A codebase is not the working folder on the machine where a change is made. It is the one tracked place the software lives, together with the recorded history of every change made to it. The conditions below are the first factor of twelve-factor, restated in decision voice.
One piece of software has one such place. A second place holding the same software is a violation.
Every change is committed. The recorded history is what makes a way back possible. Without it there is no way back, only a rebuild.
Every running instance is traceable to one commit. A running instance for which no commit is nameable is a violation.
The way back is established before the work begins. Work started with no way back already in place is a violation. The mechanism is version control.
Conformance is checkable from the record alone. The one place, the commit behind every change, and the commit behind every running instance are all nameable, and where any of the three is not, there is nothing to return to.
A way back takes more than one shape. A change that is additive and sits behind a flag has its way back in turning the flag off. The flag is itself a committed change, and a way back outside the recorded history is not one.
Inspection
Ground yourself in where this project's code actually lives, then tell me exactly which commit is running in front of people right now.
Held this, or broke it? Say which principle and what happened — tell me at /contact, subject Principles. What moves a band is somebody else's experience, and I'll publish what moved and who moved it.
SAM HENRY
Founder of SalesSmyth. I build businesses and software with AI agents and write about what holds up. The full version is on About.