[tool] Check for search paths in Swift plugins

.ci.yaml

@@ -43,6 +43,7 @@ targets:
   # TODO(stuartmorgan): Move this to ARM once google_maps_flutter has ARM
   # support. `pod lint` makes a synthetic target that doesn't respect the
   # pod's arch exclusions, so fails to build.
+  # When moving it, rename the task and file to check_podspecs
   - name: Mac_x64 lint_podspecs
     recipe: plugins/plugins
     timeout: 30

.ci/targets/mac_lint_podspecs.yaml

@@ -1,6 +1,6 @@
 tasks:
   - name: prepare tool
     script: .ci/scripts/prepare_tool.sh
-  - name: lint iOS and macOS podspecs
+  - name: validate iOS and macOS podspecs
     script: script/tool_runner.sh
-    args: ["podspecs"]
+    args: ["podspec-check"]

script/tool/CHANGELOG.md

@@ -1,3 +1,9 @@
+## 0.13.3
+
+* Renames `podspecs` to `podspec-check`. The old name will continue to work.
+* Adds validation of the Swift-in-Obj-C-projects workaround in the podspecs of
+  iOS plugin implementations that use Swift.
+
 ## 0.13.2+1
 
 * Replaces deprecated `flutter format` with `dart format` in `format`

script/tool/lib/src/main.dart

@@ -21,10 +21,10 @@ import 'fix_command.dart';
 import 'format_command.dart';
 import 'license_check_command.dart';
 import 'lint_android_command.dart';
-import 'lint_podspecs_command.dart';
 import 'list_command.dart';
 import 'make_deps_path_based_command.dart';
 import 'native_test_command.dart';
+import 'podspec_check_command.dart';
 import 'publish_check_command.dart';
 import 'publish_command.dart';
 import 'pubspec_check_command.dart';
@@ -66,7 +66,7 @@ void main(List<String> args) {
     ..addCommand(FormatCommand(packagesDir))
     ..addCommand(LicenseCheckCommand(packagesDir))
     ..addCommand(LintAndroidCommand(packagesDir))
-    ..addCommand(LintPodspecsCommand(packagesDir))
+    ..addCommand(PodspecCheckCommand(packagesDir))
     ..addCommand(ListCommand(packagesDir))
     ..addCommand(NativeTestCommand(packagesDir))
     ..addCommand(MakeDepsPathBasedCommand(packagesDir))

script/tool/lib/src/lint_podspecs_command.dart → script/tool/lib/src/podspec_check_command.dart

@@ -6,7 +6,6 @@ import 'dart:convert';
 import 'dart:io';
 
 import 'package:file/file.dart';
-import 'package:path/path.dart' as p;
 import 'package:platform/platform.dart';
 
 import 'common/core.dart';
@@ -20,23 +19,24 @@ const int _exitPodNotInstalled = 3;
 /// Lint the CocoaPod podspecs and run unit tests.
 ///
 /// See https://guides.cocoapods.org/terminal/commands.html#pod_lib_lint.
-class LintPodspecsCommand extends PackageLoopingCommand {
+class PodspecCheckCommand extends PackageLoopingCommand {
   /// Creates an instance of the linter command.
-  LintPodspecsCommand(
+  PodspecCheckCommand(
     Directory packagesDir, {
     ProcessRunner processRunner = const ProcessRunner(),
     Platform platform = const LocalPlatform(),
   }) : super(packagesDir, processRunner: processRunner, platform: platform);
 
   @override
-  final String name = 'podspecs';
+  final String name = 'podspec-check';
 
   @override
-  List<String> get aliases => <String>['podspec'];
+  List<String> get aliases => <String>['podspec', 'podspecs'];
 
   @override
   final String description =
-      'Runs "pod lib lint" on all iOS and macOS plugin podspecs.\n\n'
+      'Runs "pod lib lint" on all iOS and macOS plugin podspecs, as well as '
+      'making sure the podspecs follow repository standards.\n\n'
       'This command requires "pod" and "flutter" to be in your path. Runs on macOS only.';
 
