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

@@ -123,6 +123,9 @@ 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 {
             return

Sources/Build/BuildOperationBuildSystemDelegateHandler.swift

@@ -205,6 +205,10 @@ 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]]
 
@@ -228,6 +232,7 @@ 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

@@ -299,6 +299,11 @@ public struct SwiftToolOptions: ParsableArguments {
     @Flag()
     var useIntegratedSwiftDriver: Bool = false
 
+    /// A flag that inidcates this build should skip checking whether targets only import
+    /// their explicitly-declared dependencies
+    @Flag()
+    var disableExplicitTargetDependencyImportChecking: 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

@@ -789,7 +789,8 @@ public class SwiftTool {
                 useExplicitModuleBuild: options.useExplicitModuleBuild,
                 isXcodeBuildSystemEnabled: options.buildSystem == .xcode,
                 printManifestGraphviz: options.printManifestGraphviz,
-                forceTestDiscovery: options.enableTestDiscovery // backwards compatibility, remove with --enable-test-discovery
+                forceTestDiscovery: options.enableTestDiscovery, // backwards compatibility, remove with --enable-test-discovery
+                disableExplicitTargetDependencyImportChecking: options.disableExplicitTargetDependencyImportChecking
             )
         })
     }()

Sources/SPMBuildCore/BuildParameters.swift

@@ -127,6 +127,10 @@ 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 output a graphviz file visualization of the combined job graph for all targets
     public var printManifestGraphviz: Bool
 
@@ -191,7 +195,8 @@ public struct BuildParameters: Encodable {
         isXcodeBuildSystemEnabled: Bool = false,
         printManifestGraphviz: Bool = false,
         enableTestability: Bool? = nil,
-        forceTestDiscovery: Bool = false
+        forceTestDiscovery: Bool = false,
+        disableExplicitTargetDependencyImportChecking: Bool = false
     ) {
         let triple = destinationTriple ?? .getHostTriple(usingSwiftCompiler: toolchain.swiftCompiler)
 
@@ -221,6 +226,7 @@ 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
     }
 
     /// The path to the build directory (inside the data directory).

Tests/CommandsTests/BuildToolTests.swift

@@ -86,6 +86,18 @@ final class BuildToolTests: XCTestCase {
                 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 {