Engineering Craft › Clean Code & Principles
Boy Scout Rule
Leave the code a little cleaner than you found it.
Also known as: campsite rule, leave it cleaner
The boy scout rule says: leave the code a little cleaner than you found it. The name comes from the scouts’ habit of leaving a campsite tidier than they arrived. It was popularized for software by Robert C. Martin.
You don’t have to fix everything. Whenever you work in a file, make one small improvement along the way:
- Rename a confusing variable.
- Delete a dead function or a stale comment.
- Extract a few lines into a well-named helper.
- Add a missing test for the code you’re touching.
- Fix a typo or an obvious small mess.
# you came to fix a bug in this function, and you also...
def calc(d, r): → def price_after_discount(price, rate):Why it works
Large cleanups never get scheduled. Small improvements made continuously keep quality from decaying, and spread the effort so no one has to ask for “refactoring week” (technical debt). Every visit makes the next one easier.
Keep it safe and small
- Stay close to what you’re changing. Clean the area you’re already working on, so you understand it and can test it.
- Don’t mix big refactors into a feature PR. Reviewers need to see the real change. Put larger cleanups in separate commits or PRs (small PRs).
- Make sure tests pass, before and after (refactoring).
- Don’t reformat whole files in the same change, which buries real edits. Let a formatter handle style separately.
- Follow team conventions (following conventions).
- Don’t gold-plate. The rule says a little cleaner, not perfect.
For problems too large for a quick fix, record them and plan them (managing technical debt).