Revert "Support background indexing when cross-compiling"

Author: bnbarham

Sources/BuildSystemIntegration/SwiftPMBuildSystem.swift

@@ -616,15 +616,6 @@ package actor SwiftPMBuildSystem: BuiltInBuildSystem {
     if let configuration = options.swiftPMOrDefault.configuration {
       arguments += ["-c", configuration.rawValue]
     }
-    if let triple = options.swiftPMOrDefault.triple {
-      arguments += ["--triple", triple]
-    }
-    if let swiftSDKsDirectory = options.swiftPMOrDefault.swiftSDKsDirectory {
-      arguments += ["--swift-sdks-path", swiftSDKsDirectory]
-    }
-    if let swiftSDK = options.swiftPMOrDefault.swiftSDK {
-      arguments += ["--swift-sdk", swiftSDK]
-    }
     arguments += options.swiftPMOrDefault.cCompilerFlags?.flatMap { ["-Xcc", $0] } ?? []
     arguments += options.swiftPMOrDefault.cxxCompilerFlags?.flatMap { ["-Xcxx", $0] } ?? []
     arguments += options.swiftPMOrDefault.swiftCompilerFlags?.flatMap { ["-Xswiftc", $0] } ?? []

Sources/SKTestSupport/SkipUnless.swift

@@ -478,34 +478,6 @@ package actor SkipUnless {
     }
   }
 
-  package static func canSwiftPMCompileForIOS(
-    file: StaticString = #filePath,
-    line: UInt = #line
-  ) async throws {
-    return try await shared.skipUnlessSupported(allowSkippingInCI: true, file: file, line: line) {
-      #if os(macOS)
-      let project = try await SwiftPMTestProject(files: [
-        "MyFile.swift": """
-        public func foo() {}
-        """
-      ])
-      do {
-        try await SwiftPMTestProject.build(
-          at: project.scratchDirectory,
-          extraArguments: [
-            "--swift-sdk", "arm64-apple-ios",
-          ]
-        )
-        return .featureSupported
-      } catch {
-        return .featureUnsupported(skipMessage: "Cannot build for iOS: \(error)")
-      }
-      #else
-      return .featureUnsupported(skipMessage: "Cannot build for iOS outside macOS by default")
-      #endif
-    }
-  }
-
   package static func canCompileForWasm(
     file: StaticString = #filePath,
     line: UInt = #line

Tests/SourceKitLSPTests/BackgroundIndexingTests.swift

@@ -1018,53 +1018,6 @@ final class BackgroundIndexingTests: XCTestCase {
     )
   }
 
-  func testUseSwiftSDKFlagsDuringPreparation() async throws {
-    try await SkipUnless.canSwiftPMCompileForIOS()
-
-    var options = SourceKitLSPOptions.testDefault()
-    options.swiftPMOrDefault.swiftSDK = "arm64-apple-ios"
-    let project = try await SwiftPMTestProject(
-      files: [
-        "Lib/Lib.swift": """
-        #if os(iOS)
-        public func foo() -> Int { 1 }
-        #endif
-        """,
-        "Client/Client.swift": """
-        import Lib
-
-        func test() -> String {
-          return foo()
-        }
-        """,
-      ],
-      manifest: """
-        let package = Package(
-          name: "MyLibrary",
-          targets: [
-            .target(name: "Lib"),
-            .target(name: "Client", dependencies: ["Lib"]),
-          ]
-        )
-        """,
-      options: options,
-      enableBackgroundIndexing: true
-    )
-
-    // Check that we get an error about the return type of `foo` (`Int`) not being convertible to the return type of
-    // `test` (`String`), which indicates that `Lib` had `foo` and was thus compiled for iOS
-    let (uri, _) = try project.openDocument("Client.swift")
-    let diagnostics = try await project.testClient.send(
-      DocumentDiagnosticsRequest(textDocument: TextDocumentIdentifier(uri))
-    )
-    XCTAssert(
-      (diagnostics.fullReport?.items ?? []).contains(where: {
-        $0.message == "Cannot convert return expression of type 'Int' to return type 'String'"
-      }),
-      "Did not get expected diagnostic: \(diagnostics)"
-    )
-  }
-
   func testLibraryUsedByExecutableTargetAndPackagePlugin() async throws {
     try await SkipUnless.swiftPMStoresModulesForTargetAndHostInSeparateFolders()
     let project = try await SwiftPMTestProject(