(^136) 97 Things Every Programmer Should Know
Put Everything
Under Version
Control
Diomidis Spinellis
PUT EVERYTHiNG iN ALL YOUR PROjECTS UNDER VERSiON CONTROL.
The resources you need are there: free tools like Subversion, Git, Mercurial,
and CVS; plentiful disk space; cheap and powerful servers; ubiquitous net-
working; and even project-hosting services. After you’ve installed the version
control software, all you need in order to put your work in its repository is
to issue the appropriate command in a clean directory containing your code.
And there are just two new basic operations to learn: you commit your code
changes to the repository and you update your working version of the project
with the repository’s version.
Once your project is under version control, you can obviously track its his-
tory, see who wrote what code, and refer to a file or project version through a
unique identifier. More importantly, you can make bold code changes without
fear—no more commented-out code just in case you need it in the future,
because the old version lives safely in the repository. You can (and should) tag
a software release with a symbolic name so that you can easily revisit in the
future the exact version of the software your customer runs. You can create
branches of parallel development: most projects have an active development
branch and one or more maintenance branches for released versions that are
actively supported.
A version control system minimizes friction among developers. When pro-
grammers work on independent software parts, these get integrated almost by
magic. When they step on one another’s toes, the system notices and allows
them to sort out the conflicts. With some additional setup, the system can
notify all developers for each committed change, establishing a common
understanding of the project’s progress.