  Reusing existing solutions in the form of third-party libraries is common
practice when writing software. Package managers are used to manage
dependencies to third-party libraries by automating the process of installing
and updating the libraries. Library dependencies themselves can have
dependencies to other libraries creating a dependency network with several
levels of indirections. The library dependency network in the Swift ecosystem
encompasses libraries from CocoaPods, Carthage and Swift Package Manager (PM).
These package managers are used when developing, for example, iOS or Mac OS
applications in Swift and Objective-C. We provide the first analysis of the
library dependency network evolution in the Swift ecosystem. Although CocoaPods
is the package manager with the biggest set of libraries, the difference to
other package managers is not as big as expected. The youngest package manager
and official package manager for Swift, Swift PM, is becoming more and more
popular, resulting in a gradual slow-down of the growth of the other two
package managers. When analyzing direct and transitive dependencies, we found
that the mean total number of dependencies is lower in the Swift ecosystem
compared to many other ecosystems. Still, the total number of dependencies
shows a clear growing trend over the last five years.
