Git - Branching and Merging

title

Git for Users Training Course

author

Bernard Szlachta (NobleProg Ltd)

Branching and Merging ⌘

git branch

list all branches

git branch <branch>

create a new branch named <branch>, referencing the same point in history as the current branch

git branch <branch> <start-point>

create a new branch named <branch>, referencing <start-point> (branch, tag or commit)

git branch -d <branch>

delete the branch <branch>; if the branch you are deleting points to a commit which is not reachable from the current branch, this command will fail with a warning.

git branch -D <branch>

• forces to do even branch points to a commit not reachable from the current branch
• failed experiment branches
• use only for changes in your repository

git checkout <branch>

switch to the <branch>

git checkout -b <new> <start-point>

create a new branch <new> referencing <start-point>, and check it out

Dealing with Branches and Tags ⌘

 git clone git://git.kernel.org/pub/scm/git/git.git
 git branch
 git branch -r
 git tag
 git checkout maint
 git branch
 git checkout v1.7.4
 git branch

Creating Branches ⌘

cp repo/ repo.bak -R; cp central/ central.bak -R

Create new branch and switch working copy

git branch experiment
git checkout experiment
git checkout -b experiment

Merging ⌘

• switch to experiment
• modify the afile.txt

git commit -a
git checkout master
modify afile.txt (different part)
git commit -a
gitk --all
git branch
git merge experiment
gitk --all

Exercise (REmoving) ⌘

1. Create branch v2.x
2. Modify a couple of files in the branch
3. Merge the branch with master
4. Remove the branch v2.x

Exercises (remote branching) ⌘

• Create a branch “quickfix” from a master branch

git checkout master
git checkout -b quickfix

• create quickfix.txt in quickfix branch and commit

touch quickfix.txt
git add quickfix.txt
git commit -m "quickfix"

• switch to master

git checkout master

• Commit 2 changes into the master branch

echo 1 >> afile.txt; git commit -a -m "change1"
echo 2  >> afile.txt; git commit -a -m "change2"

• switch back to quickfix

git checkout quickfix

• analyse situation in

gitk --all

• Push the quickfix to the production

git push origin quickfix

• On production

git fetch origin quickfix
git branch -a
git checkout origin/quickfix -b quickfix

• On Devel

merge quickfix into masterbranch

• delete quickfix branch

Reverting Merges ⌘

Adding commit with reverted changes

git revert

Before Committing

git reset --hard HEAD

After Committing

git reset --hard ORIG_HEAD

use only if you committed it only to your private repo

Rebasing ⌘

git checkout -b mywork origin
echo mywork changes >> afile.txt
git commit -a
git checkout master
echo some new func >> afile_master.txt
git add afile_master.txt
git commit
gitk --all
git rebase mywork
gitk --all
git prune
gitk --all

Exercise ⌘

1. Create a branch “quickfix”
2. add a couple of changes afile.txt in quickfix branch
3. switch to master
4. Commit 2 changes into the master branch
5. switch back to quickfix
6. analyse situation in gitk --all
7. rebase quickfix branch to master
8. analyse situation in gitk -all
9. prune dangling objects
10. gitk --all

Cherry Picking ⌘

touch afile.txt git add afile.txt git commit -m "new filo" git checkout -b exp echo Not Cherry1 >> afile.txt git commit -a -m NotCherry1 echo Cherry >> afile.txt git commit -a -m Cherry echo Not Cherry2 >> afile.txt git commit -a -m NotCherry2 git checkout master echo masterchange >> afile_master.txt git add afile_master.txt git commit -a -m "Master Change" git log exp git cherry-pick 3c8f

Stashing ⌘

• git-stash to save the current state of your work
• git stash save "work in progress for foo feature"
• echo “bug fix” >> afile.txt
• git commit -a -m "fixed the bug"
• git stash pop

Workflow Structure ⌘

Combining Commits ⌘

1. Version upto 1.6

git format-patch  v1.0..HEAD
git reset v1.0
git apply *.patch
git commit

1. Version 1.7 onwords

 git reset v1.0
 git commit