[Utility] Add support for version-specific repository tags.

 - This is the second part of SE-0135.

Author: ddunbar

Sources/TestSupport/misc.swift

@@ -84,6 +84,10 @@ public func fixture(name: String, tags: [String] = [], file: StaticString = #fil
 
 /// Test-helper function that creates a new Git repository in a directory.  The new repository will contain exactly one empty file, and if a tag name is provided, a tag with that name will be created.
 public func initGitRepo(_ dir: AbsolutePath, tag: String? = nil, file: StaticString = #file, line: UInt = #line) {
+    initGitRepo(dir, tags: tag.flatMap{ [$0] } ?? [], file: file, line: line)
+}
+
+public func initGitRepo(_ dir: AbsolutePath, tags: [String], file: StaticString = #file, line: UInt = #line) {
     do {
         let file = dir.appending(component: "file.swift")
         try systemQuietly(["touch", file.asString])
@@ -92,7 +96,7 @@ public func initGitRepo(_ dir: AbsolutePath, tag: String? = nil, file: StaticStr
         try systemQuietly([Git.tool, "-C", dir.asString, "config", "user.name", "Example Example"])
         try systemQuietly([Git.tool, "-C", dir.asString, "add", "."])
         try systemQuietly([Git.tool, "-C", dir.asString, "commit", "-m", "msg"])
-        if let tag = tag {
+        for tag in tags {
             try tagGitRepo(dir, tag: tag)
         }
     }

Sources/Utility/Git.swift

@@ -59,14 +59,34 @@ public class Git {
             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.
+            // First, check if we need to restrict the tag set to version-specific tags.
             var knownVersions: [Version: String] = [:]
+            for versionSpecificKey in Versioning.currentVersionSpecificKeys {
+                for tag in tags {
+                    if tag.hasSuffix(versionSpecificKey) {
+                        let specifier = String(tag.characters.dropLast(versionSpecificKey.characters.count))
+                        if let version = Version(specifier) ?? Version.vprefix(specifier) {
+                            knownVersions[version] = tag
+                        }
+                    }
+                }
+
+                // If we found tags at this version-specific key, we are done.
+                if !knownVersions.isEmpty {
+                    return knownVersions
+                }
+            }
+            
+            // Otherwise, look for normal tags.
             for tag in tags {
                 if let version = Version(tag) {
                     knownVersions[version] = tag
                 }
             }
+
             // If we didn't find any versions, look for 'v'-prefixed ones.
+            //
+            // FIXME: We should match both styles simultaneously.
             if knownVersions.isEmpty {
                 for tag in tags {
                     if let version = Version.vprefix(tag) {

Tests/GetTests/GitTests.swift

@@ -10,11 +10,12 @@
 
 import XCTest
 
-import TestSupport
 import Basic
+import Utility
+
+import TestSupport
 
 import class PackageDescription.Package
-import class Utility.Git
 import struct PackageDescription.Version
 import struct PackageModel.Manifest
 
@@ -34,6 +35,30 @@ class GitTests: XCTestCase {
         }
     }
 
+    func testVersionSpecificTags() {
+        let current = Versioning.currentVersion
+        mktmpdir { path in
+            let gitRepo = makeGitRepo(path, tags: ["0.1.0", "0.2.0@swift-\(current.major)", "0.3.0@swift-\(current.major).\(current.minor)", "0.4.0@swift-\(current.major).\(current.minor).\(current.patch)"])!
+            XCTAssertTrue(gitRepo.hasVersion)
+            XCTAssertEqual(gitRepo.versions, [Version(0,4,0)])
+        }
+        mktmpdir { path in
+            let gitRepo = makeGitRepo(path, tags: ["0.1.0", "0.2.0@swift-\(current.major)", "0.3.0@swift-\(current.major).\(current.minor)"])!
+            XCTAssertTrue(gitRepo.hasVersion)
+            XCTAssertEqual(gitRepo.versions, [Version(0,3,0)])
+        }
+        mktmpdir { path in
+            let gitRepo = makeGitRepo(path, tags: ["0.1.0", "0.2.0@swift-\(current.major)"])!
+            XCTAssertTrue(gitRepo.hasVersion)
+            XCTAssertEqual(gitRepo.versions, [Version(0,2,0)])
+        }
+        mktmpdir { path in
+            let gitRepo = makeGitRepo(path, tags: ["0.1.0", "v0.2.0@swift-\(current.major)"])!
+            XCTAssertTrue(gitRepo.hasVersion)
+            XCTAssertEqual(gitRepo.versions, [Version(0,2,0)])
+        }
+    }
+
     func testHasNoVersion() {
         mktmpdir { path in
             let gitRepo = makeGitRepo(path, tag: nil)!
@@ -51,6 +76,7 @@ class GitTests: XCTestCase {
 
     static var allTests = [
         ("testHasVersion", testHasVersion),
+        ("testVersionSpecificTags", testVersionSpecificTags),
         ("testHasNoVersion", testHasNoVersion),
         ("testCloneShouldNotCrashWihoutTags", testCloneShouldNotCrashWihoutTags),
         ("testCloneShouldCrashWihoutTags", testCloneShouldCrashWihoutTags),
@@ -60,7 +86,11 @@ class GitTests: XCTestCase {
 //MARK: - Helpers
 
 func makeGitRepo(_ dstdir: AbsolutePath, tag: String? = nil, file: StaticString = #file, line: UInt = #line) -> Git.Repo? {
-    initGitRepo(dstdir, tag: tag)
+    return makeGitRepo(dstdir, tags: tag.flatMap{ [$0] } ?? [], file: file, line: line)
+}
+
+func makeGitRepo(_ dstdir: AbsolutePath, tags: [String], file: StaticString = #file, line: UInt = #line) -> Git.Repo? {
+    initGitRepo(dstdir, tags: tags)
     return Git.Repo(path: dstdir)
 }