Branch by Abstraction

An approach to large-scale change in a codebase that allows ongoing releases whilst the change is in progress.

• assume we have client code (dependent) and supplier code (dependency)
• introduce abstraction layer between client and supplier by modifying both
• develop new supplier code
• migrate client code to use the new supplier code via the abstraction layer
• remove old supplier code
• (optional) remove abstraction layer

References

Paul Hammant wrote about "Introducing Branch By Abstraction", 2007 blog but credits Stacey Curl with coining the phrase

Martin Fowler simplified and promoted the phrase in ~2014 page