The Product Management Soapbox - SCM Configuration Branching Ownership

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SCM Configuration Branching Ownership

Posted by Randall Becker, Nexbridge Inc., 12-Dec-1999

There's an interesting cost function associated with Branching. It's hard to draw in text characters, but important to think about. As the number of branches increases from zero, a few things happen:

The cost of sequencing (readying a feature for release) an individual change decreases, because you can pick and choose when and where you want the change to go in more readily.
The cost of unit testing the change decreases as well, because it is only being applied to a specific branch, for a specific configuration.
The cost, overall, of quality assurance goes up, because, to deploy the feature to an arbitrarily large (and ever growing) number of branches, someone has to ensure that the change is put into all relevant branches, without error.

In the last case, the costs can be so high, that it becomes "not cost effective" for companies to actually test changes in all threads. This leads to the user community ending up doing the actual testing.

From my experience, the cost functions intersect somewhere between 1 (closer to 1) and 2 branches off the mainline.