fix attempting to focus disabled textinputs (#30695)

Summary:
when we call `focus()` upon a TextInput ref which has prop `editable=false` it marks the textinput as focused in `TextInputState` even though the focus is rejected by textinput itself because it is not editable.

then, when you change `editable` prop to `true` and call `focus` again, [this condition](https://github.com/facebook/react-native/blob/e912c462eb0b7166ca5947bb5a3ee20761d910b6/Libraries/Components/TextInput/TextInputState.js#L46) or rather [this one](https://github.com/facebook/react-native/blob/1b2b2198e1b2383523b4655dc8c220d251b057d6/Libraries/Components/TextInput/TextInputState.js#L89) will evaluate to `false` and focus will not happen even though it can and should happen.

see also https://github.com/facebook/react-native/blob/0.64-stable/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js#L3895

## Changelog

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[General] [Fixed] - `focus()` on TextInput to respect its `editable` state

Pull Request resolved: #30695

Test Plan: Create a `TextInput` with prop `editable=false` and call `ref.current.focus()` upon its ref. TextInput should not be marked as focused in `TextInputState`.

Reviewed By: yungsters

Differential Revision: D34357913

Pulled By: lunaleaps

fbshipit-source-id: 9a2fb819bbb05ef213c9b5d739dec583ae0a3e6f

Author: vonovak

Libraries/Components/TextInput/TextInputState.js

@@ -73,7 +73,7 @@ function blurField(textFieldID: ?number) {
 /**
  * @param {number} TextInputID id of the text field to focus
  * Focuses the specified text field
- * noop if the text field was already focused
+ * noop if the text field was already focused or if the field is not editable
  */
 function focusTextInput(textField: ?ComponentRef) {
   if (typeof textField === 'number') {
@@ -86,7 +86,15 @@ function focusTextInput(textField: ?ComponentRef) {
     return;
   }
 
-  if (currentlyFocusedInputRef !== textField && textField != null) {
+  if (textField != null) {
+    const fieldCanBeFocused =
+      currentlyFocusedInputRef !== textField &&
+      // $FlowFixMe - `currentProps` is missing in `NativeMethods`
+      textField.currentProps?.editable !== false;
+
+    if (!fieldCanBeFocused) {
+      return;
+    }
     focusInput(textField);
     if (Platform.OS === 'ios') {
       // This isn't necessarily a single line text input

Libraries/Components/TextInput/__tests__/TextInput-test.js

@@ -79,9 +79,26 @@ describe('TextInput tests', () => {
     });
   });
 
-  it('should have support being focused and unfocused', () => {
+  function createTextInput(extraProps) {
     const textInputRef = React.createRef(null);
-    ReactTestRenderer.create(<TextInput ref={textInputRef} value="value1" />);
+    ReactTestRenderer.create(
+      <TextInput ref={textInputRef} value="value1" {...extraProps} />,
+    );
+    return textInputRef;
+  }
+
+  it('focus() should not do anything if the TextInput is not editable', () => {
+    const textInputRef = createTextInput({editable: false});
+    // currentProps is the property actually containing props at runtime
+    textInputRef.current.currentProps = textInputRef.current.props;
+    expect(textInputRef.current.isFocused()).toBe(false);
+
+    TextInput.State.focusTextInput(textInputRef.current);
+    expect(textInputRef.current.isFocused()).toBe(false);
+  });
+
+  it('should have support for being focused and blurred', () => {
+    const textInputRef = createTextInput();
 
     expect(textInputRef.current.isFocused()).toBe(false);
     ReactNative.findNodeHandle = jest.fn().mockImplementation(ref => {