# Patch Sets

version v3.4.4

As described in Changes, a change represents a single commit under review. Each change is assigned a Change-Id.

It is very common to amend a commit during the code review process. Gerrit uses the Change-Id to associate each iteration of the commit with the same change. These iterations of a commit are referred to as patch sets. When a change is approved, only the latest version of a commit is submitted to the repository.

Note | It is also possible to copy a Change-Id to a completely new commit. This is useful in situations where you want to keep the discussion around a change, but also need to completely modify your approach.

## File List

When you open a change in Gerrit, a list of affected files appears in the file list, located in the middle of the Review screen. This table displays the following information for each file:

- A checkbox, indicating the file has been reviewed

- The type of modification

- The path and name of the file

- The number of added lines and or deleted lines

## File modifications

Each file in a patch set has a letter next to it, indicating the type of modification for that file. The following table lists the types of modifications.

Table 1. Types of file modifications
Letter | Modification Type | Definition
--- | --- | ---
M | Modification | The file existed before this change and is modified.
A | Added | The file is newly added.
D | Deleted | The file is deleted.
R | Renamed | The file is renamed.
C | Copied | The file is new and is copied from an existing file.

If the status is R (Renamed) or C (Copied), the file list also displays the original name of the file below the patch set file.

## Views

By default, Gerrit displays the latest patch set for a given change. You can view previous versions of a patch set by selecting from the Patch Set drop-down list.

## Diffs

Clicking a file in the file list opens the Diff screen. By default, this screen displays a diff between the latest patch set’s version of a file and the current version of that file in the repository. You can also open a diff within the Review screen by clicking the blue triangle located in the same row as the file. To show the diffs of all files in the Review screen, click the Show Diffs link, located at the top of the file list.

You can diff between other patch sets by selecting a patch set number from the Diff Against drop-down list.

## Description

Each change in Gerrit must have a change description. This change description comes from the commit message and becomes part of the history of the project.

In addition to the change description, you can add a description for a specific patch set. This description is intended to help guide reviewers as a change evolves, such as "Added more unit tests." Unlike the change description, a patch set description does not become a part of the project’s history.

To add a patch set description, click Add a patch set description, located in the file list, or provide it on upload.

Part of Gerrit Code Review