Always set mEditable values when different in TextPlugin (#13951)

shell/platform/android/io/flutter/plugin/editing/TextInputPlugin.java

@@ -102,6 +102,10 @@ public class TextInputPlugin {
         return mImm;
     }
 
+    @VisibleForTesting Editable getEditable() {
+        return mEditable;
+    }
+
     /***
      * Use the current platform view input connection until unlockPlatformViewInputConnection is called.
      *
@@ -306,15 +310,21 @@ public class TextInputPlugin {
     }
 
     @VisibleForTesting void setTextInputEditingState(View view, TextInputChannel.TextEditState state) {
-        if (!restartAlwaysRequired && !mRestartInputPending && state.text.equals(mEditable.toString())) {
-            applyStateToSelection(state);
+        // Always replace the contents of mEditable if the text differs
+        if (!state.text.equals(mEditable.toString())) {
+            mEditable.replace(0, mEditable.length(), state.text);
+        }
+        // Always apply state to selection which handles updating the selection if needed.
+        applyStateToSelection(state);
+        // Use updateSelection to update imm on selection if it is not neccessary to restart.
+        if (!restartAlwaysRequired && !mRestartInputPending) {
             mImm.updateSelection(mView, Math.max(Selection.getSelectionStart(mEditable), 0),
                     Math.max(Selection.getSelectionEnd(mEditable), 0),
                     BaseInputConnection.getComposingSpanStart(mEditable),
                     BaseInputConnection.getComposingSpanEnd(mEditable));
+        // Restart if there is a pending restart or the device requires a force restart
+        // (see isRestartAlwaysRequired). Restarting will also update the selection.
         } else {
-            mEditable.replace(0, mEditable.length(), state.text);
-            applyStateToSelection(state);
             mImm.restartInput(view);
             mRestartInputPending = false;
         }

shell/platform/android/test/io/flutter/plugin/editing/TextInputPluginTest.java

@@ -29,6 +29,7 @@ import io.flutter.plugin.common.MethodCall;
 import io.flutter.plugin.platform.PlatformViewsController;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
@@ -73,6 +74,27 @@ public class TextInputPluginTest {
         assertEquals(1, testImm.getRestartCount(testView));
     }
 
+    @Test
+    public void setTextInputEditingState_alwaysSetEditableWhenDifferent() {
+        // Initialize a general TextInputPlugin.
+        InputMethodSubtype inputMethodSubtype = mock(InputMethodSubtype.class);
+        TestImm testImm = Shadow.extract(RuntimeEnvironment.application.getSystemService(Context.INPUT_METHOD_SERVICE));
+        testImm.setCurrentInputMethodSubtype(inputMethodSubtype);
+        View testView = new View(RuntimeEnvironment.application);
+        TextInputPlugin textInputPlugin = new TextInputPlugin(testView, mock(DartExecutor.class), mock(PlatformViewsController.class));
+        textInputPlugin.setTextInputClient(0, new TextInputChannel.Configuration(false, false, true, TextInputChannel.TextCapitalization.NONE, null, null, null));
+        // There's a pending restart since we initialized the text input client. Flush that now. With changed text, we should
+        // always set the Editable contents.
+        textInputPlugin.setTextInputEditingState(testView, new TextInputChannel.TextEditState("hello", 0, 0));
+        assertEquals(1, testImm.getRestartCount(testView));
+        assertTrue(textInputPlugin.getEditable().toString().equals("hello"));
+
+        // No pending restart, set Editable contents anyways.
+        textInputPlugin.setTextInputEditingState(testView, new TextInputChannel.TextEditState("Shibuyawoo", 0, 0));
+        assertEquals(1, testImm.getRestartCount(testView));
+        assertTrue(textInputPlugin.getEditable().toString().equals("Shibuyawoo"));
+    }
+
     // See https://github.com/flutter/flutter/issues/29341 and https://github.com/flutter/flutter/issues/31512
     // All modern Samsung keybords are affected including non-korean languages and thus
     // need the restart.