Check for changes in Package.swift on CI

.github/workflows/swift.yml

@@ -10,4 +10,4 @@ jobs:
     steps:
     - uses: actions/checkout@v1
     - name: Build & Test
-      run: make test
+      run: ON_CI=1 make test

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 All notable changes to this project will be documented in this file.
 
+## 2020-05-15
+
+`Package.swift` file is now generated. All `import` statements are parsed to do that. On CI, the check has been added to verify that `Package.swift` is commited correctly.
+
+New `make gen` command will generate both `Package.swift` and Xcode project.
+
 ## 2020-04-22
 
 A new test discovery mode `runtimeExecutableLaunch`  is added. The new test discovery mode is similar to `runtimeLogicTest` but instead of loading your xctest bundle in the xctest process of a simulator, it uses your app executable to load the xctest bundle and perform a dump. Such discovery mode is useful for xctest bundles that rely on bundle_loader symbols to be present in the runtime and thus cannot be loaded in an improper executable. 

PackageGenerator.swift

@@ -93,6 +93,15 @@ func generatePackageSwift(raplacementForTargets: [String]) throws {
         of: "<__TARGETS__>",
         with: raplacementForTargets.map { "        \($0)" }.joined(separator: "\n")
     )
+
+    if ProcessInfo.processInfo.environment["ON_CI"] != nil {
+        log("Checking for Package.swift consistency")
+        let existingContents = try String(contentsOf: URL(fileURLWithPath: "Package.swift"))
+        if existingContents != templateContents {
+            fatalError("ON_CI is set, and Package.swift differs. Please update and commit Package.swift!")
+        }
+    }
+
     log("Saving Package.swift")
     try templateContents.write(to: URL(fileURLWithPath: "Package.swift"), atomically: true, encoding: .utf8)
 }