Personal Git-related notes

I do not use Git so often to remember all the steps (and commands) to contribute to open-source projects (usually hosted on Github), so here I write down some notes.

Howtos

Add upstream tracking of a forked project:

git remote add --track master upstream https://forked_project.git

Fetch a specific branch from a source (here the case of upstream):

git remote -v  # shows all remote sources
git fetch upstream remote_branch_name:local_brach_name

Delete a branch:

git branch --delete your_branch_name      # locally
git push origin --delete your_branch_name # remotely

Pull from a given remote branch:
```
git pull origin other-branch
```

Overwrite any local changes on pull:

git fetch --all
git reset --hard origin/master

Clone all remote branches:

git clone git://example.com/myproject
cd myproject
git branch -a # to show all branches
git checkout -b experimental origin/experimental  # creates a local tracking branch

Change Github authentification from HTTPS to SSH:

#First add a public SSH key (e.g. `~/.ssh/id_rsa.pub`)
git remote -v
git remote set-url origin git@github.com:USERNAME/REPOSITORY.git
git remote -v

Configuration

Username and email:

git config --global user.name "Your Name"
git config --global user.email "your.email@your_provider.com"

Temporary cache password for one hour:

git config --global credential.helper "cache --timeout=3600"

Proxy (here at ESRF):

git config --global http.proxy http://proxy.esrf.fr:3128
git config --global https.proxy https://proxy.esrf.fr:3128

Branching workflow

Click fork button on the repo you want to contribute to.
Clone it locally to your machine.

Add upstream track for updates (here example on pymca repo):

git remote add --track master upstream git://github.com/vasole/pymca.git

To fetch and merge updates from the master original project:
```
git fetch upstream
git merge upstream/master
```
To show all remote repositories (‘origin’ is the forked one, ‘upstream’ is the original project):
```
git remote -v
```

Make a working branch and switch to it:

git branch your_branch_name
git checkout your_branch_name
git branch -a #(this will show all the branches and put * on working one)

If the working branch exists already remotely:
```
git checkout your_remote_branch
```
Push your local changes to a remote branch:
```
git push origin your_branch_name
```
Go to your fork’s webpage on Github and click ‘pull-request’ button give pull-request a name, fill in details of what changes you made, click submit button. you’re done!!

Once the pull request accepted/rejected you can delete your branch:

git branch --delete your_branch_name      #locally
git push origin --delete your_branch_name #remotely

Specific cases

Fetch a given remote branch:

git checkout --track origin/daves_branch
# This is equivalent to
git checkout -b [branch] [remotename]/[branch]

Merge master into a feature branch (well explained here, see also gitflow):

# Case 1 (single commits of the feature branch will be added to master
#        (NOTE: this will pollute the history with fragmented commits)
git checkout feature1
git merge master

# Case 2: you do not want to have the commits from the bug fixes in your feature branch
git checkout feature1
git rebase master

# Manage all conflicts that arise. When you get to the commits with the bugfixes
# (already in master), git will say that there were no changes and that maybe they
# were already applied. You then continue the rebase (while skipping the commits
# already in master) with::

git rebase --skip

Useful links

Tags

Basics explained here

New annotated tag:
```
git tag -a v1.4 -m "my version 1.4"
```
List existing tags and show details:
```
git tag
git show v1.4
```
Push to remote server:
```
git push origin v1.4
```
Delete local tag:
```
git tag -d tag_name
```
Delete remote tag:
```
git tag --delete origin tag_name
```