Only mark package swiftpm incompatible when pluginClass is present.

lib/src/tag/tagger.dart

@@ -350,6 +350,16 @@ class Tagger {
     }
   }
 
+  /// Tag if iOS/macOS plugin has migrated to Swift Package Manager (swiftpm).
+  ///
+  /// A plugin only needs to be swiftpm enabled if it has a native component, we
+  /// detect that if it has the `flutter.plugin.platforms.<os>.pluginClass` key
+  /// present in the pubspec.
+  ///
+  /// A plugin can share code and package-manager manifest between iOS and
+  /// macOS by specifying `flutter.plugin.platforms.<os>.sharedDarwinSource`.
+  ///
+  /// See https://docs.flutter.dev/packages-and-plugins/swift-package-manager/for-plugin-authors
   void swiftPackageManagerPluginTag(
       List<String> tags, List<Explanation> explanations) {
     if (!_usesFlutter) return;
@@ -369,8 +379,8 @@ class Tagger {
     var swiftPmSupport = true;
 
     for (final darwinOs in ['macos', 'ios']) {
-      if (pathExists(
-          pubspec.originalYaml, ['flutter', 'plugin', 'platforms', darwinOs])) {
+      if (pathExists(pubspec.originalYaml,
+          ['flutter', 'plugin', 'platforms', darwinOs, 'pluginClass'])) {
         isDarwinPlugin = true;
         final osDir = pubspec.originalYaml['flutter']?['plugin']?['platforms']
                     ?[darwinOs]?['sharedDarwinSource'] ==

test/goldens/end2end/url_launcher-6.3.1.json

@@ -143,8 +143,8 @@
         "title": "Platform support",
         "grantedPoints": 20,
         "maxPoints": 20,
-        "status": "failed",
-        "summary": "### [*] 20/20 points: Supports 6 of 6 possible platforms (**iOS**, **Android**, **Web**, **Windows**, **macOS**, **Linux**)\n\n* ✓ Android\n\n* ✓ iOS\n\n* ✓ Windows\n\n* ✓ Linux\n\n* ✓ macOS\n\n* ✓ Web\n\n### [*] 0/0 points: WASM compatibility\n\nThis package is compatible with runtime `wasm`, and will be rewarded additional points in a future version of the scoring model.\n\nSee https://dart.dev/web/wasm for details.\n\n### [x] 0/0 points: Swift Package Manager support\n\n<details>\n<summary>\nPackage does not support the Swift Package Manager on macOS\n</summary>\n\nIt does not contain `macos/url_launcher/Package.swift`.\n\n</details>\n\nThis package for iOS or macOS does not support the Swift Package Manager. It will not receive full points in a future version of the scoring model.\n\nSee https://docs.flutter.dev/to/spm for details.\n"
+        "status": "passed",
+        "summary": "### [*] 20/20 points: Supports 6 of 6 possible platforms (**iOS**, **Android**, **Web**, **Windows**, **macOS**, **Linux**)\n\n* ✓ Android\n\n* ✓ iOS\n\n* ✓ Windows\n\n* ✓ Linux\n\n* ✓ macOS\n\n* ✓ Web\n\n### [*] 0/0 points: WASM compatibility\n\nThis package is compatible with runtime `wasm`, and will be rewarded additional points in a future version of the scoring model.\n\nSee https://dart.dev/web/wasm for details.\n"
       },
       {
         "id": "analysis",

test/goldens/end2end/url_launcher-6.3.1.json_report.md

@@ -52,21 +52,6 @@ This package is compatible with runtime `wasm`, and will be rewarded additional
 
 See https://dart.dev/web/wasm for details.
 
-### [x] 0/0 points: Swift Package Manager support
-
-<details>
-<summary>
-Package does not support the Swift Package Manager on macOS
-</summary>
-
-It does not contain `macos/url_launcher/Package.swift`.
-
-</details>
-
-This package for iOS or macOS does not support the Swift Package Manager. It will not receive full points in a future version of the scoring model.
-
-See https://docs.flutter.dev/to/spm for details.
-
 
 ## 40/50 Pass static analysis
 

test/tag/tag_end2end_test.dart

@@ -584,7 +584,9 @@ name: my_package
         packageWithPathDeps('my_package', pubspecExtras: {
           'flutter': {
             'plugin': {
-              'platforms': {'ios': <String, dynamic>{}}
+              'platforms': {
+                'ios': <String, dynamic>{'pluginClass': ''}
+              }
             }
           }
         }, extraFiles: [
@@ -605,8 +607,14 @@ name: my_package
           'flutter': {
             'plugin': {
               'platforms': {
-                'ios': <String, dynamic>{'sharedDarwinSource': true},
-                'macos': <String, dynamic>{'sharedDarwinSource': true}
+                'ios': <String, dynamic>{
+                  'sharedDarwinSource': true,
+                  'pluginClass': ''
+                },
+                'macos': <String, dynamic>{
+                  'sharedDarwinSource': true,
+                  'pluginClass': ''
+                }
               }
             }
           }
@@ -622,12 +630,41 @@ name: my_package
           tags: contains('is:swiftpm-plugin'));
     });
 
+    test('Doesn\'t analyze when there is no pluginClass', () async {
+      final descriptor = d.dir('cache', [
+        packageWithPathDeps('my_package', pubspecExtras: {
+          'flutter': {
+            'plugin': {
+              'platforms': {
+                'ios': <String, dynamic>{
+                  'sharedDarwinSource': true,
+                  'pluginClass': ''
+                },
+                'macos': <String, dynamic>{
+                  'sharedDarwinSource': true,
+                }
+              }
+            }
+          }
+        }, extraFiles: [
+          d.dir('darwin', [
+            d.dir('my_package'),
+          ]),
+        ])
+      ]);
+      await descriptor.create();
+      final tagger = Tagger('${descriptor.io.path}/my_package');
+      _expectTagging(tagger.swiftPackageManagerPluginTag, tags: isEmpty);
+    });
+
     test('Fails with the wrong os/package_name/Package.swift', () async {
       final descriptor = d.dir('cache', [
         packageWithPathDeps('my_package', pubspecExtras: {
           'flutter': {
             'plugin': {
-              'platforms': {'macos': <String, dynamic>{}}
+              'platforms': {
+                'macos': <String, dynamic>{'pluginClass': ''}
+              }
             }
           }
         }, extraFiles: [