Add an opt-out from explicit target dependency import checking.

`--disable-explicit-target-dependency-import-checking` prevents the verification code from being run as a just-in-case option to opt-out from this warning

Author: artemcm

Sources/Build/BuildOperation.swift

@@ -161,8 +161,11 @@ 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 {
+            return
+        }
         // Ensure the compiler supports the import-scan operation
-        guard SwiftTargetBuildDescription.checkSupportedFrontendFlags(flags: ["import-prescan"], fs: localFileSystem) else {
+        guard SwiftTargetBuildDescription.checkSupportedFrontendFlags(flags: ["import-prescan"], fileSystem: localFileSystem) else {
             return
         }
 
@@ -199,7 +202,7 @@ public final class BuildOperation: PackageStructureDelegate, SPMBuildCore.BuildS
                     Set(description.targetDependencyMap.keys.filter { !targetDependenciesSet.contains($0) })
                 let importedTargetsMissingDependency = Set(imports).intersection(nonDependencyTargetsSet)
                 if let missedDependency = importedTargetsMissingDependency.first {
-                    diagnostics.emit(warning: "Target \(target) imports another target (\(missedDependency)) in the package without declaring it a dependency.", location: nil)
+                    self.observabilityScope.emit(warning: "Target \(target) imports another target (\(missedDependency)) in the package without declaring it a dependency.")
                 }
             } catch {
                 // The above verification is a best-effort attempt to warn the user about a potential manifest

Sources/Build/BuildOperationBuildSystemDelegateHandler.swift

@@ -226,6 +226,10 @@ 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
+    /// their explicitly-declared dependencies
+    let disableExplicitTargetDependencyImportChecking: Bool
+
     /// Every target's set of dependencies.
     let targetDependencyMap: [TargetName: [TargetName]]
 
@@ -253,6 +257,7 @@ public struct BuildDescription: Codable {
         self.swiftFrontendCommands = swiftFrontendCommands
         self.testDiscoveryCommands = testDiscoveryCommands
         self.copyCommands = copyCommands
+        self.disableExplicitTargetDependencyImportChecking = plan.buildParameters.disableExplicitTargetDependencyImportChecking
         self.targetDependencyMap = try plan.targets.reduce(into: [TargetName: [TargetName]]()) {
             let deps = try $1.target.recursiveTargetDependencies().map { $0.c99name }
             $0[$1.target.c99name] = deps

Sources/Commands/Options.swift

@@ -335,6 +335,11 @@ struct BuildOptions: ParsableArguments {
     @Flag()
     var useIntegratedSwiftDriver: Bool = false
 
+    /// A flag that inidcates this build should check whether targets only import
+    /// their explicitly-declared dependencies
+    @Flag()
+    var enableExplicitTargetDependencyImportChecking: Bool = false    
+
     /// Whether to use the explicit module build flow (with the integrated driver)
     @Flag(name: .customLong("experimental-explicit-module-build"))
     var useExplicitModuleBuild: Bool = false

Sources/Commands/SwiftTool.swift

@@ -792,6 +792,7 @@ 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

Sources/SPMBuildCore/BuildParameters.swift

@@ -128,6 +128,10 @@ 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
+    /// their explicitly-declared dependencies
+    public var disableExplicitTargetDependencyImportChecking: Bool
+
     /// Whether to create dylibs for dynamic library products.
     public var shouldCreateDylibForDynamicProducts: Bool
 
@@ -199,6 +203,7 @@ public struct BuildParameters: Encodable {
         isXcodeBuildSystemEnabled: Bool = false,
         enableTestability: Bool? = nil,
         forceTestDiscovery: Bool = false,
+        disableExplicitTargetDependencyImportChecking: Bool = false
         linkerDeadStrip: Bool = true,
         colorizedOutput: Bool = false,
         verboseOutput: Bool = false
@@ -236,6 +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.linkerDeadStrip = linkerDeadStrip
         self.colorizedOutput = colorizedOutput
         self.verboseOutput = verboseOutput

Tests/CommandsTests/BuildToolTests.swift

@@ -89,6 +89,18 @@ final class BuildToolTests: CommandsTestCase {
                 XCTAssertTrue(stderr.contains("warning: Target A imports another target (B) in the package without declaring it a dependency."))
             }
         }
+
+        // Verify that the disable toggle works as expected
+        fixture(name: "Miscellaneous/ImportOfMissingDependency") { path in
+            let fullPath = resolveSymlinks(path)
+            XCTAssertThrowsError(try build(["--disable-explicit-target-dependency-import-checking"], packagePath: fullPath)) { error in
+                guard case SwiftPMProductError.executionFailure(_, _, let stderr) = error else {
+                    XCTFail()
+                    return
+                }
+                XCTAssertFalse(stderr.contains("warning: Target A imports another target (B) in the package without declaring it a dependency."))
+            }
+        }
     }
 
     func testBinPathAndSymlink() throws {