Making Incremental Integration Work for You

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Does your CM Tool Support Incremental Integration
Before finishing, I want to point out additional capabilities that are lacking in most tools, which would be useful in supporting incremental integration.

·         Incremental impact analysis: There are tools that will scan in your source files and allow you to do some basic impact analysis. If I change file A, which files are impacted? What we really need to ask is: If we promote these changes for an integration build, which files are impacted? Most of the time the impact of our incremental change set will be small, but we want to be able to identify when it will be large and control change selection; this is not done to eliminate a change, but rather to better time its promotion. This is equally important to a developer in an incremental build environment as it is to a build manager.

·         Incremental build tracking:  If you're doing frequent incremental builds (or even full re-builds based on an incremental set of changes), creating baselines for each build (and perhaps variants) will be expensive. Baselines, by their definition, provide a comparison point, a point of reference, a baseline against which builds can be compared. They serve as important reference points and hide the concept of changes since they are defined as a compatible set of revisions. CM tools need to support build tracking in a baseline plus changes manner. First of all, the build definition refers to a baseline. Then it specifies a set of changes applied to the baseline. This is good for build variants, customizations, etc., but it is really ideal for incremental builds on a baseline reference. Not only is there a common reference point for easily comparing recent builds, but the definition clearly enumerates the list of changes applied to the baseline. This is friendly to incremental integration as it is easy to see what changes went into each build. The better tools will allow you to track which builds are incremental versus those which are variants or customizations, etc.

·         Removing timestamp dependencies:  Most CM tools will rely on makefile functionality (or similar) and their associated time stamp comparisons to determine what needs to be re-built. This can normally be done in a safe way, but sooner or later you get caught by it - usually in a developer role, but occasionally in a system builder role. A CM tool should be able to easily generate a build script, or at least a data file, which indicates what has to be compiled, not based on timestamps, but based on the set of selected changes and the impact they have on other files - ideally using the build definition record.

·         Incremental changes to a build environment: Once you have an incremental build definition, you want to be able to update your environment in order to do your build operation. CM tools need more flexible file retrieval capabilities so that it’s easy to populate, not based on a set of problem numbers or a baseline definition, but on the changes and the impact of the changes. Older proprietary tools (e.g. PLS and SMS) support a file expression capability for identifying and retrieving the correct set of files in one simple operation. Very few modern CM tools (e.g. CM+) support this same capability.

Reporting and Incremental Integration
Finally, it all comes down to knowing what you're doing and what you've done. Even more important than release note generation, I would claim, is the ability to be able to report

About the author

Joe Farah's picture Joe Farah

Joe Farah is the President and CEO of Neuma Technology and is a regular contributor to the CM Journal. Prior to co-founding Neuma in 1990 and directing the development of CM+, Joe was Director of Software Architecture and Technology at Mitel, and in the 1970s a Development Manager at Nortel (Bell-Northern Research) where he developed the Program Library System (PLS) still heavily in use by Nortel's largest projects. A software developer since the late 1960s, Joe holds a B.A.Sc. degree in Engineering Science from the University of Toronto. You can contact Joe at farah@neuma.com

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