Move package collection JSON models to a separate module (#3199)

Motivation:
Some publishers may opt to generate package collections on their own, which will require the JSON models. It might not be desirable to pull in all the dependencies that come with PackageCollections module.

Modifications:
Move PackageCollections/JSONModel into its own PackageCollectionsModel module and make it a product.

Result:
Package collection JSON models can be used with minimal dependencies.

Author: yim-lee

Package.swift

@@ -39,6 +39,7 @@ let package = Package(
                 "SourceControl",
                 "SPMLLBuild",
                 "PackageCollections",
+                "PackageCollectionsModel",
                 "LLBuildManifest",
                 "PackageModel",
                 "PackageLoading",
@@ -55,6 +56,7 @@ let package = Package(
                 "SPMLLBuild",
                 "LLBuildManifest",
                 "PackageCollections",
+                "PackageCollectionsModel",
                 "PackageModel",
                 "PackageLoading",
                 "PackageGraph",
@@ -69,6 +71,7 @@ let package = Package(
             targets: [
                 "SourceControl",
                 "PackageCollections",
+                "PackageCollectionsModel",
                 "PackageModel",
                 "PackageLoading",
                 "PackageGraph",
@@ -87,6 +90,11 @@ let package = Package(
             type: .dynamic,
             targets: ["PackageDescription"]
         ),
+        
+        .library(
+            name: "PackageCollectionsModel",
+            targets: ["PackageCollectionsModel"]
+        ),
     ],
     targets: [
         // The `PackageDescription` targets define the API which is available to
@@ -139,11 +147,16 @@ let package = Package(
             dependencies: ["SwiftToolsSupport-auto", "Basics", "PackageLoading", "PackageModel", "SourceControl"]),
 
         // MARK: Package Collections
+        
+        .target(
+            /** Package collections models */
+            name: "PackageCollectionsModel",
+            dependencies: []),
 
         .target(
             /** Data structures and support for package collections */
             name: "PackageCollections",
-            dependencies: ["SwiftToolsSupport-auto", "Basics", "PackageModel", "SourceControl"]),
+            dependencies: ["SwiftToolsSupport-auto", "Basics", "PackageModel", "SourceControl", "PackageCollectionsModel"]),
 
         // MARK: Package Manager Functionality
 
@@ -249,6 +262,9 @@ let package = Package(
         .testTarget(
             name: "PackageGraphPerformanceTests",
             dependencies: ["PackageGraph", "SPMTestSupport"]),
+        .testTarget(
+            name: "PackageCollectionsModelTests",
+            dependencies: ["PackageCollectionsModel"]),
         .testTarget(
             name: "PackageCollectionsTests",
             dependencies: ["SPMTestSupport", "PackageCollections"]),

Sources/CMakeLists.txt

@@ -11,6 +11,7 @@ add_subdirectory(Build)
 add_subdirectory(Commands)
 add_subdirectory(LLBuildManifest)
 add_subdirectory(PackageCollections)
+add_subdirectory(PackageCollectionsModel)
 add_subdirectory(PackageDescription)
 add_subdirectory(PackageGraph)
 add_subdirectory(PackageLoading)

Sources/PackageCollections/CMakeLists.txt

@@ -1,14 +1,12 @@
 # This source file is part of the Swift.org open source project
 #
-# Copyright (c) 2020 Apple Inc. and the Swift project authors
+# Copyright (c) 2020-2021 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
 # See http://swift.org/LICENSE.txt for license information
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 add_library(PackageCollections
-  JSONModel/JSONCollection.swift
-  JSONModel/JSONCollection+v1.swift
   Model/Collection.swift
   Model/CVE.swift
   Model/License.swift