How to compare two commit ranges in git with git range-diff

Git is a free, open-source, version control system that can be used to keep track of changes that goes into any project file. It can also be used by multiple individuals who wish to collaborate on any software development project.

The git range-diff function is used to compare two git ranges. It takes in two commit ranges which are to be compared as arguments in the command line. It then displays the comparison between the two commits, which includes any deleted, modified, or newly added lines.

Real-world example

Now that we have a basic understanding of what git and the git range-diff function are, let's look at an example to understand further how this function is used.

Let's say we are working on a large project and wish to incorporate a new feature into the project, so we create a new branch and start working on the feature. We push any updates onto the branch that we have just created.

After we are finished with the new feature, we merge the branch on which the feature resides with the main branch. Now we want to verify if all the changes we did on the feature branch were present on the main branch.

For this, we will use the git range-diff function. We will give it the commit ranges of the feature branch(f1—f3) and the merged branch(f1`—f3`) from the first commit to the last commit. We will then cross-check to verify if all changes were successfully incorporated into the main code.

Implementation

Now that we have understood the purpose of this function, we will now understand how we are going to implement it.

Installing git and required packages

First, we will install git so that we can access and manipulate repositories. We can see the steps to install git below.

1. First, we will open the terminal. Linux-based systems can use the shortcut "Ctrl + Alt + T" or simply open the terminal through the search bar.

2. Once inside the terminal, we will enter the following command to install git (for Ubuntu-based systems).

3. We need to ensure the version of git we are installing is 2.23 or higher. To check the version of our git installation, we can use the command below.

4. Next, we have to install the git-extras package that contains the git range-diff function. We will use the command below to install the package.

Cloning the repository

Now that we have installed git, we will clone the repository on which we will compare commit ranges. We can see the steps to clone a git repository below.

1. First, we will first get the repository link from GitHub.

2. Once we have the link, we will then open the terminal. In the terminal, we will enter the following command to clone the repository.

3. Next, we will change directories to the one where our project files are contained using the command:

4. We can also see the commit made to the project by viewing the logs using the command:

The git log command shows an output similar to the code snippet attached below. Here we can see hash values against the commit, which we can use as input ranges in the git range-diff command.

Note: The above output contains commit hashes that are not useable. The user must use their commit hash values for the command to work.

Using the git range-diff command

Now that we are in the git directory, we will use the git range-diff command here and provide the commit ranges as arguments to the command.

Below is the syntax for the command to compare the commit ranges.

In the command above, <f1>..<f3> <f1`>..<f3`> represent the git ranges that are to be compared.

We can simply replace f1, f3, f1`, and f3` with commit hashes of the commit ranges we wish to compare.

Live demonstration

Here we can see a terminal that we can use to execute the command we had gone through above.

Below is a list of commands that we covered above. We can use these commands in the terminal to understand how the git range-diff function work.

Note: Replace <link to repository> with your own git repository link and the <f1>..<f3> <f1`>..<f3`> values with your repositiories commit hashes.