The logic to generate manifest source from existing parsed manifest data structures misquoted some package version requirement ranges.

This fixes those cases, producing a semantically equivalent package manifests.  Since the model does not capture how a particular range was specified, it is not possible to recreate the original shorthands.

A future improvement can either extend the model to record the original spelling of the range requirements, or can apply heuristics to shorten the rules in the future (e.g. automatically derive `upToNextMajor()` etc.

This also eliminates an extra whitespace before the minimum tools version declaration when the specified tools version allows it, so older parsers can parse the generated manifests.

rdar://76559428

Author: abertelrud

Sources/PackageModel/ManifestSourceGeneration.swift

@@ -25,8 +25,9 @@ extension Manifest {
     public var generatedManifestFileContents: String {
         /// Only write out the major and minor (not patch) versions of the
         /// tools version, since the patch version doesn't change semantics.
+        /// We leave out the spacer if the tools version doesn't support it.
         return """
-            // swift-tools-version: \(toolsVersion.major).\(toolsVersion.minor)
+            // swift-tools-version:\(toolsVersion < .v5_4 ? "" : " ")\(toolsVersion.major).\(toolsVersion.minor)
             import PackageDescription
 
             let package = \(SourceCodeFragment(from: self).generateSourceCode())
@@ -129,9 +130,9 @@ fileprivate extension SourceCodeFragment {
             params.append(SourceCodeFragment(key: "url", string: data.location))
             switch data.requirement {
             case .exact(let version):
-                params.append(SourceCodeFragment(enum: "exact", string: version.description))
+                params.append(SourceCodeFragment(enum: "exact", string: "\(version)"))
             case .range(let range):
-                params.append(SourceCodeFragment(enum: "range", string: range.description))
+                params.append(SourceCodeFragment("\"\(range.lowerBound)\"..<\"\(range.upperBound)\""))
             case .revision(let revision):
                 params.append(SourceCodeFragment(enum: "revision", string: revision))
             case .branch(let branch):

Tests/WorkspaceTests/ManifestSourceGenerationTests.swift

@@ -37,8 +37,14 @@ class ManifestSourceGenerationTests: XCTestCase {
                                     completion: $0)
             }
 
-            // Generate source code for the loaded manifest, write it out to replace the manifest file contents, and load it again.
+            // Generate source code for the loaded manifest,
             let newContents = manifest.generatedManifestFileContents
+            
+            // Check that the tools version was serialized properly.
+            let versionSpacing = (toolsVersion >= .v5_4) ? " " : ""
+            XCTAssertTrue(newContents.hasPrefix("// swift-tools-version:\(versionSpacing)\(toolsVersion.major).\(toolsVersion.minor)"), newContents)
+            
+            // Write out the generated manifest to replace the old manifest file contents, and load it again.
             try fs.writeFileContents(packageDir.appending(component: Manifest.filename), bytes: ByteString(encodingAsUTF8: newContents))
             let newManifest = try tsc_await {
                 manifestLoader.load(at: packageDir,
@@ -159,6 +165,35 @@ class ManifestSourceGenerationTests: XCTestCase {
         try testManifestWritingRoundTrip(manifestContents: manifestContents, toolsVersion: .v5_3)
     }
 
+    func testPackageDependencyVariations() throws {
+        let manifestContents = """
+            // swift-tools-version:5.4
+            import PackageDescription
+
+            let package = Package(
+                name: "MyPackage",
+                dependencies: [
+                   .package(url: "/foo1", from: "1.0.0"),
+                   .package(url: "/foo2", .revision("58e9de4e7b79e67c72a46e164158e3542e570ab6")),
+                   .package(path: "../foo3"),
+                   .package(path: "/path/to/foo4"),
+                   .package(url: "/foo5", .exact("1.2.3")),
+                   .package(url: "/foo6", "1.2.3"..<"2.0.0"),
+                   .package(url: "/foo7", .branch("master")),
+                   .package(url: "/foo8", .upToNextMinor(from: "1.3.4")),
+                   .package(url: "/foo9", .upToNextMajor(from: "1.3.4")),
+                   .package(path: "~/path/to/foo10"),
+                   .package(path: "~foo11"),
+                   .package(path: "~/path/to/~/foo12"),
+                   .package(path: "~"),
+                   .package(path: "file:///path/to/foo13"),
+                ]
+            )
+            """
+        try testManifestWritingRoundTrip(manifestContents: manifestContents, toolsVersion: .v5_3)
+    }
+
+
     func testResources() throws {
         let manifestContents = """
             // swift-tools-version:5.3