5 branchC | 4 branchB | 3 | | 2'' branchA | | 2 | | | | 6 origin/master, HEAD -> master | | | / | / |/ 1 | 0

git merge branchA # the merge is fast-forward

 5 branchC | 4 branchB | 3 | | 2'' branchA, HEAD -> master | | 2 | | | | 6 origin/master | | | / | / |/ 1 | 0

git checkout branchB

 5 branchC | 4 HEAD -> branchB | 3 | | 2'' branchA, master | | 2 | | | | 6 origin/master | | | / | / |/ 1 | 0

git rebase master branchB # 2 should be dropped as 2'' is already is the branch

resolve merge conflicts

 5 branchC | | 4' HEAD -> branchB | | 4 | | | | 3' | | 3 | | | | 2'' branchA, master | | 2 | | | | 6 origin/master | | | / | / |/ 1 | 0

git checkout branchC

 5 HEAD -> branchC | | 4' branchB | | 4 | | | | 3' | | 3 | | | | 2'' branchA, master | | 2 | | | | 6 origin/master | | | / | / |/ 1 | 0

git rebase branchB branchC
resolve merge conflicts # As the rebase replays all the commits in branchB history that are not in branchC history, it will replay 2, 3, 4 and 5; that why, if you had conflicts, you may encounter them again
```
  5' HEAD -> branchC | 4' branchB | 3' | 2'' branchA, master | 6 origin/master | / / / 1 | 0 
```
design change requires refactoring branchA
git checkout master
git pull

git checkout -b refactorA

 5' branchC | 4' branchB | 3' | 2'' branchA, master, HEAD -> refactorA | 6 origin/master | 1 | 0

edit refactorA
git add ...
git commit

git review

 5' branchC | 4' branchB | | 7 HEAD -> refactorA | | 3' | | / 2'' branchA, master | 6 origin/master | 1 | 0

git checkout branchB

 5' branchC | 4' HEAD -> branchB | | 7 refactorA | | 3' | | / 2'' branchA, master | 6 origin/master | 1 | 0

git rebase refactorA branchB <== is this a mistake?

resolve merge conflicts (three sets of conflicts)

 5' branchC | | 4'' HEAD -> branchB | | 4' | | | | 7 refactorA | | 3' | | / 2'' branchA, master | 6 origin/master | 1 | 0

git review
git log # As you rebased your branch branchB on top of refactorA which is created from master who merged branchA, branchA commits are in branchB

git rebase with multiple sub-branches

Question

1 answers

solution1
0 2017-06-23 09:34:48

git rebase with multiple sub-branches

Question

1 answers

solution1 0 2017-06-23 09:34:48

solution1
0 2017-06-23 09:34:48