[file_selector_android] Handle a null stream from openInputStream

packages/file_selector/file_selector_android/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.5.2+11
+
+* Fixes a crash when the content provider returns no stream for a selected
+  file; the pick now completes with an error instead.
+
 ## 0.5.2+10
 
 * Updates pigeon dev_dependency to ^27.3.2 for analyzer 14 compatibility.

packages/file_selector/file_selector_android/android/src/main/java/dev/flutter/packages/file_selector_android/FileSelectorApiImpl.java

@@ -351,6 +351,13 @@ FileResponse toFileResponse(@NonNull Uri uri) {
 
     final byte[] bytes = new byte[size];
     try (InputStream inputStream = contentResolver.openInputStream(uri)) {
+      if (inputStream == null) {
+        // `ContentResolver#openInputStream()` returns null when the provider cannot serve the
+        // file (for example after the provider crashed). Reading it would throw a
+        // NullPointerException on the activity-result callback, i.e. the main thread.
+        Log.w(TAG, "The content provider returned no stream for the selected file.");
+        return null;
+      }
       final DataInputStream dataInputStream = objectFactory.newDataInputStream(inputStream);
       dataInputStream.readFully(bytes);
     } catch (IOException exception) {

packages/file_selector/file_selector_android/android/src/main/java/dev/flutter/packages/file_selector_android/FileUtils.java

@@ -124,6 +124,11 @@ public static String getPathFromUri(@NonNull Context context, @NonNull Uri uri)
   public static String getPathFromCopyOfFileFromUri(@NonNull Context context, @NonNull Uri uri)
       throws IOException, SecurityException, IllegalArgumentException {
     try (InputStream inputStream = context.getContentResolver().openInputStream(uri)) {
+      if (inputStream == null) {
+        // The provider cannot serve the file (see `FileSelectorApiImpl#toFileResponse`); surface
+        // it as the IO failure it is instead of dereferencing the null stream in `copy()`.
+        throw new IOException("The content provider returned no stream for the file.");
+      }
       String uuid = UUID.nameUUIDFromBytes(uri.toString().getBytes()).toString();
       File targetDirectory = new File(context.getCacheDir(), uuid);
       targetDirectory.mkdir();

packages/file_selector/file_selector_android/android/src/test/java/dev/flutter/packages/file_selector_android/FileSelectorAndroidPluginTest.java

@@ -12,6 +12,7 @@
 import static org.mockito.Mockito.lenient;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.mockStatic;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
@@ -288,6 +289,60 @@ public void openFilesCompletesWithError_whenSecurityExceptionInGetPathFromCopyOf
   // Regression test for https://github.com/flutter/flutter/issues/159568: the
   // single-file `openFile` path must likewise surface a copy failure to Dart
   // instead of crashing.
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  @Test
+  public void openFileCompletesWithError_whenProviderReturnsNullStream()
+      throws FileNotFoundException {
+    final ContentResolver mockContentResolver = mock(ContentResolver.class);
+    final Uri mockUri = mock(Uri.class);
+
+    final Cursor mockCursor = mock(Cursor.class);
+    when(mockCursor.moveToFirst()).thenReturn(true);
+    when(mockCursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)).thenReturn(0);
+    when(mockCursor.getString(0)).thenReturn("filename");
+    when(mockCursor.getColumnIndex(OpenableColumns.SIZE)).thenReturn(1);
+    when(mockCursor.isNull(1)).thenReturn(false);
+    when(mockCursor.getInt(1)).thenReturn(30);
+    when(mockContentResolver.query(mockUri, null, null, null, null, null)).thenReturn(mockCursor);
+    // A provider that cannot serve the file answers the open with null; previously this reached
+    // `DataInputStream#readFully` and threw a NullPointerException on the main thread.
+    when(mockContentResolver.openInputStream(mockUri)).thenReturn(null);
+
+    when(mockObjectFactory.newIntent(Intent.ACTION_OPEN_DOCUMENT)).thenReturn(mockIntent);
+    when(mockActivity.getContentResolver()).thenReturn(mockContentResolver);
+    when(mockActivityBinding.getActivity()).thenReturn(mockActivity);
+    final FileSelectorApiImpl fileSelectorApi =
+        new FileSelectorApiImpl(
+            mockActivityBinding, mockObjectFactory, (version) -> Build.VERSION.SDK_INT >= version);
+
+    final boolean[] callbackCalled = new boolean[1];
+    final Throwable[] failure = new Throwable[1];
+    fileSelectorApi.openFile(
+        null,
+        new FileTypes(Collections.emptyList(), Collections.emptyList()),
+        ResultCompat.asCompatCallback(
+            (reply) -> {
+              callbackCalled[0] = true;
+              failure[0] = reply.exceptionOrNull();
+              return null;
+            }));
+
+    verify(mockActivity).startActivityForResult(mockIntent, 221);
+
+    final ArgumentCaptor<PluginRegistry.ActivityResultListener> listenerArgumentCaptor =
+        ArgumentCaptor.forClass(PluginRegistry.ActivityResultListener.class);
+    verify(mockActivityBinding).addActivityResultListener(listenerArgumentCaptor.capture());
+
+    final Intent resultMockIntent = mock(Intent.class);
+    when(resultMockIntent.getData()).thenReturn(mockUri);
+    listenerArgumentCaptor.getValue().onActivityResult(221, Activity.RESULT_OK, resultMockIntent);
+
+    assertTrue(callbackCalled[0]);
+    assertNotNull(failure[0]);
+    assertTrue(failure[0].getMessage().contains("Failed to read file"));
+    verify(mockObjectFactory, never()).newDataInputStream(any());
+  }
+
   @SuppressWarnings({"rawtypes", "unchecked"})
   @Test
   public void openFileCompletesWithError_whenSecurityExceptionInGetPathFromCopyOfFileFromUri()

packages/file_selector/file_selector_android/android/src/test/java/dev/flutter/packages/file_selector_android/FileUtilsTest.java

@@ -10,8 +10,10 @@
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.mockStatic;
 import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
 import static org.robolectric.Shadows.shadowOf;
 
 import android.content.ContentProvider;
@@ -68,6 +70,18 @@ public void before() {
     }
   }
 
+  @Test
+  public void getPathFromCopyOfFileFromUri_throwsIOExceptionForNullStream() throws IOException {
+    Uri uri = Uri.parse("content://dummy/dummy.txt");
+
+    ContentResolver mockContentResolver = mock(ContentResolver.class);
+    when(mockContentResolver.openInputStream(uri)).thenReturn(null);
+    Context mockContext = mock(Context.class);
+    when(mockContext.getContentResolver()).thenReturn(mockContentResolver);
+
+    assertThrows(IOException.class, () -> FileUtils.getPathFromCopyOfFileFromUri(mockContext, uri));
+  }
+
   @Test
   public void getPathFromUri_returnsExpectedPathForExternalDocumentUri() {
     // Uri that represents Documents/test directory on device:

packages/file_selector/file_selector_android/pubspec.yaml

@@ -2,7 +2,7 @@ name: file_selector_android
 description: Android implementation of the file_selector package.
 repository: https://github.com/flutter/packages/tree/main/packages/file_selector/file_selector_android
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+file_selector%22
-version: 0.5.2+10
+version: 0.5.2+11
 
 environment:
   sdk: ^3.12.0