Improve container widget (#98389)

packages/flutter/lib/src/widgets/container.dart

@@ -389,10 +389,9 @@ class Container extends StatelessWidget {
         maxHeight: 0.0,
         child: ConstrainedBox(constraints: const BoxConstraints.expand()),
       );
-    }
-
-    if (alignment != null)
+    } else if (alignment != null) {
       current = Align(alignment: alignment!, child: current);
+    }
 
     final EdgeInsetsGeometry? effectivePadding = _paddingIncludingDecoration;
     if (effectivePadding != null)

packages/flutter/test/widgets/container_test.dart

@@ -633,6 +633,21 @@ void main() {
     expect(tapped, false);
   });
 
+  testWidgets('Container discards alignment when the child parameter is null and constraints is not Tight', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      Container(
+        decoration: const BoxDecoration(
+        borderRadius: BorderRadius.all(Radius.circular(1)),
+      ),
+      alignment: Alignment.centerLeft
+    ));
+
+    expect(
+      find.byType(Align),
+      findsNothing,
+    );
+  });
+
   testWidgets('using clipBehaviour and shadow, should not clip the shadow', (WidgetTester tester) async {
     final Container container = Container(
       clipBehavior: Clip.hardEdge,