feat: Package traits

[vladimirleonidovich]

Is there a way to specify which traits of a package I want to enable via XcodeGen specification?

[philprime]

Coming here from getsentry/sentry-cocoa, we’d love this feature. We have a macOS CLI sample that depends on our SDK via SPM and needs to enable a package trait (NoUIFramework) so the SDK builds without UIKit/AppKit.

For now we keep the .xcodeproj in version control with traits set in the pbxproj. In the generated project, traits appear in two places:

On the package reference (XCLocalSwiftPackageReference) the traits are an array of strings:

/* Begin XCLocalSwiftPackageReference section */
		5E768911F94FAF5B7FB66121 /* XCLocalSwiftPackageReference "my-dependency" */ = {
			isa = XCLocalSwiftPackageReference;
			relativePath = path/to/my-dependency;
			traits = (
				NoUIFramework,
			);
		};
/* End XCLocalSwiftPackageReference section */

For the spec I would propose an optional traits array on the package/product dependency so the spec can drive both of the above, e.g.:

dependencies:
  - package: Sentry
    product: SentrySPM
    traits:
      - NoUIFramework

Traits are supported in Xcode 26.4 Beta and Swift 6.1+ (SE-0450).