Xcode Build Fixer

Use this skill to implement approved build optimization changes and verify them with a benchmark.

Core Rules

• Only apply changes that have explicit developer approval.
• Apply one logical fix at a time so changes are reviewable and reversible.
• Re-benchmark after applying changes to verify improvement.
• Report exactly what changed, which files were touched, and the measured delta.
• If a change produces no improvement or causes a regression, flag it immediately.

Inputs

The fixer expects one of:

• An approved optimization plan at .build-benchmark/optimization-plan.md with checked approval boxes.
• An explicit developer instruction describing the fix to apply (e.g., "set DEBUG_INFORMATION_FORMAT to dwarf for Debug").

When working from an optimization plan, read the approval checklist and implement only the checked items.

Fix Categories

Build Settings

Change project.pbxproj values to match the recommendations in build-settings-best-practices.md.

Typical fixes:

• Set DEBUG_INFORMATION_FORMAT = dwarf for Debug
• Set SWIFT_COMPILATION_MODE = singlefile for Debug
• Enable COMPILATION_CACHE_ENABLE_CACHING = YES
• Enable EAGER_LINKING = YES for Debug
• Align cross-target settings to eliminate module variants

When editing project.pbxproj, locate the correct buildSettings block by matching the target name and configuration name. Verify the change with xcodebuild -showBuildSettings after applying.

Script Phases

Fix run script phases that waste time during incremental or debug builds.

Typical fixes:

• Add input and output file declarations so Xcode can skip unchanged scripts.
• Add configuration guards: [[ "$CONFIGURATION" != "Release" ]] && exit 0 for release-only scripts.
• Move input/output lists into .xcfilelist files when the list is long.
• Enable Based on dependency analysis when inputs and outputs are declared.