COMP1531
⚽ Teamwork
2.1 – Git – Team Usage
In this lecture
Why?
Git is primarily useful when working with others, and
working with others effectively is important
What?
Branching
Merging
Merge Requests
Live Demo
Most of today’s explanations will be covered via a live
demo. If you want to follow a written guide, then
please checkout .Atlassian’s git guide
https://www.atlassian.com/git
The git tree model
Git can be understood as a tree-like structure.
Git is a collection of commits.
Each commit has one parent. Each commit can have multiple
children (i.e. branches)
A branch essentially is just a pointer to a particular commit.
To try and bring two separate branches together onto the same
commit is a process of “merging”
Source: https://github.com/frappe/charts/issues/180
Branches
Your “master” branch is just a pointer to a particular
commit on master (usually the latest).
You can create your own branch if you want to
continue on a separate thread of working, unrelated
to the master branch.
git checkout -b new_branch_name1
Branches
This then allows you to continue making commits on a
separate “branch”.
There is no limit for the number of branches you can
have in a repository.
Branches
Your local repository can also “check out” (work with)
a single branch at a time. You can swap between
branches using the checkout command.
It’s generally good practice to ensure you have no
staged or unstaged changes on your branch before
swapping to another.
git checkout branch_to_swap_to1
Merging
The process of “incorporating work on another branch
into mine” is known as merging. The two most
common cases of merging you’ll see are:
Merging master into your work whilst you develop
on it (so you’re integrated small changes often,
rather than a big change suddenly)
Merging your work into master once your branch is
stable enough to merge into master
The merge command let’s you specify the branch you
want merged into your current branch.
git merge master1
Merging
# Commits made
on your branch
Commits made on
master branch
Command & Outcome
1 Yes No Nothing to do
2 No Yes from your branch, git merge master
Will “fast forward” merge (i.e. simply bring your branch pointer to
the same commit as master, effectively no merge)
3 No Yes from your branch, git merge master
Will “fast forward” merge (i.e. simply bring master’s branch to the
same commit as your branch, effectively no merge)
4 Yes Yes from your branch, git merge master
Will merge master into your branch, but a merge commit will get
made (either automatically or manually)
5 Yes Yes from master branch, git merge your_branch
Will merge your branch into master, but a merge commit will get
made (either automatically or manually)
The following describe a scenarios of scenarios with respect to merging between
your working branch and master
Merge Requests
In most industries, you cannot merge your branch into master via the
command line. Instead, we allow our git site (e.g. gitlab) to do this via a
Merge Request (a web-based GUI that helps manage merges into master)
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