demo as part of the peer review
Finally, it's important that there is control over what is going to go into a build. High impact and high risk changes should be accepted early in the process, before the full team begins working on the release cycle. Tight control must be exercised as release dates approach. It's fine to have a developer who can fix 30 problems a week, but if those are all low priority problems, and we're nearing in on the release date, the result may not be desireable. Typically, somewhere between 10% and 30% of problem fixes will introduce undesireable side effects. If only 5 of the problems really needed to be fixed for the release, there's a much better chance of not having a severe problem resulting. Still, if it's earlier in the release cycle, there's time to absorb such side effects and fix the problems before they go out the door.
When you're controlling what goes into a build, it is really ineffective to do so at build time. This will likely create a minor revolt among the developers, who have worked hard to complete their work. Instead, you want to ensure that change control is starting prior to assignment of changes to the design team members. Ideally, developers begin work by selecting tasks/problems/features which have been approved and assigned to them. Then there's no rejection of unwanted functionality or problem fixes.
Perhaps an even more critical side effect of having a change control process up front is that work flows from the developer through the process and into integration in pretty much the same order. This reduces the need for rollbacks, branches and merges, and allows you to adopt a more optimized promotion scheme, and ideally one where you don't even need to create separate promotion branches. This in turn makes it easier to automate selection of changes, as pre-approved changes can flow through the system as soon as they are successfully peer reviewed.
Manage the Superset Baseline, Build Subsets
Many organizations create and manage a baseline for every build. While this provides for full reproducibility, managing a large number of baselines can be complex. Typically a product has a number of variants. While it is important to try to move variant configuration into run-time or at least deployment, there are a number of cases where this is not or can not be done. In this case, the best strategy is to manage a superset from a baseline perspective, while building subsets. It's natural to configure a product from a subset of the baseline. Instead of dozens of baselines, a single baseline is used for management and reference purposes. Each build can be customized, as long as the CM tool tracks the build definition in terms of the baseline.
For example, build of the baseline with the English option; build of the baseline with European standards; build the baseline with a specific customization for NASA. Tracking of builds involves identifying the baseline, identifying the option tags, and identifying any additional change packages that need to be added to it. As emergency fixes are added, new builds can be easily readied just by adding in the change packages for those fixes. No need to specifically commission a new baseline.
At Neuma, we create baselines occasionally, and then create a series of regular builds off of each baseline, not just for customer delivery, but for "nightly builds". It's easy to look at the difference between builds just by looking at the changes that have been added to each. It's like building a new house by saying: