Introduce debugWithActiveLayoutCleared to avoid duplicated code (#114003)

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

@@ -1591,6 +1591,26 @@ abstract class RenderObject extends AbstractNode with DiagnosticableTreeMixin im
   static RenderObject? get debugActiveLayout => _debugActiveLayout;
   static RenderObject? _debugActiveLayout;
 
+  /// Set [debugActiveLayout] to null when [inner] callback is called.
+  /// This is useful when you have to temporarily clear that variable to
+  /// disable some false-positive checks, such as when computing toStringDeep
+  /// or using custom trees.
+  @pragma('vm:prefer-inline')
+  static T _withDebugActiveLayoutCleared<T>(T Function() inner) {
+    RenderObject? debugPreviousActiveLayout;
+    assert(() {
+      debugPreviousActiveLayout = _debugActiveLayout;
+      _debugActiveLayout = null;
+      return true;
+    }());
+    final T result = inner();
+    assert(() {
+      _debugActiveLayout = debugPreviousActiveLayout;
+      return true;
+    }());
+    return result;
+  }
+
   /// Whether the parent render object is permitted to use this render object's
   /// size.
   ///
@@ -3399,22 +3419,11 @@ abstract class RenderObject extends AbstractNode with DiagnosticableTreeMixin im
     String? prefixOtherLines = '',
     DiagnosticLevel minLevel = DiagnosticLevel.debug,
   }) {
-    RenderObject? debugPreviousActiveLayout;
-    assert(() {
-      debugPreviousActiveLayout = _debugActiveLayout;
-      _debugActiveLayout = null;
-      return true;
-    }());
-    final String result = super.toStringDeep(
-      prefixLineOne: prefixLineOne,
-      prefixOtherLines: prefixOtherLines,
-      minLevel: minLevel,
-    );
-    assert(() {
-      _debugActiveLayout = debugPreviousActiveLayout;
-      return true;
-    }());
-    return result;
+    return _withDebugActiveLayoutCleared(() => super.toStringDeep(
+          prefixLineOne: prefixLineOne,
+          prefixOtherLines: prefixOtherLines,
+          minLevel: minLevel,
+        ));
   }
 
   /// Returns a one-line detailed description of the render object.
@@ -3427,18 +3436,7 @@ abstract class RenderObject extends AbstractNode with DiagnosticableTreeMixin im
     String joiner = ', ',
     DiagnosticLevel minLevel = DiagnosticLevel.debug,
   }) {
-    RenderObject? debugPreviousActiveLayout;
-    assert(() {
-      debugPreviousActiveLayout = _debugActiveLayout;
-      _debugActiveLayout = null;
-      return true;
-    }());
-    final String result = super.toStringShallow(joiner: joiner, minLevel: minLevel);
-    assert(() {
-      _debugActiveLayout = debugPreviousActiveLayout;
-      return true;
-    }());
-    return result;
+    return _withDebugActiveLayoutCleared(() => super.toStringShallow(joiner: joiner, minLevel: minLevel));
   }
 
   @protected