[Utility] Sink version extraction into Utility.Git.

Author: ddunbar

Package.swift

@@ -43,7 +43,8 @@ let package = Package(
         Target(
             /** Abstractions for common operations, should migrate to Basic */
             name: "Utility",
-            dependencies: ["POSIX", "Basic"]),
+            dependencies: ["POSIX", "Basic", "PackageDescription"]),
+            // FIXME: We should be kill the PackageDescription dependency above.
         Target(
             /** Source control operations */
             name: "SourceControl",

Sources/Get/Git.swift

@@ -46,21 +46,3 @@ extension Git {
         return Repo(path: dstdir)!  //TODO no bangs
     }
 }
-
-extension Git.Repo {
-    var versions: [Version] {
-        let out = (try? Git.runPopen([Git.tool, "-C", path.asString, "tag", "-l"])) ?? ""
-        let tags = out.characters.split(separator: "\n")
-        let versions = tags.flatMap(Version.init).sorted()
-        if !versions.isEmpty {
-            return versions
-        } else {
-            return tags.flatMap(Version.vprefix).sorted()
-        }
-    }
-
-    /// Check if repo contains a version tag
-    var hasVersion: Bool {
-        return !versions.isEmpty
-    }
-}

Sources/Get/Version.swift

@@ -23,12 +23,4 @@ extension Version {
     static var maxRange: Range<Version> {
         return self.min..<self.max
     }
-
-    static func vprefix(_ string: String.CharacterView) -> Version? {
-        if string.first == "v" {
-            return Version(string.dropFirst())
-        } else {
-            return nil
-        }
-    }
 }

Sources/Utility/Git.swift

@@ -14,6 +14,18 @@ import func POSIX.getenv
 import libc
 import class Foundation.ProcessInfo
 
+import struct PackageDescription.Version
+
+extension Version {
+    static func vprefix(_ string: String) -> Version? {
+        if string.characters.first == "v" {
+            return Version(string.characters.dropFirst())
+        } else {
+            return nil
+        }
+    }
+}
+
 public class Git {
     public class Repo {
         public let path: AbsolutePath
@@ -41,6 +53,40 @@ public class Git {
             }
         }(self)
 
+        /// The set of known versions and their tags.
+        public lazy var knownVersions: [Version: String] = { repo in
+            // Get the list of tags.
+            let out = (try? Git.runPopen([Git.tool, "-C", repo.path.asString, "tag", "-l"])) ?? ""
+            let tags = out.characters.split(separator: "\n").map{ String($0) }
+
+            // First try the plain init.
+            var knownVersions: [Version: String] = [:]
+            for tag in tags {
+                if let version = Version(tag) {
+                    knownVersions[version] = tag
+                }
+            }
+            // If we didn't find any versions, look for 'v'-prefixed ones.
+            if knownVersions.isEmpty {
+                for tag in tags {
+                    if let version = Version.vprefix(tag) {
+                        knownVersions[version] = tag
+                    }
+                }
+            }
+            return knownVersions
+        }(self)
+
+        /// The set of versions in the repository.
+        public var versions: [Version] {
+            return [Version](knownVersions.keys)
+        }
+
+        /// Check if repo contains a version tag
+        public var hasVersion: Bool {
+            return !versions.isEmpty
+        }
+        
         public var branch: String! {
             return try? Git.runPopen([Git.tool, "-C", path.asString, "rev-parse", "--abbrev-ref", "HEAD"]).chomp()
         }

Tests/GetTests/GitTests.swift

@@ -12,16 +12,25 @@ import XCTest
 
 import TestSupport
 import Basic
-@testable import Get
-import struct PackageModel.Manifest
+
 import class PackageDescription.Package
 import class Utility.Git
+import struct PackageDescription.Version
+import struct PackageModel.Manifest
+
+@testable import Get
 
 class GitTests: XCTestCase {
     func testHasVersion() {
         mktmpdir { path in
             let gitRepo = makeGitRepo(path, tag: "0.1.0")!
             XCTAssertTrue(gitRepo.hasVersion)
+            XCTAssertEqual(gitRepo.versions, [Version(0,1,0)])
+        }
+        mktmpdir { path in
+            let gitRepo = makeGitRepo(path, tag: "v0.1.0")!
+            XCTAssertTrue(gitRepo.hasVersion)
+            XCTAssertEqual(gitRepo.versions, [Version(0,1,0)])
         }
     }