[Build] Fix a bug where computeLLBuildTargetName used wrong test product to infer destination

When there are multiple packages involved, they are going to introduce
mutliple `<package-name>PackageTests` products. While inferring a destination
for a module we need to find the product it belongs to and infer based
on whether that product has any direct macro dependencies or not.

Author: xedin

Sources/Build/BuildOperation.swift

@@ -573,11 +573,17 @@ public final class BuildOperation: PackageStructureDelegate, SPMBuildCore.BuildS
 
     /// Compute the llbuild target name using the given subset.
     func computeLLBuildTargetName(for subset: BuildSubset) async throws -> String {
-        func inferTestsDestination(graph: ModulesGraph) -> BuildParameters.Destination {
-            if graph.allProducts.filter({ $0.type == .test }).first(where: \.hasDirectMacroDependencies) != nil {
-                return .host
+        func inferTestDestination(
+            testModule: ResolvedModule,
+            graph: ModulesGraph
+        ) throws -> BuildParameters.Destination {
+            for product in graph.allProducts where product.type == .test {
+                if product.modules.contains(where: { $0.id == testModule.id }) {
+                    return product.hasDirectMacroDependencies ? .host : .target
+                }
             }
-            return .target
+
+            throw InternalError("Could not find a product for test module: \(testModule)")
         }
 
         switch subset {
@@ -601,7 +607,7 @@ public final class BuildOperation: PackageStructureDelegate, SPMBuildCore.BuildS
             } else if product.type == .macro || product.type == .plugin {
                 config.buildParameters(for: .host)
             } else if product.type == .test {
-                config.buildParameters(for: inferTestsDestination(graph: graph))
+                config.buildParameters(for: product.hasDirectMacroDependencies ? .host : .target)
             } else {
                 config.buildParameters(for: .target)
             }
@@ -632,7 +638,7 @@ public final class BuildOperation: PackageStructureDelegate, SPMBuildCore.BuildS
             } else if module.type == .macro || module.type == .plugin {
                 config.buildParameters(for: .host)
             } else if module.type == .test {
-                config.buildParameters(for: inferTestsDestination(graph: graph))
+                try config.buildParameters(for: inferTestDestination(testModule: module, graph: graph))
             } else {
                 config.buildParameters(for: .target)
             }

Sources/_InternalTestSupport/MockPackageGraphs.swift

@@ -212,7 +212,7 @@ package func macrosTestsPackageGraph() throws -> MockPackageGraph {
                     )
                 ]
             ),
-            Manifest.createFileSystemManifest(
+            Manifest.createRootManifest(
                 displayName: "swift-syntax",
                 path: "/swift-syntax",
                 products: [

Tests/BuildTests/BuildOperationTests.swift

@@ -137,19 +137,37 @@ final class BuildOperationTests: XCTestCase {
     func testHostProductsAndTargetsWithoutExplicitDestination() async throws {
         let mock  = try macrosTestsPackageGraph()
 
+        let hostParameters = mockBuildParameters(destination: .host)
+        let targetParameters = mockBuildParameters(destination: .target)
         let op = mockBuildOperation(
-            productsBuildParameters: mockBuildParameters(destination: .target),
-            toolsBuildParameters: mockBuildParameters(destination: .host),
+            productsBuildParameters: targetParameters,
+            toolsBuildParameters: hostParameters,
             packageGraphLoader: { mock.graph },
             scratchDirectory: AbsolutePath("/.build/\(hostTriple)"),
             fs: mock.fileSystem,
             observabilityScope: mock.observabilityScope
         )
 
-        let result = try await op.computeLLBuildTargetName(for: .product("MMIOMacros"))
+        let mmioMacrosProductName = try await op.computeLLBuildTargetName(for: .product("MMIOMacros"))
         XCTAssertEqual(
             "MMIOMacros-\(hostTriple)-debug-tool.exe",
-            result
+            mmioMacrosProductName
+        )
+
+        let mmioTestsProductName = try await op.computeLLBuildTargetName(
+            for: .product("swift-mmioPackageTests")
+        )
+        XCTAssertEqual(
+            "swift-mmioPackageTests-\(hostTriple)-debug-tool.test",
+            mmioTestsProductName
+        )
+
+        let swiftSyntaxTestsProductName = try await op.computeLLBuildTargetName(
+            for: .product("swift-syntaxPackageTests")
+        )
+        XCTAssertEqual(
+            "swift-syntaxPackageTests-\(targetParameters.triple)-debug.test",
+            swiftSyntaxTestsProductName
         )
 
         for target in ["MMIOMacros", "MMIOPlugin", "MMIOMacrosTests", "MMIOMacro+PluginTests"] {
@@ -160,6 +178,14 @@ final class BuildOperationTests: XCTestCase {
             )
         }
 
+        let swiftSyntaxTestsTarget = try await op.computeLLBuildTargetName(
+            for: .target("SwiftSyntaxTests")
+        )
+        XCTAssertEqual(
+            "SwiftSyntaxTests-\(targetParameters.triple)-debug.module",
+            swiftSyntaxTestsTarget
+        )
+
         let dependencies = try BuildSubset.target("MMIOMacro+PluginTests").recursiveDependencies(
             for: mock.graph,
             observabilityScope: mock.observabilityScope

Tests/BuildTests/CrossCompilationBuildPlanTests.swift

@@ -295,14 +295,17 @@ final class CrossCompilationBuildPlanTests: XCTestCase {
             observabilityScope: scope
         )
 
-        // Make sure that build plan doesn't have any "target" tests.
+        // Make sure that build plan doesn't have any "target" tests except SwiftSyntax ones.
         for description in plan.targetMap where description.module.underlying.type == .test {
-            XCTAssertEqual(description.buildParameters.destination, .host)
+            XCTAssertEqual(
+                description.buildParameters.destination,
+                description.module.name == "SwiftSyntaxTests" ? .target : .host
+            )
         }
 
         let result = try BuildPlanResult(plan: plan)
-        result.checkProductsCount(2)
-        result.checkTargetsCount(17)
+        result.checkProductsCount(3)
+        result.checkTargetsCount(20)
 
         XCTAssertTrue(try result.allTargets(named: "SwiftSyntax")
             .map { try $0.swift() }
@@ -313,6 +316,7 @@ final class CrossCompilationBuildPlanTests: XCTestCase {
         try result.check(destination: .host, triple: toolsTriple, for: "MMIOMacros")
         try result.check(destination: .target, triple: destinationTriple, for: "MMIO")
         try result.check(destination: .host, triple: toolsTriple, for: "MMIOMacrosTests")
+        try result.check(destination: .target, triple: destinationTriple, for: "swift-syntaxPackageTests")
 
         let macroProducts = result.allProducts(named: "MMIOMacros")
         XCTAssertEqual(macroProducts.count, 1)

Tests/PackageGraphTests/CrossCompilationPackageGraphTests.swift

@@ -91,7 +91,7 @@ final class CrossCompilationPackageGraphTests: XCTestCase {
                 "SwiftSyntaxMacrosTestSupport"
             )
 
-            result.check(testModules: "MMIOMacrosTests", "MMIOMacro+PluginTests", "NOOPTests")
+            result.check(testModules: "MMIOMacrosTests", "MMIOMacro+PluginTests", "NOOPTests", "SwiftSyntaxTests")
             result.checkTarget("MMIO") { result in
                 result.check(dependencies: "MMIOMacros")
             }