Chapter 7. Source Control
Many different methodologies for building software applications exist, and though the theories about team structure, work allocation, design, and testing often differ, one point that they agree on is that there should be a single repository for all source code for an application. Source control is the process of storing source code (referred to as checking code in) and accessing it again (referred to as checking code out) for editing. When we refer to source code, we mean any resources, configuration files, code files, or even documentation that is required to build and deploy the application.
Source code repositories also vary in structure and interface. Basic repositories provide a limited interface through which files can be checked in and out. The storage mechanism can be as simple as a file share, and no history may be available. Yet this repository still has the advantage that all developers working on a project can access the same file, with no risk of changes being overwritten or lost. Most sophisticated repositories not only provide a rich interface for checking in and out, such as merging and other resolution options, but can also be used from within Visual Studio to manage the source code. Other functionality that a source control repository can provide includes versioning of files, branching, and remote access.
Most organizations start using a source control repository to provide a mechanism for sharing source code between participants in a project. Instead of developers having to manually copy code to and from a shared folder on a network, the repository can be queried to get the latest version of the source code. When a developer finishes his or her work, any changes can simply be checked into the repository. This ensures that everyone in the team can access the latest code. Also, having the source code checked into a single repository makes it easy to perform regular backups.
Version tracking, including a full history of what changes were made and by whom, is one of the biggest benefits of using a source control repository. Although most developers would like to think that they write perfect code, the reality is that quite often a change might break something else. Being able to review the history of changes made to a project makes it possible to identify which change caused the breakage. Tracking changes to a project can also be used for reporting and reviewing purposes, because each change is date stamped and its author indicated.