In this blog we will explore the concept of -

• Branches
• Push, pull, merge
• Pull Request and how can we contribute to any repo.

To understand above concepts we will follow a hands on appraoch of doing things -

Repo - Repository - Folder in Git.

Methods to access an existing repo -

• Directly download the repo from GitHub and open it in our terminal
• We can fork the repo using fork button on github - This creates a own copy of the repo under your account.
• We can use git clone command to clone the repo locally. Command - git clone “Add repo-link here”

We will understand the concepts of cloning, remote conenction establishment, branching through the below steps.

Let’s create a new repo in GitHub. I have created a test_repo.

We get somthing like this -

Copy the link here.

Use the git clone command to clone the repo locally -

Let’s add a few files into it and we will also use some of the commands from our previous blog to add the files into staging, commit the changes, then push the code into GitHub.

I have created two files in the repo. [ You can refer prev blog / google it to create files in a repo ]

To push the code to GitHub we need to establish a remote connection with the GitHub repo.

Why do we want to push code - Everyone with the repo link can view the updates in the code.

Command to establish remote connection - git remote add “remote-connection-name” “repo-link”

To view all exsisting remote connections in that repo .
Command - git remote -v

By default a remote connection with name origin is created if we use git clone command.

We can remove connection using command - git remote remove “remote-connection-name” .

Suppose we want to develop a project and we have a team of developers. We create a repo on GitHub. We then add a remote connection to that repo via our terminal, to make changes in our local system independently and then push those changes to the repo.

Why do we create a remote connection - To make changes locally in our system verify them once if they are proeprly working from our side and then pushing those to the github for the team to look into and review before deploying it.

I have also forked a public repo for example and did few things in the code.
Ex- git remote add origin https://github.com/NirDiamant/RAG_Techniques.git

To view all existing remote connections - git remote -v

Generally what happens is the repo’s main/ master branch is directly conencted to the hosting platform where our application in deployed. Any changes to the main branch will be reflecting in our production directly. To avoid any unnecessary issues , the main branch of the repo is locked so that none of the developers can directly push the code to the production without proper check . So each developer creates a seperate branch of the same repo, makes his/her changes then raises a pull request [PR], the manager / testing team after verification of the changes pushes the code into main branch.

By default after cloning a repo, a master branch is created in the local repo, which wil be conneced to the master branch of the repo.

We need to use remote conenction name to push changes into GitHub / MASTER branch.

How do we create branches - Using command
git branch

To view all existing branches - git branch -a
Naming convention followed while creating branches- Developer Name/Feature Name

Fetch - Used to pull the code of the github repo.

Use command - git fetch origin [ No branch is specifed always defults to MASTER]

We will manually add few changes in our repo from GitHub to understand fetch in the GitHub repo. I have added changes in the two base files created via GitHub web app.

To compare changes from your local repo master branch to the github repo’s master branch we use - git diff master origin/master

So we have made changes directly in the MASTER branch of repo in the GitHub.

Using fetch command we can always pull the latest committed code form the repo and store it via remotes/origin/MASTER. We can compare our repo code with latest github repo code and if needed shall be copied into our local repo to maintain sync with the changes in the repo.

Branching - Switch command

We can update our repo with the newly made changes using git pull command. But we need to set upstream branch to enable push and pull changes. We can assume upstream branch as a tracker for changes between the local master branch of the GitHub repo and master branch of Github repo.

Command - git branch —set-upstream-to=origin/MASTER

Now we can pull changes using pull command - git pull origin [If no branch is specified defaults to MASTER]

To observe all the commit history and updates of each branch - We can do it using command git log —oneline. When perfoming git log from MASTER branch provides us commits of all branches.

The branch Ankith/Feat1 is at commit 7864cda i.e. behind the master branch of the local repo by two commits. So now we can merge these changes in Ankith/feat1 branch from the MASTER branch of local repo to main sync with among all branches in the repo.

Explore checkout and restore commands in git.

Let’s understand merge —squash . Suppose we make multiple commits in Ankith/feat1 branch .

Head pointer in the git always points the latest commit,

Here we did few commits in the specific branch - Ankith/Feat1

When we use merge command all the three commits are merged into MASTER .

Instead we can also merge all the commits of Ankith/feat1 into MASTER branch using single commit by squashing all the commits into a single commit.

Initially the requried changes in MASTER branch accoding to Ankith/feat1 are placed into staging area. On commiting changes are made in MASTER branch using a single commit.

Generally we delete the branch once the changes are oushed to master branch.

Pushing - To push changes made in the local MASTER branch into Github
Command - git push origin.

Rebase - Suppose we have two branches Ankith/Feat2, MASTER. Suppose my firend has added many features into the MASTER branch. In this case of many changes in a MASTER branch i.e. all the structure of your Ankith/Feat2 branch is different from initial setup then we can use rebase to setup sync among the all branches, so that there are no merge conflicts.

Here we can resolve merge conflicts either automatically or manually.

We can explore the above topics in a bit depth by using these commands and playing with them.

Explore about how Pull Request is created in an org and in open source contributions, if possible add pull request to my repo - https://github.com/ANKITHDEEGOJU/Test_Repo

If possible do create your open repo and configure it to allow PR”s from others by modifying the main branch settings. [ Explore Protected Branches]

A small clarity - if you are the owner of the repo then your are connected to the MASTER branch by default, else you can push code directly to your branch and then raise a PR [if admin of the repo provides you access to create your own branch]. Generally people fork the repo , create their individual branch in the local repo , then push code to the master branch of this local repo, check if everything is fine. Then send PR to admin/ maintainer to accept the updates. Then the maintanienr verfies the code changes then accepts the pull request , merges changes into the main/MASTER branch of the repo.

Reference - Git Cheat Sheet