   @override
@@ -69,9 +69,32 @@ class LintPodspecsCommand extends PackageLoopingCommand {
 
     for (final File podspec in podspecs) {
       if (!await _lintPodspec(podspec)) {
-        errors.add(p.basename(podspec.path));
+        errors.add(podspec.basename);
       }
     }
+
+    if (await _hasIOSSwiftCode(package)) {
+      print('iOS Swift code found, checking for search paths settings...');
+      for (final File podspec in podspecs) {
+        if (_isPodspecMissingSearchPaths(podspec)) {
+          const String workaroundBlock = r'''
+  s.xcconfig = {
+    'LIBRARY_SEARCH_PATHS' => '$(TOOLCHAIN_DIR)/usr/lib/swift/$(PLATFORM_NAME)/ $(SDKROOT)/usr/lib/swift',
+    'LD_RUNPATH_SEARCH_PATHS' => '/usr/lib/swift',
+  }
+''';
+          final String path =
+              getRelativePosixPath(podspec, from: package.directory);
+          printError('$path is missing seach path configuration. Any iOS '
+              'plugin implementation that contains Swift implementation code '
+              'needs to contain the following:\n\n'
+              '$workaroundBlock\n'
+              'For more details, see https://github.com/flutter/flutter/issues/118418.');
+          errors.add(podspec.basename);
+        }
+      }
+    }
+
     return errors.isEmpty
         ? PackageResult.success()
         : PackageResult.fail(errors);
@@ -92,7 +115,7 @@ class LintPodspecsCommand extends PackageLoopingCommand {
     // Do not run the static analyzer on plugins with known analyzer issues.
     final String podspecPath = podspec.path;
 
-    final String podspecBasename = p.basename(podspecPath);
+    final String podspecBasename = podspec.basename;
     print('Linting $podspecBasename');
 
     // Lint plugin as framework (use_frameworks!).
@@ -126,4 +149,46 @@ class LintPodspecsCommand extends PackageLoopingCommand {
     return processRunner.run('pod', arguments,
         workingDir: packagesDir, stdoutEncoding: utf8, stderrEncoding: utf8);
   }
+
+  /// Returns true if there is any iOS plugin implementation code written in
+  /// Swift.
+  Future<bool> _hasIOSSwiftCode(RepositoryPackage package) async {
+    return getFilesForPackage(package).any((File entity) {
+      final String relativePath =
+          getRelativePosixPath(entity, from: package.directory);
+      // Ignore example code.
+      if (relativePath.startsWith('example/')) {
+        return false;
+      }
+      final String filePath = entity.path;
+      return path.extension(filePath) == '.swift';
+    });
+  }
+
+  /// Returns true if [podspec] could apply to iOS, but does not have the
+  /// workaround for search paths that makes Swift plugins build correctly in
+  /// Objective-C applications. See
+  /// https://github.com/flutter/flutter/issues/118418 for context and details.
+  ///
+  /// This does not check that the plugin has Swift code, and thus whether the
+  /// workaround is needed, only whether or not it is there.
+  bool _isPodspecMissingSearchPaths(File podspec) {
+    final String directory = podspec.parent.basename;
+    // All macOS Flutter apps are Swift, so macOS-only podspecs don't need the
+    // workaround. If it's anywhere other than macos/, err or the side of
+    // assuming it's required.
+    if (directory == 'macos') {
+      return false;
+    }
+
+    // This errs on the side of being too strict, to minimize the chance of
+    // accidental incorrect configuration. If we ever need more flexibility
+    // due to a false negative we can adjust this as necessary.
+    final RegExp workaround = RegExp(r'''
+\s*s\.(?:ios\.)?xcconfig = {[^}]*
+\s*'LIBRARY_SEARCH_PATHS' => '\$\(TOOLCHAIN_DIR\)/usr/lib/swift/\$\(PLATFORM_NAME\)/ \$\(SDKROOT\)/usr/lib/swift',
+\s*'LD_RUNPATH_SEARCH_PATHS' => '/usr/lib/swift',[^}]*
+\s*}''', dotAll: true);
+    return !workaround.hasMatch(podspec.readAsStringSync());
+  }
 }

script/tool/pubspec.yaml

@@ -1,7 +1,7 @@
 name: flutter_plugin_tools
 description: Productivity utils for flutter/plugins and flutter/packages
 repository: https://github.com/flutter/plugins/tree/main/script/tool
-version: 0.13.2+1
+version: 0.13.3
 
 dependencies:
   args: ^2.1.0