build-debugging

A 'No such module' error occurs when Xcode cannot find a Swift package you've added. Clear derived data, verify the package is linked in Build Phases, check that the target membership is set correctly, and rebuild. If using SwiftPM, ensure the package dependency is declared in Package.swift and that version constraints allow the expected version to resolve.

'Multiple commands produce' errors happen when duplicate build rules or files generate the same output. Diagnose by checking Build Phases for duplicate Copy Bundle Resources or Compile Sources entries, remove conflicting CocoaPods or SwiftPM declarations, and verify no files are assigned to multiple targets. Rebuild after cleaning derived data.

Diagnose SwiftPM resolution issues by examining version constraints in Package.swift, checking dependency graphs for conflicts, running `swift package resolve` from the command line, and inspecting Package.resolved. Verify internet connectivity, validate semantic versioning in dependency declarations, and test with explicit version pinning to isolate constraint conflicts.

CocoaPods conflicts arise from incompatible version constraints across pods. Run `pod repo update`, review the Podfile for conflicting version specs, use `pod install --repo-update` to refresh, and check `Podfile.lock` for resolution details. Consider broadening version ranges or pinning specific compatible versions across dependent pods.

Yes, you can combine CocoaPods and SwiftPM in one project, but managing both requires careful dependency tracking to avoid conflicts. Use CocoaPods for Objective-C libraries and SwiftPM for Swift packages where possible, ensure no pod declares a dependency also pulled by SwiftPM, and test build settings in both local development and CI pipelines.

CI and local build divergence typically stems from cached derived data, environment-specific build settings, or missing dependency resolution steps. Reproduce by cleaning caches between builds, verify SwiftPM and CocoaPods are installed and updated identically in CI, confirm Xcode versions match, and validate that all framework search paths and build settings are set explicitly rather than relying on defaults.