draft solution to add errorMessage with onChangeText

The final solution should add a new instance variable mErrorMessage in ReactTextUpdate
https://github.com/fabriziobertoglio1987/react-native/blob/c5762a77a9e720e0129175afc38c7dcf23bea7bd/ReactAndroid/src/main/java/com/facebook/react/views/text/ReactTextUpdate.java#L153

The method is called from
https://github.com/facebook/react-native/blob/c5762a77a9e720e0129175afc38c7dcf23bea7bd/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextInputManager.java#L370

Author: fabOnReact

Libraries/Components/TextInput/AndroidTextInputNativeComponent.js

@@ -698,6 +698,7 @@ export const __INTERNAL_VIEW_CONFIG: PartialViewConfig = {
     inlineImageLeft: true,
     editable: true,
     fontVariant: true,
+    android_errorMessage: true,
     borderBottomRightRadius: true,
     borderBottomColor: {process: require('../../StyleSheet/processColor')},
     borderRadius: true,

ReactAndroid/src/main/java/com/facebook/react/uimanager/ViewProps.java

@@ -84,7 +84,7 @@ public class ViewProps {
   public static final String BACKGROUND_COLOR = "backgroundColor";
   public static final String FOREGROUND_COLOR = "foregroundColor";
   public static final String COLOR = "color";
-  public static final String ERROR_MESSAGE = "errorMessage";
+  public static final String ANDROID_ERROR_MESSAGE = "android_errorMessage";
   public static final String FONT_SIZE = "fontSize";
   public static final String FONT_WEIGHT = "fontWeight";
   public static final String FONT_STYLE = "fontStyle";

ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactEditText.java

@@ -105,6 +105,7 @@ public class ReactEditText extends AppCompatEditText
   private boolean mDetectScrollMovement = false;
   private boolean mOnKeyPress = false;
   private TextAttributes mTextAttributes;
+  private @Nullable String mErrorMessage;
   private boolean mTypefaceDirty = false;
   private @Nullable String mFontFamily = null;
   private int mFontWeight = UNSET;
@@ -144,6 +145,7 @@ public ReactEditText(Context context) {
     mKeyListener = new InternalKeyListener();
     mScrollWatcher = null;
     mTextAttributes = new TextAttributes();
+    mErrorMessage = null;
 
     applyTextAttributes();
 
@@ -235,6 +237,11 @@ public boolean onKeyUp(int keyCode, KeyEvent event) {
     return super.onKeyUp(keyCode, event);
   }
 
+  public void setErrorMessage(String error) {
+    mErrorMessage = error;
+    setError(error);
+  }
+
   @Override
   protected void onScrollChanged(int horiz, int vert, int oldHoriz, int oldVert) {
     super.onScrollChanged(horiz, vert, oldHoriz, oldVert);
@@ -565,6 +572,9 @@ public void maybeSetText(ReactTextUpdate reactTextUpdate) {
       // try to update state if the wrapper is available. Temporarily disable
       // to prevent an infinite loop.
       getText().replace(0, length(), spannableStringBuilder);
+      if (mErrorMessage != null && getError() != mErrorMessage) {
+        setError(mErrorMessage);
+      }
     }
     mDisableTextDiffing = false;
 

ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextInputManager.java

@@ -372,9 +372,9 @@ public void updateExtraData(ReactEditText view, Object extraData) {
     }
   }
 
-  @ReactProp(name = ViewProps.ERROR_MESSAGE)
-  public void setAndroidErrorMessage(ReactEditText view, String error) {
-    view.setError(error);
+  @ReactProp(name = ViewProps.ANDROID_ERROR_MESSAGE)
+  public void setErrorMessage(ReactEditText view, String error) {
+    view.setErrorMessage(error);
   }
 
   @ReactProp(name = ViewProps.FONT_SIZE, defaultFloat = ViewDefaults.FONT_SIZE_SP)

packages/rn-tester/js/examples/TextInput/TextInputSharedExamples.js

@@ -483,7 +483,7 @@ function ErrorExample(): React.Node {
         Type error in the below TextInput to display an error message.
       </Text>
       <TextInput
-        errorMessage={error}
+        android_errorMessage={error}
         onBlur={() => setError('onBlur')}
         onEndEditing={() => setError('onEndEditing')}
         onChangeText={newText => {