Fix deferred components startup threading and improve .so search algorithm. (flutter/engine#26429)

engine/src/flutter/shell/common/shell.cc

@@ -1313,8 +1313,15 @@ void Shell::LoadDartDeferredLibrary(
     intptr_t loading_unit_id,
     std::unique_ptr<const fml::Mapping> snapshot_data,
     std::unique_ptr<const fml::Mapping> snapshot_instructions) {
-  engine_->LoadDartDeferredLibrary(loading_unit_id, std::move(snapshot_data),
-                                   std::move(snapshot_instructions));
+  task_runners_.GetUITaskRunner()->PostTask(fml::MakeCopyable(
+      [engine = engine_->GetWeakPtr(), loading_unit_id,
+       data = std::move(snapshot_data),
+       instructions = std::move(snapshot_instructions)]() mutable {
+        if (engine) {
+          engine->LoadDartDeferredLibrary(loading_unit_id, std::move(data),
+                                          std::move(instructions));
+        }
+      }));
 }
 
 void Shell::LoadDartDeferredLibraryError(intptr_t loading_unit_id,

engine/src/flutter/shell/platform/android/io/flutter/embedding/engine/deferredcomponents/PlayStoreDeferredComponentManager.java

@@ -425,18 +425,34 @@ public class PlayStoreDeferredComponentManager implements DeferredComponentManag
     List<String> apkPaths = new ArrayList<>();
     // If not found in APKs, we check in extracted native libs for the lib directly.
     List<String> soPaths = new ArrayList<>();
+
     Queue<File> searchFiles = new LinkedList<>();
+    // Downloaded modules are stored here
     searchFiles.add(context.getFilesDir());
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+      // The initial installed apks are provided by `sourceDirs` in ApplicationInfo.
+      // The jniLibs we want are in the splits not the baseDir. These
+      // APKs are only searched as a fallback, as base libs generally do not need
+      // to be fully path referenced.
+      for (String path : context.getApplicationInfo().splitSourceDirs) {
+        searchFiles.add(new File(path));
+      }
+    }
+
     while (!searchFiles.isEmpty()) {
       File file = searchFiles.remove();
-      if (file != null && file.isDirectory()) {
+      if (file != null && file.isDirectory() && file.listFiles() != null) {
         for (File f : file.listFiles()) {
           searchFiles.add(f);
         }
         continue;
       }
       String name = file.getName();
-      if (name.endsWith(".apk") && name.startsWith(componentName) && name.contains(pathAbi)) {
+      // Special case for "split_config" since android base module non-master apks are
+      // initially installed with the "split_config" prefix/name.
+      if (name.endsWith(".apk")
+          && (name.startsWith(componentName) || name.startsWith("split_config"))
+          && name.contains(pathAbi)) {
         apkPaths.add(file.getAbsolutePath());
         continue;
       }
@@ -459,7 +475,7 @@ public class PlayStoreDeferredComponentManager implements DeferredComponentManag
     }
 
     flutterJNI.loadDartDeferredLibrary(
-        loadingUnitId, searchPaths.toArray(new String[apkPaths.size()]));
+        loadingUnitId, searchPaths.toArray(new String[searchPaths.size()]));
   }
 
   public boolean uninstallDeferredComponent(int loadingUnitId, String componentName) {

engine/src/flutter/shell/platform/android/test/io/flutter/embedding/engine/deferredcomponents/PlayStoreDeferredComponentManagerTest.java

@@ -14,6 +14,7 @@ import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.when;
 
+import android.annotation.TargetApi;
 import android.content.Context;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
@@ -32,6 +33,7 @@ import org.robolectric.annotation.Config;
 
 @Config(manifest = Config.NONE)
 @RunWith(RobolectricTestRunner.class)
+@TargetApi(21)
 public class PlayStoreDeferredComponentManagerTest {
   private class TestFlutterJNI extends FlutterJNI {
     public int loadDartDeferredLibraryCalled = 0;
@@ -90,9 +92,12 @@ public class PlayStoreDeferredComponentManagerTest {
     PackageManager packageManager = mock(PackageManager.class);
     ApplicationInfo applicationInfo = mock(ApplicationInfo.class);
     applicationInfo.metaData = metadata;
+    applicationInfo.splitSourceDirs = new String[1];
+    applicationInfo.splitSourceDirs[0] = "some.invalid.apk";
     when(packageManager.getApplicationInfo(any(String.class), any(int.class)))
         .thenReturn(applicationInfo);
     doReturn(packageManager).when(spyContext).getPackageManager();
+    doReturn(applicationInfo).when(spyContext).getApplicationInfo();
     return spyContext;
   }
 
@@ -239,6 +244,30 @@ public class PlayStoreDeferredComponentManagerTest {
     assertEquals(jni.loadingUnitId, 123);
   }
 
+  @Test
+  public void searchPathsSearchesSplitConfig() throws NameNotFoundException {
+    TestFlutterJNI jni = new TestFlutterJNI();
+    Context spyContext = createSpyContext(null);
+    doReturn(null).when(spyContext).getAssets();
+    String apkTestPath = "test/path/split_config.armeabi_v7a.apk";
+    doReturn(new File(apkTestPath)).when(spyContext).getFilesDir();
+    TestPlayStoreDeferredComponentManager playStoreManager =
+        new TestPlayStoreDeferredComponentManager(spyContext, jni);
+    jni.setDeferredComponentManager(playStoreManager);
+
+    assertEquals(jni.loadingUnitId, 0);
+
+    playStoreManager.installDeferredComponent(123, "TestModuleName");
+    assertEquals(jni.loadDartDeferredLibraryCalled, 1);
+    assertEquals(jni.updateAssetManagerCalled, 1);
+    assertEquals(jni.deferredComponentInstallFailureCalled, 0);
+
+    assertEquals(jni.searchPaths[0], "libapp.so-123.part.so");
+    assertTrue(jni.searchPaths[1].endsWith(apkTestPath + "!lib/armeabi-v7a/libapp.so-123.part.so"));
+    assertEquals(jni.searchPaths.length, 2);
+    assertEquals(jni.loadingUnitId, 123);
+  }
+
   @Test
   public void invalidSearchPathsAreIgnored() throws NameNotFoundException {
     TestFlutterJNI jni = new TestFlutterJNI();