Flip the --disable-explicit-target-dependency-import-checking option to an opt-in enable option.

While we work on optimizing incremental build performance of this check, it would be nice to have it as an opt-in option.

Author: artemcm

Sources/Build/BuildOperation.swift

@@ -161,7 +161,7 @@ public final class BuildOperation: PackageStructureDelegate, SPMBuildCore.BuildS
     // Emit a warning if a target imports another target in this build
     // without specifying it as a dependency in the manifest
     private func verifyTargetImports(in description: BuildDescription) throws {
-        guard !description.disableExplicitTargetDependencyImportChecking else {
+        guard description.enableExplicitTargetDependencyImportChecking else {
             return
         }
         // Ensure the compiler supports the import-scan operation

Sources/Build/BuildOperationBuildSystemDelegateHandler.swift

@@ -226,9 +226,9 @@ public struct BuildDescription: Codable {
     /// The map of copy commands.
     let copyCommands: [BuildManifest.CmdName: LLBuildManifest.CopyTool]
 
-    /// A flag that inidcates this build should skip checking whether targets only import
+    /// A flag that inidcates this build should perform a check for whether targets only import
     /// their explicitly-declared dependencies
-    let disableExplicitTargetDependencyImportChecking: Bool
+    let enableExplicitTargetDependencyImportChecking: Bool
 
     /// Every target's set of dependencies.
     let targetDependencyMap: [TargetName: [TargetName]]
@@ -257,7 +257,7 @@ public struct BuildDescription: Codable {
         self.swiftFrontendCommands = swiftFrontendCommands
         self.testDiscoveryCommands = testDiscoveryCommands
         self.copyCommands = copyCommands
-        self.disableExplicitTargetDependencyImportChecking = plan.buildParameters.disableExplicitTargetDependencyImportChecking
+        self.enableExplicitTargetDependencyImportChecking = plan.buildParameters.enableExplicitTargetDependencyImportChecking
         self.targetDependencyMap = try plan.targets.reduce(into: [TargetName: [TargetName]]()) {
             let deps = try $1.target.recursiveTargetDependencies().map { $0.c99name }
             $0[$1.target.c99name] = deps
@@ -270,8 +270,8 @@ public struct BuildDescription: Codable {
             }
             targetCommandLines[target.c99name] =
                 try desc.emitCommandLine(scanInvocation: true) + ["-driver-use-frontend-path",
-                                                                  plan.buildParameters.toolchain.swiftCompiler.pathString]
-            if desc.testDiscoveryTarget {
+                                                                  plan.buildParameters.toolchain.swiftCompilerPath.pathString]
+            if desc.isTestDiscoveryTarget {
                 generatedSourceTargets.append(target.c99name)
             }
         }

Sources/Commands/SwiftTool.swift

@@ -792,10 +792,10 @@ public class SwiftTool {
                 enableParseableModuleInterfaces: options.build.shouldEnableParseableModuleInterfaces,
                 emitSwiftModuleSeparately: options.build.emitSwiftModuleSeparately,
                 useIntegratedSwiftDriver: options.build.useIntegratedSwiftDriver,
-                disableExplicitTargetDependencyImportChecking: build.disableExplicitTargetDependencyImportChecking,
                 useExplicitModuleBuild: options.build.useExplicitModuleBuild,
                 isXcodeBuildSystemEnabled: options.build.buildSystem == .xcode,
                 forceTestDiscovery: options.build.enableTestDiscovery, // backwards compatibility, remove with --enable-test-discovery
+                enableExplicitTargetDependencyImportChecking: options.build.enableExplicitTargetDependencyImportChecking,
                 linkerDeadStrip: options.linker.linkerDeadStrip,
                 verboseOutput: self.logLevel <= .info
             )

Sources/SPMBuildCore/BuildParameters.swift

@@ -128,9 +128,9 @@ public struct BuildParameters: Encodable {
     /// Whether to use the explicit module build flow (with the integrated driver)
     public var useExplicitModuleBuild: Bool
 
-    /// A flag that inidcates this build should skip checking whether targets only import
+    /// A flag that inidcates this build should check whether targets only import
     /// their explicitly-declared dependencies
-    public var disableExplicitTargetDependencyImportChecking: Bool
+    public var enableExplicitTargetDependencyImportChecking: Bool
 
     /// Whether to create dylibs for dynamic library products.
     public var shouldCreateDylibForDynamicProducts: Bool
@@ -203,7 +203,7 @@ public struct BuildParameters: Encodable {
         isXcodeBuildSystemEnabled: Bool = false,
         enableTestability: Bool? = nil,
         forceTestDiscovery: Bool = false,
-        disableExplicitTargetDependencyImportChecking: Bool = false
+        enableExplicitTargetDependencyImportChecking: Bool = false,
         linkerDeadStrip: Bool = true,
         colorizedOutput: Bool = false,
         verboseOutput: Bool = false
@@ -241,7 +241,7 @@ public struct BuildParameters: Encodable {
         self.enableTestability = enableTestability ?? (.debug == configuration)
         // decide if to enable the use of test manifests based on platform. this is likely to change in the future
         self.testDiscoveryStrategy = triple.isDarwin() ? .objectiveC : .manifest(generate: forceTestDiscovery)
-        self.disableExplicitTargetDependencyImportChecking = disableExplicitTargetDependencyImportChecking        
+        self.enableExplicitTargetDependencyImportChecking = enableExplicitTargetDependencyImportChecking                
         self.linkerDeadStrip = linkerDeadStrip
         self.colorizedOutput = colorizedOutput
         self.verboseOutput = verboseOutput

Tests/CommandsTests/BuildToolTests.swift

@@ -79,9 +79,9 @@ final class BuildToolTests: CommandsTestCase {
         #if swift(<5.5)
         try XCTSkipIf(true, "skipping because host compiler doesn't support '-import-prescan'")
         #endif
-        fixture(name: "Miscellaneous/ImportOfMissingDependency") { path in
+        try fixture(name: "Miscellaneous/ImportOfMissingDependency") { path in
             let fullPath = resolveSymlinks(path)
-            XCTAssertThrowsError(try build([], packagePath: fullPath)) { error in
+            XCTAssertThrowsError(try build(["--enable-explicit-target-dependency-import-checking"], packagePath: fullPath)) { error in
                 guard case SwiftPMProductError.executionFailure(_, _, let stderr) = error else {
                     XCTFail()
                     return
@@ -91,9 +91,9 @@ final class BuildToolTests: CommandsTestCase {
         }
 
         // Verify that the disable toggle works as expected
-        fixture(name: "Miscellaneous/ImportOfMissingDependency") { path in
+        try fixture(name: "Miscellaneous/ImportOfMissingDependency") { path in
             let fullPath = resolveSymlinks(path)
-            XCTAssertThrowsError(try build(["--disable-explicit-target-dependency-import-checking"], packagePath: fullPath)) { error in
+            XCTAssertThrowsError(try build([], packagePath: fullPath)) { error in
                 guard case SwiftPMProductError.executionFailure(_, _, let stderr) = error else {
                     XCTFail()
                     return