Use a different path extension for swift-testing builds.

Currently, SwiftPM is using the same path to build swift-testing and XCTest content. This works about 90% of the time because we only need one or the other at any given moment, but it causes some workflows to fail on Linux because the build system sees the existing build product and assumes the build has already completed, which is incorrect. Darwin doesn't seem to be affected (because the XCTest build product is a bundle rather than an executable.)

This PR selects a different path extension, ".swift-testing", for swift-testing's build product.

Author: grynspan

Sources/Build/BuildOperationBuildSystemDelegateHandler.swift

@@ -393,7 +393,8 @@ public struct BuildDescription: Codable {
             return try BuiltTestProduct(
                 productName: desc.product.name,
                 binaryPath: desc.binaryPath,
-                packagePath: desc.package.path
+                packagePath: desc.package.path,
+                library: desc.buildParameters.testingParameters.library
             )
         }
         self.pluginDescriptions = pluginDescriptions

Sources/SPMBuildCore/BuildParameters/BuildParameters.swift

@@ -286,12 +286,16 @@ public struct BuildParameters: Encodable {
             guard !targetTriple.isWASI() else {
                 return try RelativePath(validating: "\(product.name).wasm")
             }
-
-            let base = "\(product.name).xctest"
-            if targetTriple.isDarwin() {
-                return try RelativePath(validating: "\(base)/Contents/MacOS/\(product.name)")
-            } else {
-                return try RelativePath(validating: base)
+            switch testingParameters.library {
+            case .xctest:
+                let base = "\(product.name).xctest"
+                if targetTriple.isDarwin() {
+                    return try RelativePath(validating: "\(base)/Contents/MacOS/\(product.name)")
+                } else {
+                    return try RelativePath(validating: base)
+                }
+            case .swiftTesting:
+                return try RelativePath(validating: "\(product.name).swift-testing")
             }
         case .macro:
             #if BUILD_MACROS_AS_DYLIBS

Sources/SPMBuildCore/BuiltTestProduct.swift

@@ -24,24 +24,39 @@ public struct BuiltTestProduct: Codable {
     public let packagePath: AbsolutePath
 
     /// The path of the test bundle.
+    ///
+    /// When the test product is not bundled (for instance, when using XCTest on
+    /// non-Darwin targets), this path is equal to ``binaryPath``.
     public var bundlePath: AbsolutePath {
-        // Go up the folder hierarchy until we find the .xctest bundle.
+        // Go up the folder hierarchy until we find the .xctest or
+        // .swift-testing bundle.
+        let pathExtension: String
+        switch library {
+        case .xctest:
+            pathExtension = ".xctest"
+        case .swiftTesting:
+            pathExtension = ".swift-testing"
+        }
         let hierarchySequence = sequence(first: binaryPath, next: { $0.isRoot ? nil : $0.parentDirectory })
-        guard let bundlePath = hierarchySequence.first(where: { $0.basename.hasSuffix(".xctest") }) else {
+        guard let bundlePath = hierarchySequence.first(where: { $0.basename.hasSuffix(pathExtension) }) else {
             fatalError("could not find test bundle path from '\(binaryPath)'")
         }
 
         return bundlePath
     }
 
+    /// The library used to build this test product.
+    public var library: BuildParameters.Testing.Library
+
     /// Creates a new instance.
     /// - Parameters:
     ///   - productName: The test product name.
     ///   - binaryPath: The path of the test binary.
     ///   - packagePath: The path to the package this product was declared in.
-    public init(productName: String, binaryPath: AbsolutePath, packagePath: AbsolutePath) {
+    public init(productName: String, binaryPath: AbsolutePath, packagePath: AbsolutePath, library: BuildParameters.Testing.Library) {
         self.productName = productName
         self.binaryPath = binaryPath
         self.packagePath = packagePath
+        self.library = library
     }
 }

Sources/SPMTestSupport/SwiftPMProduct.swift

@@ -44,12 +44,7 @@ extension SwiftPM {
         }
     }
 
-    /// Path to currently built binary.
-    public var path: AbsolutePath {
-        return Self.testBinaryPath(for: self.executableName)
-    }
-
-    public static func testBinaryPath(for executableName: RelativePath) -> AbsolutePath {
+    public static func xctestBinaryPath(for executableName: RelativePath) -> AbsolutePath {
         #if canImport(Darwin)
         for bundle in Bundle.allBundles where bundle.bundlePath.hasSuffix(".xctest") {
             return try! AbsolutePath(AbsolutePath(validating: bundle.bundlePath).parentDirectory, executableName)
@@ -114,15 +109,15 @@ extension SwiftPM {
 #endif
         // FIXME: We use this private environment variable hack to be able to
         // create special conditions in swift-build for swiftpm tests.
-        environment["SWIFTPM_TESTS_MODULECACHE"] = self.path.parentDirectory.pathString
+        environment["SWIFTPM_TESTS_MODULECACHE"] = Self.xctestBinaryPath(for: executableName).parentDirectory.pathString
 #if !os(Windows)
         environment["SDKROOT"] = nil
 #endif
 
         // Unset the internal env variable that allows skipping certain tests.
         environment["_SWIFTPM_SKIP_TESTS_LIST"] = nil
 
-        var completeArgs = [self.path.pathString]
+        var completeArgs = [Self.xctestBinaryPath(for: executableName).pathString]
         if let packagePath = packagePath {
             completeArgs += ["--package-path", packagePath.pathString]
         }

Sources/XCBuildSupport/XcodeBuildSystem.swift

@@ -56,7 +56,8 @@ public final class XcodeBuildSystem: SPMBuildCore.BuildSystem {
                         BuiltTestProduct(
                             productName: product.name,
                             binaryPath: binaryPath,
-                            packagePath: package.path
+                            packagePath: package.path,
+                            library: buildParameters.testingParameters.library
                         )
                     )
                 }

Tests/CommandsTests/BuildToolTests.swift

@@ -506,7 +506,7 @@ final class BuildToolTests: CommandsTestCase {
                 return buildArenaPath.appending(component: filename)
             }
 
-            let dummySwiftcPath = SwiftPM.testBinaryPath(for: "dummy-swiftc")
+            let dummySwiftcPath = SwiftPM.xctestBinaryPath(for: "dummy-swiftc")
             let swiftCompilerPath = try UserToolchain.default.swiftCompilerPath
 
             var environment = [