One change at a time

A single commit should contain only changes related to a single user story or issue. For instance, don't mix formatting changes with bug fixes. In other words: A change should have only one reason to be reverted.

Motivation

In case of problems it is very helpful to be able to blame just a few lines that were changed, instead of 20 files that contain everything from reformatting, refactoring log statements to changes in the transaction API.

Applicability

All projects where source control is used.

Application

  • Apply changes one at a time, e.g. when you fix two issue tracker tickets in the same file, record the changes for both fixes as separate commits in version control.
  • Separate code clean up from functional changes. So Don't combine formatting changes and semantic changes in a single commit.
  • Check each changeset before you push it to the central repository, to see if it communicates your intention.

Effects

  • Easier to inspect and review changes in SCM history.
  • Enables cherry-picking of changes.
  • Reduces hassle if a change needs to be reverted

References

The Xebia Essentials Cards

This page is part of the Xebia Essentials, a pack of flash cards about Software Development Done Right. You can get your own deck of Essentials cards in the Xebia store.