[Workspace] Enable package mirror for graph root dependencies

<rdar://problem/45744090> Enable package mirroring for graph root dependencies

Author: aciidgh

Sources/PackageGraph/PackageGraphRoot.swift

@@ -56,10 +56,11 @@ public struct PackageGraphRoot {
         public let requirement: Requirement
 
         /// Create the package reference object for the dependency.
-        public func createPackageRef() -> PackageReference {
+        public func createPackageRef(config: SwiftPMConfig) -> PackageReference {
+            let effectiveURL = config.mirroredURL(forURL: self.url)
             return PackageReference(
-                identity: PackageReference.computeIdentity(packageURL: url),
-                path: url,
+                identity: PackageReference.computeIdentity(packageURL: effectiveURL),
+                path: effectiveURL,
                 isLocal: (requirement == .localPackage)
             )
         }
@@ -101,13 +102,13 @@ public struct PackageGraphRoot {
     }
 
     /// Returns the constraints imposed by root manifests + dependencies.
-    public var constraints: [RepositoryPackageConstraint] {
+    public func constraints(config: SwiftPMConfig) -> [RepositoryPackageConstraint] {
         let constraints = packageRefs.map({
             RepositoryPackageConstraint(container: $0, requirement: .unversioned)
         })
         return constraints + dependencies.map({
             RepositoryPackageConstraint(
-                container: $0.createPackageRef(),
+                container: $0.createPackageRef(config: config),
                 requirement: $0.requirement.toConstraintRequirement()
             )
         })

Sources/Workspace/Workspace.swift

@@ -155,8 +155,9 @@ public class Workspace {
             let inputIdentities = root.manifests.map({
                 PackageReference(identity: $0.name.lowercased(), path: $0.url)
             }) + root.dependencies.map({
-                let identity = PackageReference.computeIdentity(packageURL: $0.url)
-                return PackageReference(identity: identity, path: $0.url)
+                let url = workspace.config.mirroredURL(forURL: $0.url)
+                let identity = PackageReference.computeIdentity(packageURL: url)
+                return PackageReference(identity: identity, path: url)
             })
 
             var requiredIdentities = transitiveClosure(inputIdentities) { identity in
@@ -550,7 +551,7 @@ extension Workspace {
         var updateConstraints = currentManifests.editedPackagesConstraints()
 
         // Create constraints based on root manifest and pins for the update resolution.
-        updateConstraints += graphRoot.constraints
+        updateConstraints += graphRoot.constraints(config: config)
 
         // Record the start time of dependency resolution.
         let resolutionStartTime = Date()
@@ -929,8 +930,9 @@ extension Workspace {
             return DependencyManifests(root: root, dependencies: [], workspace: self)
         }
 
-        let rootDependencyManifests = root.dependencies.compactMap({
-            return loadManifest(forURL: $0.url, diagnostics: diagnostics)
+        let rootDependencyManifests: [Manifest] = root.dependencies.compactMap({
+            let url = config.mirroredURL(forURL: $0.url)
+            return loadManifest(forURL: url, diagnostics: diagnostics)
         })
         let inputManifests = root.manifests + rootDependencyManifests
 
@@ -1141,7 +1143,7 @@ extension Workspace {
             // Use root constraints, dependency manifest constraints and extra
             // constraints to compute if a new resolution is required.
             let dependencies =
-                graphRoot.constraints +
+                graphRoot.constraints(config: config) +
                 // Include constraints from the manifests in the graph root.
                 graphRoot.manifests.flatMap({ $0.dependencyConstraints(config: config) }) +
                 currentManifests.dependencyConstraints() +
@@ -1164,7 +1166,7 @@ extension Workspace {
         // Create the constraints.
         var constraints = [RepositoryPackageConstraint]()
         constraints += currentManifests.editedPackagesConstraints()
-        constraints += graphRoot.constraints + extraConstraints
+        constraints += graphRoot.constraints(config: config) + extraConstraints
 
         // Record the start time of dependency resolution.
         let resolutionStartTime = Date()

Tests/WorkspaceTests/WorkspaceTests.swift

@@ -2408,6 +2408,16 @@ final class WorkspaceTests: XCTestCase {
                     ],
                     versions: ["1.0.0", "1.4.0"]
                 ),
+                TestPackage(
+                    name: "Bam",
+                    targets: [
+                        TestTarget(name: "Bam"),
+                    ],
+                    products: [
+                        TestProduct(name: "Bar", targets: ["Bam"]),
+                    ],
+                    versions: ["1.0.0", "1.5.0"]
+                ),
             ]
         )
 
@@ -2426,8 +2436,13 @@ final class WorkspaceTests: XCTestCase {
         }
 
         try workspace.config.set(mirrorURL: workspace.packagesDir.appending(component: "Baz").asString, forPackageURL: workspace.packagesDir.appending(component: "Bar").asString)
+        try workspace.config.set(mirrorURL: workspace.packagesDir.appending(component: "Baz").asString, forPackageURL: workspace.packagesDir.appending(component: "Bam").asString)
 
-        workspace.checkPackageGraph(roots: ["Foo"]) { (graph, diagnostics) in
+        let deps: [TestWorkspace.PackageDependency] = [
+            .init(name: "Bam", requirement: .upToNextMajor(from: "1.0.0")),
+        ]
+
+        workspace.checkPackageGraph(roots: ["Foo"], deps: deps) { (graph, diagnostics) in
              PackageGraphTester(graph) { result in
                  result.check(roots: "Foo")
                  result.check(packages: "Foo", "Dep", "Baz")
@@ -2439,6 +2454,7 @@ final class WorkspaceTests: XCTestCase {
             result.check(dependency: "Dep", at: .checkout(.version("1.5.0")))
             result.check(dependency: "Baz", at: .checkout(.version("1.4.0")))
             result.check(notPresent: "Bar")
+            result.check(notPresent: "Bam")
         }
     }