Branches

What are branches?#

In case you have not looked at a source control tool before, “branching” is a core concept.

Repository with no branch#

A series of changes to a repository might look like this:

Direction of arrows in Git diagrams
The arrows in the above diagram point backward in time. This is a convention standard in Git diagrams. It indicates that each commit depends on the previous commit back to the initial commit. In the above diagram, the last change C depends on B which in turn is dependent on A.

The letters do not have a specific meaning here. They simply indicate multiple changes to lines that are grouped together.

Here, change A is made, then B, and then C. This might be informally called the main line. Most of the time, it’s called the “master” in Git.

Adding branch to a repository#

But let’s say someone wants to make an experimental change but does not want to affect the main line. They might branch the code at point C:

Study the above diagram, and make sure you understand it.

While the main line has continued with changes D and E, another branch has been created from C that has one change: F made to it. This experimental branch does not include the D and E changes, and the master branch does not include the experimental changes.

That way, users can choose to get a view of the source on the main line branch or the experimental one.

That’s all a branch is: a set of changes from a specific point in time.