* seperate out registry requirement from source control requirement

* refactor manifet encoding and parsing to more clearly define dependency type and associated metadata
* make .upToNextMajor and .upToNextMinor extensions on Range<Version> to reuse across new requirment types
* adjust tests

Author: tomerd

Sources/Commands/Describe.swift

@@ -99,25 +99,19 @@ fileprivate struct DescribedPackage: Encodable {
     }
 
     /// Represents a package dependency for the sole purpose of generating a description.
-    struct DescribedPackageDependency: Encodable {
-        let identity: PackageIdentity
-        let name: String?
-        let url: String?
-        let requirement: PackageDependency.Requirement?
+    enum DescribedPackageDependency: Encodable {
+        case fileSystem(name: String?, path: AbsolutePath)
+        case sourceControl(name: String?, location: String, requirement: PackageDependency.SourceControl.Requirement)
+        case registry(identity: PackageIdentity, requirement: PackageDependency.Registry.Requirement)
 
         init(from dependency: PackageDependency) {
-            self.identity = dependency.identity
-            self.name = dependency.explicitNameForTargetDependencyResolutionOnly
             switch dependency {
             case .fileSystem(let settings):
-                self.url = settings.path.pathString
-                self.requirement = nil
+                self = .fileSystem(name: dependency.explicitNameForTargetDependencyResolutionOnly, path: settings.path)
             case .sourceControl(let settings):
-                self.url = settings.location
-                self.requirement = settings.requirement
+                self = .sourceControl(name: dependency.explicitNameForTargetDependencyResolutionOnly, location: settings.location, requirement: settings.requirement)
             case .registry(let settings):
-                self.url = nil
-                self.requirement = settings.requirement
+                self = .registry(identity: settings.identity, requirement: settings.requirement)
             }
         }
     }

Sources/PackageDescription/PackageDependency.swift

@@ -65,111 +65,6 @@ import Foundation
 /// without having to update your package manifest and without losing access to
 /// existing packages.
 public final class Package {
-
-    /// A package dependency of a Swift package.
-    ///
-    /// A package dependency consists of a Git URL to the source of the package,
-    /// and a requirement for the version of the package.
-    ///
-    /// The Swift Package Manager performs a process called *dependency resolution* to
-    /// figure out the exact version of the package dependencies that an app or other
-    /// Swift package can use. The `Package.resolved` file records the results of the
-    /// dependency resolution and lives in the top-level directory of a Swift package.
-    /// If you add the Swift package as a package dependency to an app for an Apple platform,
-    /// you can find the `Package.resolved` file inside your `.xcodeproj` or `.xcworkspace`.
-    public class Dependency: Encodable {
-
-        /// An enum that represents the requirement for a package dependency.
-        ///
-        /// The dependency requirement can be defined as one of three different version requirements:
-        ///
-        /// **A version-based requirement.**
-        ///
-        /// Decide whether your project accepts updates to a package dependency up
-        /// to the next major version or up to the next minor version. To be more
-        /// restrictive, select a specific version range or an exact version.
-        /// Major versions tend to have more significant changes than minor
-        /// versions, and may require you to modify your code when they update.
-        /// The version rule requires Swift packages to conform to semantic
-        /// versioning. To learn more about the semantic versioning standard,
-        /// visit [semver.org](https://semver.org).
-        ///
-        /// Selecting the version requirement is the recommended way to add a package dependency. It allows you to create a balance between restricting changes and obtaining improvements and features.
-        ///
-        /// **A branch-based requirement**
-        ///
-        /// Select the name of the branch for your package dependency to follow.
-        /// Use branch-based dependencies when you're developing multiple packages
-        /// in tandem or when you don't want to publish versions of your package dependencies.
-        ///
-        /// Note that packages which use branch-based dependency requirements
-        /// can't be added as dependencies to packages that use version-based dependency
-        /// requirements; you should remove branch-based dependency requirements
-        /// before publishing a version of your package.
-        ///
-        /// **A commit-based requirement**
-        ///
-        /// Select the commit hash for your package dependency to follow.
-        /// Choosing this option isn't recommended, and should be limited to
-        /// exceptional cases. While pinning your package dependency to a specific
-        /// commit ensures that the package dependency doesn't change and your
-        /// code remains stable, you don't receive any updates at all. If you worry about
-        /// the stability of a remote package, consider one of the more
-        /// restrictive options of the version-based requirement.
-        ///
-        /// Note that packages which use commit-based dependency requirements
-        /// can't be added as dependencies to packages that use version-based
-        /// dependency requirements; you should remove commit-based dependency
-        /// requirements before publishing a version of your package.
-        public enum Requirement {
-            case exactItem(Version)
-            case rangeItem(Range<Version>)
-            case revisionItem(String)
-            case branchItem(String)
-            case localPackageItem
-
-            var isLocalPackage: Bool {
-                if case .localPackageItem = self { return true }
-                return false
-            }
-        }
-
-        /// The name of the package, or `nil` to deduce the name using the package's Git URL.
-        public let name: String?
-
-        /// The location of the package dependency.
-        public let location: String?
-
-        @available(*, deprecated, renamed: "location")
-        public var url: String? {
-            get {
-                return self.location
-            }
-        }
-
-        /// The registry identity of package dependency.
-        public let identity: String?
-
-        /// The dependency requirement of the package dependency.
-        public let requirement: Requirement
-
-        /// Initializes and returns a newly allocated requirement with the specified url and requirements.
-        init(name: String?, url: String, requirement: Requirement) {
-            self.name = name
-            self.location = url
-            self.requirement = requirement
-            self.identity = nil
-        }
-
-        /// Initializes and returns a newly allocated requirement with the specified identity and requirements.
-        init(identity: String, requirement: Requirement) {
-            self.identity = identity
-            self.requirement = requirement
-            self.location = nil
-            self.name = nil
-        }
-    }
-
     /// The name of the Swift package.
     public var name: String