Stream Refactoring with Pass-throughs

One of the greatest stories ever told is your software configuration management or CM process through the lense of a StreamBrowser. No other tool gives you the power to both visualize and manipulate your software development process in real-time. Over time, you’ll notice your stream hierarchy evolving into an elaborate tree effectively telling the story.

There are a number of techniques to help navigate the tree such as the GUI zoom feature and good naming conventions. But the unsung hero of stream organization is the pass-through stream. You probably already know about other types of streams such as dynamic, workspace, snapshot, and timebasis. Just like its siblings, the pass-through stream is also a configuration of source code but comes with a unique feature — all elements promoted to it are are automatically promoted to the pass-through’s parent stream, hence the name.

So what exactly are the benefits?

• Group logically related child streams for organizational purposes.
• A handle to reparent groups of streams without requiring an unnecessary promotion (to it).
• Set include/exclude rules to be applied to all children streams without the unecessary promote step.
• As an advanced technique, you can create a reftree on a pass-through to do software builds wherever the passthrough is currently parented — say last weeks build or last nights build — offering easy, visual, manual control over which configuration is built.

Lets put this knowledge to use. In the following diagram, you’ll see how a relatively sophisticated process model is cleanly organized with pass-through streams. There are a few pattern motifs used for organizing active development, nightly builds, system test builds, official release codelines, and customer one-offs. Notice how collapsing them all (left image) leaves the high-level process-centric streams nice and clean looking. Furthermore, notice how the names of the pass-through streams help tell the story of what activity is happening where.

Using pass-through streams is a passive refactoring technique that does not interfere with inheritance and can be introduced safely without disrupting development activity. In my experience, the more organized your stream structure, the happier the end users.

/happy refactoring/ – dave