Selection menu not showing when selection is 0,0 (#49000)

packages/flutter/lib/src/rendering/editable.dart

@@ -409,8 +409,14 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
   ) {
     // Changes made by the keyboard can sometimes be "out of band" for listening
     // components, so always send those events, even if we didn't think it
-    // changed.
-    if (nextSelection == selection && cause != SelectionChangedCause.keyboard) {
+    // changed. Also, focusing an empty field is sent as a selection change even
+    // if the selection offset didn't change.
+    final bool focusingEmpty = nextSelection.baseOffset == 0
+      && nextSelection.extentOffset == 0
+      && !hasFocus;
+    if (nextSelection == selection
+        && cause != SelectionChangedCause.keyboard
+        && !focusingEmpty) {
       return;
     }
     if (onSelectionChanged != null) {

packages/flutter/test/material/text_field_test.dart

@@ -857,6 +857,27 @@ void main() {
     expect(handle.opacity.value, equals(1.0));
   });
 
+
+  testWidgets('Long pressing a field with selection 0,0 shows the selection menu', (WidgetTester tester) async {
+    await tester.pumpWidget(overlay(
+      child: TextField(
+        controller: TextEditingController.fromValue(
+          const TextEditingValue(
+            selection: TextSelection(baseOffset: 0, extentOffset: 0),
+          ),
+        ),
+      ),
+    ));
+
+    expect(find.text('PASTE'), findsNothing);
+
+    final Offset emptyPos = textOffsetToPosition(tester, 0);
+    await tester.longPressAt(emptyPos, pointer: 7);
+    await tester.pumpAndSettle();
+
+    expect(find.text('PASTE'), findsOneWidget);
+  });
+
   testWidgets('Entering text hides selection handle caret', (WidgetTester tester) async {
     final TextEditingController controller = TextEditingController();