Add reason logging to v1 embedding warning message (#94636)

packages/flutter_tools/lib/src/project.dart

@@ -546,7 +546,8 @@ class AndroidProject extends FlutterProjectPlatform {
   }
 
   void checkForDeprecation({DeprecationBehavior deprecationBehavior = DeprecationBehavior.none}) {
-    if (getEmbeddingVersion() == AndroidEmbeddingVersion.v1) {
+    final AndroidEmbeddingVersionResult result = computeEmbeddingVersion();
+    if (result.version == AndroidEmbeddingVersion.v1) {
       globals.printStatus(
 '''
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
@@ -562,6 +563,10 @@ to migrate your project. You may also pass the --ignore-deprecation flag to
 ignore this check and continue with the deprecated v1 embedding. However,
 the v1 Android embedding will be removed in future versions of Flutter.
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+The detected reason was:
+
+  ${result.reason}
+━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
 '''
       );
       switch (deprecationBehavior) {
@@ -581,13 +586,17 @@ the v1 Android embedding will be removed in future versions of Flutter.
   }
 
   AndroidEmbeddingVersion getEmbeddingVersion() {
+    return computeEmbeddingVersion().version;
+  }
+
+  AndroidEmbeddingVersionResult computeEmbeddingVersion() {
     if (isModule) {
       // A module type's Android project is used in add-to-app scenarios and
       // only supports the V2 embedding.
-      return AndroidEmbeddingVersion.v2;
+      return AndroidEmbeddingVersionResult(AndroidEmbeddingVersion.v2, 'Is add-to-app module');
     }
     if (appManifestFile == null || !appManifestFile.existsSync()) {
-      return AndroidEmbeddingVersion.v1;
+      return AndroidEmbeddingVersionResult(AndroidEmbeddingVersion.v1, 'No `${appManifestFile.absolute.path}` file');
     }
     XmlDocument document;
     try {
@@ -602,7 +611,7 @@ the v1 Android embedding will be removed in future versions of Flutter.
     for (final XmlElement application in document.findAllElements('application')) {
       final String? applicationName = application.getAttribute('android:name');
       if (applicationName == 'io.flutter.app.FlutterApplication') {
-        return AndroidEmbeddingVersion.v1;
+        return AndroidEmbeddingVersionResult(AndroidEmbeddingVersion.v1, '${appManifestFile.absolute.path} uses `android:name="io.flutter.app.FutterApplication"`');
       }
     }
     for (final XmlElement metaData in document.findAllElements('meta-data')) {
@@ -610,14 +619,14 @@ the v1 Android embedding will be removed in future versions of Flutter.
       if (name == 'flutterEmbedding') {
         final String? embeddingVersionString = metaData.getAttribute('android:value');
         if (embeddingVersionString == '1') {
-          return AndroidEmbeddingVersion.v1;
+          return AndroidEmbeddingVersionResult(AndroidEmbeddingVersion.v1, '${appManifestFile.absolute.path} `<meta-data android:name="flutterEmbedding"` has value 1');
         }
         if (embeddingVersionString == '2') {
-          return AndroidEmbeddingVersion.v2;
+          return AndroidEmbeddingVersionResult(AndroidEmbeddingVersion.v2, '${appManifestFile.absolute.path} `<meta-data android:name="flutterEmbedding"` has value 2');
         }
       }
     }
-    return AndroidEmbeddingVersion.v1;
+    return AndroidEmbeddingVersionResult(AndroidEmbeddingVersion.v1, 'No `<meta-data android:name="flutterEmbedding" android:value="2"/>` in ${appManifestFile.absolute.path}');
   }
 }
 
@@ -629,6 +638,19 @@ enum AndroidEmbeddingVersion {
   v2,
 }
 
+/// Data class that holds the results of checking for embedding version.
+///
+/// This class includes the reason why a particular embedding was selected.
+class AndroidEmbeddingVersionResult {
+  AndroidEmbeddingVersionResult(this.version, this.reason);
+
+  /// The embedding version.
+  AndroidEmbeddingVersion version;
+
+  /// The reason why the embedding version was selected.
+  String reason;
+}
+
 // What the tool should do when encountering deprecated API in applications.
 enum DeprecationBehavior {
   // The command being run does not care about deprecation status.

packages/flutter_tools/test/general.shard/plugins_test.dart

@@ -1632,6 +1632,11 @@ class FakeAndroidProject extends Fake implements AndroidProject {
   AndroidEmbeddingVersion getEmbeddingVersion() {
     return embeddingVersion;
   }
+
+  @override
+  AndroidEmbeddingVersionResult computeEmbeddingVersion() {
+    return AndroidEmbeddingVersionResult(embeddingVersion, 'reasons for version');
+  }
 }
 
 class FakeWebProject extends Fake implements WebProject {

packages/flutter_tools/test/general.shard/project_test.dart

@@ -196,6 +196,7 @@ void main() {
           contains('Build failed due to use of deprecated Android v1 embedding.')
         );
         expect(testLogger.statusText, contains('https://flutter.dev/go/android-project-migration'));
+        expect(testLogger.statusText, contains('No `<meta-data android:name="flutterEmbedding" android:value="2"/>` in '));
       });
       _testInMemory('Android project not on v2 embedding ignore continues', () async {
         final FlutterProject project = await someProject();