My first assignment as a professional programmer was to build another person’s program. I learned right away not to assume a project will build just because the author says it will. I’ve seen the same pattern repeated everywhere I’ve worked. Despite version control systems and procedures, there’s usually some detail in the developer’s head that doesn’t get codified and only the original developer can build the project easily.
The first step in making software builds reproducible is documentation. There’s got to be a document explaining how to extract the project from version control and build it. Requiring screen shots helps since developers have to rehearse their own instructions in order to produce the shots.
The second step is verification. Documentation needs to be tested, just like software. Someone who hasn’t worked on the project needs to extract the code onto a clean machine and build the project using only written instructions — no conversation with the developer allowed. Everyone thinks their code is easy to build; experience says most people are wrong.
The verifiers need to rotate. If one person serves as build master very long, they develop the same implicit knowledge that the original programmers failed to codify.
The third step is automation. Automated instructions are explicit and testable. If automation also saves time, so much the better, but automation is worthwhile even if it does not save time. Clift Norris and I just wrote an article on CodeProject entitled Automated Extract and Build from Team System using PowerShell that helps with this third step if you’re using Visual Studio and VSTS.